Chrony Results: .45 BPM


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ClemBert
April 6, 2011, 11:23 PM
I took the Walker out today to do a test drive of the new chrony. I fired quite a few rounds through the Walker today...both .45 Colt and .45 BPM (http://www.youtube.com/watch?v=GCrnpH64Qz8). The results posted here are very preliminary. I had the Walker sitting back 15 feet from the chrony. When I got up to the 52 grain .45 BPM rounds I started having quite a bit of difficultly with unrecorded/error reports. I had thought it was the position of the sun causing all the problems but I confirmed it was the big loudenboomers. When I dropped back to firing .45 Colt rounds everything was recorded fine. Next time I go out I'm gonna drop back another 5 feet to 20 feet total.

I wouldn't try to draw any conclusions based on these results. They are mostly posted for grins. I need to go back and analyze the results a bit more. Mostly, I just need to get back out there and fire more rounds. :D

The .45 BPM is fairly respectable. However, I see how it is that the .357 Magnum took the cake in 1934 with that heathen powder. :fire:

http://i40.photobucket.com/albums/e212/SyberTiger/Firearms/Colt%20Walker/45%20BPM%20Test%20Firing/ChonyResults04-06-2011.jpg

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Pulp
April 7, 2011, 11:12 PM
Sounds like a good day of shooting. Interesting results. And most of today's .357 Mag cartridges aren't loaded to the old 158 grain at 1550 of 1934 standard. You're BPM and .45Colt are still quite respectable cartridges.

Foto Joe
April 8, 2011, 12:26 PM
If I read it right, it looks like your 55gr load with the 150's exceeded the 60gr load with the same bullet. Granted you've got a LOT more testing to do before you can reach any conclusions but...

I'm wondering if you might have hit the limiting factor on your barrel length. Because Black Powder burns at a constant rate, one would think that there would come a time when you run out of barrel before you run out of powder.

Did you wind up covering the sensors with tape like we talked about or are they protected on that Chronograph?

Oyeboten
April 9, 2011, 04:18 AM
I always shoot from 10 Yards when using the Chronograph ( Handgun only, no Rifle).

Any closer, and, one can have the ejecta interfere with the readings.

ClemBert
April 9, 2011, 11:01 PM
If I read it right, it looks like your 55gr load with the 150's exceeded the 60gr load with the same bullet. Granted you've got a LOT more testing to do before you can reach any conclusions but...

I'm wondering if you might have hit the limiting factor on your barrel length. Because Black Powder burns at a constant rate, one would think that there would come a time when you run out of barrel before you run out of powder.

Did you wind up covering the sensors with tape like we talked about or are they protected on that Chronograph?

One reason why I said that a conclusion couldn't be drawn from the data is the high number of "error" shots I had. I had prepared 12 cartridges of the 55 grain 150 BigLubes and 12 of the 60 grain 150 BigLubes. I only managed to gather 4 and 5 data points, respectively. So out of those 24 total cartridges fired 15 were in error.

It could very well be that the barrel is just too short to take advantage of anything more that 55 grains in the .45 BPM. Hard to say just yet. The barrel length does come into play at some point. I think with FFg the point of diminishing returns would happen sooner than with FFFg. Just an educated guess. Swiss BP might do better in a short barrel versus GOEX. Perhaps a tighter crimp could change that. The 55 grain loads had 1/8" powder compression and no drop tube. The 60 grain loads were droped with a drop tube and had 0.200" compression. Both had a similar minimal crimp. I used a 0.030" fiber wad in all loads. I have yet to recover a spent fiber wad.

BTW, the powder charges were all weighed NOT volumetrically measured.

I did not cover the sensors. I think there is a plastic lens over the sensors. They are recessed deeply in molded plastic so it is hard to say.

ClemBert
April 9, 2011, 11:24 PM
Some of you fellas may be wondering why I didn't move the firearm farther back from the chrony when I realized the short distance (15 feet) was causing a problem with the loudenboomers.

http://i40.photobucket.com/albums/e212/SyberTiger/Firearms/Chronograph/Chrony001.jpg

http://i40.photobucket.com/albums/e212/SyberTiger/Firearms/Chronograph/Chrony003.jpg

Pictures are worth 1000 words. As you can see in the first picture the test fixture is staked down to keep it from sliding back. Underneath the front of the test fixture are two additional pieces of rebar. After spending the time setting it up I didn't feel like moving it after a long day of testing.

The chrony had be be sunk down as the test fixture with firearm were sitting too low. If it was an easier task of separating the two even further to 20 feet or more I would have. But, both the test fixture and the chrony were pretty much setup and not easily moved.

The red dot on the cardboard box is from a bore sighting laser sitting in the Walker's barrel. It definitely made setting things up easy that day.

Oyeboten
April 10, 2011, 04:23 AM
Yes, there is a sort of zone where additional Powder will not increase Velocity with the same Bullet for a particular Barrel Length.

Tigher Crimp, heavier Compression ( I compress about 1/4 inch for .38 Special with 3F Goex), heavier Bullet, Bullet sized to be a few thousands larger than the Barrel Bore ( if the Cylinder Bores will allow it), all can contribute to higher Velocities with BP.

Changing to 'Swiss' I am sure would also increase Velocity.


I sure hope I can get back on to my BP Metallic Cartridge Revolver experiments sometime soon, and try and intentionally study these details methodically.

Foto Joe
April 10, 2011, 11:29 AM
I see your dilemma with doing a reset to space the fixtures out a little bit. I can also see how this could possibly drive you a little nuts before you get it dialed in.

I take advantage of using a tri-pod for my chronograph but I'm in a little different situation. No matter if I'm in Wyoming or Arizona, I've got thousands of square miles of nothin' surrounding me. So hopping in the Rhino and driving two miles puts me in a place where I can shoot pretty much 360 degrees allowing me to adjust for the angle of the sun. You may wind up finding out that you can only use the set-up between X hour and Y hours during the day.

On the other hand, they do make indoor sky-screens for these things that contain their own LED lighting. I'll bet it would work great at nite if you used the indoor LED's and think of all the pretty flames you'd get to see then.

Oyeboten
April 10, 2011, 03:09 PM
1226 FPS and 200 Grain Bullet is pretty darned respectable!


Unless there are concerns about strain, 50-odd Grains and a 250 Grain Bullet ( if that combo would fit ) would be interesting to investigate also of course.


'Swiss' Powder ought to up the Velocities somewhat, also.


If memory serve, the standard Issue Ammunition for the .45-70 Rifle was rated to about 1450 FPS, with a 450 Grain Bullet ( and of course, 70 Grains of Powder).

250 Grain is probably a reasonable limit though, for this Revolver, far as that goes, I would think...unless staying within medium charges anyway.

ClemBert
April 10, 2011, 10:29 PM
40gr FFFg, 250gr BigLube, .45 Colt - 982 fps

46gr FFFg, 250gr BigLube, .45 BPM - 972 fps

I'm a bit disappointed in the .45 BPM with 250 grain BigLube and 46 grains of FFFg. The .45 Colt with 40 grains performed just as well. The difference in compression between the .45 Colt w/ 40 grains and the .45 BPM w 46 grains is 0.375" vs 0.0625", respectively. I think I'm going to retry the .45 BPM with 46 grains but compress the powder 0.375" and add grits for filler on top to see if I can improve upon a somewhat disappointing configuration thus far.

A 45-70 Government rifle has the advantage of a much longer barrel.

Foto Joe
April 10, 2011, 10:35 PM
Just out of curiousity, what size bullets are you using? .452's or .454's?

I'm wondering if you used the .457's if you would get a better seal on the barrel. If I recall Loren from Dash Caliber told me that they drop out of the mold at .457

Just a thought.

ClemBert
April 10, 2011, 10:42 PM
For the roundball loads I'm using 0.454. For the bullets I have them sized to 0.452. In both cases I rely on bullet expansion/obturation since the Uberti Walkers tend to have groove diameters of 0.457 - 0.458.

You still have to get the bullet to fit in a 460 S&W casing. I have to use the case expander to get a 0.452 to start.

Foto Joe
April 11, 2011, 11:36 AM
You still have to get the bullet to fit in a 460 S&W casing. I have to use the case expander to get a 0.452 to start.

I forgot about the cartridge part of this equation. I'm not even familiar with 460 S&W other than they were made to take the wrong powder. From this I'm assuming 460 has about as much to do with the actual caliber as 38 does to 38 Special?

However...on my 45 Colt loads, I use exclusively .454's both in bullets and RB's. I don't size the 45 brass so that makes life a little easier too.

More now than before, I'm thinkin' that you just aren't getting the bullet expansion/obturation to seal those grooves off sufficiently. Maybe try 15gr by volume of cornmeal under the bullet as a filler with the veggie wad between the filler and powder. My theory has been that cornmeal filler can/will act as a defacto gas-check, although I personally haven't been able to prove it. I did see some slight increases in muzzle velocity on one gun when I tested the idea, but it didn't do squat on another so I flushed the idea. Who knows, maybe it will provide you with a little more MV on less powder.

ClemBert
April 11, 2011, 12:59 PM
I have yet to learn why the .460 S&W Magnum name contains the number 460. Why it isn't called the .45 S&W Magnum or the .454 S&W Magnum is beyond me. The name does imply that up to a .460 caliber bullet is to be used. However, the case neck dimensions are actually spec-ed out to 0.478 versus the .45 Colt at 0.480. Thus, the .460 S&W casing is actually 0.002" smaller.

Typical bullets used for .460 S&W are 0.451 jacketed and 0.452 cast. To my knowledge there isn't a reason why 0.454 will not work. It just requires stretching the brass another 0.002".

More now than before, I'm thinkin' that you just aren't getting the bullet expansion/obturation to seal those grooves off sufficiently.

I take it that this is just a gut feel kind of thinkin'? Is there a reason to believe that a 0.452 bullet just can't expand to 0.458? It's hard to say whether or not the bullet is obturating the groove diameter or not. We could be pushing on these projectiles as hard as anyone can reasonably expect given the 9" barrel.

Next time I place and order with Dash I'll have him size the bullets to 0.454. Given that 0.452 is the standard diameter for modern 45 caliber firearms whereas 0.454 is reserved for some much older weapons. However, we are talking about a reproduction of a mid-19th century firearm with a large groove diameter (0.458) but with a small bore diameter (0.438).

At 60 grains there isn't a lot of room in the casing for filler. In fact a drop tube is required or else the powder will spill out. I'm using weighed charges in place of volumetric charges. I find that my volumetric measure is consistently throwing lower than expected charges when set to 60 grains. I'm positive I can add more compression to the 60 grains loads. Currently I compress to 0.200". Maybe compress to 0.375", add a few grains of grits, and another fiber wad. We'll see....maybe Wednesday if I get my act together.

Foto Joe
April 12, 2011, 12:13 PM
I take it that this is just a gut feel kind of thinkin'?

You would REALLY expect me to have any type of scientific proof would you?

My theory on the filler is basically: By not using a wad between the filler an the base of the bullet, the filler will be pushed past the base into the grooves blocking the escape route for expanding gas or at least slowing it down.

I believe it was mykeal who posted his reasons for why this wouldn't work on an earlier thread I started. To be honest with you, he's probably right, but the idea sounded good to my less than anylitical mind, if you know what I mean. You people who are engineers sometimes give me a raging headache just trying to keep up with your train of thought, let alone understand it.

andrewstorm
April 12, 2011, 09:47 PM
try 60 grains 777 3f and mild compression,over a 255 gr hornady............:eek:

ClemBert
April 12, 2011, 09:53 PM
andrewstorm,

Send me your converted Walker and I'll give it a go. ;)

Oyeboten
April 13, 2011, 12:43 AM
In my imagining...

Ideally, Cylinder Bores will be a little ( couple of thousandths ) larger than the Groove Diameter of the Barrel.

With this, when this is Metallic Cartridge, the Bullet would be sized to the stepped Cylinder Bores, for an easy-press slip-fit, and no less...(or, when Cap & Ball, the same, but of course the Bullet or Ball ends up being finally sized, in being force-pressed into the Cylinder Chambers from the front).

Then, there will be virtually no or about the least possible blow by, whether or not 'filler' aids in obturating excess clearance of Bullet to Barrel fit ( and in slghtly undersized fits, I would imagine it indeed does ).

Thus occasioning the best FPS for any given Loading.

ClemBert
April 13, 2011, 04:18 PM
I'm ready to give it the "ol' college try" once again. This time I opted to go with higher compression of the powder and used grits to take up the additional space. Now I have: powder, then fiber wad, then grits, then another fiber wad, then the projectile. I was very impressed with the results of the highly compressed powder in the .45 Colt loads with 40 grains FFFg. I think this go around will give me a clear indication of what addition compression does. I think it will also answer the question of whether or not 60 grains of BP has exceeded the capability of this cylinder and barrel configuration. That is if I don't blow everything to kingdom come. :uhoh:

http://i40.photobucket.com/albums/e212/SyberTiger/Firearms/Colt%20Walker/45%20BPM%20Test%20Firing/45BPMLoads005jpg.jpg

andrewstorm
April 13, 2011, 11:52 PM
You got a mess a hogs that need shootin down yonder,that 1847 bpm looks up to the task:D ill bet shell hold at 60 gr 3f 777,at least fer a 1000 shots

ClemBert
April 14, 2011, 12:06 AM
The problem with 777 is that it doesn't like to be compressed. That makes it unusable as a 60 grain load because 60 grains even through a drop tube leaves only 1/8" for the bullet. In other words, 60 grain loads have to be compressed to make room for the bullet. Ergo, 777 is not a good candidate here if you are lookin' for loudenboomers. A better way to give it more beans to work with is to use Swiss instead of Goex since BP loves compression.

ClemBert
April 14, 2011, 05:26 PM
When I last left this I had loaded up a tray of new .45 BPM cartridges with the intent on finding out if higher BP compression could increase performance. I ended up with a mixed bag. Here are the latest chrony results.

http://i40.photobucket.com/albums/e212/SyberTiger/Firearms/Colt%20Walker/45%20BPM%20Test%20Firing/ChonyResults04-14-2011.jpg

The performance of the 46 grain FFFg cartridge with 250 grain BigLube got a nice bump from higher compression. The velocity went up from 972 to 1014. It's only a 4% gain but it was nice to consistently be over the 1000 ft/sec mark.

I tried out a 48 grain version with the same bullet and also got nice results. 1032 ft/sec with the energy approaching 600 ft-lbs.

The performance of the 55 grain FFFg cartridge wtih 150 grain Biglube actually went down. :mad: I guess there is a point when the powder has just been compressed too much. Did I squeeze all the oxygen out of the cartridge? :rolleyes: The drop was fairly significant IMHO. 1392 ft/sec (1/8" compression) down to 1232 ft/sec (3/8" compression)...an 11% drop! That extra 1/4" of compression really dumbed it down.

There really wasn't a change for the 60 grain FFFg loads. While I did manage to compress the powder more there really wasn't a whole lot more I could compress. With 60 grain FFFg you have to use a drop tube just to get it into the cartridge without it spilling out everywhere. By the time you compress the powder down for the bullet you've already compressed it pretty darn good.

I think I'll be as bold as to start to formulate some conclusions:

1. There isn't much to be gained with going over 55 grains of FFFg. 60 grains FFFg makes for a little more smoke-n-boom but there isn't a great performance increase with either the 141 roundball or 150 BigLube bullet. :cuss:

2. 48 grains of FFFg and a 250 grain BigLube bullet makes for an excellent load. 591 ft/lbs energy

3. 52 grains of FFFg and a 200 grain BigLube bullet makes for an excellent load. 598 ft/lbs energy

4. 55 grains of FFFg and a 150 grain BigLube bullet makes for an excellent load. 577 ft/lbs energy

5. Roundball loads are not worthwhile as the 150 grain BigLube bullet gives similar performance and also provides for a lube groove whereas the roundball cartridge provides no lube. The roundball is also more difficult to load into a cartridge and potentially creates a concern that the ball will jar loose under recoil.

6. 60 grains loads are for the pure pleasure of making the most possible smoke-n-boom and freaking smokeless heathens out of their wits. :evil:

Once again, I did not observe any damage to the wedge or arbor of the Walker. I did however notice that every single daggum screw on the Walker was loose by the time I was done. :banghead: Even the trigger/bolt springs's screw was backing out. :eek:

Foto Joe
April 14, 2011, 08:57 PM
I think that you need to pat yourself on the back. You've taken a 9" barrel and managed to push a projectile out of it at considerably above the speed of sound. That's no easy feat with a Black Powder pistol.

I'm still thinking that you're not getting the gas seal that would allow you to optimize the load though. I went back and looked up the numbers for my 45 Colt loads to find out how they compared.

.454 250gr Big Lube RNFP
40gr 3f Swiss
over powder veggie wad with enough compression to get the bullet to seat correctly.

1,065 fps with 592 ft. lbs.

The SAA is a Dakota clone with a 12" barrel. I don't have or have access to a SAA with a shorter barrel than that, but I doubt very seriously if I could get anywhere near those numbers with say a 5" barrel.

I quit loading these by the way simply because they hurt like H**L to shoot out of a light gun. That and the thing gets so hot after two cylinders I can hardly touch the cylinder.

I keep some around just so when I do run into somebody who thinks their SAA loaded with the wrong powder is impressive, I can hand them a couple and let them be the judge as to what a 45 Colt used to feel like.

ClemBert
April 14, 2011, 11:35 PM
I'm still thinking that you're not getting the gas seal that would allow you to optimize the load though. I went back and looked up the numbers for my 45 Colt loads to find out how they compared.

I'm still waiting to hear your theory as to why you're still thinkin' this. :scrutiny:

I had a second thoughts about having Dash make up a batch of 0.454 bullets for me. Because of a brain fart I forgot that I still have chamber throats (1/3" long) that measure 0.4525 in diameter. So, those 0.454 bullets aren't going to gain me anything.

One thing to consider is that in cap-n-ball mode this Walker has cap-n-ball cylinder chambers of 0.450. Thus, a 0.454 roundball gets shaved down to 0.450 when loaded. We count on that soft lead ball getting squished outward to seal the barrel to prevent blow-by. Since I'm using 0.452 bullets we are already ahead of the game by 0.002 versus cap-n-ball style shooting. The lead BigLube bullets are also very soft and similar to lead roundballs. They also have much more surface area than a roundball to obturate the expanding gas.

I do wonder what Swiss would do for me but I don't have any. :cuss:

I'll just wait for you to load up some 40 grain GOEX loads and let me know the drop in velocity. From there I'll just protraculate a number based on the SWAG method. ;)

ReloaderEd
April 15, 2011, 01:11 AM
[COLOR="Blue"]A very intersting discussion. Do you have chrony results for a 160gr Lee RN,Flat End for the 45 Colt/BPM ? Reading all the information on your testing makes me wonder if the lighter bullets would be the way to go. Higher velocity, less recoil in the 45 Colt with good ft/lbs of energy. But then why would you need the heavy Walker? I would appreciate your thoughts Clem. Thands and Be Safe.LOR]

ClemBert
April 15, 2011, 09:55 AM
You must be taking about this bullet mold (http://www.midwayusa.com/viewproduct/?productnumber=264838) that is used to make the subject bullet. I don't cast my own bullets for now. Perhaps some day. If someone wants to send me a batch of them I'll test them in the .45 BPM. I'm not necessarily buying into the less recoil aspect of the discussion. I've shot 48 grains of FFFg and a 250 grain bullet as well as 55 grains of FFFg and a 150 grain bullet. On the one hand a 150 grain bullet is lighter than 250 grains but on the other hand you are shooting it with 55 grains of BP versus 48 grains. They seem to offset each other.

From the point of "equal and opposite reaction" one load's bullet energy is 591 ft-lbs while the other's is 577 ft-lbs. Like you said, good thing a Walker weighs 4.5 lbs. :)

Something tells me Foto Joe's Dakota clone weighs a bit less than 4.5 lbs. No wonder he uses the name "ClemBert" as a cuss word :cuss: whenever he shoots those 40 grain .45 Colts. I told him they were "fun" loads. :p

Foto Joe
April 15, 2011, 11:21 AM
I'm still waiting to hear your theory as to why you're still thinkin' this.

For no other reason than I would have thought you could get a better speed out of the BPM. That said, it's still extremely impressive to get as much velocity as you have out of a Black Powder revolver.

I'll just wait for you to load up some 40 grain GOEX loads and let me know the drop in velocity.

I've tried it and there's a little problem with that. Given that Swiss is about 10% heavier/denser than Goex, I found it almost impossible to stuff all 40gr of Goex into the brass and still be able to seat the bullet. Of course I wasn't using a compression die at the time, all I had was that compression plug from TOTW.

Now that we know how fast they go, when are we going to find out how accurate they are?:rolleyes:

ClemBert
April 15, 2011, 12:34 PM
I think the BPM is limited in this particular Walker. The most limiting factor is the barrel length, I believe. Now if I could slap on a 12" or an 18" barrel off of a buntline we'd be in business. :cool:

Now that we know how fast they go, when are we going to find out how accurate they are?

Accuracy?....Hell, just the boom and all that smoke is likely to give any critter a heart attack and fall over from shear fright. :D No need to maim the lil' fella!

I'd like to think if I quit shakin' in my boots and flinchin' as I'm about to pull the trigger I'd come close to hittin' an evil good fer nothin' tin can at 25 yards. ;)

arcticap
April 15, 2011, 01:39 PM
I'm curious about the how the velocity of .45 BPM cartridge compares to the velocity of the original Walker percussion cylinder when loaded with the same size bullets and amount of powder.
How much velocity is gained?
That's one way to measure what the pure gain is in performance by converting one's Walker to the .45 BPM.
The desire for even higher velocity over what has already been attained doesn't answer how much of an increase has already been achieved just by simply converting.
If any of that comparative data can be shown then folks could see what the actual gain is by having their gun converted.
What are some of the estimated or actual velocity gains for any of the various bullets? For instance, how about when loaded with 50 or 55 grains of powder?

ClemBert
April 15, 2011, 02:18 PM
I'm curious about the how the velocity of .45 BPM cartridge compares to the velocity of the original Walker percussion cylinder when loaded with the same size bullets and amount of powder.
How much velocity is gained?
That's one way to measure what the pure gain is in performance by converting one's Walker to the .45 BPM.
The desire for even higher velocity over what has already been attained doesn't answer how much of an increase has already been achieved just by simply converting.
If any of that comparative data can be shown then folks could see what the actual gain is by having their gun converted.
What are some of the estimated or actual velocity gains for any of the various bullets? For instance, how about when loaded with 50 or 55 grains of powder?

Those are good questions.

Keep in mind, the goal of the .45 BPM was to have a cartridge version of what was available to a Walker in cap-n-ball mode. In other words, a mechanism to get beyond the 40 grain limitation of a .45 Colt converted Walker. My intention was not to exceed what a Walker in cap-n-ball mode was capable of. That was the point of using a 150 grain bullet....to match as close as is reasonably possible to a 141 round ball load. I have no expectations that a 150 grain bullet with 60 grains of BP will exceed the performance of the cap-n-ball equivalent...although it may...or it may not.

The experiment you ask for is on my list. I just purchased the chrony so I had not had a chance to measure the Walker with 55 or 60 grains loads and a round ball in cap-n-ball mode. Most likely I would only do some chrony measurements for 141 RB on top of 55 and 60 grain loads. I have no plans to do conical type testing.

Although it would not be an exact one-to-one comparison I wouldn't mind hearing some Walker chrony results from others to understand about what I should expect.

TheRodDoc
April 15, 2011, 02:55 PM
Have you considered the cyl. gap? It can be loosing up to 100 fps / .001" of gap.

To test, place empty unprimed case in bottom chamber and slide a thick enough feeler gage in behind that empty to hold the cyl. ahead against the forcing cone. No gap. See how much it gains.

I would also not compress the powder at all. Bullet just sitting on settled powder. no wad for a test at least.
I would think crushing the powder as much as you have been doing is forcing the powder to burn from one end to the other of it's length in chamber by not letting the flame travel around and through the powder granules to ignite it all quicker.

ClemBert
April 16, 2011, 01:05 PM
I'm curious about the how the velocity of .45 BPM cartridge compares to the velocity of the original Walker percussion cylinder when loaded with the same size bullets and amount of powder.
How much velocity is gained?

Since I don't have my own data yet I'll borrow some data from when I first asked about chrony results for a Walker (http://thefiringline.com/forums/showthread.php?p=4250275).

For what it's worth, here is a bunch of data from a Uberti Walker. The measure is one of those adjustable volume things that seem to be calibrated for Goex. Swiss powder thrown from the same measure weights a few grains more due to density but when weighed, Swiss is still "hotter" than goex.

As to calibration, all I know is that I have used two chronographs on the same day on more than one occasion and the readings were very close together.

I note no fall off in accuracy between 55 and 60 grain charges or from one type of powder to the next but attempting to use very light charges could result in wild velocity variations because projectiles really need to be set down on top the powder column with possibly a bit of compression to get consitent ignition and burn. I have tried various combinations with and without overpowder wads finding no significant difference in velocities or round to round consistency. The better treated wads will keep the barrel clean for extended firing while leaving them off is ok too if you clean out the (considerable) powder fouling after shooting a chamber full. A cursory pass or two through the bore with a spit patch will do the trick.

Walker-Uberti

Charge Velocity Extreme Spread
{5 rounds}
140 Grain Ball
55 Gr/Vol Goex FFFg 1001 fps 54
60 Gr/Vol Goex FFFg 1115 fps 46
60 Gr/Vol Pyrodex P 1221 44
60 Gr/Vol A Pioneer 974 80
60 Gr/Vol Swiss FFFg 1278 53
55 Gr/Vol Swiss FFg 956 46
60 Gr/Vol PyrodexRS 1045 35
37 Gr/Vol H 777 1201 72

200 Grain Lee Bullet
40 Gr/Vol Goex FFFg 927 40
45 Gr/Vol Swiss FFFg 1074 33
45 Gr/Vol Pyrodex P 1087 47

170Grain Original Pattern Picket Bullet
40 Gr/Vol Swiss FFFg 1031 36
Energy 402 ft/lbs
45 Gr/Vol Goex FFFg 1026 84
45 Gr/Vol Swiss FFFg 1158 35
Energy 506 ft/lbs
45 Gr/Vol. Pyrodex P 1035 57


An Ed SANOW article from a Feb '98 issue of HANDGUNNER mag lists a vel of 1287 fps w/ 60 gr BP and 141 gr roundball.

The article was entitled "BP Stopping Power" and they shot perc revolvers into gelatin as well.

The Walker, and the Dragoons, were the hands down winners.


My most recent data:

http://i40.photobucket.com/albums/e212/SyberTiger/Firearms/Colt%20Walker/45%20BPM%20Test%20Firing/ChonyResults04-14-2011.jpg

It would seem that my 141 grain roundball .45 BPM cartridge with 60 grains of FFFg Goex is comparable to the data above in the whole scheme of things. It tells me that the .45 BPM with 141 RB is doing pretty much what one would expect from a 141 RB with 60 grains of BP in cap-n-ball mode. That means....Mission Accomplished. :)

ClemBert
April 16, 2011, 01:17 PM
Have you considered the cyl. gap? It can be loosing up to 100 fps / .001" of gap.

To test, place empty unprimed case in bottom chamber and slide a thick enough feeler gage in behind that empty to hold the cyl. ahead against the forcing cone. No gap. See how much it gains.

I would also not compress the powder at all. Bullet just sitting on settled powder. no wad for a test at least.
I would think crushing the powder as much as you have been doing is forcing the powder to burn from one end to the other of it's length in chamber by not letting the flame travel around and through the powder granules to ignite it all quicker.

Yeah, I think it is time to go check the cylinder gap again and see if anything has loosened up besides the screws. ;)

I thought it was pretty much a given that black powder performs better with some level of compression versus none....at least that what I've read from numerous posts on numerous forums. Of course the big question is "how much compression is optimal?". I'd like to think I'm compressing the powder not crushing the powder but there's no doubt that in some cases I've really worked too hard to get the powder in a space that's too small. :eek:

As I understand it. BP burns through contact. That is, granules start to burn when they come into contact with other burning granules. So compressing the powder to some degree helps this process by putting granules closer to other granules. The idea is that BP burns linearly. That is, from the bottom of the case and moving upward (at a very fast pace through deflagration). I don't think the BP burns by flames jetting out and lighting all the granules at the same time. Maybe someone would like to back me up :D or shoot me down....:cuss:

Oyeboten
April 16, 2011, 03:27 PM
It would be easy enough to test the difference between Cartridges which have their BP compressed, and, those which do not, keeping all else equal ( but for Bullet Seating depth I s'pose).


Bear in ming if you do elect to try '777', that it is more powerful than GOEX by weight, and that it should not have any compression, so, un-compressed 50 Grains of '777' ought to be close to a compressed 60 Grains of Goex as for yield.


Swiss is also reputed to be about 10 or more percent more powerful than GOEX, where, it would be easy to make some comparitive tests with the two.


What is your Bore between the Lands of the Barrel?

ClemBert
April 16, 2011, 03:37 PM
The performance of the 55 grain FFFg cartridge wtih 150 grain Biglube actually went down. I guess there is a point when the powder has just been compressed too much. Did I squeeze all the oxygen out of the cartridge? The drop was fairly significant IMHO. 1392 ft/sec (1/8" compression) down to 1232 ft/sec (3/8" compression)...an 11% drop! That extra 1/4" of compression really dumbed it down.

Oyeboten,

I think I showed what over compression can do to performance. I have to admit that I had a cartridge where I mashed the bullet in too deep so I used a kinetic bullet puller to take it apart. On that particular cartridge I had compressed the powder to the point where it was powder was more like a giant pellet. I had to really dig at it to remove the powder.

The groove and lands diameter is less than impressive on an Uberti Walker.

Lands: 0.438"
Groove: 0.458"
Bullet: 0.452"

I really think I'm getting reasonable and expected results. If you look at the .45 BPM 141 grain RB numbers I referenced above you can see that I'm getting approximately what others see in cap-n-ball mode.

Oyeboten
April 16, 2011, 07:21 PM
There might be a sort of graduated scale of COmpression for BP -

No Compression

Some Compression

Optimum Compression

Too much Compression.


Tradition and old practice appear to advocate good Compression ( Lol...which I take it, means, enough but not too much or too little).


Probably the Ballistics advantage of the Conversion Cylinder will be for heavier Bullets.

Even though I know that was not your original intention necesarily, but, seems to me that with lower weight projectiles, I am not surprised that the FPS is on par with a non-Converted Walker.

250 - 300 Grian, and good Compression of the GOEX, is where I would expect higher FPS than a non-Converted WALKER.

makos_goods
April 19, 2011, 07:30 PM
Have you considered the cyl. gap? It can be loosing up to 100 fps / .001" of gap.

To test, place empty unprimed case in bottom chamber and slide a thick enough feeler gage in behind that empty to hold the cyl. ahead against the forcing cone. No gap. See how much it gains.

I would also not compress the powder at all. Bullet just sitting on settled powder. no wad for a test at least.
I would think crushing the powder as much as you have been doing is forcing the powder to burn from one end to the other of it's length in chamber by not letting the flame travel around and through the powder granules to ignite it all quicker.

roddoc,
I have to disagree with you on this. You need a refresher in Fluid Dynamics, specifically on gas flow. Go crack the books and get back to us.

A loss of 100fps/.001" is totally erroneous, where did you pull that from?

I need to look through my old files, but about 40 years ago (probably in the late 60's or early '70s) there was a good article in the American Rifleman about the effects of cylinder gap and velocity loss. This was a subject of interest at the time because of the introduction of the .22 Jet in the S&W 53. "Everyone" was convinced it was a losing velocity because of the revolver's cylinder gap. A chambered test barrel was constructed and they found there was NOT a significant loss as they expected. The author of the article set out to find just how much of a loss there was for each .001" of cylinder gap. He started with the cylinder literally butted up against the barrel face using shims and a yoke he sacrificed for the project. Then he moved it back in .001” increments until he reached .010”. He found the first .001” experienced a 3% loss in velocity. Then contrary to what anyone besides someone who understands gas flow, each additional .001” only experienced an incremental (not overall) additional 1% loss.

So if you started at 1,800 fps with zero gap you would be at 1,579 with .010” That’s a loss of 220 fps. No one in their right mind would run a revolver at “zero” so let’s extrapolate a bit and assume a “super tight” gap of .002” That means it would start at 1,728 (which is actually about right for a .22 Jet) and then end at 1,579 for a .01” gap that a loss of only 149fps or 8.6%. I have an interest in that info because I have built some improved short .22 K-Hornets on Smith revolvers, not the Kay-Chuk I had to be difficult and do it the hard way with a personal wildcat ( I was younger and more hard headed then…).

Then there are several articles that have been done using Dan Wesson revolvers because you can set the barrel gap. They have been done with the .44 mags, .357 and at least one with the .22LR. I had a “kit” model 15-V and I played around with it in the ‘80s. That’s what taught me the practical application of cylinder gap.

Here is an article from Shooting Times, June 1983 about a well done test with a Dan Wesson 22-VH. You will see the results were once again different than what the wives’ tales recount and even what the author expected.

http://i627.photobucket.com/albums/tt358/Mako_CAS/Odds%20and%20Ends/ShootingTimesJune1983_CylinderGap_Page_1.jpghttp://i627.photobucket.com/albums/tt358/Mako_CAS/Odds%20and%20Ends/ShootingTimesJune1983_CylinderGap_Page_2.jpghttp://i627.photobucket.com/albums/tt358/Mako_CAS/Odds%20and%20Ends/ShootingTimesJune1983_CylinderGap_Page_3.jpg

ADDED 4/20

I couldn't find my older American Rifleman magazines but this report was originally published on THR a couple of years ago.

Notice how little it changes per .001". The .38 spl low pressure loads are what we should be looking at for BP, it is right in the velocities and corresponding pressures we discuss on this forum. The high pressure table is there to provide another set of data points. Notice how this correlates well with what I remembered from the American Rifleman article and correlates with the Dan Wesson test above.
http://i627.photobucket.com/albums/tt358/Mako_CAS/Odds%20and%20Ends/Velocityloss.png




So, Clembert I wouldn’t worry too much about your cylinder gap. The problem is the amount of BP and the barrel length to burn it in. You’ve run up against the wall of diminishing returns even with the fastest granulation that would be safe in that revolver. I will recommend that you compress the “tar” out of your loads and apply a very heavy crimp. Fill your case vibrate it down and add more if necessary, a drop tube might be called for. Then make sure you get at least 1/8” compression (more if you can get it).

BP is a very inefficient propellant, you get 60% uncombusted materials even with an optimized barrel length for the charge. So, only 40% of the charge is potentially converted into propelling gases and that once again assumes you have a tube long enough to take advantage of it. At some point you’re just spewing burning and unburned particles out the muzzle. It makes for “purty” night shooting and some hair singing results…

Try and compress it more and see if you can squeeze a bit more velocity out of it. Crimp it hard to help the pressure build a bit.

You seem like a bright guy, what is your training in? I have several friends who are engineers out of Clemson.

Regards,
Mako

ClemBert
April 19, 2011, 08:40 PM
Thanks Mako. :)

I'd have to admit my crimps tend to be on the lighter side. I generally have been doing the minimal amount to take "the flare" out after using the expander die. That last group of 50 rounds I did I went with a heavier crimp but I'm far from really mashing the crimp well within the crimp grooves.

I think my diminishing returns really kicked in at around 55 grains FFFg. As you said the relatively short 9" barrel of the Walker is a limiting factor. One of which I may be at or near with 55 grains. I'll try some loads with a heavier crimp next time. For the 60 grains loads I was using a 24" drop tube. Even if I find out that 60 grains is going beyond the "useful" amount of powder I'd probably keep a few loudenboomers around just for the smoke-n-boom effect. :D

Just for grins I measured the cylinder gap on a couple of my Ruger heathen revolvers. The Blackhawk had a gap of 0.010 while the SingleSix came in at 0.005. I was a bit surprised to see that larger gap on the Blackhawk.

You seem like a bright guy, what is your training in? I have several friends who are engineers out of Clemson.

Formal education would be Electrical Engineering. For a living I work as a consultant in the electronics industry. Specifically, designing ASICs (Application Specific Integrated Circuits) for many different computer/electronics related industries such as VOIP, RFID, video, set top boxes, etc. I'm one of the guys that design those little computer chips that contain millions upon millions of transistors.

arcticap
April 19, 2011, 09:56 PM
I think my diminishing returns really kicked in at around 55 grains FFFg. As you said the relatively short 9" barrel of the Walker is a limiting factor.

I think that the fffg powder [& it's brand] is also a limiting factor. Since granulation controls the burn rate, what about mixing in smallish, incremental amounts of ffffg?
Substituting very small percentage increases of it at a time should be safe to help extrapolate another velocity data curve.
There's ffffg fines in every can of black powder anyway, it's just that it's not separated and the percentage of it contained in each pound isn't obvious.
Maybe just enough ffffg can be added to each cartridge at first to make up for whatever velocity is perceived to be lost through the barrel cylinder gap.
Anyway, I don't believe that the maximum velocity has been reached yet without further testing.
Has Swiss powder even been tried, or another powder containing Alder charcoal?
It's a sporting powder that's most suitable for BP cartridges.

ClemBert
April 19, 2011, 10:02 PM
I think Swiss would be the next logical choice.

However, y'all are killin' me. I've matched what I believe the Walker does with 60 grains of FFFg and a roundball. But y'all want me to push that poor Walker even harder. :uhoh:

I'm all for pushing this thing until the barrel goes down range. After all, I'm on a closed coarse and that is what I built that test fixture for. But which ones of y'all are going to kick in for a new Walker to help poor ol' ClemBert out? :scrutiny:

:neener:

makos_goods
April 19, 2011, 10:17 PM
Clembert,
I suspected you were an engineer based on your methodology. You don't have to explain microprocessors to me, I spent 9 years in the semi conductor industry.

Crimping is gooooood...I am a believer in hard crimps with any revolver and especially with BP. I saw articaps suggestion about the duplex load, I have avoided them except with modern ordnance so I can't comment. Of course you can get more velocity with some of the substitute powders. It's a misconception that powder needs air space around it to burn. BP has it's own oxidizer and even with intimate contact the grains in contact will burn on their surfaces. There isn't any way you can compress it with your loading process to the point you will inhibit burning, in fact the opposite will be true with each opposing surface feeding and intensifying the opposite grain's combustion.

In closed vessel tests compressed powder has a higher conversion rate to gas and at a higher rate. Powder has to be fragmented to create the external surface area, but then benefits from close proximity and containment to achieve more efficient combustion.

Regards,
Mako

makos_goods
April 19, 2011, 10:40 PM
articap,
Did you know that willow actually has a higher energy content by weight than alder? I know the opposite is believed because of the better European powders. It's not just the charcoal, it's also the pre and post processing of that charcoal and the other two ingredients.

Have you ever inspected Swiss and Goex together under a microscope? You will see a notable difference.

Both Alder and Willow are in the lighter wood groups. There are lighter ones such as balsa and they have higher energy contents, they make a faster burning gunpowder which isn't as useful as a propellant. You can use almost any cellulose based material to make charcoal and there are even sugar powders. There is an "ideal" range for the energy content (which is primarily density based) of charcoal to make BP suitable for propellant. There are other forms which are more useful for blasting powder.

This is very much akin to nitrocellulose powders that each have a useful pressure curve and range. You wouldn't use a fast burning powder like Bullseye for a rifle cartridge, the same is true with charcoals there is a sweet spot for the 75/15/10 ratios of BP. Many people don't realize you can manipulate the weight ratios based primarily on the density of the charcoal to achieve the fuel/oxidizer and reaction modifier (sulfur) to achieve (within reason) a more consistent from lot to lot powder than simply and blindly mixing the 75/15/10 ratio by weight alone.

Well enough of that... I agree with you on trying Swiss, it is worth a shot (no pun intended...)

~Mako

arcticap
April 19, 2011, 10:59 PM
There's also something about the moisture content of Swiss which is suppose to impart a moister burn.
The increased polishing of the individual grains of powder is suppose to be more desirable too.
The Alder branches are suppose to be better when they're picked at a younger age and are more tender, and then processed into charcoal while they're fresher. And it needs to be debarked to make for a cleaner charcoal.
Maybe it's even hand picked by a family cottage industry? :rolleyes:

Cop Bob
April 20, 2011, 02:30 PM
I'm Impressed... nobody can say that BP won't preform.... Nice set up BTW...

I wouldn't want to be in front of ANY of them....

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