Chrony Results: .45 BPM

[ClemBert]

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. 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.

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.

 

[Pulp]

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]

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]

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]

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]

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.





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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

clem

try 60 grains 777 3f and mild compression,over a 255 gr hornady............

 

[ClemBert]

andrewstorm,

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

 

[Oyeboten]

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]

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.

 

[andrewstorm]

orlando clem

You got a mess a hogs that need shootin down yonder,that 1847 bpm looks up to the task ill bet shell hold at 60 gr 3f 777,at least fer a 1000 shots

 

[ClemBert]

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]

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.



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. 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.

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.

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.

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.

 

[Foto Joe]

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]

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.

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.

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]

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]