Going over max on Magnum Rifle


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Trent
March 10, 2013, 01:18 PM
I've pushed handgun ammo past max before, on 9mm and 45, but I've never really pushed rifle past max. My theory has always been "whatever it hits won't care if it's going 100fps slower".

But on a recent test of 300 Win Mag on load development, I found my best load of 26 lots tested, sitting at a charge of 69.8gr of H4831SC w/ 220 gr Sierra Match kings. Sierra lists that as the max charge for that powder / weight / bullet combination.

I'm seating my Sierras longer than the book, by .108", which gives me a little additional capacity; and that "max" charge doesn't show any signs whatsoever of overpressure. Primers are still rounded on the corners, not set back, no detectable expansion of the web area, etc.

With the "best" group being at the high end, I'm tempted to push forward to see if it tightens up further. :)

With the background out of the way, my question is;

What increment should I use for testing beyond listed max on a case this large?

1% increments would be about 0.6 gr, 0.5% increments about 0.3gr (rounded down).

With H4831SC being resistant to temperature changes I'm not nearly as worried about load development in the winter / early spring and shooting in the dead heat of summer, as I would be with other powders.

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Trent
March 10, 2013, 01:19 PM
Whoops posted in Rifle forum instead of reloading; can a mod move please?

rcmodel
March 10, 2013, 01:24 PM
I'm not nearly as worried about load development in the winter / early spring and shooting in the dead heat of summerYou should be when pushing the envelope that close to the lick'm and stick'm edge.

You might get a paper cut next summer!

Resistant to temperature changes doesn't mean immune to temperature changes.

rc

buck460XVR
March 10, 2013, 02:25 PM
Checkin other sources(Hodgdon and Lyman), I found max charges for the Sierra 220gr RN in 300 Win Mag that exceeded your load, but could find nothing anywhere else for the 220gr MatchKings. Most folks figure reloading manuals have a certain amount of "margin of error" figured into the max loads listed. While that may be true, it doesn't justify readily exceeding it just for chips and giggles. Myself, if I was unhappy with accuracy and I could not find a published load showing a higher charge rate, I would try another powder before I went above published loads. But then I wouldn't intentionally load 9mm to over +P+ either.

Kachok
March 10, 2013, 02:57 PM
Before you start going over max why not try out a couple faster powders. Nosler lists a 220gr Partition in a 24" barrel 300 Win Mag at 2762fps with IMR 7828 and RL22 only 10fps behind, both are slower burning and faster moving then 4831. RL22 is my favorite, and the only powder I have ever used over max charges with, the stuff does not get weird pressure spikes working up, compresses very well, and it burns as slow as a Alabama summer so it is very well suited to very heavy for caliber bullets

Trent
March 10, 2013, 03:33 PM
RC; good point. I'm shooting in 40 degree weather with 40 degree ammo, if I work this up to the brink and then shoot it on a nice hot Illinois 100+ degree day, I might be in for a bad time.

I think I'll load TWO 5 round batches up at .3gr and .6gr over, just to see if the trend continues with the group sizes shrinking. I've got more case capacity because I'm loading a longer OAL than the "book tests", so there's a little wiggle room there anyway.

Buck; different seating depth and bearing surfaces make it somewhat risky to exchange load listings for bullets. It's not JUST a matter of powder vs. bullet weight. Those bullets have a much different bearing surface and recommended seating depth. The 220Gr RN have a very long bearing surface, but they are "shorter" overall than the MatchKings, so they don't have to be seated as deep. Both of those factors play in to the load.

Kachok; I've tried H4350 which is a considerably faster powder. However, the results I got were pretty inconsistent. Out of 5, 5 shot groups, I had an average group size of 1.142", with a low of .944 and a high of 1.471. Compared to H4831SC I had an average group size of .989 with a low of .795 and a high of 1.350.

In ALL tests I've done with this rifle since I got the Krieger barrel on it, I've found a pattern - it prefers either very low or at-max charges. The group sizes grow as you get to the middle point between the two.

It's very likely I'll end up with TWO loads I like for this rifle, since "Starting charge" and "Max charge" are both giving me consistent sub MOA groups. Meanwhile the exact middle is giving me consistent 1.5 MOA groups.

The lower of the two loads will be used for practice, easier on the barrel (and me!).

ngnrd
March 10, 2013, 05:43 PM
It's very likely I'll end up with TWO loads I like for this rifle, since "Starting charge" and "Max charge" are both giving me consistent sub MOA groups. Meanwhile the exact middle is giving me consistent 1.5 MOA groups.

The lower of the two loads will be used for practice, easier on the barrel (and me!).
That's certainly a good option. Of course, even 1.5 MOA is plenty good enough for most hunting.

gamestalker
March 10, 2013, 06:23 PM
RL22 became new best friend a number of years ago for the 7mm RM. And more recently it has done the same thing with the .270 win. However, it is such a slow burning powder that exceeding maximum published data by more than a tad is impossible, you simply can't get any more in the case.
GS

buck460XVR
March 10, 2013, 06:34 PM
Buck; different seating depth and bearing surfaces make it somewhat risky to exchange load listings for bullets. It's not JUST a matter of powder vs. bullet weight. Those bullets have a much different bearing surface and recommended seating depth. The 220Gr RN have a very long bearing surface, but they are "shorter" overall than the MatchKings, so they don't have to be seated as deep. Both of those factors play in to the load.

Trent....I know all about bullet profiles, seating depths and bearing surfaces. If you re-read my post slowly, you'll see no-where did I recommend using info for the other bullet. All I said was I found higher charge rates for the other bullet and NO info whatsoever in other sources for the powder/bullet combo you listed. Kinda why I didn't give the powder charge rates.......for fear you might try to use it. Also why I said if I couldn't find a higher published load recipe, I'd try another powder, instead of playing with above max loads. Like the knowledge of bullet profiles, seating depths and bearing surfaces, this is just basic reloading.

Walkalong
March 10, 2013, 07:36 PM
You might get a paper cut next summer!Oh yea.

I retest everything in July/August here where I sometimes record temps over 100 degrees. Some loads that were fine in 50 to 70 degree weather simply are not at those temps.

Trent
March 10, 2013, 08:44 PM
Well, I worked up one set at 70.1gr.

I couldn't do more... because I ran out of that particular lot # of H4831SC, AND I'm out of Winchester Large Rifle Magnum primers. I had enough to build 50 rounds to experiment a little around the high & low end.

I'm down to my last pound of H4831SC now (diff lot # tough), and have to switch to Remington primers (have 2k of their WLRM equivalent).

I'm loading a series of proof rounds with the new components later tonight.

Unfortunately this will probably be it for my 300 Win Mag experiments until components become available. This last pound of H4831SC is the last of the mohicans here, out of H1000, out of H4350. Don't have any other powders that are suitable.

Frigging shortages are starting to irritate me.

Edit; and Buck, I didn't mean to sound condescending in my post. I tend to explain myself too much, so there's no mistake about what I mean, and sometimes it comes across as cocky, arrogant, or condescending in print. No ill will intended though. I'm an engineer by trade so I tend to over-explain and over-think things. :)

witchhunter
March 10, 2013, 09:26 PM
When I get close, I go .1 grain at a time. One round of each, shoot them 1 at a time and look them over. When I go as high as I can I pull the rest and log that as my max for that rifle. Then check them in August!!! 1 at a time....

Bmac1949
March 11, 2013, 02:19 PM
Good thread, makes me realize that i have some homework to do before I attempt max loads. That's if I ever need to. what I'm loading now (270, 308 and 30-30) give me the best groups well before I need to load to the max.

Trent
March 11, 2013, 04:25 PM
I've never had a best group at Max before with any other rifles..


Now I've got four different sets of test data on this barrel from four different loads; all showing a preference for the low end and high end of the range.

So my next two tests are to experiment around upper and lower ends a little, in .4 increments (about .05% increments) to see if I can find a sweet spot. One test will be at current OAL which is .001 from the lands; the second will be .010 from the lands. (Just to see if a minor OAL change makes any difference).

ranger335v
March 11, 2013, 07:58 PM
"What increment should I use for testing beyond listed max on a case this large?"

Trent, no offense is intended but I believe anyone asking that question should stick to the book max, for sure I'M not going to comment on it! But I will say that seating long runs rifle peak pressure up, not down.

Trent
March 11, 2013, 09:59 PM
"What increment should I use for testing beyond listed max on a case this large?"

Trent, no offense is intended but I believe anyone asking that question should stick to the book max, for sure I'M not going to comment on it! But I will say that seating long runs rifle peak pressure up, not down.

I'm not jamming the bullet in to the lands. I've measured where the lands start (precisely), to confirm the measurements given by Krieger for the reamer they used on my barrel. I have extra space to work with here, this isn't a factory barrel. :)

That effectively gives me extra case capacity to work with, which doesn't increase pressure; but rather, lowers it. I've fired ammo out of this gun that I had leftover for my old barrel. In the last barrel that ammo was showing flattened / set back primers (74.5gr H1000/220gr MK). That ammo, in this barrel, the primers are still nice, and round, and pretty. Can't even tell which of the brass was at the starting load, and which was the max, after I tumbled them.

I agree with you if you load long enough to get the bullet up on the lands, you're going to run in to problems; but I'm not. :)

Trent
March 11, 2013, 10:01 PM
I will add; To a point; there's the whole free-bore Weatherby trick they used on their rifles, to reduce pressure. But that's cheating. :)

jmr40
March 11, 2013, 10:23 PM
What does your chronograph say? When developing loads it is your best guage. If the book says a max load is 64 gr of powder. And that will get 3000 fps, then 3000 fps is your max load, not 64 gr of powder. It is the velocity you are getting that determines chamber pressure. Some guns might need a little more powder to reach the same velocity and pressure than another gun

I've had some powders reach 3000 fps while still 2 gr below book max. I've had loads that were 50-100 fps below 3000 fps when right at book max.

The problem with loading over the max powder charge is that while that load may be perfectly safe in your rifle, it might not be in mine. I've seen two identical rifles shoot the same ammo 130 fps different.

Trent
March 11, 2013, 10:58 PM
jmr40;

I've seen that in handguns, too. My Springfield 1911 shoots 230gr jacketed bullets 100fps faster than my Glock 21. :)

I didn't have my chrono out this last trip - was pouring down rain. But this next test I will have it with me.

After that, I have to work up everything all over again (switching primer brands due to lack of Winchester primers), and will have a new lot of powder (as soon as I can FIND any). In fact, the last lonely 1lb bottle of H4831SC I have is a different lot from the testing I did previously, so I'm re-proofing with it before I shoot any of the hotter loads.

Trent
March 11, 2013, 10:59 PM
Oh, my first F-Class match is April 7th, so I'm working under a time limit, too.

With the component shortage the first match may very well also be my LAST one for awhile. :(

Coltdriver
March 11, 2013, 11:01 PM
I just picked up my second magnum. I sold my 300 WSM because at the high end it was just brutal to shoot. Now I have a .270 WSM and am surprised at how close to the design maximum the higher end loads are. Like 63K psi on a 65K design.

I was also surprised at how, when approaching the max load, a very tiny amount of powder really upped the pressure.

So with a Ruger #1 I would not be as concerned as with a "insert lesser brand name here".

But there is no way I'd risk my health over a few tenths of a grain. You may be able to pick up a bit more accuracy by adjusting col or paying more attention to the brass.

Your call of course. Your health too.

Trent
March 11, 2013, 11:15 PM
My 300 Win isn't too unpleasant to shoot...

... In the winter time, with a thick coat on.

http://i.imgur.com/fWVZImql.jpg

In the summer, with a t-shirt, it's a little harsh. But not as bad as some of my rifles. I think the Swiss K-31 kicks about 2x as hard. But maybe it's just the steel buttplate my shoulder don't like. :)

Trent
March 11, 2013, 11:17 PM
But there is no way I'd risk my health over a few tenths of a grain. You may be able to pick up a bit more accuracy by adjusting col or paying more attention to the brass.


Yeah I decided on a .3 increment increase to 70.1, then .2 increment to 70.3. Not going past that; if I don't find what I'm looking for, I just don't find it.

As far as brass prep, not much more I can do. I'm already sorting by weight, unifying primer pockets, deburring flash holes, neck turning, seating with a (too expensive) air buffered competition seating die, collet neck sizing to get uniform seating tension, only reloading wearing my lucky socks, and sacrificing virgins. It takes a LONG time to get a box of ammo worked up.

Oh, and I was kidding about the socks.

Clark
March 12, 2013, 03:45 AM
I work up until I find the threshold of short brass life, and then back off a safety margin, and that is my load.

If I calculate or measure various errors that drive the magnitude of the safety margin, some are subjective, like "How sloppy will I be reloading?"

What I like to do is reload where I shoot.
I work up until a case gets a loose primer pocket, reduce the charge and look for the threshold of long brass life.
I like to reload the same case over and over with the same charge until it wears out.
If at 49 gr I can use the brass 10 times and at 50 gr I can use the brass twice, I would back off from the 49 gr.
With Hodgdon extreme powder or Alliant AR-COMP, I only back off 4%, so that would be .96 x 49 gr = 47 gr would be my load for hunting.

ironworkerwill
March 12, 2013, 10:06 AM
I used max load on very short barreled Ruger M77 7mm-08 130gr sierra mk at 2.8 col using 46.9 gr of h414 and hit 2650fps then used a col of 2.835(close but not on lands) and shot 2550. I brought the load up to a charge of 47.1gr and got really close to previous max charge velocity( stepping up .1gr at a time). The little gun likes this load- 100yd 3shot groups at 7/8'' stock rifle with no bedding or free float. I would like to have a longer col but it will not fit in the Ruger's mag. This is my experience submitted for conversational use only.

Trent
March 16, 2013, 12:18 PM
In addition to the Sierra 220gr max load, got another experiment to run as well. :)

I've read mixed reviews on CNC lathe turned bullets; but some long range shooters swear by them. So (after getting over sticker shock), I thought I'd give some a try.

http://i.imgur.com/rh4CklZl.jpg

Bullets are mfg by Cutting Edge. Cost was just north of a buck 33 a bullet. Picked up two varieties; MTH C32 and MTH C48.

Also picked up boxes of:

Hornaday Interbond 180gr (100ct)
Nosler Accubond 200gr (2 boxes, 50ct)
Nosler Custom Competition 190 gr (100ct)
Berger OTM Tactical 230 gr (100ct)
Berger Hybrid Target 230gr (100ct)
Berger Classic Hunter 185gr (100ct)

By the time I get through all of these tests this year, in addition to what I've already put down the bore (245 rounds so far), I'll be through well over half of my barrel life!

BTW, it feels good to shoot magnum rifle. While everyone else in the US is scrambling to fight over midweight 308's and 223's, all this stuff was in-stock and arrived at my door two days after ordering from MidwayUSA.

http://i.imgur.com/h4oOWNWl.jpg

murf
March 16, 2013, 01:07 PM
try a different (or several) primer. reduce load 5% and work up. that may get you a lower pressure "sweet spot". the sierra data was shot using a federal 215 primer (hint).

what brand of cases are you running?

you also said the bullet is close to the lands. less freebore means more pressure. i would take the chrony and make sure those load aren't going too fast.

a couple changes to components can have an additive affect on pressure.

luck

murf

Trent
March 16, 2013, 01:43 PM
Using Winchester cases.

I'll take the chrony out tomorrow, today there's a heck of a north crosswind blowing. Tomorrow we'll still have 10-12mph winds but it'll be easterly, mostly at my back. :)

The cases aren't showing any pressure signs at all at 69.8gr. I've got these loaded up to test tomorrow; working my way around start / max a little since both of those ranges showed promising groups on several previous tests.

H4831SC 65.0
H4831SC 65.4
H4831SC 65.8 << replicating previous min test
H4831SC 66.2
H4831SC 66.6

(65.8 gave es=0.869, v=0.785, h=0.470)

H4831SC 69.0
H4831SC 69.4
H4831SC 69.8 << replicating previous max test
H4831SC 70.1

(69.8 gave es=0.795, v=0.703, h=0.409)

es=extreme spread
v=vertical spread (elevation)
h=horizontal spread (windage)

I was doping wind good last time I was out, had a gusty 10-15mph crosswind but managed to put together 15 sub-MOA 5 shot groups (out of 20 fired). I've been hoping for a non-windy weekend to get a better read on things.

I've shot the heck out of Sierra 220's over the years; but want to play around with some of the other brands to see how they shoot.

Problem is I have enough powder left for *maybe* 90 shots, and powder is scarce as hens teeth right now.. so I have to pick & choose where I go from here (particularly since half that powder will be burned in one F-Class shoot in 3 weeks...).

Clark
March 16, 2013, 08:02 PM
http://www.thehighroad.org/attachment.php?attachmentid=140084&d=1302286062

When I plug your load
...70.1 H4831sc 220 gr Sierra MK 300WM into Quickload, I get 57.5kpsi.

H4831 Temp change:
Hodgdon claims from 0 to 125 degrees, H4831sc 168 gr 300WM will get 10 fps velocity change due to temperature change. That is down in the shot to shot noise.
I have had trouble with action and the magnum case head at 108 kpsi Quickload. [see pic]
I had to throw the piece of brass away, the primer pocket was so loose that the primer fell out.
The VZ24 i had converted to magnum bolt face had some plastic deflection in the lugs and lug abutments. I lapped it out, and shot a number of animals with that rifle.

When I back off for a conservative load for hunting, it is typically 70kpsi Quickload.

SlamFire1
March 16, 2013, 09:00 PM
I am going to give the "Nanny" caution:

Firearms are designed to sustain a load and carry that load for a reasonable number of cycles. I am now of the opinion that firearms are designed to withstand a finite number of cycles before fatigue fracture, though they could go an infinite number of cycles if the firearm was made heavy enough. It makes sense that small arms are designed for lifetimes around 10,000 cycles as that is several times more than the barrel life. Machine guns are designed using the same materials and loads but they are much heavier because they are expected to fire 20,000 or more rounds without the action failing. The basic difference between rifles and machine guns is weight. I recently heard a Vickers 303 weighed 84 pounds, compare that to a SMLE which weighs around 10 pounds. There are good reasons the Vickers could fire tens of thousands if not hundreds of thousands of rounds.

When you push an action beyond its design limits you reduce, and I don’t know how much but there are a number failure theories about this, the cycles to fatigue fracture.

I recommend looking at this thread:

Fatigue Life of 4140 steel

http://castboolits.gunloads.com/showthread.php?150409-Ruger-om-44-convertible&highlight=convertible

Clark
March 16, 2013, 11:30 PM
http://www.jonaadland.com/SN.jpg
Another engineer drew this Rem 700 bolt fatigue graph for me 9 years ago.

One might infer that if I found the threshold of yield, that fatigue at 10,000 round is [450/650] 108kpsi = 75 kpsi with magnum case heads for my 1924 Mauser.

That seems reasonable.
Here is a Rem700 338 Lapua bolt face.
Would you like to run the numbers on this?

That is why I laugh when ever I see the words "designed for".
I hear those words all the time at the gun show.
I have been designing things for a long time.
To understand how things get designed... read the entire catalog of Dilbert cartoons.

I was a tike hanging around when my father designed his first gun, the M55, in the early 1950s.
Israel still has some and the bring them out to shoot up Lebanon. They have lasted for a while.

Trent
March 17, 2013, 01:01 AM
Clark; My brass comes out prettier than yours. THAT is some rough looking brass.

In fact, with magnification, after mixing all 10 groups of brass I shot last time, I couldn't figure out which were shot at "max" in the book (actually, slightly over by .1).

But.. visible details aside, five cases failed the case length gauge (barely) and had to be set aside for trimming.

Bet you $5 I know which lot those 5 those came from. :)

The chambering job Krieger did is zero clearance; there's zero measurable growth between the original unfired case and the fired case, measured base to belt, and base to shoulder. This allows me to only touch the neck on resizing.

I still have to be mindful of brass flow, but as long as I monitor it I shouldn't have a problem with case life; not at the pressures I'm pushing. I'm only going .5 gr over max (less than 1%) just to see if the groups tighten up. If they do, great. If they don't.. well, no reason to push that hard, or harder.

I'm looking for the most accurate load, period. Trying every bullet and powder combination along the way that I can get my grubby hands on.

On the last barrel on this gun I just had it figured out about the time it was shot out, then had to start all over. :)

Clark
March 17, 2013, 01:53 PM
That brass is at 108kpsi. I am into experimenting. That is not a practical load.

The threshold of long brass life in belted magnum case heads is down around 75 kpsi.

The main thing is to keep that brass dedicated to one rifle and don't set the shoulder back more than .001 or .002".

If a rifle has metal fatigue from shooting 10,000 rounds at the threshold of long brass life, get a better rifle.

SlamFire1
March 19, 2013, 11:17 AM
That is why I laugh when ever I see the words "designed for".
I hear those words all the time at the gun show.
I have been designing things for a long time.
To understand how things get designed... read the entire catalog of Dilbert cartoons

If you have ever been inside any Company with engineers, you will see Dilbert Cartoons pinned to the cubicle walls. Dilbert is great because every one can relate to the human interactions and human failings found in organizations. Such as the cartoons where the Boss goes to the refrigerator in the snack room and steals food and sodas from co-workers lunch bags. Happens everywhere. But, Dilbert is no more real life than the Cop shows or CSI shows or “West Wing” is the Presidency.

But, if you as a designer would not design the structure of a locking mechanism based on load and on service life, I am curious to know just how you would design it?

You have a picture of a Rem 700 bolt with a bolt face widened for a 338 Lapua cartridge, use that as an example.

ranger335v
March 19, 2013, 12:00 PM
"What increment should I use for testing beyond listed max on a case this large?"

Reloading is not a modern grade school "group think" project. I started reloading in '65, started handloading a few years later.

In my humble but experienced opinion, anyone asking such a question is far too inexperienced to get any answer other than to stick with book loads.

Clark
March 19, 2013, 01:40 PM
Most of my male relatives are engineers.
My wife is an engineer.
We explained to the kids what an engineer is by showing them Dilbert cartoons. We told them we have to deal with the pointy haired guy every day.

"Laws, like sausages, cease to inspire respect in proportion as we know how they are made." - John Saxe 1869

"How did I make money?
I set my own rate for designing things using math, while communicating with managers like they were attention deficit disorder 5 year olds with a gun pointed at me." - Clark Magnuson 2013

And the gun in the hand of the pointy haired guy in Dilbert is real.
"It is time to shoot the engineers and release the design" - [An engineering manager looking at me] 1979

What does it all mean?
We could design things well, but there is always a trade off with cost and schedule... so we don't.

Trent
March 20, 2013, 09:45 AM
"What increment should I use for testing beyond listed max on a case this large?"

Reloading is not a modern grade school "group think" project. I started reloading in '65, started handloading a few years later.

In my humble but experienced opinion, anyone asking such a question is far too inexperienced to get any answer other than to stick with book loads.

I started loading in 1998; so you've got a few years on me.

The reason I asked the question was I'd never gone over max published data on this large of a cartridge. With 9mm / 45 ACP, when I go over max it's generally .1gr at a shot. But .1 grain on a cartridge that small is 1.5% steps. Meanwhile, .1grain on a big belted magnum seems a bit on the paranoid side - 0.15% steps.

My question, if you actually bothered reading it, was would .5% or 1% increments be better suited for pushing past maximum.

But thanks for the insult on my handloading competency after 15 years at a bench, I always enjoy a good ego check with my morning coffee.

Clark
March 20, 2013, 01:42 PM
Trent,
I work up rifles in 1 gr steps.
I work up 32 S&W Long in 0.1 gr steps. What separates a useless wimpy load in 32 from a useless load with a stuck case in the revolver can be as little as a grain.

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

Here is a work up i did this week, but i have been doing work ups for 13 years.

1911 Commander with 185 gr Sierra JHP match, Starline 45acp +P brass, and Power Pistol at 1.25" OAL :
5.5 gr FTE Quickload 631 fps 6,760 psi
5.7 gr FTE
5.8 gr FTE
5.9 gr sometimes FTE sometimes OK Quickload 670 fps 7,503 psi
6.0 gr sometimes FTE sometimes OK Quickload 679 fps 7,700 psi
6.1 gr ok Quickload 689 fps 7,900 psi
6.25 gr ok Quickload 704 fps 8,210 psi
6.5 gr ok Quickload 728 fps 8,748 psi
9.0 gr ok Quickload 976 fps 15,592 psi
7.0 gr ok Quickload 777 fps 9,893 psi
10.0 gr ok Quickload 1,077 fps 19,341 psi
11.0 gr ok Quickload 1178 fps 23,800 psi..feel the recoil in the hand for 5 minutes from that one shot

As you can see, I make a 2 gr leap, yet I also do 0.1 gr increment when I am searching for a threshold. In this case it was the threshold of the gun jamming, but usually it is the threshold of long brass life.

I was trying to compare the 2.5 foot pounds of energy to push the slide back with the 4 foot pounds of kinetic energy the slide had.

scottishkat
March 20, 2013, 06:51 PM
220 GR. SIE RN Hodgdon H4831 .308" 3.340" 66.0 2533 44,900 CUP 71.0 2685 53,100 CUP

Hodgdons web site says 71 gr max for 220 grain sierra rnd nose. 53,100 cup is lower than others for pressure. H4831SC is a good powder for 300 win mag IMR 7828 is good as well. Good Luck

Trent
March 22, 2013, 06:27 PM
Trent,

11.0 gr ok Quickload 1178 fps 23,800 psi..feel the recoil in the hand for 5 minutes from that one shot[/I]


Wait a minute. Aren't you that guy who has blown up all those guns?? I think I remember reading a thread on here about someone who has blown up a half dozen or so handguns. :)


Hodgdons web site says 71 gr max for 220 grain sierra rnd nose. 53,100 cup is lower than others for pressure. H4831SC is a good powder for 300 win mag IMR 7828 is good as well. Good Luck


Yeah I'm going to slowly go up until A) the groups or velocity spread gets worse or B) brass actually begins to show SOME signs of pressure; right now there's nothing.

Testing has been on hold due to work schedule; been working 12-14 hour days the last two weeks. Haven't had any energy on the weekends.

Dave Rishar
March 27, 2013, 01:09 AM
Wait a minute. Aren't you that guy who has blown up all those guns?? I think I remember reading a thread on here about someone who has blown up a half dozen or so handguns.

If this is the Clark M. that I seem to recall from the rec.guns days, then he has indeed blown up a few guns in the name of science. He was busting myths before it was cool.

In fact, IIRC (and it's been a number of years and beers since then), the Clark that I'm thinking of was largely responsible for clearing up the CZ-52 vs. TT-33 debate. Conventional wisdom had it that the CZ was stronger due to its action. A Clark who may or may not have been our Clark felt that it was the thickness of the chamber hood and not the action that was important, and he blew up a pistol to prove it to the world. He'd already done the math, but people don't want to hear about math. They want to hear about things blowing up unexpectedly.

He's too humble to boast, but I'm not too humble to boast on someone else's behalf. The Clark that I'm thinking of performed a number of very interesting experiments at his own expense, and at least part of the shooting world benefited from them. As humble as he is, he might consider reposting some of these in one place for our edification, as we have a new generation of shooters who don't even know what rec.guns in particular, and Usenet in general, were, and missed out on a lot of wisdom.

gamestalker
March 27, 2013, 05:14 PM
I load magnum rifle and often use loads that push the envelope. But when working up I take it nice and slow once I start approaching the mid range charges, like in .1 gr. increments slow. It's prudent to remember that you are working with a cartridge that operates in the upper 50K to 60K range, you wouldn't want that pressure range to suddenly jump to the 70k+ range or more. And I think this is especially more of a concern when you consider you may be up close to the lands, which brings up another aspect. Have you determine how far from the lands you are, and, are you maintaining the same distance from the lands throughout the work up? This is pretty much a cardinal rule of reloading, in that, any time you change some aspect of the load, such as seating depth in this case, you must take the load back down, and work back up again. Not doing so can bite you in the butt, trust me.

GS

Trent
March 28, 2013, 07:30 AM
Yes, I know precisely where the lands are in relation to each projectile type I load.

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