flattened primers

[pumpguy]

I have a question about some .357 magnum cases. I load for my GP100 in just about all cases. I use Federal, Starline, Remington, CBC?(range pickups), and Winchester. I generally load 15gr of 2400 behind a 158gr TC from Saeco. This proves to be a very accurate load in my gun and fun to shoot. The question I have is does anybody else have problems with flattened primers in Winchester .357 mag cases. All my other cases show no signs of pressure problems. I have never done a study on case volume, but, is this a problem with anyone else? Thanks!:???:

[standles]

Winchester brass has always been pretty good to me.

With your mix of sources I would say you might have some range pickup that is past its prime. Sometimes folks leave stuff o nthe range because they do not want it back.


Could be another was loading hot and the primer pockets are a little loose. The primer is backing out more that the others with a tighter pocket. Decap a few of each and mic the pockets.


steven

[Dale53]

Pumpguy;
One guy's flattened primers is another guy's "normal". Comparison pictures will help us greatly to help you.

I have heard, but have not been able to verify, as yet, that the new 2400 is "hotter" than old issues. The scuttlebutt is that the formulation has changed due to National Security Issues (trying to prevent the bad guys from using modern smokeless powders for "infernal devices").

You might query Alliant about this. If this is true (and I have no way presently of confirming this) then your load may need to be backed off if you are using "new" 2400.

If you have chronograph data from "old" powder, you could compare this with the "new" powder. Chronographs are not pressure guns but if you are using the same powder charge and the old gives you much less speed (fps) than the new, then you know where to look.

FWIW

Dale53

[Bass Ackward]

If you have narrowed it to brass then you need to investigate there. I seriously doubt that you have a volume related issue. Especially with a powder as slow as 2400.

Could it be they are too long for your chambers and not releasing your bullet? My GP100 is generous in width, but not length. This stands to reason as the front of a reamer wears the most as it is cutting the most. Even if they are within spec, if the brass is soft, then the same pressure could lengthen them to the point that they are too long. But if the brass is soft, you would get sticky extraction of which you don't complain. So I'd check how long they are in comparison to the others just to see.

[pumpguy]

I kind of thought of those things. I checked lengths and they are all good. I checked this by using some once fired brass and got the same thing. I have not mic'd the pockets, but, they don't seem to press in any easier. I am not bashing Winchester brass. I load a ton of it. I never really considered this load overly hot and was really surprised to see them. In fact, I used the once fired brass because I figured I had just mixed in enough range pick up stuff that someone else had loaded too hot. I don't get any change in accuracy with them and they do not extract hard. I would post pictures, but I am not smart enough to figure it out. They basically look like little tree stumps that have been cut off just above the roots. I suppose I could just back off when I load Winchesters, but, where is the fun in that??????

[felix]

Winnie cases in the 357 mag are somewhat heavier, thicker. Check that out too, just in case (literally) this last statement is true today as it was in 1980 when I got all of my 357 brass from pressure test loads, with many different headstamps. Even got several hundred Smith&Wesson 357 cases which were way too thick to reload with 360 sized boolits. SuperVel had the best cases in terms of consistency, and were about like the Remmies at the time, perhaps a tad thicker. ... felix

[GP100man]

i usually back off when using W-W brass.i dont have my notes at hand but .5grs comes to mind for 2400.
ill add that some primers are softer & flatten even with moderate pressure,try a different primer. just my 2cents worth!!!!!


GP100man

[pumpguy]

GP100man,
Do you mean that you load 14.5gr of 2400?

[GP100man]

pumpguy
i had to go get my notes in rem& starline 14.5grs in W-W 14.0grs of 2400.
i have no chrono but the W-W brass would push a cast boolit to lead a little that the rem& starline i could shoot 100s with no leading,same batch of boolits cast 12/11/91.
ps :shooting a 6" colt KC at the time.& what kind of primer are we talking about wsp or rem1 1/2 ,cci ???

:cbpour:

GP100man

[S.R.Custom]

Measure and compare the rim thicknesses, could be a headspace issue. Also check and compare the diameters of the flash holes.

Winchester Brass is indeed a bit heavier and not as generous in volume, but to the tune of only a few grains. Unless you are loading right on the ragged edge to start with, this won't even be notceable. I have, on the other hand, seen brass with thinner rims, and/or too generously radiused primer pockets, and both conditions can cause flattened primers, particularly if someone has gone and hogged out the flash hole.

And no, 2400 has NOT changed over the years. It is a cannister grade powder, and its performance specifications have not changed. What has changed over the years, however, is the energy content and brisance of the primers being used...

[Mohillbilly]

I have had "normal" flatten primers in a New, high quaity gun and factory New (winchester) ammo.Perfectly normal,and yet I would have called it "flattend primers".....The quality of the gun, and ammo were beyond reproach there fore flattend primers were normal.The more I reloaded and worked with this the more I relized it was right........Bye the way the gun was a Grizzly Mark 1 and the cartridge was .45 winmag . Both very strong.I suspect the copper/brass primer metal was thin/weak for that pressure. I did not worry though, as I figured factory loads were stought enough, and I would not load anything else any "hotter".......I do belive where I stopped, is NOT the top of what it will do.....If I need more from a .45 I'll pull out a"bigger gun",like a Casull, Dan Wesson,Automag,Wildey,ect. or use a bigger slug(.475 or .50)......