lose primer pockets, why?

[10X]

I have an issue with my brass. it is hornady 7-08 that I reformed to 260 ackley.
I got 100 1x fired cases and have loaded them:
1x with 45 grains of H4831 with a 140 grain nosler ballistic tip. this time fire formed them
1x with 46 grains of H4831 with a 140 grain berger VLD
1x with 47 grains of H4831 with a 140 grain berger VLD
so that makes it 4x loads counting the factory load and now the primers are lose on 50% of the cases and actually fall out of 9.
I have never had this problem before and I ran very hot loads in 22-250 and 222. not just a few but thousands of pushing the limit loads and never ever had a problem like this. I really suspect there is a problem with the brass. I (think) I am no where near the realm of daredevil with the load I am using. other than the primer pocket issue the brass is in excellent condition. have not needed to trim.

help

 

[WapitiBob]

Brass mfg would be my guess. I get loose primers on Rem 7stw brass at about the same time line. I picked up some Nosler brass a while back and there is substantial difference in the virgin primer pocket diameter. I haven't pinned them yet but would guess off hand about 2 thou. It took two hands to seat some primers in the nosler brass. I also have a small chip drag in my chamber wall (a small pocket). It shows on my Rem brass as a .0015 high lump. It doesn't show on the nosler brass, not even a ghost image.

 

[Barrelnut]

I use Hornady brass for a Creedmoor. It is somewhat soft and primer pockets will open up quickly if you run it hard. Some of my brass has 10 firings on it though and the pockets are still useable, but the loads are not hot at all.

 

[rcoody]

I have an issue with my brass. it is hornady 7-08 that I reformed to 260 ackley.
I got 100 1x fired cases and have loaded them:
1x with 45 grains of H4831 with a 140 grain nosler ballistic tip. this time fire formed them
1x with 46 grains of H4831 with a 140 grain berger VLD
1x with 47 grains of H4831 with a 140 grain berger VLD
so that makes it 4x loads counting the factory load and now the primers are lose on 50% of the cases and actually fall out of 9.
I have never had this problem before and I ran very hot loads in 22-250 and 222. not just a few but thousands of pushing the limit loads and never ever had a problem like this. I really suspect there is a problem with the brass. I (think) I am no where near the realm of daredevil with the load I am using. other than the primer pocket issue the brass is in excellent condition. have not needed to trim.

help

I certainly would not spend the time reforming hornady brass.

Lapua or Norma are the only ones worth the effort.

 

[bigedp51]

Brass hardness and how the base is constructed has a great deal to do with how long your primer pockets last. Below are the Rockwell hardness figures for .223/5.56 brass.

LC 2008 = 96
Lapua 223 Match = 86
Winchester 223 = 69
Remington "R-P" = 49

http://bulletin.accurateshooter.com...r-brass-5-56-and-223-rem-base-hardness-tests/

Below the thickness of the flash hole web in the base of the case adds radial strength and helps keep the base of the case from stretching. The military Lake City case on the right has a much thicker flash hole web than the commercial case on the left.

Below the thicker flash hole web adds strength to the base of the case. Add this to the hardness of the brass of the Lake City brass and you have a case made Ford Truck Tough. As you saw above Lapua has the hardest brass of all commercial cases and is almost as hard as Lake City.

When your chamber pressure exceeds the elastic limits of the brass the case will stretch in the unsupported base. The base expansion varies with chamber pressure and brass hardness.

Simple Trick for Monitoring Pressure of Your Rifle Reloads | Hodgdon Reloading

 

[Santiam338]

Every time I reload my 300 WM Hornady brass I throw some away because of loose primer pockets..

On the other hand,when I had my 260 Ackley built I bought 100 260 Lapua cases..I think I will have to rebarrel before I wear the Lapua brass out..Good stuff.

 

[10X]

thanks for confirming thats its the brass. now to find 260 lapua in stock. have checked 3 places and none in stock. I did find 7-08 in stock

 

[Darkker]

I have an issue with my brass. it is hornady 7-08 that I reformed to 260 ackley.
I got 100 1x fired cases and have loaded them:
1x with 45 grains of H4831 with a 140 grain nosler ballistic tip. this time fire formed them
1x with 46 grains of H4831 with a 140 grain berger VLD
1x with 47 grains of H4831 with a 140 grain berger VLD

Without your velocities, that info isn't very helpful; however...
Load data by grains, is not a gospel; merely a reference. The velocity associated with the grains is what tells you where your powder lines-up burning rate wise, compared to tested data.
I would hazzard that you are over-pressure.

 

[10X]

chrony testing results

1) 2760 cold first shot of the day. rifle was not cleaned from yesterday.
2) 2764
3) 2770
4) 2760
5) 2768

ES of 10
average of 2764.4

temp is 15f and clear
elevation 1250ft
chrony was at 12ft from the muzzle
load is
46 grains of H4831
hornady 7-08 case reformed to 260AI
federal 210 primer
barrel length 26" 1:8 twist
berger 140VLD #26504

this is from 2 months ago

I did chrony the 47 grain loads but I cant find my results. from memory it was average of 2850 and temp was 50f all other info is the same

 

[bigedp51]

10X

Below is my scrap brass bucket and at the time of the photo 95% of the brass below was once fired factory loaded Federal .223 cases from around 2009. All this brass had oversized primer pockets after "ONE" firing.

To sort out these cases before sizing and loading I would use a two inch rod to measure the flash hole web thickness.

I would also use pin gauges to check for over sized primer pockets.

And cases with questionable primer pockets after seating the primer are checked with a Lee depriming tool. If the primer can be pushed with just finger pressure the case goes in the scrap brass bucket.

 

[Santiam338]

I run my 260ai considerably faster than that without any primer pocket issues.. I do not think you are over pressure..

 

[Darkker]

So here is the thing, Pressure behind the bullet is what creates velocity. Velocity isn't free, and doesn't magically appear because we want it to; although that would be great.
Anyway. The 260 tops out(Pressure wise) with a 140gr bullet at about 2680-ish with that powder, and about 2 grains under your load. So, if you go faster, it's because of increased pressure. Without a PT, we can't see what's happening in your rifle. I can tell you from Tracing the Creedmoor and 308 that to gain 100fps, you are going to need an additional 10-15,000psi.

Now there could be a brass issue, but most brass excepting *** Federal; in modern rifles begins to show "signs" and stretch when you are in the 72,000+ psi range.

 

[dwm]

You could have a headspace issue as well. Too short a headspace or not having a false shoulder or not seating bullets long into the lands while fireforming will create a lot of pressure and can losen primer pockets.

 

[bigedp51]

I have read many post where someone said too short of headspace will increase chamber pressure. Military headspace for the .303 Enfield rifle is .064 minimum and .074 maximum. My No.4 Mk2 has had the headspace set from .058 to .084 and this never had anything to do with changing chamber pressure. The only effect it had was on how far the case would stretch when fired.

So how would tight headspace effect chamber pressure when neck sized only cases become tighter fitting to the chamber dimensions each time they are fired. And when setting the headspace to .058 the bolt face was just barely kissing the rear of the case on the Enfield below. I know I heard it before, so don't tell me I should not have played with my bolt head until I nearly went blind.