Primers backing out

[whelen fan]

Hi fellas.

I'm shooting 3006 brass sized with a 35 whelen FL die with a 230gr noe mold and 16.5gr unique. Shoots good but the primers back out after being shot. I'm assuming this is because the shoulder isn't where it should be and I'm wondering what to do about this.

Thoughts?

[dtknowles]

You don't say what you have for a rifle but I assume it is a Bolt Action. Does the action close easily, then maybe you are pushing the shoulder back to far. Back out you sizing die until the bolt won't close on a sized case than then run it in until the bolt will close but with some resistance.

This will get the shoulder in the right place but the primers might still back out a little. The firing pin pushes the case forward a little and if the pressure is low enough the case stays forward but the primer backs up. This happens more with cases with little or no shoulder.

Tim

[JSnover]

What's the history of the rifle? Might not be a bad idea to borrow a go-no gage.

[500MAG]

What load data are you using? Possibly a light load?

[whelen fan]

This is a remington 700 classic. Works perfectly with 35 whelen ammo. And also no problems with real loads in 3006 brass and a 225gr interlock.

The primer problem only happens when I take 3006 brass and use a FL 35 whelen die and then shoot my plinking loads with cast.

[too many things]

don't full length resize, just neck size

[Bodean98]

Try this:
http://castboolits.gunloads.com/show...Loads-in-30-06
post #34
Good info by HWNMNBS

[runfiverun]

fire form with a full power jacketed load.

with lighter cast loads you can change your cases head space just by the firing pin driving the case forward in the chamber.
if you get them to the proper dimension to start with it takes longer for this to happen.

[CPL Lou]

fire form with a full power jacketed load.

with lighter cast loads you can change your cases head space just by the firing pin driving the case forward in the chamber.
if you get them to the proper dimension to start with it takes longer for this to happen.

^^^ What he said.

CPL Lou

[M-Tecs]

Try this:
http://castboolits.gunloads.com/show...Loads-in-30-06
post #34
Good info by HWNMNBS

I miss the good old days.

[Scharfschuetze]

With very light loads, the pressure in the primer pocket is higher than the pressure in the powder chamber. This is what drives your case forward and shrinks your case between its head and datum point and thus the shrinking headspace and protruding primers.

The solution for your squib or very light load cases is to drill the flash hole out a bit and that helps in reducing pressure in the primer pocket. I keep my modified squib load cases separated and I have shot them more times than I can count without any shrinkage in the base to datum point measurement. Rimmed cases do not need this as the rim is strong enough to resist the case getting pushed forward.

Good case measuring tools such as Mo's and Stoney Point (now Hornady) will help you keep track of such things.

[Wayne Smith]

Guys, it happens in every load and every shot. It is so reliable that John Garand designed his first semi-auto rifle around the principle of the primer backing out of the case! Then the army started crimping primers and he went to the gas design.

What happens is that the primer backs out initially and with normal loads the recoil of the case against the bolt face re-seats it. Light power loads don't have enough recoil impulse to accomplish this.

[whelen fan]

So don't worry about it? As long as I keep my plinking brass separate from my full power loads all should be well I'm guessing. If the should does move back far enough eventually I can chuck the brass or expand the neck past 35, create a false shoulder and start all over again.

[Irascible]

"You don't say what you have for a rifle but I assume it is a Bolt Action. Does the action close easily, then maybe you are pushing the shoulder back to far. Back out you sizing die until the bolt won't close on a sized case than then run it in until the bolt will close but with some resistance.

This will get the shoulder in the right place but the primers might still back out a little. The firing pin pushes the case forward a little and if the pressure is low enough the case stays forward but the primer backs up. This happens more with cases with little or no shoulder."
Tim

What he says. You have a modern gun, not one designed to fire dirty, muddy ammo in the middle of a battle.

[Scharfschuetze]

Guys, it happens in every load and every shot. It is so reliable that John Garand designed his first semi-auto rifle around the principle of the primer backing out of the case! Then the army started crimping primers and he went to the gas design.

Not true. If a rifle is headspaced properly and ammo is loaded to its proper dimmensions, then the primer cannot back out. Headspace gauges and case measuring tools will confirm this. You can run a repeatable series of tests to prove case shrinkage with squib loads by segregating 10 cases of standard flash holes and 10 cases with drilled flash holes and then loading squib loads in both and then keeping track of the shrinkage with a good case measuring tool between your two groups of cases.

John Garand's initial designs for his rifle did indeed use a primer actuated mechanism. While clever, it was really a dead end in the end and I know of no military or sporting rifles that ever went into large scale production using this form of operation. The combined gas pressure in primer pocket and the case pushed the primer back against a button on the bolt face thus initiating the cycle of the rifle. What is important to note here is that the rifle was designed to allow the primer to set back. It was not the result of "it always happening" as a solid bolt face will not allow this when all is to spec between headspace and case dimensions. Garand's experimental model of 1923 was the last of a series of his designs that used the primer set back system as he moved on to a gas cup design rifle and then finally to the gas piston design that we are all familiar with.

The military had something like 2 billion cal 30 rounds with crimped in primers in storage at about this time frame and the primer set back designs required a non crimped round to function. Budgets of the 20s probably killed off any idea of obsoleting so much ammo with a new design. This is the reason that General of the Army MacArthur used to kill off the .276 Pederson round that John Garand preferred for his later rifle designs.

Military ammo has generally enjoyed crimped in primers since WWI when the advent of full auto machine guns mandated the extra step in production.

I load for the 35 Whelen and use the 200 grain RCBS design boolit. With velocities in the neighborhood of 1,700 fps and higher I've not noted any primer set back or case shrinkage using cases with un-modified flash holes. When loading 158 grain cast boolits designed for revolvers at lower velocities over Unique powder, I use the drilled out flash hole cases (see my original post) and I have not suffered any shrinkage of cases or protruding primers.

My 35 Whelen based on a Military Mauser 98 action.

[HangFireW8]

Try this:
http://castboolits.gunloads.com/show...Loads-in-30-06
post #34
Good info by HWNMNBS

Too bad he didn't list his rifle. I wonder if the massive 1903 firing pin would have different results than, say, a 700.

[dtknowles]

Too bad he didn't list his rifle. I wonder if the massive 1903 firing pin would have different results than, say, a 700.

In his second post he said it was a 700.

[Shuz]

FWIW--Yesterday I was shooting my Remington 700 CDL in .35 Whelen with a Noe 360-318HP boolit, sized to .359. Both 16 and 17g of Unique for powder charges. Primers were CCI 200. Some of the brass used was .30-06 necked up and others were original .35 Whelen brass. The 16g charge chrono'd an average of 1550fps with an Sd of 16. Accuracy was only so so with the occasional flyer that really opened up the group to 4" @100 yds. The 17g charge chrono'd 1571 fps with an Sd of 9. The accuracy was much better, approx 2"@100yds. Interestingly, the 17g charges were driving cup pointed boolits at 245g, whereas the 16g charges were driving standard hollow points that weighed 235g.
The point I really wanted to make.....was that at no time did my primers back out on either load.

[Don Fischer]

Backed out primer's accompanied by the case being blackened down onto the shoulder and below say's to me, not enough pressure. What happen's is the case doesn't expand enough to seal the chamber and the primer back's up a bit but not enough pressure to drive the case back and re-seat the primer. Try using more pressure!

[gnostic]

If the loads too light, the primers will back out. What's the rest of the case look like, smoked up maybe?