What can cause loose primer pockets besides hot loads and too many reloadings?

[thefitter]

This is a gas gun, (JP Enterprises in 6.5 CM)...and I'm not loading hot at all.

After 2 firings I'm starting to get loose primer pockets. At first I thought it was the Hornady brass I was using so I tried Lapua but I'm getting the same results.

Is there anything about a semi auto bolt face or action that can cause this?

Thanks

 

[tobycoda]

what brand of primers are you using? What do you determine is not hot loads..You need enough to work the action..Are the primers falling out or are they just seating easy...

 

[nosualc]

Are you using a primer pocket uniforming tool, or an aggressive method of cleaning primer pockets? If so, you could be removing material from the pocket walls.

Otherwise, I think you're loading hotter than you think you are.

-nosualc

 

[dkhunt14]

Soft brass and big chambers can also cause this. Matt

 

[thefitter]

what brand of primers are you using? Fed What do you determine is not hot loads..Published loading data & Quickload You need enough to work the action..???Are the primers falling out or are they just seating easy...No, but there is a distinct difference in the removal feel.

Thanks

 

[Terry]

Soft brass and big chambers can also cause this. Matt

+1

Too much room at the base.

 

[thefitter]

Soft brass and big chambers can also cause this. Matt

I don't think that the Lapua brass is soft but a loose chamber is a definitely a possibility.

If that's really the case it is pissing me off. I thought it was the Horandy brass so I invested in all the tools and components to fireform 22-250 Lapua brass into 6.5 CM.

Probably not a damn thing I can do about this right?

I have other gas guns that don't do this!!


Thanks

 

[Thud]

One overlooked cause of loose primer pockets is a decapping pin to deep in the case.
The pin is pushed to deep because the length of the expander and pin is set incorrectly and it pushes on the base of the shell and bows out the primer pocket. Reset pin length so it pushed out the old primer with little resistence.

 

[thefitter]

One overlooked cause of loose primer pockets is a decapping pin to deep in the case.
The pin is pushed to deep because the length of the expander and pin is set incorrectly and it pushes on the base of the shell and bows out the primer pocket. Reset pin length so it pushed out the old primer with little resistence.

Thanks for the info but I have a small press dedicated only to decapping and I never bottom out in the process.

 

[thefitter]

Anybody have any idea what dimensions I should have on a 6.5 CM chamber in a gasser? I can measure the fired brass and see what I'm getting.


Thanks

 

[jonbearman]

What primers are you using?

 

[thefitter]

What primers are you using?

FED LR

thanks

 

[jonbearman]

If you change to wolf or cci it may get you more time with the brass. Measure the base of a fired case and an unfired and see if you have expansion there.

 

[Thud]

One overlooked cause of loose primer pockets is a decapping pin to deep in the case.
The pin is pushed to deep because the length of the expander and pin is set incorrectly and it pushes on the base of the shell and bows out the primer pocket. Reset pin length so it pushed out the old primer with little resistence.

Thanks for the info but I have a small press dedicated only to decapping and I never bottom out in the process.

Check the length of the decap pin assembly. Doesn't have anything to do with press.

 

[thefitter]

If you change to wolf or cci it may get you more time with the brass. Measure the base of a fired case and an unfired and see if you have expansion there.

What difference would the primer make?

New = 0.466

Fired = 0.470

Thanks

 

[jonbearman]

If you are measuring the pocket with verniers it may be lying to you. My nosler brass did the same thing and converted to a different primer and got multiple firings out them.

 

[thefitter]

If you change to wolf or cci it may get you more time with the brass. Measure the base of a fired case and an unfired and see if you have expansion there.

Those measurements were of the base of the case as you suggested not the pocket.

Thanks

 

[Dos XX]

If you change to wolf or cci it may get you more time with the brass. Measure the base of a fired case and an unfired and see if you have expansion there.

What difference would the primer make?

New = 0.466

Fired = 0.470

Thanks

Are you saying the case head expanded .004 after firing?

 

[thefitter]

If you change to wolf or cci it may get you more time with the brass. Measure the base of a fired case and an unfired and see if you have expansion there.

What difference would the primer make?

New = 0.466

Fired = 0.470

Thanks

Are you saying the case head expanded .004 after firing?

Yes, those are the measurements.

Thanks

 

[dkhunt14]

That is a lot for one firing. I would guess you got real soft brass; a large chamber or you are too hot. Seeing you are getting that much expansion I would guess a large chamber at back end. Do they keep getting bigger on more firings? Matt