How Loose Can a Primer Pocket Be?

[sscoyote]

...and still function OK?

 

[bigedp51]

It depends if you are shooting a bolt action or a semi-auto, the semi-auto needs tighter primers.

So you need to know the primer diameter and the primer pocket diameter and determine the primer tension.

I use pin gauges to check the primer pocket diameter.

And if the primer feels loose when seating I use a Lee depriming tool and if the primer can be moved with just finger pressure the case goes into the scrap brass bucket.

And if your bolt face looks like this after your checks you will need to go to the gym and build up your finger strength.
(or use a smaller pin gauge.)

 

[watercam]

For my match rifle (bolt gun), when the primer seats with virtually no resistance, I mark it, shoot it for practice or local match then toss (recycle) it. At that point I plan upon replacing all the brass from that 100 round box as they have all been exposed to the same number of firings with the same load and they are surely toast as well. But I try not to let it get quite that bad before they are replaced.

 

[bsumoba]

in a semi-auto, if it goes in easily, I might not shoot it. I have has primers get stuck in the action of my LR-308 doing this, to the point I couldn't get the action open.

in a bolt action, if there is almost no resistance and I cannot "tap" the primer out gently on the edge of a table, then I shoot it one more time and toss it. as another poster mentioned, I will mark it and toss it.

 

[bigedp51]

Just remember your primer is like a car engine piston and if it leaks you have blow by and this is what is going to etch your bolt face. Head clearance and the amount the primer moves to the rear and then seated again by the bolt face can effect primer leakage when too loose.

 

[sscoyote]

Got it--thks. guys

 

[jonbearman]

Gee wiz Ed how did you get a picture of my colt ar bolt my cousin ruined for me?

 

[LC Tikka]

Cannot wait until an enterprising Primer Maker, thinks outside the pocket and supplies oversized primers for use in "still good brass" with some level of loose primer pocket.
Also nothing like another custom fit option for the high end target reloaders.
LC

 

[vanwhyjr]

Has anyone had any success with Hart's case saver tool? http://www.rwhart.com/store/proddetail.asp?prod=dhb-f-swage-lg

 

[nhm16]

Cannot wait until an enterprising Primer Maker, thinks outside the pocket and supplies oversized primers for use in "still good brass" with some level of loose primer pocket.
Also nothing like another custom fit option for the high end target reloaders.
LC

Russian primers (Wolf/Tula/PMC?) are allegedly slightly oversized. At least I found that to be the case when comparing Wolf KVB-7s to CCI BR2s.

 

[amlevin]

One can get away with looser primer pockets if they are kept nice and clean. When fired, the pressure inside the cup drives it against the side of the primer pocket creating a seal. That is as long as there isn't any fouling that holds the cup away and provides a path for the hot gas to pass through.

If you look at Big Ed's frequently posted picture of the AR-15 bolt, note that the damage is a series of "Holes" in a circle rather than a nice smooth circle. This is where the "jet's" of hot gas have hit the bolt face rather than a circular wall of flame.

If all one does is scrape out the carbon around the flash hole and pays no attention to the side of the primer pocket than you risk premature damage even if the case passes the "Pin gauge test".

Either SS Pin tumbling media or ultrasonic cleaning minimizes the buildup of crud in this area.

 

[amlevin]

Cannot wait until an enterprising Primer Maker, thinks outside the pocket and supplies oversized primers for use in "still good brass" with some level of loose primer pocket.
Also nothing like another custom fit option for the high end target reloaders.
LC

Russian primers (Wolf/Tula/PMC?) are allegedly slightly oversized. At least I found that to be the case when comparing Wolf KVB-7s to CCI BR2s.

Not so sure they're "oversized". Perhaps just at the top limit for diameter though.

 

[Richard Jones]

http://www.longrangehunting.com/forums/f28/tighten-primer-pockets-heres-how-152361/

 

[Charles]

Very good question and a lot of good answers,the picture's where what i needed just primed a bunch of 221 case's and i know there were some loose one's will go back and recheck.

 

[searcher]

When installing the Tula or Wolf primers in a hand priming tool, the seating force required is significantly higher than any other domestic primer. I run a lot of Federal A/R Match and Remington 7 1/2 primers in my a/R's. When pockets loosen a bit, I have often made the appropriate powder adjustment and given the brass several more loadings by switching to the Russian primers. In a couple of A/R's - that is all I run. Brass is most often replaced with primers still tight enough for good service.

 

[bigedp51]

If you look at Big Ed's frequently posted picture of the AR-15 bolt, note that the damage is a series of "Holes" in a circle rather than a nice smooth circle. This is where the "jet's" of hot gas have hit the bolt face rather than a circular wall of flame.

When you post a photo or drawing it is "imprinted" in the persons brain when looked at, whereas printed words you read can fade away.

Therefore the people who see the bolt face will mentally say eroded bolt face "BAD" and tight primer pockets "GOOD".

Frequently posted picture of the AR-15 bolt face "GOOD", short term, long term and alzheimer's memory loss "BAD".

All it takes is to have this happen to you just once and tight primer pockets take on a new meaning.

The person who posted the AR15 bolt face in a AR15 forum said it was cheaper to replace the bolt face than worry about primer pockets.

So what is cheaper, a new bolt or new brass? And my pin gauge is .0002 smaller than max allowable diameter of the primer pocket.

 

[tenring]

I have heard that the Hart tool works fine for one loading, but opens up again after that and you need to keep tightening it. I use CCI 405 primers in my Dasher until they seat with no difficulty, then I switch to Wolf or Tula and get about 3 more loadings.

21st Century makes a small tool that is designed to test pockets by insertion. I think t was about $24.

 

[amlevin]

So what is cheaper, a new bolt or new brass? And my pin gauge is .0002 smaller than max allowable diameter of the primer pocket.

DPMS Bolt assembly $44.99

1K LC unprimed brass $209


Just out of curiosity, other than looking like crap, just exactly what does that etched bolt face do? It's kind of like 'Top Strap Erosion" on a magnum revolver. Not an issue until so much metal is removed the structural integrity of the firearm is compromised. How many rounds do you think it would take before the structural integrity of that AR-15 bolt would be compromised?

Until this pitting extends into the firing pin hole it's not an operational issue and at that point that $44.99 is probably a lot less than all the brass one has tossed earlier due to a gauge measurement.

 

[bigedp51]

Just out of curiosity, other than looking like crap, just exactly what does that etched bolt face do?

The rounded edge of the primer will flow into the pit (pits) and possibly cause the primer edge to rupture .
And the loose primer pops out of the primer pocket and into the trigger group jamming the rifle.
(very bad in a mass zombie attacks and you need to be a extremely fast runner) :

And who in their right mind wants the bolt face to look like the surface of the moon.

So what got your panties in a bunch or do you like loose primer pockets that leak and damage the bolt face.

BCM Bolt Assembly $89.95

1K Once fired LC brass $94.00

Three five gallon buckets of once fired .223/5.56 brass FREE from a Policeman friend. And the primer pockets checked with a pin gauge .0002 smaller than the max allowable diameter of the primer pocket. No leaks, no runs, no errors.

My primer pockets pass the high German quality standard of "Googintight" and are not Loosey Goosey.

The above message was brought to you by "The Society for the prevention of cruelty to bolt faces".

 

[Shrek]

Or you can take a 3/4" hardened ball bearing and a grade 8 bolt slid down the neck and rest the primer pocket on the bearing in a vice and give it a couple of taps and tighten them up. I did my first thirty last week and it has worked great so far. No leaking around the edges and everything was tight. I'll need to watch for signs of case head separation but my 6.5 Norma brass may last a looong time now instead of just a couple of firings.