Primer pockets

[RonS]

What are the telltale signs of the primer pockets wearing out? And how can I prevent this in the future? I have been shooting maximum loads in my 223/5.56 rifles, AR's and bolt guns. I use mainly LC brass.

 

[fredhorace77]

when the primer can be seated with very little force...ive seen some bad enough that you could just push the primer in by hand with your pinky finger...thats worn out...lol

 

[Scott Harris]

As stated by Ron: when seating pressure is little to none its time to throw the brass out. You can prevent it by firing more modest loads. Those of us in competitive shooting are running loads hot enough that the pockets get loose....sooner or later. With a load a bit below max, I can get about 12-18 reloads from my 223 Lapua brass. If I run them hot in a bolt action, it becomes 6-10 reloads. My AR brass lasts longer than my bolt gun brass because I'm running about 1 full grain less in the AR.

 

[RonS]

Thanks for info, I've been very much under the weather these last few days but hope to be 100% by Monday. I will keep these tips in mind from now on.

 

[amlevin]

One way to check for primers pockets that have reached the end of their working life is to carefully inspect the fired round. At the first sign of any gas leakage in the form of soot trails, toss it. Next is to deprime using a depriming only die. The amount of pressure to remove the primer is a good indication. If you do this at the same time as you size, the loose pocket is masked beneath the sizing pressure.

Following this method at least keeps you from wasting a primer by seating it in a loose pocket and then realizing that it's loose.

 

[jlow]

Amlevin – you bring up an interesting point as to using the pressure needed to deprime to evaluate how loose a primer pocket is. I must say that I have mixed feeling about this. To start, I would really like to believe this to be true since it would be so convenient, but one thing that holds me back is the thought that the primer must expand when the round is fired and so even if it was very loose to begin with, it may get tighter after firing?

I have been thinking about this and would like to offer an alternative which may also not be agreeable to everyone and that is to deprime the primer after initial seating. You can see where I am coming from on this i.e. the primer has not fired and so by depriming it, you can get the actual feel of how tight a fit this is. Now, someone may ask why would it be different than how hard it was to seat it? It’s a good question but the fact is seating pressure appears to be a poor indicator in my experience. I have done this many times and have always be surprised at the force needed to push a primer out of what feels like a loose pocket.

A potential disadvantage of this method is of course you are depriming a live primer which does carry some risk. However as most who have done this, it is perfectly safe as long as you do it gently which of course you would in this case since you are trying to feel the force needed. There is yet another potential problem and that is you may alter the performance of the primer by pushing on it but that as far as I know is only theoretical at this point.

Would be interested in hearing what others think.

 

[madderg]

I use strictly Lapua brass, and I check that the pocket is cut well and use a primer pocket tool ONCE. All times after I use a steel brush to clean the pockets. A lot of folks use the primer tool every time and oversize the pocket.

 

[amlevin]

Amlevin – you bring up an interesting point as to using the pressure needed to deprime to evaluate how loose a primer pocket is. I must say that I have mixed feeling about this. To start, I would really like to believe this to be true since it would be so convenient, but one thing that holds me back is the thought that the primer must expand when the round is fired and so even if it was very loose to begin with, it may get tighter after firing?

In a tight primer pocket, the primer only expands with the case head. If elastic limits are not reached, the case head will return to it's original dimensions ( or real close).

In a loose primer pocket, or one that has finally decided to stretch and not "spring back" yes the primer will expand but it will have a certain amount of spring back of it's own. Not much granted but it's been my experience that when depriming as a separate operation, with no masking forces like those needed for sizing, it's pretty evident that some primers are clearly looser than others. Those are the ones that certainly warrant closer inspection, at least for signs of gas leakage on the sides.

I'm one that believes Brass Inspection involves a lot more than just "looking at it" as you put it in a block or bin. I put on the "magnifiers" and check the primer pockets of all those that give up their primers too easily in my mind.