Loose primer pockets?

C

cdoc42

New member
I had an experience yesterday that made me rethink the possible cause. It is not unusual for me to find a slight variation when I seat bullets in my .270 and 6.5mm Creedmoor. I loaded 10 rounds each in the Creedmoor with 40.0gr of H4350, and seated 140gr ELD-M, 147gr ELD-M and 140gr Hornady SSTs. As an example, the SSTs were seated to an OAL, base-to-ogive, of 2.255” for a 0.02” jump to the lands. When I primed the cases I stood each one up and they did not rock or sway. But I had 4 of the 10 seat 2.257 to 2.259 inches which, in the past, I figured was a slight change in the position of the ogive during bullet manufacture, and I would just adjust and reseat to the desired OAL. The same thing happened with the other two 10-round sets.
When I stood the 4 up on the table, they rocked and swayed, indicating the primers were no longer flat. Instead of reseating them, I gently “re-primed” by pressing the primers back in. That solved the problem. They measured 2.255”.
That brought me to consider that just maybe, since the cases are not 100% full with powder, there’s enough air in those cases that seating the bullet pushes the primers back out a bit. These are cases that may have been fired 15 or more times and maybe the primer pockets are not as tight as others that don’t deliver the same problem.
What do you think?
 
It does sound like the primer pockets are loosening, and the compressed air is pushing the primer out as you seat the bullet. You are at Hodgdon's maximum load, so at 15 repetitions, that's not an unreasonable thing to see happen, especially if the case brand is one with a reputation for softer heads, like Hornady. Another sign would be starting to get primer leaks that pit your bolt face.

Take one of the cases this has happened to and use a small hole gauge to get a transfer measurement of the inside with a micrometer. Another method is to spray inside the primer pocket with PAM or another mold release, then knead together a little of one of those five or ten-minute epoxy putties you buy in a stick and push it into the pocket just far enough to touch the bottom and let it set and pull it out or let it get really firm and push it out with your decapping rod and then measure its diameter. With either method, do the same with a new case of the same brand to get a comparison. There is also a primer pocket GO and NO-GO gauge you can buy.

There used to be a tool available to tighten primer pockets back up again, but it has been discontinued for a while. You could make one, I suppose. On the other hand, 15 reloads is not bad life expectancy for a rifle case running a maximum load, so you most likely need to decide how much trouble it is worth to make them last longer.
 
Thanks, Unclenick. I generally ditch cases when the necks crack or I see a faint line developing near the head which will lead to a fractured case. I use the RCBS APS primer seat system and I can often "feel" a loose primer pocket, and at that point, I'll ditch that case as well. If I decide to really pay attention, I can detect a case that seats a bit easier than another, indicating it is perhaps a bit loose. I'll load it anyway but mark it for trash after it has been fired. Given my proclivity to experiment, I'm drawn to your recommendation for the Go-No go gauge.....
 
If seating a bullet causes the air in the case to push the primer out (Any amount) then I'd say your case pocket to primer fit is too loose, no matter what the pocket measures.

And, of course be aware that different maker's primers can have different amounts of friction fit. I've experienced Rem primers that felt much easier to seat than CCI primers, in the same cases (as an example).

I'd say if you get a loose "feel" seating, or the primer "backs out" any, toss the brass, its done.

Cases are relatively cheap, if you get 15 full loads I'd say you got your money's worth and then some.
 
Sometimes another option with loose pockets is to find some Tula or Wolf primers and try them. I’ve found in general they are a touch oversize and are a little harder to seat in normal sized pockets.
 
You could also invest in the CORRECT tools to crimp/stake the primers in place (like the military requires) but I wouldn't spend the money or the effort, I'd just replace the brass with new.

(and, if you can't get the correct tools, don't even try it!)
 
Primer pockets will loosen (enlarge) over time of multiple reloadings ...
The lower the pressure ... the less enlargment takes place .
The higher the load pressure , the faster the enlargement happens .

The primer pocket should be tight enough to resist the force of seating a bullet , it doen't matter how much powder is in the case , when a bullet is seated the mechanical pressure of the air is compressed and pushes on the primer ... If seating a bullet causes the primer to protrude ... the pocket has become too enlarged to safely reload .

The pockets must be tight enough to hold the primers securely ... if they protrude upon bullet seating ... best to retire them . The next step if you keep reloading them is the primers Fall Out the pockets when you pick the round up !!! Ask me how I know this ... it was 1967 and I only had 20 30-06 cases ... I didn't know brass wore out and I reloaded them to death !
Gary
 
In over 40 years of loading, I've never used max loaded brass more than 7 times. They've ALL had loose pockets from 5-7 rounds.
 
I used the gauges last night to familiarize myself and I found them particularly useful using the "Go" gauge to assess the AR-15, .223 cases that need the primer pocket swaged. I was given 2 ammo boxes full of once-fired .223 brass by the local police chief but they apparently mixed military and standard cases and I can't definitively discern the difference just by looking at the deprimed pockets. Frustrated by multiple cases that won't accept the primers put resizing and loading them on the back burner, and I have just been relying on recapturing my own fired cases at the range. Now I can deprime, check them with the "Go" gauge, and start using that inventory.
 
Anecdote Alert, do not try this at home in the 21st century.

The first place I heard of Loctite was an article in a 1970s gunzine.
The author was trying to squeeze every shot out of his brass, so he was gluing in the primers as the pockets loosened.

A friend has done the same for Long Range ammo, overloaded to minimize windage.
 
jetinteriorguy said:
Sometimes another option with loose pockets is to find some Tula or Wolf primers and try them. I’ve found in general they are a touch oversize and are a little harder to seat in normal sized pockets.
Click to expand...
Sometimes another option with loose pockets is to find some Tula or Wolf primers and try them. I’ve found in general they are a touch oversize and are a little harder to seat in normal sized pockets.
Click to expand...

I also can, and do, attest to this (wolf primers seem to fit larger, tighter)... as well as other posts in this thread.

I've only experienced wallered-out primer pocket issues in 270 fwiw.
 
I found the SAAMI specs and made my own go-no go gauges on the lathe and after using them I dont know why every reloader doesn't have a set. Having a loose primer or one that is to tight is one of the most aggravating things for me.

Brownells has them last I knew so just google "primer pocket gauge".
 
reloader28 said:
I found the SAAMI specs and made my own go-no go gauges on the lathe and after using them I dont know why every reloader doesn't have a set. Having a loose primer or one that is to tight is one of the most aggravating things for me.

Brownells has them last I knew so just google "primer pocket gauge".
Click to expand...
Yes. These are necessary tools if you reload.

Sent from my Pixel 3 using Tapatalk
 
Useful, I can see, but hardly necessary.

Loose primer pockets are easily identified by the feel of primer seating, or by their performance the last time the case gets fired.
 
cdoc42 said:
Now I can deprime, check them with the "Go" gauge, and start using that inventory.
Click to expand...

The GO gauge will tell you which ones need crimp removal. But if the NO-GO gauge slips in, you definitely have loose pockets.

I got the gauges Ballistic Tools makes, and the digital Mitutoyo caliper says they are dead on to the last tenth of a thousandth. Turned on nice CNC gear, apparently. Someone else on the board got one from Ballistic Tools that had a defect, but the company quickly sent a replacement. One review on Amazon says his LP NO-GO was three ten-thousandths bigger than advertised, so he narrowed it down with 400 grit wet-dry sandpaper. I mention these incidents to make folks aware is possible for either source to make a mistake, and it wouldn't hurt to confirm what you got with a micrometer that resolves tenths of a thousandth.

Incidentally, Ballistic Tools also has a nifty gauge for resized necks to confirm how much interference fit ("neck tension") you have achieved on your resized cases.
 
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