Enlarged Primers Pockets--/ What is the cause?

K

kwak

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Minuteman
Dec 13, 2010
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#1
I am reloading for my 308 AR and the primer pockets are getting to big and the primers are falling out.

If it was for a bolt gun it would not be so bad but in the automatic it is nothing but trouble. I watched one fall out as I was loading it into the gun.

I measured some of the brass and can see that they are enlarged even though they still had the primers in them.

What is the cause and what can be done about it? THANKS
 
#2
Re: Enlarged Primers Pockets--/ What is the cause?

I take it you are reloading ....
Too much pressure, back the load off.
Could also have some soft brass, but loose pockets is usually a sign of high pressure. Depends on your requirements, some folks load hot and only get 3 to 5 loading from brass prior to loose pockets.
 
#4
Re: Enlarged Primers Pockets--/ What is the cause?

You need to be much more observant, as a handloader. You missed several clues, somewhere along the way.

How, exactly, did you arrive at the load in question? BB
 
#5
Re: Enlarged Primers Pockets--/ What is the cause?

Multiple possible causes for this.

Brass mfg'er?
Load data?

I've seen overgassed 308s trash primer pocket, cut down amount of gas cycling BCG and problem goes away.

Could be your load is just too hot, gas guns are not bolt guns. Burn rate of powder many not be good fit to gas gun yet a great powder for bolt gun.

Could be you need a heavier buffer? Is this a CAR or standard buffer? If a CAR buffer, how heavy a buffer are you running?

Gas system length: are you running a CAR, a mid, an intermediate, or a standard?

Need more information to be able to give you an informed answer.

Primers falling out of case is bad ju-ju regardless of rifle type. How are you priming your brass? You should be able to tell a loose pocket when seating primer and cull that case immediately.
 
#6
Re: Enlarged Primers Pockets--/ What is the cause?

Listen to what everybody else is saying here. (I'm learning too.) Most likely pressure. Does your brass have the imprint of the bolt face? Can you see where it washed into the ejector hole on the bolt face?

BUT I will add that I did have a bad batch of FC headstamp brass in .223 that just had oversize primer pockets. Once fired brass and some of it you could tap a primed case on my benchtop and the primer would back out of the case. Federal primers start out being a bit larger in outside diameter than other brands anyway from my measurements. I weeded out all the offending cases and had no more trouble. I don't know if FC .308 brass may have the same trouble, and I haven't had trouble with .223 FC since that one incident. That was back in the '90's sometime. A bad batch of brass CAN happen.
 
#7
Re: Enlarged Primers Pockets--/ What is the cause?

If you can't tell a primer pocket is too big when you SEAT a primer, then you just need to cease and desist, now, before you or someone else ends up getting hurt....
 
#9
Re: Enlarged Primers Pockets--/ What is the cause?

Just as a side note to looose primer pockets ,i was priming some brass today and wanted to try some of the Russian primers and boy are they so tight i emptied my primer tool so i only had one at a time in it in case it went off . Arnie
 
#10
Re: Enlarged Primers Pockets--/ What is the cause?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">If you can't tell a primer pocket is too big when you SEAT a primer, then you just need to cease and desist, now, before you or someone else ends up getting hurt.... </div></div>

^^^^This and then some.
 
#11
Re: Enlarged Primers Pockets--/ What is the cause?

"What is the cause and what can be done about it? THANKS"

Well, there is nothing but pressure that CAN swell case heads is there? But, what the heck, maybe you could put a drop of Crazy Glue on the primers to hold 'em in?
laugh.gif
wink.gif
 
#12
Re: Enlarged Primers Pockets--/ What is the cause?

The above post <span style="text-decoration: line-through">is sarcasm, BTW.</span> contains bad advice.

see my post in another thread:

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">I started handloading in the 60's, using a Lee Loader for the only rifle I owned at the time, a 270 Win. It didn't take long to see the shortcomings with that system. I was an avid reader of loading manuals, but beyond that and a monthly edition of Guns & Ammo by Bob Hutton, (my hero) that was it, I had to learn it all, on my own.

These forums should be the cat's ass, a wonderful resource, but from what I have observed, we have a new breed of instant gratification types that get on the Internet with questions that should have been mastered in handloading 101.

God! I hate regulation in any form, but perhaps it is time for some type of "driver's license test" before allowing them to sally forth, not a care in the world, ie: too busy to grasp basic concepts, simple but essential steps, things that should come second nature after a few years, "time in grade".

Everybody has to start someplace, but there seems to be a basic lack of respect for the whole enchilada.

end of rant, thank you. BB </div></div>
 
#13
Re: Enlarged Primers Pockets--/ What is the cause?

"The above post is sarcasm, BTW."

BB, my post isn't sarcasm, it's a fact followed by a little 'tongue in cheek humor', which is something Califonians rarely seem to understand. That's okay.
smile.gif

 
#14
Re: Enlarged Primers Pockets--/ What is the cause?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kwak</div><div class="ubbcode-body">What is the cause and what can be done about it? THANKS </div></div>
(1) Peak Pressure above std max peak, an
(2) Max "Normal" pressure with a much longer time line,...
 
#15
Re: Enlarged Primers Pockets--/ What is the cause?

Fuzz, my apologies, I will edit my post. I thought it was kinda important that the original poster not take it seriously. BB

PS Californians almost always recognize negative comments directed towards them, and that's okay, too. BB
 
#16
Re: Enlarged Primers Pockets--/ What is the cause?

For what it's worth... Not all primers are the same size. CCIs and Remington seem to be larger (tighter) and Winchester seems to be smaller.

Using larger primers is no substitute for backing off a too hot load however.
 
#17
Re: Enlarged Primers Pockets--/ What is the cause?

I thank all of you for your sincere posts in trying to help me figure it out.

All loads are well below the MAX powder charge with Varget my main choice. I also use H4895-IMR 4064 and IMR XBR 8208.

I inspect each case after firing for any signs of over pressure. And I have found no evidence of over pressure.

I then resize and deprime them and put them in the polisher. Each case get another look before resizing. Never have I had a case that came out of the gun without the primer intact before this.

I reprime them after polish and trim if necessary. I really can't tell if the primer is easy or hard to seat. It all feels the same to me with the press I use.

I did measure the primer pockets on the 7 cases that the primers fell out of and they were all way to big. All the other cases that I have in the same batch are just fine. It seems that I just managed to get all the bad cases together at one time in the same lot.

It appears that I will just have to measure the primer pockets as part of my case prep procedure in the future. All the bad cases were FGMM. Not one RP case was effected.

Thanks again
 
#18
Re: Enlarged Primers Pockets--/ What is the cause?

Have you changed primer brands lately? I've noticed that it seems CCI primers when used then being replaced by Winchester or Federal primers the pocket feels less snug.
 
#19
Re: Enlarged Primers Pockets--/ What is the cause?

Ditch the Federal brass in the autoloader . Federal has long been known to be overly soft , well documented in the high power community . I Had bad experiences with a long throated service rifle yacking the primers at normal load levels with Federal . Now a days , federal brass goes in the recycle tub .
 
#20
Re: Enlarged Primers Pockets--/ What is the cause?

That is the answer. My understanding is that Fed brass from FGMM are only good for one reload. I only use Win brass which I keep track of the number of reloads.
 
#21
Re: Enlarged Primers Pockets--/ What is the cause?

WTF...those are asinine comments from 67 an jlow....if you don't exceed factory pressures you'll get 6 to 10 reloads from Federal. You simply cannot get quarts out of pint pots. Overload them if you wish. You WILL get shorter life out of ANY brand of brass. Some will stand more abuse. I'll bet there are LOTS of shooters out there that would love to have your once fired Federal brass from your recycle bin. Even out of the auto-loader. Might even pay you for shipping. JMHO
 
#22
Re: Enlarged Primers Pockets--/ What is the cause?

I have loaded once fired lake city brass (all from same lot) that has loose primer pockets.
I have loaded thousands of rounds of .223 and this is the only brass I have had problems with. It seems one in fifty rounds will not hold a primer. I shoot mixed brass out of my AR and whenever I have a primer issue it is always from that lot of brass. It might just be the brass if it hasn't been reloaded multiply times. Pressure is a common cause of loose primers but, in my case, problems after one firing with the factory powder charge is likely something else.
 
#23
Re: Enlarged Primers Pockets--/ What is the cause?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: former naval person</div><div class="ubbcode-body">WTF...those are asinine comments from 67 an jlow....if you don't exceed factory pressures you'll get 6 to 10 reloads from Federal. You simply cannot get quarts out of pint pots. Overload them if you wish. You WILL get shorter life out of ANY brand of brass. Some will stand more abuse. I'll bet there are LOTS of shooters out there that would love to have your once fired Federal brass from your recycle bin. Even out of the auto-loader. Might even pay you for shipping. JMHO </div></div>

And IMHO , I wouldn't , and don't use Federal brass in my deep chamber auto loaders . My long line Badger barreled piece is chambered for 77 and 80 grain projectiles . Generous headspace may cause pressure spikes that some softer brass can not tolerate , at standard loading levels . Good read here http://www.usrifleteams.com/forums/index.php?showtopic=6071 .

Any way , If you want around 1000 pieces of Federal 223 , You or anyone can PM me . Its yours for price of postage and a 12 pack , brass goes for around a buck a pound here . I have no issues getting 4 or 5 loadings with 308 Federal brass in my normal chambered bolt guns . If I was loading for an AR10 or the like , I personally would use non Federal brass .
 
#24
Re: Enlarged Primers Pockets--/ What is the cause?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 67rschev</div><div class="ubbcode-body">
former naval person said:
WTF...those are asinine comments from 67 an jlow....if you don't exceed factory pressures you'll get 6 to 10 reloads from Federal. You simply cannot get quarts out of pint pots. Overload them if you wish. You WILL get shorter life out of ANY brand of brass. Some will stand more abuse. I'll bet there are LOTS of shooters out there that would love to have your once fired Federal brass from your recycle bin. Even out of the auto-loader. Might even pay you for shipping. JMHO </div></div>

And IMHO , I wouldn't , and don't use Federal brass in my deep chamber auto loaders . My long line Badger barreled piece is chambered for 77 and 80 grain projectiles . Generous headspace may cause pressure spikes that some softer brass can not tolerate , at standard loading levels . Good read here http://www.usrifleteams.com/forums/index.php?showtopic=6071 ."

Exactly. This is the message I got from my FC brass experience as well, although it only happened with one batch of FC brass years ago. FC primers are bigger than the CCI's I replace them with from the get-go. If FC primers are larger in dia than what I'm replacing them with, wouldn't it stand to reason that the primer pocket is already a bit oversize? I weeded out all the FC cases during my LIGHT-LOADED primer losing experience and the problem went away. And any loose primer pockets are caught during the priming operation when I feel one with little/no resistance. Over-gassed autoloaders tend to show pressure signs long before a bolt gun would too.
Click to expand...
 
#26
Re: Enlarged Primers Pockets--/ What is the cause?

Where are you getting your brass?

Reason I ask...I've now had 2/5 internet deals for "once fired" brass that absolutely wasn't. I just bought up a bunch of Grendel brass recently, and only 50% of the "PPU" passes my inspection. Granted its Privi, but my once fired PPU cases from a couple boxes of Wolf Gold are still tight after two reloads.

Other deal was for once fired police range pickup brass, again "once fired," that has the headstamps shot off most cases.

Be careful buying "ONCE FIRED" off the boards.
 
#27
Re: Enlarged Primers Pockets--/ What is the cause?

"All the bad cases were FGMM. Not one RP case was effected."

"Bad" applied to FGM cases is a relitive term, relitive to what you want from them. Yes, Federal cases are slightly softer than others, it's no secret and Fed knows it quite well so we don't need to let them know. FGM cases are plenty strong but they don't withstand repeated high pressure reloads as well as others. But, <span style="text-decoration: underline">because they ARE softer</span>, <span style="font-style: italic">they will last much longer if we reduce the pressures a tad</span>. Thus, making the proper choice of cases rests on what we seek from them.

 
#29
Re: Enlarged Primers Pockets--/ What is the cause?

I can't offer proof, scientifically, but my theory is that hot loads affect the base area of the cartridge in the same way that annealing the entire case would do.

*Read cautions in annealing threads concerning the proper location to apply heat; and where NOT to apply it.

In other words, you will wind up with primer pockets that have lost all temper and will not hold a primer with sufficient tension. Go a bit further and they will fall out or back out on recoil.

I am not on board concerning "soft" FC brass. Keep your handloads in the same ballpark as factory ammunition and I don't think you will have reason to complain. just my opinion. BB
 
#30
Re: Enlarged Primers Pockets--/ What is the cause?

So all of my Federal Match 1-fired (out of bolt gun) that I bought from a guy I should load up and shoot out of my bolt gun? I was planning on shooting it out of my GAP10.

Primers go into this brass smooth, unlike some other brass, where it feels like I'm jamming the primers in.
 
#31
Re: Enlarged Primers Pockets--/ What is the cause?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">I can't offer proof, scientifically, but my theory is that hot loads affect the base area of the cartridge in the same way that annealing the entire case would do.

*Read cautions in annealing threads concerning the proper location to apply heat; and where NOT to apply it.

In other words, you will wind up with primer pockets that have lost all temper and will not hold a primer with sufficient tension. Go a bit further and they will fall out or back out on recoil.

</div></div>

Brass is hardened by work and softened by heat......

If you ponder the physics of what is taking place you'll realize your theory is not right. It takes temperature <span style="font-style: italic">and</span> time to anneal brass. The blast of a powder charge might be hot enough for the instant it's present but it certainly isn't long enough to anneal anything. If your theory were right, and since the entire piece of brass, is, well, brass, the entire case would anneal itself with every shot thus nullifying any reason for this reloading forum.

Deforming primer pockets due to a hot load is a function of the pressures and forces placed directly rearward on the weakest part of a case head, the center where there is thinner metal and a hole. The key word there is deformed, actual physical deformation that can be measured.
 
#32
Re: Enlarged Primers Pockets--/ What is the cause?

Then, it's a good thing I didn't attempt to offer "proof". That's a the problem with analogies, they sometimes make no sense whatever. Not least of which, the annealing process is a black art, if I could think of a good analogy?

In any case, a loose primer is a function of dimension and not tension. BB
 
#34
Re: Enlarged Primers Pockets--/ What is the cause?

Not at all, Sir. It is I who can't seem to assemble words into intelligent sentences and must/bravely accept responsibility. I will be more careful, aware the caliber of lurkers around these parts. BB
smile.gif
 
#37
Re: Enlarged Primers Pockets--/ What is the cause?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kwak</div><div class="ubbcode-body">I thank all of you for your sincere posts in trying to help me figure it out.

All loads are well below the MAX powder charge with Varget my main choice. I also use H4895-IMR 4064 and IMR XBR 8208.

I inspect each case after firing for any signs of over pressure. And I have found no evidence of over pressure.

I then resize and deprime them and put them in the polisher. Each case get another look before resizing. Never have I had a case that came out of the gun without the primer intact before this.

I reprime them after polish and trim if necessary. I really can't tell if the primer is easy or hard to seat. It all feels the same to me with the press I use.

I did measure the primer pockets on the 7 cases that the primers fell out of and they were all way to big. All the other cases that I have in the same batch are just fine. It seems that I just managed to get all the bad cases together at one time in the same lot.

It appears that I will just have to measure the primer pockets as part of my case prep procedure in the future. All the bad cases were FGMM. Not one RP case was effected.

Thanks again
</div></div>

I bought a case of new, FGGM ammo, and most of it was run through my Remington bolt gun. When I went to reload it, I had the same issues.

I'm not using Federal brass anymore!!
 
#39
Re: Enlarged Primers Pockets--/ What is the cause?

As far as I'm concerned, the enlarged primer pockets are "urban legend" because I have never experienced them in over 40 years of handloading. Just a few pictures in magazines, maybe on the Internet, but not something jacked out of a gun I own.

Of course, I take reasonable care in my load development and am fairly anal about the accuracy of my finished product. If I ever had one of these "enlarged" primer pockets, I guarantee, it would only be ONE, not seven!

Blaming this stuff on Federal brass is stupidity. I bet none of it happens with factory ammo, just their carefully assembled reloads, right? Dream on MF! BB

PS Yeah, try Lapua
 
#40
Re: Enlarged Primers Pockets--/ What is the cause?

Hey Buzz , just because you've never experienced them , doesn't mean they are not out there . Heres a couple examples of high quality Federal brass , both on the left crapped the primer on first reload with a mild load , screwed up my 200 yard timed string . 24 grains Varget , rem 7 1/2 , 75 grain Hornady HPBT . Notice how centered the flash holes are . Dats some high quality brass for sure . Still no takers on the free Federal brass i offered .

 
#41
Re: Enlarged Primers Pockets--/ What is the cause?

After reading through the posts, I noticed the mention of Remington and FGMM brass. Might keep in mind the case capacity varies between manufacturers. A safe load in Remington brass may not be in FGMM. Case in point, a load in Winchester brass for my .243 AI is not safe with Nosler brass.
 
#42
Re: Enlarged Primers Pockets--/ What is the cause?

67-for your consideration. Yes, I can believe that it is possible to fire loads so hot that they enlarge primer pockets. My point is, (pause for effect) that you cannot show me a factory Federal case with blown primers, much less enlarged primer pockets.

In my world, that means your handloading is suspect. BB
 
#43
Re: Enlarged Primers Pockets--/ What is the cause?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gau17</div><div class="ubbcode-body">You should always be able to feel how your primers are seating. No matter which method you use or caliber you load for. </div></div>

Beginning to wonder if anyone was gonna point this out. ^^^

I've put a lot of reloaded FGMM brass threw my AR10T with 44.6 gr Varget pushing 178 Amax's with no primer pocket issues but I pitch them after 3 reloadings because at 5 I start getting a few very hard to see tiny cracks. To the OP though, the first thing I would do is get a system I could "feel" the primer seat with.

okie
 
#44
Re: Enlarged Primers Pockets--/ What is the cause?

Yes, that is obvious. One of the first things you do in case prep and you really have to wonder how somebody can miss it? Maybe they shouldn't be handloading if stuff like this doesn't register? Yeah, it's safe and all that, but there are things you have to be aware of, this is not something you can do while drunk or preoccupied with other things. And, here we are, more worried than he is; he checks in once and comes up with a solution:

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kwak</div><div class="ubbcode-body">

It appears that I will just have to measure the primer pockets as part of my case prep procedure in the future. All the bad cases were FGMM. Not one RP case was effected.


</div></div>

I never heard of anybody measuring primer pockets prior to seating new primers, as a precaution! Somebody ain't getting it. BB
 
#46
Re: Enlarged Primers Pockets--/ What is the cause?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: okiefired</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gau17</div><div class="ubbcode-body">You should always be able to feel how your primers are seating. No matter which method you use or caliber you load for. </div></div>

Beginning to wonder if anyone was gonna point this out. ^^^


</div></div>

Actually, it was........
 
#47
Re: Enlarged Primers Pockets--/ What is the cause?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: okiefired</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gau17</div><div class="ubbcode-body">You should always be able to feel how your primers are seating. No matter which method you use or caliber you load for. </div></div>

Beginning to wonder if anyone was gonna point this out. ^^^


</div></div>

Actually, it was........ </div></div>

Yeah, but you went off on other tangents....made you easy to overlook.
smile.gif


okie
 
#49
Re: Enlarged Primers Pockets--/ What is the cause?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">Now was that really called for?

Sorry my "tangents", as you put it, went WAY over your head........ </div></div>

Ah, that was a joke brother....thus the little smiley thing at the end of my post. But you take as you will...and I promise you nothing you say is gonna go over my head.

okie
 
#50
Re: Enlarged Primers Pockets--/ What is the cause?

OK; we simplify.

When cartidges fire, enough pressure is generated to stretch all portions of the case outward. The chamber also expands some, then the pressure diminishes and everything shrinks back down to roughly the original dimensions. Not quite, and this difference results in primer pocket growth.

How big things get and how much pocket growth occurs is a direct consequence of peak pressures, but some growth is always present. Primer pockets are always growing with each firing, but how fast this growth occurs is a matter of pressure management. Too much pressure results in too much growth, too soon.

Some brands of brass have a rep for softness; Fed first, then Rem. I use Win and find it's a good compromise between quality and cost; and that's all I expect I'll ever really find with this..., a good compromise.

The ultimate conclusions about primer pocket growth and hotter loads are fairly straightforward and obvious.

Greg
 
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