Signs of a loose primer pocket?

twofifty · Posted: Sun Jun 08, 2008 6:07 pm Post subject: Signs of a loose primer pocket?

I've taken to throwing away brass into which a new primer seats too easily. I use the Lee Auto-Prime unit; whenever a primer presses into place with little effort, that brass gets turfed right away.

As you know, I am new to reloading. This procedure may be too cautious, but seems like a reasonable way to prevent gasses from blowing past the primer and damaging the bolt face or worse.

How do you guys decide that a primer pocket is oversized?

shadowdrak · Rookie Member Joined: May 18, 2008 Posts: 13

New to reloading myself and this is a pretty interesting question about loose primer seating. Does use of the Lee Ram Prime work better than say the prime seater that RCBS has (does one seat the primer better than the other? Does the Lee Auto Prime II consist of the Ram Prime and the primer feeder?

twofifty

From what I've gathered from the 'net, most folk use hand-held priming devices rather than priming at the press. Definitely more convenient, some say you get a better 'feel' that way. Don't know how popular the RCBS strip-priming device is (the one that uses CCI primers loaded into plastic strips).

Speaking of feel, apparently primers give best and most consistent ignition when they are firmly seated into their pocket. Not crushed in, but a tight bottomed-out feel. This is supposed to push the primer cup into contact with the primer pocket bottom - this way the primer will not shift forward when the firing pin hits it.

As to seating depth, my primers often end up seated 3 to 5 thou deeper than what is considered 'normal'. I don't worry about that since ignition has never failed with the Win brass and WLR primers I use. It is said that for safety, the primer never be seated less than flush with the cartridge base.

Back to the subject at hand. Whatever you use to seat primers, after awhile, you'll come to know how much resistance to expect when pressing in a primer. When a new primer goes in with great ease, I take that as a sign that the pocket has stretched beyond safe tolerances.

To ensure that the felt resistance I get when using the Lee Auto-Prime is consistent, my case prep includes: using the Lee primer pocket cleaner thingy to scrape out carbon residue/ignition grit. Since I do not tumble clean brass, I also give the pockets a quick twist with 99% USP Isopropyl Alcohol on an ear swab. This leaves the pocket carbon and grit-free.

Shadowdrak, have you run into loose primer pockets? Mine seem to be occuring after the 4th or 5th firing.

Let's see what the others have to say about this.

Bushmaster

O K guys... One of the neat things about the Lee Auto Prime II is that if you have a primer that seats too easy the Auto Prime II can still seat that loose primer just a bit to spread it. I'm cheap so I hate to toss a case with a worn primer pocket and a new primer so I relegate it to range use so as not to loose that one primer then toss the case. As long as the primer will not 'bump' out it will be safe enough to use as range brass that one time. I would not take it to the field however...

All my primers are seated a few thousands below the case head. Not sure where you read that, but I was taught that they must be seated just under flush with the case head. I guess all of my primers are not seated "normal"...

Most often the reason for loose or worn primer pockets is cheap brass or loading the case to maximum levels. Most firearms shoot better and have less wear and tear on them with moderate or less powder charges. A lot shoot much more accuratly with lower then maximum powder charges.

By The Way...Not everyone uses a hand priming tool...

twofifty

Bushmaster wrote:

O K guys... One of the neat things about the Lee Auto Prime II is that if you have a primer that seats too easy the Auto Prime II can still seat that loose primer just a bit to spread it.

... I'm cheap so I hate to toss a case with a worn primer pocket and a new primer so I relegate it to range use so as not to loose that one primer then toss the case. As long as the primer will not 'bump' out it will be safe enough to use as range brass that one time. I would not take it to the field however...

All my primers are seated a few thousands below the case head. Not sure where you read that, but I was taught that they must be seated just under flush with the case head.

By The Way...Not everyone uses a hand priming tool...

I was tempted to do that, but I figured I'd end up losing track of that case, only to stumble onto it again the next time 'round after pushing a new primer into it. Primers cost a few pennies, and gaining one more firing from a case is not worth much to cheap old me.

I saw that pic of your new Lee Classic Cast with the AutoPrimeII setup. Must be nice. Did you shorten the handle stroke much on yours? Mine is shortened by a good 2.5".

The seated depth info I have is from Lyman's 48th Ed., p. 57, where it is said that "Most primers should be seated 0.003: to 0.005" below flush. If the reloader endeavors to seat primers at a nominal depth of 0.004" below flush, normal variations found in primer heights and primer pockets will generally result in seating depths within the suggested tolerance."

Some of mine end up seated .007 to .008" and yet it all works fine: no failures to fire, no pierced primers, no carbon seepage. To check for proper seating, I drag each case out of the AutoPrime's shellholder which gives me tactile info that the primer is at the very least flushed up.

Bushmaster

Loose track of the cases with loose or warn primer pockets? Don't you have a felt pen or "Sharpy" on your loading bench? Just mark the case head...

No...I left mine full stroke so I won't have to strain (I'm naturally lazy) to resize .30-06 cases...

O K...Lyman's 48th is one of the best manuals out there and reasonably priced. You had mentioned above that you concidered flush with the case head as"normal". As you have just quoted, no it's not...

twofifty

Bushmaster wrote:

Loose track of the cases with loose or warn primer pockets? Don't you have a felt pen or "Sharpy" on your loading bench? Just mark the case head...

O K...Lyman's 48th is one of the best manuals out there and reasonably priced. You had mentioned above that you concidered flush with the case head as"normal". As you have just quoted, no it's not...

Bushy, I am sorry but I do not consider that flush primers are normal, nor did I state that they are. Please re-read what I actually said in my post:

"As to seating depth, my primers often end up seated 3 to 5 thou deeper than what is considered 'normal'. I don't worry about that since ignition has never failed with the Win brass and WLR primers I use. It is said that for safety, the primer never be seated less than flush with the cartridge base."

Then I quoted Lyman's:
"Most primers should be seated 0.003" to 0.005" below flush."

Then I finished with:
" Some of mine end up seated .007 to .008" and yet it all works fine."

Bushmaster

Yup...That's how I read it..You mentioned"normal" And I took that as being flush with the case head. You can seat them deep enough that the firing pin won't reach the primer with enough force to set it off too.

Vince

I use a single stage press, not a hand primer, and usually feel two small "bumps" as I seat a primer. If I don't feel those "bumps" I check out the primer. If it is fully seated then I assume that the pocket is starting to stretch a bit. These cases get assigned to plinking duty.

A stretched primer pocket is a very rare occurrence for me as, like Bushy said, don't load to max...something I don't do because of the reduced wear and tear on the cases, and frankly I get better accuracy with the reduced load.

Cheers, Vince

SwampFox

Many folks make the mistake of using brass past its accuracy stage of life. Brass does and will fail. The hotter the load the shorter the life span of brass.

However, when brass starts to "give up the ghost" it is time to S can the entire bunch. You should be following the normal process of segregating your fired brass and keeping it together by the number of times fired. If you are not over pressure and the brass shows fatigue, enlarged pockets, no elasticity at the neck, split necks, web ring, head seperation, etc. The entire bunch should go to the scrap dealer.

Brass is cheap compared to the entire reloading process and not using good condition, fully preped brass is without excuse. You should not reload to make average ammo, you can buy average ammo at any store.

Every accuracy load is different. Some loads are only accurate at max pressure, density and velocity. Other loads are very accurate mid way of the start to max scale. Judge where you are on that scale, yourself, after awhile you will get a feel for brass lifespan.

Not saying much more than Vince or Bushy, just saying it a bit differently.
Best,
Ed

Bushmaster

Swampy is right. I,also, keep a running log on the number of times I have loaded, trimmed, powder and amount, bullet and primer...If I have 5% damaged cases in a specified group of cases (50 ea handgun and 20 ea rifle) that particular set is in the recycle can...Otherwise I replace the one or two cases with a fresh one and keep going. This has worked for me. But you must remember. I inspect all my cases at least 7 times before the bullet is mounted onto the case mouth prior to seating and an eighth time after the bullet has been seated....

Pumpkinslinger

While experimenting with some 180 grain bullets for the .357 Magnum, and using previously fired cases, I noticed that some of the primers in the batch seated a bit too easily. After I seated a bullet I had a little trouble getting one of the rounds out of the shell holder. Sure enough, the air compressed in the case had pushed the primer part way back out of the pocket! That batch of brass was thrown away. Those were nickeled cases, which seem to me to have a much shorter life than plain brass.

twofifty

Vince and Bushy, your culling procedure involves relegating brass to plinking or range duty when a particular case too easily accepts a primer.

I don't see that from a safety standpoint, there is any difference between firing a tired case while hunting as opposed to firing it while plinking or punching paper. Surely a case's residual integrity is not dependant on whether it is being fired at game or at paper. Determining the remaining strength of a case is an inexact process no matter how good one's notetaking and case marking.

Presumably then, your plinking or range cases are loaded to lower pressures than your hunting loads?

My loads run somewhere in the middle third in terms of powder grains and therefore, presumably, pressures. My next batch of brass will be neck sized with occasional partial FL sizing, as opposed to a FL regime, to minimize overworking the body & lengthen case life.

Vince

twofifty wrote:

Vince and Bushy, your culling procedure involves relegating brass to plinking or range duty when a particular case too easily accepts a primer.

I don't see that from a safety standpoint, there is any difference between firing a tired case while hunting as opposed to firing it while plinking or punching paper. Surely a case's residual integrity is not dependant on whether it is being fired at game or at paper. Determining the remaining strength of a case is an inexact process no matter how good one's notetaking and case marking.

Presumably then, your plinking or range cases are loaded to lower pressures than your hunting loads?

I can't speak for Bushy, but first up...to the question on whether or not my range loads are loaded to a lower pressure than my field loads, no, exactly the same load. After the dodgy round has been used, the case then goes into my "buggery" box. When I have sufficient scrap in there to make the trip worthwhile it all goes to the scrap metal yard.

I keep a running record of every time I load a case and whilst I don't work to a percentage loss like Bushy does, when I feel that the cases have done their best work I inspect them all and dispose of them if they have had it.

I intend buying a LEE Collet Neck Sizing die in an attempt to lengthen the life of my cases.

Cheers, Vince

PaulS

Record keeping is key to knowing your ammo and the condition it is in.
I haven't had a loose primer pocket for close to thirty years. Some of my cases have been loaded 20 times. I found out a long time ago that those "hot" loads were hard on brass, my gun and me. I would rather shoot the "X" out of the bull then have a couple of hundred more feet covered each second. Hunting and target shooting both require more accuracy than velocity. The guys who have loose primers after firing the brass 3 or 5 times are shooting loads that are too hot for their guns. If you can't get at least 10 loadings from a single brass then you need to drop the powder level.
My opinion - yours may be different and you are free to express it - just don't try to change mine. I am too old and stubborn to listen to some young'n tell me how to load ammo.