primer piercing?

[G.T.]

Hello to all, I have recently been working on a Luger that has a unique issue... It runs perfectly on 115 gr. WW box target loads, but on 115 gr. S&B ball ammo, it works great, but it pierces the primer almost every time? It shows up readily as a black hole and cannot be missed?... Now, the barrel does/or has, had/or have, an issue with a very thin ridge for the case mouth to headspace on, (corrected with a chamber reamer) but the cartridges measure out identically? And, the chamber is correct to close on the -GO- , but not on the -NO GO- ?? Does anyone know the correct firing pin protrusion dimension?.... Back to the range tomorrow.... with some sample guns that are as of yet, without issue?... Best to all, til....lat'r.....GT

[LU1900]

It seem to be from 1,1 mm to 1,35 mm

[DonVoigt]

And be sure the nose of the striker is round, and smooth; no pitting or chips.

Some primer metal is much thinner than other brands, so in a "marginal" situation you have what you are experiencing.

Remind me to send you one of the gages I made.

[G.T.]

Hi Don, I'd love one! Thanks for thinking of me, ol'buddy! ... BTW, GTFS .275 will be here on next Monday.... looking forward to the same quality, slightly different profile.... .300" next.... best to all, til....lat'r....GT....

[rhuff]

GT,

Have you compared the overall length of the firing pin to one that does not cause primer piercing?? Just a thought. As I recall, the S&B primers are not considered "soft" like the Federal primers.

[G.T.]

Hi Doc, I've measure a few spares, and trimmed about .010" off the offending unit, and it looks correct, we will see how it does at the range... On the barreled receiver that first exhibited the problem with S&B, I believe, suffered from the same situation as your shooter that we re-chambered and set back?.. did that pop holes in the primer or just fail to fire at all?...
I was able to restore some of the lip for the case mouth to stop against, but not sure if it's enough for all commercial cartridges concerned... I will let you know after the next range test with the now shorter FP protrusion?... til...lat'r.....GT....

[Rick W.]

G.T.,

I would suspect around 45-55 would be ok. A friend from Europe gave me a real mckoy Luger firing pin gage, but as usual, never used it; always just measured for the above numbers.

I would expect the white box to be a bit milder than most.

Headspace comes to mind of course, but I am sure you check those things. Some of todays brass is on the short side.

The other odd thing might be the firing pin to breechblock hole fit, does the whitebox show primer flow beginnings? I sure see a lot of primer flow and perfs in cases on the ground at the local range.

OTS ammo can be at fault at times, but have to admit, most are pretty good with their QC/QA.

The new sights sound great, heck of a lot easier for most than fabricating your own.

regards as usual.

[G.T.]

Hi Rick! Always good to hear from you! I will be going to the range probably tomorrow, and will scan the brass more closely this time.. I thought the problem would be obvious, but as I've never used anything but WW target, the problem may be more pronounced then I originally thought...
The head space is within tolerances with the gauges.. and the brass is close in relation to the chamber and the other ammo type.. But, the S&B may be jjjuuussssttt slipping past the stop ridge/rim in the chamber?... It was practically non-existent, and I gave it a few turns with a finishing reamer, now at least, it is visible and seems to stop the cartridge at the proper depth?...I will report back tomorrow with some definite "happens" or " doesn't happen?" again, it is good to see your post Rick, best to you, and to your as well, til...lat'r...GT

[DonVoigt]

Measure the diameter of the various rounds at the case mouth, crimp or lack of may be causing the difference.

I suspect the headspace gages are sharper and maybe larger in diameter at the case mouth than the brass cartridges.

Try a few rounds of Wolf Steel case, they seem to have a larger and sharper case mouth.

[mrerick]

A 9mm cartridge should headspace on the case mouth. If there is enough taper crimp for a round to push through the chamber ridge that stops the cartridge and establishes headspace, the cartridge is defective.

A secondary cause might relate to the length of the entire toggle train and any play caused by wear at any of the axle pins, and where the breech face has been positioned relative to the head of the cartridge. You might also look at the fitting and condition of the extractor.

[Mac Cat]

only time that ever happened to me, it was from reloads (thin primers)

[rhuff]

Originally Posted by G.T.

On the barreled receiver that first exhibited the problem with S&B, I believe, suffered from the same situation as your shooter that we re-chambered and set back?.. did that pop holes in the primer or just fail to fire at all?...
... til...lat'r.....GT....

My barreled receiver that you "rescued" would fail to fire with all factory ammo except the PMC brand. The PMC brass is a bit thicker, and it would still headspace on that mangled chamber ridge that the "bubba gunsmith" produced. Never any pierced primers with it, but large firing pin depressions.

[G.T.]

Went to the range, and even though the firing pin was .010" shorter, and is as short or shorter than any of my other Lugers, it still pierced the primer on the barrel I'm trying to save?.. I put the same ammo thru a known excellent working Luger and it DID NOT pierce the primers?... Soooo, the brass case mouth it going in past the chamber front edge, and then setting back over the pin upon firing?... Das barrel is kaput, me thinks?........ more as I learn it!.... Best to all, and thanks Doc for your replies! Always good to hear from you.... til....lat'r.....GT.....

[DonVoigt]

Originally Posted by mrerick

A 9mm cartridge should headspace on the case mouth. If there is enough taper crimp for a round to push through the chamber ridge that stops the cartridge and establishes headspace, the cartridge is defective.

A secondary cause might relate to the length of the entire toggle train and any play caused by wear at any of the axle pins, and where the breech face has been positioned relative to the head of the cartridge. You might also look at the fitting and condition of the extractor.

Marc,
if you read all of GT post, you will see that he is trying to "save" a worn out barrel with almost no chamber left. So in this case it is the barrel not the ammo that is the problem. There is a measurable crimp variation from brand to brand and lot to lot on ammo.

The fact that he has checked the chamber with gages shows that the "stopping" ring at the front is just large enough to catch the sharp edge of the gage, but not the "soft, and tapered edge of some brass.

The extractor does not even enter the equation, it not intended to "hold" the cartridge against the breech face.

GT's problem is clear, least to me it is, JMHO.

[Rick W.]

G.T.

Win some, lose some; comes to mind.

Guess there is a limit to everything; safety has to come first.

I had a little longer posting for a minute or two, then thought better of it. Curiosity and knowledge can go hand in hand, but not in all environments.

Things can get complicated on this forum at times.

I admire your attempts/talents in restorations.

[G.T.]

Thanks for the note and input... I value both ... As for the barrel, I believe you are correct, and it's time to stop CPR... I may still try to set it back, but it is so thin in the flange, even this may be throwing away time better spent... But, I did learn quite a bit on this go around, although I'm not quite sure that I yet understand all I've learned???? .... Oh well, I hope the forum found the journey interesting?.... On the good side, I got to go to the range three times in a row! That's fun all by itself... best to all, til...lat'r....GT....

[John Sabato]

Here is an idea... I have never tried it but I don't know why it would not work. How about sleeving the barrel, or better yet if the rifling is okay, cutting and reaming the chamber wide and sleeving only the chamber? Just machine and then silver solder a newly made chamber liner into place...

Sort of like putting a new sleeve into an engine block...

Whatdoyouthink?

[G.T.]

Hi John! Good to hear from you! All good ideas to try, but with nice new barrels still costing around $100.00, it's probably best to spend the time elsewhere? ... Then, you also have a liability issue to consider as well, if it fails for ANY reason, the blame always go back to the modifier, as in, you become the factory! But, the input is sound and appreciated, it does seem such a waste... BUT...
I installed a new "MADE IN GERMANY" 4" 9mm barrel, and it is snug on closing to the -GO- gage, and it range tested perfectly?...
All the piercing issues disappeared... Everyone is happy now.... Best to all, til....lat'r....GT....