High Primers in Lake City 223 Cases

[GrocMax]

Sounds to me like a crimp not being 100% removed plus a slightly larger OD primer. As the base of the cup gets close to the area where the crimp is, your priming tool force makes you stop thinking its bottomed out. Try a higher force on an empty case that has a high primer, if it finally goes all the way in, deprime, redo the crimp and try again. The usual safety caveats apply here.

Swagers do need adjustment and ones that register off the web can occasionally go too shallow and not get all of it.

 

[mac86951]

Sounds to me like a crimp not being 100% removed plus a slightly larger OD primer. As the base of the cup gets close to the area where the crimp is, your priming tool force makes you stop thinking its bottomed out. Try a higher force on an empty case that has a high primer, if it finally goes all the way in, deprime, redo the crimp and try again. The usual safety caveats apply here.

Swagers do need adjustment and ones that register off the web can occasionally go too shallow and not get all of it.

Or push the crimp into the pocket; which then needs cutting out via uniformer.

 

[232]

I have went through over 30,000 (new unprimed) LC nato cases that have never had a problem. Yes I know that some think these are seconds or mil rejects, but I would like to see the stats that show the difference. I use an old Lee round primer and have no proud primers. 95% were formed to 20vt or .221 and held tolerances better than the touted brasses.

BTW I use CCI primers - 400 450 or no41 all work well.

 

[GrocMax]

To paraphrase Captain Beefheart-

"Its the crimp, the crimp!"

 

[BoydAllen]

On the fired primers standing proud of the case head....the reason for this is that your loads are too mild. If you do a little experiment where you gradually increase your powder charge, staying within the maximum in manuals, you will see that the problem disappears at some point when you have enough pressure to stretch the case back to the bolt face. Shooting the same brass over and over with light loads (rimless cases) can progressively push their shoulders back until the amount that the primers protrude becomes quite noticeable. If you load one of those cases to a top but safe load, you will immediately get an incipient separation that will show up as a bright line a short distance above the extractor groove. There will also be a groove on the inside of the case in the same area. This is not internet research, or something that I read in a book. I did an experiment years ago. In the original post, what you called cup thickness is not, and the primer pocket depth that you listed is incorrect. Measure the total thickness of the primer, and carefully remeasure the depth of the primer pocket, several times. The fellow that posted about the radius in the corners of the pockets may be right with regard to cases that you cannot seat the primers below flush in, and your primer pocket depth measurements will not pick this up. Buy a primer pocket uniformer that is not adjustable and cut your pockets with it, as deep as it will let you go. Just because bolt guns do not have slam fire issues does not mean that you should fire rounds with primers that are above flush. As far as the Black Hills ammo goes, I would contact them about having it replaced for free. Obviously they had a glitch in their quality control. That can happen to anyone.

 

[ricco1949]

Joe,
My cases do not allow the primers to seat properly, but the Black Hills ammo showed me that there is another situation that I dont know how to handle. That is the cases not growing and the primers moving rearward. How do I get a reference length from a fired case if it doesn't grow when fired?

I have ordered a primer pocket uniformer as you suggested, and that will get me started.

Thanks
Richard

Richard:
I had the same problem, cases not fire forming, with Lake City brass that had previously been sized for an AR. I was now firing the cases in a Remington 700 factory chamber . The cases would not fire form with 29.5 grains of CFE 223 and a 40 V-max with a hard jam even after annealing. I expanded all the necks up to 6.5 MM to create a false shoulder and then received perfect fire formed brass. I first tried expanding to 6MM with indifferent results.

 

[243winxb]

 

[232]

I do not think this has been brought up, but with fired casings, especially from a semi or full auto firearm, the rim/base may have a proud spot from extraction that will interfere with primer seat tolerance.

 

[Roach]

This is just a guess but you need to adjust the Dillon swagger to go farther. I believe you're pushing the pocket out/back enough. If you still have issues after swaging you should uniform the pockets.

 

[dickn52]

Lyman makes a great case prep 5 station tool, and it can actually clean a primer pocket and fix this. I use LC brass, CCI400 primers and shoot a Mod 12 Savage LRPV with fantastic success.