Buffalo Bore popping primers.

[Dieselman]

I took my Kimber TLE 10mm out yesterday and ran a bunch of different loads through it.  Had no problems with any of my handloads or any of my Underwood factory ammo.  However, I ran five rounds of Buffalo Bore 220 gr Hard cast and popped four out of five primers. Two were completely missing and two were knocked half way out of the brass. 



After seeing this, I quit firing the BB load.    Be careful out there if you are shooting Buffalo Bore products.

[Dieselman]

Here is a follow up picture that I just took of a new large pistol primer that I set in the primer pocket of one of the cases that popped the primer. As you can see, it loosely dropped about 85% into the brass before stopping. I think I probably could have got it to go in further had I cleaned the soot and crap out of the primer pocket first.  I probably could push it in most of the rest of the way by hand if I wanted to.

[Intercooler]

  Can you pull a bullet, take a picture of the powder and charge weight? Anything odd going on in the barrel with leading? I still think when primers are totally missing that something is up with the pistol.

[Dieselman]

  Can you pull a bullet, take a picture of the powder and charge weight? Anything odd going on in the barrel with leading? I still think when primers are totally missing that something is up with the pistol.

Yep, just give a few minutes and I will have that data for you.

[Intercooler]

I'm wondering if they are using the Lovex powder in this now and might be creating an issue.

[Dieselman]

Ok, charge weight is 8.4 grains.



Powder is very very small flattened ball podwer.  Much smaller than Longshot. More the size of True Blue, but only flattened.


I have Chronographed this exact same box of ammo earlier this winter and four shots across the chrono with this same gun yielded : 1197 fps, 1195 fps, 1204 fps, 1198 fps.   At that time I was getting some severely flattened primers, but none that had blown.
As far as my barrel goes. It looks totally fine.  No lead or copper fouling. My gun has an EGW flat bottom firing pin stop and a heavier recoil spring.  I shoot some pretty hot underwood loads through this gun with no issues.   This buffalo bore load is the only one to ever give me problems. 

[The_Shadow]

I have seen some StarLine brass have loose pockets...may or may not be the issue.
Heavy charges with slower burning powders can cause the casing to be expanded tight to the chamber walls when ejection starts, primer may move as the barrel drops from lock up.

Loose primer pockets can let the primer start to push the slide and barrel out of battery.

I wonder if it is CFE or AutoComp...another could be Ramshot Silhouette but that would be pushing it at that charge weight.

[The_Shadow]

These powder shortages are really showing the commercial guys are also having to deal with other products.

[Intercooler]

   And the brass looks pretty good from what I see. Can you take a measurement up from the extractor groove? I'm starting to think what The Shadow is saying makes more sense.

[Dieselman]

Ok  I am showing a measurement of .4265

[The_Shadow]

Usually New Star Line measures 0.4215" - 0.4220" above the start of the extractor cut

[Dieselman]

Usually New Star Line measures 0.4215" - 0.4220" above the start of the extractor cut

I have never bothered to measure my brass at the base before, so I have nothing to go by. But I assume that this amount of expansion is considered normal or ok?  This Kimber has a magnificently well supported chamber.

[The_Shadow]

With the good casing support along the sides the expansion could be hammering out the casehead.  Star Line is a softer brass as made for the handloaders.

[Taterhead]

My guess is that the case head diameter has grown noticeably compared to an unfired case. That would indicate that the primer pockets are expanding, and that is an all-but-certain indication of a pressure problem -- unless the brass metallurgy is totally out of whack.

If there is a building up of lead in the barrel, then that might be the culprit. The bore diameter to bullet diameter relationship could also be in play. Tight bore, wide bullet with lots of bearing surface. I think the simplest answer is that there is too much powder in that case for the platform that you're shooting.

So what would be happening is that pressure is enlarging the primer pocket and loosening the hold on the primer. In the ejection cycle, the case is abruptly stopped and re-directed by the ejector. The momentum of the loose primer keeps it going in the rearward direction, and it separated from the case.

Last year it took me about two months to convince a friend that he was popping primers due to a pressure problem. He was blaming the brass, his rifle, even the colds air density... just above any other conspiracy that he could come up with from ad nauseam internet research. He's also fond of his cheep electronic powder dispenser and scale. I FINALLY convince him to pull down his ammo. Guess what he found... a 20% overcharge! Lessons learned were that cheap electronic scales are not trustworthy, calibration weights are not the same as check weights, and if it looks like a pressure problem then eliminate pressure as the issue first before going down the rabbit hole.

Yikes!

[Dieselman]

I'm showing an unfired 220 BB case as .420