RFI - SSA 77gr OTM ruptured cases

Never dealt with this before so looking for some insight.  I recently built an SPR-ish upper to try my hand as long(er) range shooting.  Most components are BCM with a Lothar Walther LW50 18" midlength barrel.  I purchased a couple different loads in the 70gr range to see which ones it liked best.  One of the loads I purchased was the SSA 77gr OTM (from Sportsman's Guide).  I shot a five shot group with it and went down to check my target.  When I came back I policed up my brass and found that 4 of the 5 rounds I had fired resulted in split cases.  I didn't feel or realize anything odd when I fired the rounds.  Groups were not out of the ordinary for my abilities (ie shitty as usual) and the brass all ejected in a pattern similar with everything else I've fired through this.

So, what do you guys think?  Knowing Sportsman's Guide I checked the box and didn't see anything about them being factory seconds.  Do I contact SSA and ask for help?  Did I get a bad batch or is something screwed up with my gun?  Never had a problem with mil-surp 55gr, the Federal 77gr or the Hornady (forget which load was but the heavier stuff) that I also fired that day.  Needless to say I haven't fired any more of the SSA because I'd like to keep all my eyes, teeth, and fingers where they are supposed to be.

Thanks in advance!

"These are the rules. Everybody fights, nobody quits. If you don't do your job I'll kill you myself."

 

Joined: 04/01/2004     Location:  Twin Cities, MN

Original Post

I should have added, the barrel has the Wylde chamber.  Also, the ruptures ran length-wise on the brass; roughly in the middle of the case body, but did not extend to either the base or shoulder.

"These are the rules. Everybody fights, nobody quits. If you don't do your job I'll kill you myself."

 

Joined: 04/01/2004     Location:  Twin Cities, MN

There's no easy Internet answer for this, but you can fairly reliably isolate it into some causes:

1. Out of spec chamber - possibly larger than spec dimension on chamber diameter.

2. Out of spec cartridge brass - 

I doubt it was an overpressure event, as that usually shows with popped primers.

Kind of what I was thinking but again, I'm new to this issue.  The chamber passed .223 go/no-go gauges and considering I saw no negative effects on the other factory rounds I fired, I'm hoping/guessing it was the brass.  Nosler Customer Service replied pretty quickly to an inquiry so we'll see what happens.  I'm hoping it was just a bad batch because the SSA price for ammo is a positive.

"These are the rules. Everybody fights, nobody quits. If you don't do your job I'll kill you myself."

 

Joined: 04/01/2004     Location:  Twin Cities, MN

As for headspace gauging, that's a nice thing to do and somewhat expected, but almost never an issue.  Plus, if you did have headspace issues, the case failures aren't going to be longitudinal failures, but case head separation type breaks.

I would try other ammo and see if something similar happens.  I'm betting that brass was out of spec (too hard).

Pics and info forwarded to Nosler.  Not expecting anything out of them and I have no real complaints.  I've shot SSA ammo for a number of years and this is the first issue (albeit minor = no damage or injury) I have experienced.  Hopefully they can help identify the issue and save others from problems down the road.  I did shoot other ammo that same day with no problems to include some Federal 77gr, Winchester 64gr(?), and Lake City 55gr milsurp.  Hoping it was just bad brass...

"These are the rules. Everybody fights, nobody quits. If you don't do your job I'll kill you myself."

 

Joined: 04/01/2004     Location:  Twin Cities, MN

I cannot help with your brass issues, but figured I would pitch Lapua ;-) - I just bought a LaRue Builder's kit to do precisely the same thing you're working on (because I'm waiting for the PredatOBR in 6.5 CM...maybe for a long, long time...and, frankly, it would be nice to not suck before shelling out for that kind of hardware).   My super scientific testing occurred at 105 yards, with an Aimpoint PRO, off a shooting bag - the Lapua 69 grain stuff shot waaaaay tighter than the 77 gr OTM I tried, or the various other "plinker" grade projos I had on hand.  If 5.56 is anything like virtually every other rifle caliber, Lapua brass is where it's at anyway!

________________________

Daggers Forward - Daggers In!

Essayons et Faisons

Add Reply

Likes (0)
Copyright Lightfighter Tactical Forum 2002-2016
×
×
×
×
×