Recently we have had more issues of Prvi Partizan SS109 62gr. ammo blowing primers while shooting. Some of them are staying lodged in the chamber area and some are blowing into the lower receiver. I have even found anvils lodged into the upper receiver. The weapons in question were Bushamster M4geries.
I am looking to hear more feedback from other users that have had this problem especially from those in Iraq who may be using it. Thanks.
Could be an ammo problem or chamber problem. Many times taking the Ned Christiansen 5.56mm NATO neck and throat reamer to the chamber on an AR cures the rifles of this problem.
Even though the rifle companies say their barrels are chambered in 5.56mm sometimes they are but are on the bottom edge of the spec.
That is possible. Unfortunately, I cannot do this in Iraq to over 500 carbines and we are not experiencing the problem with M855 or the older 55gr. ball. My feeling is the ammo and I remember another company having the problem with the same ammo in 2005.
When Priv’s M193 first came out, it was doo doo!
Maybe they’ll have to work the bugs out of their SS109 too.
Based on the lot numbers most of what we have was made in 2006 and some in 2004. If anyone else has any insight into this please let me know.
Hmm, I think we have all 07 production, but I will see if I can pull some lot numbers tonight.
TR
Damn, beat me to it. My money says that the chambers are not true 556 NATO.
C4
2004 was the shit M193 year. I don’t know about 06, but 07 M193 runs good in all of my guns.
I’ve tried some SS109 and it was junk. I could feel the difference in the recoil, some were very light.
Also, don’t discount out of spec brass. I had a buddy with 99 Lot Adcom. I had 98 lots and it worked great. I also had “blown” primers. Just for grins I measured the primer pocket size on the 99 lot stuff and it was .177, all my other stuff was .174.
Anyone else measure it?
Max primer pocket size should be .1745 according to the specs I have. Take a case that has lost its primer and you might find the pocket blown out to as much as .180. The pocket is usually elongated to that dimension, that is, not perfectly round.
Not sure what the industry spec is but primers generally measure no larger than .1755… no wonder they fall out.
If that were the case, then the Milspec 5.56 that we have M193/ M855 would do the same thing and it doesn’t. As a matter of fact these weapons have been in country since 2004 and there have never been issues like this until the switch to the PP ammo. Yesterday, I was on the range during one of the incidents where every 2-3 rds. were doing this. I then loaded a mag with (20) LC M855 rds. and no problem.
All I can tell you is what I saw when I measured with my calipers. I saw this with Adcom 99 lot ammo. It’s at least worth a 30 second check with the ammo in question.
To Ned’s comment, I did roll the case “around” the caliper to be sure I had it in the correct place, getting a good measurement and that the primer hole was round. I did it with about 5 cases they all came out the same.
I’d like to see if someone else comes up with the same result with other ammo. I think the only thing holding the primer in was the sealer. I’ve had some Adcom 99 lot stuff get mixed in with my reloading brass and the primer fell out before it got around my Dillon 550 and into the hopper.