I have two cases that blew at the rim, I had loaded them a couple of years ago for my FAL. 43.5 Varget, 168 fmjbt. once fired LC brass, Win primer. Have shot them when I first loaded them no problem. The first one blew in my R25. I took some of them down and everything looked good. I shot some in my FAL blew another one. tore 10 more down everything looks fine. I checked head space and went over the brass from top to bottom. I guess some of the brass is bad even if it looks good. No pressure signs except the blown rim, primer looks good not flat. Could it be slam fireing? I am not going to shoot anymore of them, It has got me scared.
Blew a couple of cases
- Thread starter Tnwhip
- Start date
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We're talking case head seperation here right? Can you post a couple pics?
I think you are using too much powder and I'd recommend starting over with your load. The photos show the brass you are using is NATO brass. NATO brass is great, and I've got thousands of rounds the stuff. NATO brass has a smaller internal case capacity compared to commercial .308 brass since it has thicker walls than commercial brass and has to hold up in belt-fed machine guns.
I always start 2 grains under the recommended starting point for any powder and work up. Looking at the Hodgdon website, 45.0g is the maximum recommend load. Since you are using 43.5, I'm thinking that you've exceeded the pressure ceiling for the brass/powder combo you've chosen. Also, take a look at your seating depth, since bullets seated deeper into the case will increase chamber pressure.
I've found a load at 42.5g Varget for my R700 AAC-SD. I won't try anything higher.
I always start 2 grains under the recommended starting point for any powder and work up. Looking at the Hodgdon website, 45.0g is the maximum recommend load. Since you are using 43.5, I'm thinking that you've exceeded the pressure ceiling for the brass/powder combo you've chosen. Also, take a look at your seating depth, since bullets seated deeper into the case will increase chamber pressure.
I've found a load at 42.5g Varget for my R700 AAC-SD. I won't try anything higher.
wnc-coyote
Well-Known Member
I doubt your load is the problem. I have seen this happen a few other times. Most likely what is happening is the bullet and brass have been together so long they have formed a bond between each other. This will act like a super heavy crimp which takes a lot of pressure to release the bond between them. In other cases like yours I have simply seated the bullet a little deeper which will break the bond and allow you to shoot them safely.
Like I said there is no pressure signs on any of the brass. It sure has got me jumpy. I messed up two mags. If I do anything I want install a mag. I sure don't want to mess the bolts either. They are in the canneture now I will pull the bullets up some. I can go another 20 or .030 and still fit in the mag. 43.5g is two grains under but I may drop back to 42.5 on the load and see what it does also. I have only shot factory ammo in the R25 but I have shot this load a bunch in the FAL.
I think dropping down is a wise idea. 7.62 NATO brass has a different (smaller) internal capacity than commercial .308 brass, so the maximum charge for NATO brass is going to be different (less) than commercial brass. You could have big problems using the maximum commercial powder load in NATO brass.
Better safe than sorry.
Better safe than sorry.
Laelkhunter
Well-Known Member
Agree with reducing the powder charge. Rule of thumb is reduce by 10%, which would be a 4.0 grain reduction.
Also, the FAL (military type weapon) might not have as close tolerances as the R25 so loads in the FAL might not create as much pressure as those fired in the R25.
Also, the FAL (military type weapon) might not have as close tolerances as the R25 so loads in the FAL might not create as much pressure as those fired in the R25.
