Remington 7600

[sobo4303]

Anyone else have this quirky situation?

Purchase a 7600 (new) in 243. Worked it a bit as the magazine needed to be "broke in" as it would sometimes jam on second or fourth round. Works flawlessly now.

On just about all of my (1st reload) casings there is a stretch/shiny mark about a 1/4" from the head of the casing. Not hot loads by any means either. Four of the casings actually split at that point. The split casings were not jammed in the chamber and simply fell out when the rifle was elevated. Tried new factory, same thing...a shiny "stretch mark".

I thought it was a headspace issue so I tried to use headspace gauge, but with extractor intact it was useless. Took to a gunsmith and he took apart but indicated that those bolts are a little different, and he thought it gauged ok. I know that the bolt would not close on the field gauge, but would close on no-go.

Anybody else have this issue?

Aside from the casings, the rifle shoots very well and I quite like it's accuracy and very fast action, just a little confused as to the bizarre casing behavior.

 

[warrenb]

I noticed it in the first gun I reloaded for. A 7600 308. No splits but a definite demarcation line about 1/4 inch up from the base of the case. The brass had stretched thats all. I actually had the head space checked and it was fine. When resizing, I just size a little more than bumping the shoulder but don't full size. I see very little stretch on further firing. Just make sure the rounds feed.
I have a 7600 in 243 and I can see a mark on the brass too but I really have to look harder. I can usually see a mark on brass from my bolts also. I'd post a pic of what I'm talking about but photo bucket is painfully slow tonight.

I would investigate case splits on first firing further however, but if head space has been checked then ......

 

[sobo4303]

Thanks

I full size resize. I have an M14 which I leave about .005". Is this the sort of thing that worked for you as well?

With the M14, it was a definite headspace issue. One would not expect that with a brand new Remington.

 

[warrenb]

I presume you mean 5 thousands gap between the shellholder and the base of the die? Shell holders and dies vary. You will need to experiment with how much you need to push the shoulder back to achieve good feeding/chambering.

 

[tiriaq]

If you are getting case separations like that, an excessive headspace condition exists with that rifle and those reloads.
You can compensate by resizing appropriately.
Incidentally, might be an idea to turf the cases from that lot. If some separated, more are likely to.