SCAR 17 6.5CM; is this chamber out of spec or just oversized?

[ARKEMAXUS]

Had my SCAR 17 762 barrel assembly cannibalized and re-barreled by Deadshot barrels in 6.5CM. Fit and finish are great, however, after getting out to the range I've noticed my spent brass has a ring around the base that's indicative of either case head separation or just a larger than normal chamber. Did this on my loads and factory.

TOP PIECE OF BRASS is after firing, the thickest section (where paper clip is pointing, yes, I did the paper clip inside the case test for case head separation) measures .476-.477 but on my 2 buddy's 6.5 brass this section measures .468-.470. MIDDLE PIECE OF BRASS was after using lots of lube and forcing it through my sizing die which took way too much force so I obviously stopped near the bottom. BOTTOM CASE is after sizing.

So what do you think; just an over sized chamber or is this chamber simply out of spec? Brass is only on first or second firing.

 

[ARKEMAXUS]

Anybody?

 

[Desert_Racer]

Can you feel that ring if you run your fingernail over it? Does it feel like it “steps up” to the case body?

If you have a barrel that is not sufficiently supporting the case head, you absolutely need to not fire another round through it and send it back. You do not want a case head separation.

 

[ut755ln]

Had my SCAR 17 762 barrel assembly cannibalized and re-barreled by Deadshot barrels in 6.5CM. Fit and finish are great, however, after getting out to the range I've noticed my spent brass has a ring around the base that's indicative of either case head separation or just a larger than normal chamber. Did this on my loads and factory.

TOP PIECE OF BRASS is after firing, the thickest section (where paper clip is pointing, yes, I did the paper clip inside the case test for case head separation) measures .476-.477 but on my 2 buddy's 6.5 brass this section measures .468-.470. MIDDLE PIECE OF BRASS was after using lots of lube and forcing it through my sizing die which took way too much force so I obviously stopped near the bottom. BOTTOM CASE is after sizing.

So what do you think; just an over sized chamber or is this chamber simply out of spec? Brass is only on first or second firing. View attachment 7898889

You should google it but Mac on the Military Arms Channel has been having all kind of trouble with his SCAR in 6.5 specifically. If I recall, the first iteration was deforming the brass and it was puncturing the primers. SCAR fixed and sent it back and his brass issue looks like yours.

 

[Desert_Racer]

You should google it but Mac on the Military Arms Channel has been having all kind of trouble with his SCAR in 6.5 specifically. If I recall, the first iteration was deforming the brass and it was puncturing the primers. SCAR fixed and sent it back and his brass issue looks like yours.

That was a factory SCAR 20. Not a SCAR 17 that has been rebarreled by Deadshot, as is the OP’s case.

 

[ut755ln]

That was a factory SCAR 20. Not a SCAR 17 that has been rebarreled by Deadshot, as is the OP’s case.

Fair point, I just remembered the SCAR in 6.5 no bueno

 

[ARKEMAXUS]

Can you feel that ring if you run your fingernail over it? Does it feel like it “steps up” to the case body?

If you have a barrel that is not sufficiently supporting the case head, you absolutely need to not fire another round through it and send it back. You do not want a case head separation.

Yes, I can feel the ring. It's obviously an out of spec chamber if it's stretching the brass 7 thousandths above the case head over what it is on all my friend's 6.5 spent brass. I've seen this before on a friend's rifle so I'm just going to send it back to Deadshot. Owner there has contacted me to return it. We'll see how it goes... Thanks for the replies.