JP Enterprises in 6.5mm Creedmoor hard on brass?

[thefitter]

My JP is beating the shit out of my brass. I've got the usual dings in the case from a gasser but I've also got these 2 weird gouges parallel on the neck like the round is catching on something chambering or extracting.

 

[bunsen27]

Do you have the JP adjustable gas block and if so have you tuned it to your specific load?

 

[The Lawn Ranger]

Close off your gas block slightly.

 

[6brshooter]

Barrel extension marks? I built a 6.5 cm upper a couple years ago using a 24" criterion from Fulton armory. When i looked at the extension i immediately thought this is going to be rough on nks &shoulders of cm brass. I used a small sanding drum and taper stones on a dremel. Basically just broke, smoothed the edges. I had the barrel off of the upper and had the chamber plugged. There was a triangle shaped abutment that was inbetween the feed ramps. On this abutment was a sharp ridge, i slightly rounded it without out touching the top/barrel extension lug. Combined with a jp gas block the fired brass looked like it came from a bolt gun.

 

[thefitter]

I apologize if this is a stupid question but how would adjusting the gas block remove the gouges? This is something obviously digging into the brass.

Thanks

 

[ORD]

I apologize if this is a stupid question but how would adjusting the gas block remove the gouges? This is something obviously digging into the brass.

Thanks

It may help...or it may not.

If the rifle is overgassed, then reducing the gas volume will help slow things down and ease up on the excessive wear/tear on your brass (to varying degrees...YMMV).

Sounds to me like its happening upon chambering like what 6br said above. Could be burrs/rough edges on the barrel extension making the marks. If so, polishing things up should help to reduce (or perhaps even eliminate) the gouges in your brass that you are experiencing.

Just remember though...gas guns are notoriously TOUGH on brass to begin with. Your brass will still get the crap beat out of it, but I think you can certainly make improvements to minimize the damage.