MR2000 and carbon rings

[BlackGrouper]

Would changing the seating depth on the currrent load do the same?

Might help but at mag length probably not much. What twist are the barrels?

 

[jelenko]

Three of them were 7.5; one 8.
With the throat eroded by 85 thousandths, I think we've found the problem.
I'm now thinking that all four had more rapid fire rounds that I had thought.

 

[jelenko]

Just wanted to say Thank You for everyone who responded.
BTW; here's a barrel life calculator that includes time between shots.
While about 1/2 of my shots are rapid fire with two strings of 5 shots each fired within ~ 20 seconds [the other 20 seconds is used to establish NPA and a mag change].
For the load I'm using, it estimates barrel life of 621 rounds if all were rapid fire.

 

[pdhntr]

Three of them were 7.5; one 8.
With the throat eroded by 85 thousandths, I think we've found the problem.
I'm now thinking that all four had more rapid fire rounds that I had thought.

For what it's worth, after many years of using 22-250s and 223s on pds, I have found the 223s don't last as long as most expect when shot hard.

My 22-250s I am cutting and rechambering at about 2000 rounds as they will start to lose accuracy. Make of barrel has not made a distinct difference.

Jim

 

[243Mendoza]

...My AR port was heavily eroded at the port and rifle lost a lot of accuracy. It was shaving off jacket material....

How can you tell if the eroded port is shaving the jacket off the bullet? Do you recover the bullets for examination?

 

[SeabeeKen]

How can you tell if the eroded port is shaving the jacket off the bullet? Do you recover the bullets for examination?

How else would copper jacket material get in the port? The port was heavily eroded and loaded with copper