boogie
09-21-2013, 11:52 AM
Just bought a M12 F/TR chambered in .223 rem. I was measuring the chamber using a Hornady gauge and a 80gr SMK bullet. The number I got was 2.347" COAL and a BTO of 1.845. This puts that 80 grain bullet deep into the case. When I do it the "Old School" way and use a dummy rnd seating the bullet deeper until the bolt falls closed with no resistance I get a BTO of 1.990". Someone on another forum suggested that what I might be feeling with the Hornady gauge is a tight freebore and just think I'm hitting the lands. This is not my first time measuring a rifles chamber but considering the difference in lengths I'm getting it's a possibility.
Using the Hornady gauge again I pushed the bullet until it stopped and I knew for sure it was jammed into the lands. Then using a rod on the muzzle end moved the bullet back and forth until I felt it was just touching the lands. My average length this time was BTO 1.900
So, for anyone shooting this rifle, what's your COAL and BTO with 80gr SMKs? Are you jamming or jumping? If your using Varget or Pro2000MR how much and what velocities are you getting? Any help or suggestions would be greatly appreciated.
Thanks
Jay
Using the Hornady gauge again I pushed the bullet until it stopped and I knew for sure it was jammed into the lands. Then using a rod on the muzzle end moved the bullet back and forth until I felt it was just touching the lands. My average length this time was BTO 1.900
So, for anyone shooting this rifle, what's your COAL and BTO with 80gr SMKs? Are you jamming or jumping? If your using Varget or Pro2000MR how much and what velocities are you getting? Any help or suggestions would be greatly appreciated.
Thanks
Jay