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Bart B. · October 23, 2013, 01:36 PM

140's leaving a 1:12 twist 7mm Rem Mag barrel at 3100 fps spin about 186,000 rpm; enough to stabilize them way down range.

I doubt that barrel's got a gain twist. While popular with black powder long barreled Kentucky rifles shooting round balls and marginally popular with 30 to 40 caliber black powder centerfire rifles of years gone by, none have been used in modern, accurate rifle barrels.

Gain twist barrels with jacketed bullets is akin to threading a 1/4-20 soft bolt into a 1/4-28 thread hard nut. The bolt threads get stripped. So do jacketed bullets going through gain twist rifling. I'm not aware of anyone who can lap a gain twist barrel to internal dimension tolerances standard rifling twists allow.

October 23, 2013, 01:36 PM	#12
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	140's leaving a 1:12 twist 7mm Rem Mag barrel at 3100 fps spin about 186,000 rpm; enough to stabilize them way down range. I doubt that barrel's got a gain twist. While popular with black powder long barreled Kentucky rifles shooting round balls and marginally popular with 30 to 40 caliber black powder centerfire rifles of years gone by, none have been used in modern, accurate rifle barrels. Gain twist barrels with jacketed bullets is akin to threading a 1/4-20 soft bolt into a 1/4-28 thread hard nut. The bolt threads get stripped. So do jacketed bullets going through gain twist rifling. I'm not aware of anyone who can lap a gain twist barrel to internal dimension tolerances standard rifling twists allow.