Re: mcgowen barrels?
Plummed right, they are execellent, a builder here in town uses them exclusively, great luck.
And they are faster than normal.
I had a 30" 7mm SAUM, 180 Berger at 3180fps, no pressure. You'll be hard pressed to find published data that fast. Set it back 2&1/2', still shot 3160 for a total of 2900 rds.
I rebarreled it with a 25" Brux, barely getting 2900 out of same load.
You won't be disappointed.