Thread: Short barrel 6.5prc vs .270win

Some rough MAXIMUM numbers from GRT both in a 17" barrel, and using 2209 for a full burn:
270win 145gr eldx ~4gr more powder ~2740fps.
6.5 PRC 143gr eldx ~2700fps

The equivalent 308 load would use 2208:
308win 200gr eldx ~2300fps

Originally Posted by Magnetite

Some rough MAXIMUM numbers from GRT both in a 17" barrel, and using 2209 for a full burn:
270win 145gr eldx ~4gr more powder ~2740fps.
6.5 PRC 143gr eldx ~2700fps

The equivalent 308 load would use 2208:
308win 200gr eldx ~2300fps

Using faster powders just to get a 100% burn means sacrificing speed. Switch the PRC to 63gr of 2225 and GRT says you get 2775fps (and still a 99% burn, because reaching full chamber pressure burns more powder than an extra few inches of barrel).

Also stick to a 165gr in the 308 and it'll tell you that you can reach 2600 with 43.5gr of 2206. Or 2700 with a 150gr and 44.5gr.

Originally Posted by Pommy

Using faster powders just to get a 100% burn means sacrificing speed. Switch the PRC to 63gr of 2225 and GRT says you get 2775fps (and still a 99% burn, because reaching full chamber pressure burns more powder than an extra few inches of barrel).

Also stick to a 165gr in the 308 and it'll tell you that you can reach 2600 with 43.5gr of 2206. Or 2700 with a 150gr and 44.5gr.

I ignored 2225 because it's a compressed load. And went with 200gr for the 308 because it's a scaled up 270 145gr:
145x(308/277)^3 = 199gr

2225 in a long throated 270 would be a hoot though.