Q I recently purchased a Winchester Model 70 in .300 Winchester Magnum with the intention of having it rechambered for a case with a longer neck.
I looked at the .300 PRC but will it work? Is there another cartridge that I can rechamber for that has a longer neck and will give higher velocities?
Brian Pearce
A: You are right when you suspect that the .300 PRC wouldn’t work. Being shorter, it would alter the location of the shoulder in the chamber unless the barrel was set back and this brings problems with the stock.
To obtain a longer neck and higher velocities your best bet may be the .300 Weatherby Magnum. It has a bit more capacity than the .300 Win Mag and you’d also gain a 1.4mm (.057”) longer neck and maybe 100fps in velocity.
The .300 Weatherby is a splendid round in my experience.
Just a suggestion, what about 300RUM? This cartridge uses the same boltface, and can be easily loaded back to 300WM velocity when required but will blitz the 300 Weatherby for velocity with just standard loads. Cases are easier to obtain and cheaper too.