A friend of mine donates his once fired winmag brass to me. This was hornady 2x reloaded with berger 155.5's at 3300fps. Not even really a hot load. No, there was no excessive headspace. I bump the shoulder .002" at the max.
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Op, I think you're on the right track with the 300PRC. As much as it hurts me to say that, being a diehard winmag fan. As others have mentioned, you have to put in some extra effort with the chambering and building your ammo to really make it shine. The PRC was built for it right out of the gate.
With what you're putting together, you'll probably come in around the 18-20 pound mark or more if you want to put weights on your chassis.
My winmag comes in around 17lbs now I think. I run it suppressed with a brake full time, and it's hard for me not to shoot 50 rounds every time I take it out. It's probably my favorite rifle to shoot, I just don't get a chance to stretch it's legs as often as I'd like.
Poor picture of the rifle but here it is. Trued 700 with a heavy palma contour 9 twist bartlein, jewell trigger, in a krg bravo. Loaned it to a family member for a nilgai hunt here in TX. Can't remember where. The 215 hybrid left the muzzle at 2920 and dumped him at 585 yards.
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