25 PRC

133 bergers, BR2 primers, lapua brass, 59.5g H1000 and a col of 2.950 got right around 3155 MV in the barrel I chambered. It was pushed up to 60.5 by the guy who owns it. This is what worked in this barrel. Start lower and work up. 56g of H1000 ran 2901 MV. I started there.
 
133 bergers, BR2 primers, lapua brass, 59.5g H1000 and a col of 2.950 got right around 3155 MV in the barrel I chambered. It was pushed up to 60.5 by the guy who owns it. This is what worked in this barrel. Start lower and work up. 56g of H1000 ran 2901 MV. I started there.
Awesome, thanks! I got bitten by the 25 bug now!!
 
There are also reamers out there I've seen for a .25-300 RUM, Kirby Allen has his 257 Allen and 25 stalker cases.

But that I suspect is too much for what I wanna do, which isn't to launch the ultra heavy high bc bullets so much as just have a .257 wby on steroids for the fun of it, see how dang fast you could make a 75-115 grain bullet go. I've been consulting with people on here and elsewhere who have done these kinds of ridiculous overbore builds and they've all affirmed that if I'm not slinging the ABSOLUTE heaviest bullets possible there's really no more speed to be wrung out of the rum case, but the stw or 300 weatherby case does meaningfully outrun the .257 wby, especially out of long barrels.
 
That's the only thing keeping me from doing one is the brass, I'm save all my brass for my 2 7 stws. And I have a 257 Blackbird already so I was kinda thinking maybe a 25 souper.
I'm most strongly leaning towards 25-300 weatherby at this point. Peterson makes 6.5-300 weatherby brass. Very straightforward. And shouldn't it work to just use one of those reamers with interchangeable pilots - put a 25 cal pilot on a 6.5-300 reamer?

I've never done this before, all factory rifles so far, excited to do this in a few years probably but also need to learn as much as I can.
 

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