Got my hands on some 8mm RM brass . To make it 7STW is it as simple as lubing it and running it through a full length sizing die, or are there other steps ? Need a little advice from someone with experience . Thanks in advance.
8mm RM brass to 7STW ?
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Bghunter338
Well-Known Member
Yes, but if you have an anealer I would anneal first. But if you don't its not the end of the world.
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Thanks
agree with this ^^^^^
Dad has a split rate that's off the charts.
But doesn't anneal.!?
He's going all the way down to 25STW though.
But doesn't anneal.!?
He's going all the way down to 25STW though.
Calvin45
Well-Known Member
That's a huge difference. Like he's going from 8mm to 257 stw or from 7 to 257?
I have wondered how that much squeeze would work. I was going to try a .270 but came across a reamer for 7x68s to go a different direction.
I think he uses 7STW brass, and goes to .257
Bought him some Bertram but he hasn't used it yet.
Bertram doesn't get much love on this forum but I have several needs for Bertram products. Works for me.
Calvin45
Well-Known Member
If you don't mind my asking, what barrel length are you guys running that cartridge with and what kind of velocities are you getting?
Reason I ask is I'm thinking about doing a thing haha, a .25-300 weatherby to be specific. Which would be more or less the same thing as a .257 stw ballistically I would think. The stw shoulder is a hair further ahead, but the weatherby case is actually slightly less taper still, any difference in capacity is likely academic more than anything and just a matter of different brands I suspect. Anyways, disregard the mess on the shelf, here's 4 dummy rounds I put together just to compare the other day, a .25-06 AI, .257 weatherby, 25-300 win mag, and this .25-300 weatherby idea.
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according to my reference books, volume of weatherby 300mag = 137gr H2O ; Winchester 300mag = 116gr H2O
He maxed around 3900-3950? @ 26" with a 100gr best I recall. 28-30" would definitely be better. R25/Fed 215m
If I did anything of the sort it would be a 25 Mega.
Long is OUT. Short(er) is IN.
If I did anything of the sort it would be a 25 Mega.
Long is OUT. Short(er) is IN.
Calvin45
Well-Known Member
I think we had this talk about case geometry awhile ago haha. I happen to like curvy and tall (talking about weatherby cases here…) but to each their own
Yeah I hear you on the barrel length for such overbore rounds. I always thought the 6.5-300 and .30-378 were kind of stupid (still awesome) to cripple with 26 inch pipes.
This beast I'm wanting to try if I ever find time for it is gonna be looooong….i have an 8 twist bartlein 257 barrel in my possession already, and it's 32 inches long. Curious if the 134 eld m will survive the rpms. Also curious to see how fast I can get a 75 grain hammer hunter. A stubby little 24 inch 257 weatherby hit 4170 fps. Another 8 inches of pipe and some more case capacity won't hurt haha.
Calvin45
Well-Known Member
I'm afraid that's way out to lunch, not even the 30-378 weatherby has 137 grains h20 capacity. The 300 weatherby is right around 100, and the hornady cases I measured, when filled only to the shoulder neck junction, measure around 94-96 grains of water (not exact certainty)
