450 Marlin Bolt Gun Question

I would really like some input about selecting the right twist rate for a 450 marlin I'm having built. I have a P14 action that I want to have turned into a sporter. I believe Marlin uses a 1:20 twist rate for their lever action rifles in this cartridge. Is that the best twist rate for 350-400 grain bullets? <img src="/ubbthreads/images/graemlins/help.gif" alt="" />

I would contact Charlie Sisk. He is a big fan of bolt-action .450's and has built several.

MD

Mule Deer,

Thanks for the information. I'll contact him and see what he can tell me.

Personally, given the weight of the P14 action, I'd go a straight 458Win and then reload it back to 450Marlin velocities. On a sporterised M17 I have, I've considered the 450Marlin and 458American but the 458WM just makes the most sense and seems most practical. If I was building a lighter weight sporter, then yes maybe I'd build a 458American ... but particularly in Australia, I'm wary of commiting to 450Marlin brass from one manufacturer that I can't make from something else.
Cheers...
Con

Con,

You do make a good point. Actually, I did consider the 458 WM for this project, but have been leaning towards the 450. I may reconsider the cartridge selection.

Steyr was showing a 450 Marlin SBS at the SHOT Show. Drop them a line and see if it's ready for production.

It's easier to make a big cartridge shoot soft than a little one shoot big.

Actually, Charlie reports very little difference in the handloaded .450 and .458, and he has pressure-testing equipment. It just depends on what you want. I'd still talk to him, as he's built several BA .450's and knows what's up.

MD

I'll definitely give him a call before making the final decision on the cartridge choice of this project. I could make a case for either one.

Quote

Charlie reports very little difference in the handloaded .450 and .458

I'd love a bit more info on this please MD. Don't follow you yet.

He hasn't found much difference in muzzle velocity when both cartridges are loaded to the same pressures.

MD

Wow. The little 450 is even more of a thumper than I thought. To be able to fit that kind of power into a handy short action is strangely attractive. Thanks.