1 in 16 twist in 45-100?

[leftiye]

I've got a Siamese mauser that's been a basket case for about 20 years now. I was going to make it into something like an overlong .458 Alaskan (3.5" LOA). (based on .50 basic headsize).

Recently, I acquired a NEF Handi rifle with the idea of reaming it out to .45-100 (2.5"). I found a bunch of cases at Cabela's that were a good price (I thought). But what with the weight of the gun, and the consensus on this site that such thangs kick like he!!, and are problematical to load down, I decided to leave it a 45-70.

So I thought that I'd make the Siamese Mauser into a 45-100 maybe. Should be nasty enough for jackrabbits anyhoo. My question is - would it be adviseable to get a .458 barrel with 1 in 16 twist rate? Is the tighter twist too much for 300 grainers? Is it beneficial or even needed for the 500 grainers? They are all over the place, and Midway has an Adams & Bennett blank on sale until the end of Feb..

Is anyone familiar with this brand? I saw one on ebay, and it seemed there wasn't much interest.

While I'm at it I'd like to throw out a chamber layout, and see what you guys with experience think about it. How well would it work to put a long freebore on a 45-70 single shot chamber, say as much as .5" so that say a 300 grainer, (sized tight, and which has a .5" cylindrical portion) would be totally in the throat say upon primer firing. The boolits would be seated out in the case so as to have as little jump as possible. This would align the boolit into the leade very well, and keep pressures from deforming the boolits maybe as I want to use soft boolits (with gas checks). Thanks, Ted

[MT Chambers]

My 45/100 barrel is a Green Mtn. 1-18" twist and it handles my 595gr. paper patch bullets fine.

[JeffinNZ]

Should be fine. I shoot Lyman 311008's at 115gr out of my .303's with 1 in 10 twists designed for 215gr bullets.

[Bass Ackward]

I have had a 14 Twist that was accurate with 300 grains. But it limited the top end or forced harder bullets how ever you want to look at it. On the other hand my 20 twist handles everything up to 525 grains which is as heavy as I have shot.

If it's cast, keep your twist rate as slow as necessary to stabilize the heaviest bullet you intend to shoot.

[montana_charlie]

While I'm at it I'd like to throw out a chamber layout, and see what you guys with experience think about it. How well would it work to put a long freebore on a 45-70 single shot chamber, say as much as .5" so that say a 300 grainer, (sized tight, and which has a .5" cylindrical portion) would be totally in the throat say upon primer firing. The boolits would be seated out in the case so as to have as little jump as possible.
Have you looked into 'breech seating'? Your description sounds very much like that practice.

About the twist rate...
Taking 1:18 as the norm for 500 to 550 grain .45 caliber bullets, you might go to 16 if you wanted to shoot longer (heavier) slugs...and toward 20 for the shorter (lighter) ones.

Just for a comparison between 'old' thinking and modern thought, what is the standard twist rate for something like the .458 Winchester Mag. round?
CM

[38-72]

I shoot 400 to 500 gr bullets in my BPCR 45-90 with a 1-16 twist. No problems.

[Larry Gibson]

My Siamese Mauser 45-70 barrel has a 1-22" twist and it works fine with 210 gr through 510 gr bullets. Not trying to throw water on your fire but with the Lee C457-500-F seated to the crimp groove and crimped there isn't much room left in the magazine. A 45-90 case with that bullet is right at magazine length. Unles you are using lighter eight short bullets the 45-100 may be too long. Also I can load the 500 gr Lee bullet to 2050 fps in the 45-70 case and the 400 gr Barnes SP to 2300 fps and 2400 fps with the Lyman 458483GC but the recoil is not fun anymore) so there really isn't any need for more boiler room, especially with cast bullets.

Larry Gibson

[leftiye]

Larry, I "fixed" the magazine long ago. Took off that feed ramp, and welded a new front end onto the magazine box. It will (WILL) accept 3.5 length ca'tridges now.

[Larry Gibson]

Larry, I "fixed" the magazine long ago. Took off that feed ramp, and welded a new front end onto the magazine box. It will (WILL) accept 3.5 length ca'tridges now.

That being the case (pun intended) it would seem a worthwhile project. You do have a sissy pad for the shoulder, right? Oh what a good time it will be;-)

Larry Gibson

[leftiye]

Well, I've got a 45-70 already. I envision this gun as a dangerous game stopper. Probably never use it except for to bruise my shoulder. Already am a firm believer in "Limb Savers" from hunting Elk with a .375 Ackley Imp.. Can't leave that Siamese Mauser action going to waste, can I?