14" twist in 45-70??

[Wolfer]

Green mtn has some .458 barrels with 14" twist that are not too bad priced. I'm wanting to build 4 Swedish rolling blocks into 45-70. I won't be shooting anything heavier than 405 gr and at trapdoor speeds.
Is this too fast a twist? I would prefer a 1/20 or thereabouts but haven't found one at a price I like.

[country gent]

I would look for a 1-18 or 1-20. My 1-18s (3 45-70s, 1 45-90) do well with bullets in the 400-550 grn range with BP loads. 1-20 will do the 405s and shorter 500 grn ( lyman 500 gov round nose) but the longer pointier bullets may not perform as well in it at longer distances.

I normally shoot the 500-550 grn weights in 45 cal out to 500 yds. The bullets are the lyman 510 grn govt round nose. Mine cast a bullet that is a light fit on the nose and .460 body. It shoots well in my rifles. Next is the lyman 535 grn postel, my mould has been lapped to .460, My mould has also been converted to a hoch style nose pour. It shoots very well in all my 45-70s but the 45-90 likes even heavier bullets. The last is a Old west 45 shilouette bullet similar to the postel with a short bore riding section and 550 grns. This is my favorite bullet so far in all 4 45 cal rifles. It performs very well out to 500 yds.

I cast these from 20-1 alloy shoot as cast and pan lube them. I also ladle cast them from a gas fired pot that holds 130lbs of alloy when full. Reason is when casting these heavy bullet running 2 moulds a 10-20 lb pot dosnt last long. I also like the small temp spreads with this much metal absorbing the heat.

I have heard and read some are going to 16 twist for the long heavy bullets. For what you want to do the 1- 18 should do well with the 405s and not restrict the use of the longer heavier bullets is ever needed or desired. My 45-90 is a 1-18 twist green mountain. 45-70s are 1 pedersoli made barrel 1-18 twist, 1 1-18 badger barrel, and last is a BRC made 1-18 twist with choke in it made by Al Story. barrel lengths are from 32"-34". Rifles are on the heavy side running 11 1/2lbs - 13 lbs.

Some of the barrel makers sites have twist calculators available. Check several of them and crunch the numbers see what they give you. I believe the 1-14 twists are more appropriate for the smokless 45 cals like 458 mag 460 weatherby and the various wildcats.

[Outpost75]

The 1:14" twist will stabilize 500-grain FMJ bullets subsonic for use with a suppressor if that sort of thing floats your boat.

[dkf]

The 1:14 twist is the most popular twist rate for the .458socom. It is good for any of the subsonic weights with a 10.5" or longer barrel and all supersonic weight bullets for the .458socom. The most common .458socom barrel lengths are between 10.5"-16". The 45-70 is capable of being loaded hotter than the .458socom in a lot of rifles however trap door velocities are fairly low by 45-70 standards. I would say the 1:14 will do ok for your application but may not be ideal.

[Outpost75]

If you want a fun blooper rifle try chambering that 1:14" twist barrel with a .45 Colt or .454 Casull chamber, with same throat as for the .458 Winchester and load the Hornady 500-grain FMJ with a compressed nominal caseful of RL7, IMR3031 or IMR4895.....

[Wolfer]

Upon further study it appears the 14" twist should be ok for my purposes. Running the lee 340 or 405 or maybe the Gould boolit to 1200 fps or thereabouts with smokeless in a 67/89 rolling block.
I'm quite confident I can take a deer with these loads in the river bottom brush thickets I hunt.

GM does have a tapered octagon barrel with 20" twist but it's twice the money and may be a little heavier than I would like. Seriously thinking about giving it a try though.