i have saw twist rates up and down the scale. from 1-48 to 1-72 i know the 1-48 is fairly standard now days. what do you think of a 1-72 for round ball in 45?
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opinions of best twist rate for 45
- Thread starter olskool
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From what I have learned (which isn't much) a slower twist rate is preferred for round ball. A faster twist is wanted for conical. 1:48 is the happy medium that doesn't excel with either, but shoots both with acceptable accuracy.
I personally have a 45 with 1:66 twist that shoots round ball very well. But I have also found a 160 grain conical that does well out of it due to it being short (.450) in length giving it the approximate dimensions of a round ball.
Hope this helps.
I personally have a 45 with 1:66 twist that shoots round ball very well. But I have also found a 160 grain conical that does well out of it due to it being short (.450) in length giving it the approximate dimensions of a round ball.
Hope this helps.
i had read that 1-48 came along when TC rifles came along. they used it to stabilize conical bullets. and from what i also read the RB will stabilize pretty good with just about ant twist,,,,,,,,,,,,,,,,,,
Erwan
45 Cal.
With a.450" cal., it depends on what kind of bullets you expect to use, a twist rate of 1/66 is very good with the patched round balls and at the opposite, a 1:48" twist rate is inferior when using long or ogival bullets. From 1:66" (for me the best or no far) to 1,48" the best is to use patched round balls, and with long/ogival bullets, you better do with a 1:20" and perhaps shorter...
Phil Coffins
69 Cal.
I won’t offer an opinion but will add an observation. The original Hawken rifles in all calibers have been measured to have 1 in 48” rifling. These rifles were highly thought of in their day. Depth and form of rifling should be considered as well as twist.
I get good results with a round ball in a 1 in 70 twist
longcruise
70 Cal.
I think it would work just fine. Especially with those SC deer loads.
I shoot a lot with a 1:48 45 cal and accuracy is excellent. I nearly always shoot 45 gr 3f but have shot 50 gr a few times. It's a small game and target rifle so I've never gone to hotter loads.
There's a whole lot of "conventional wisdom" about twist, caliber etc., but don't let yourself get caught up in rules without testing the limits.
The slower twists will require more powder to get the spin needed to stabilize the ball. Twists of 1 in 40 to 1 in 66 are good. Perhaps more important than twist rate is the depth of the rifling. The round ball requires sufficient depth of rifling for the patch to properly engage the ball and the rifling. I have a very accurate 45 caliber rifle with a twist rate of 1 in 56 and about a depth of rifling of 0.010". The lands should be narrower than the grooves. So, it's not just the twist.
The main determining factor for twist rate is the length of the projectile, somewhat in relation to its diameter. The longer it is, the faster it needs to rotate in order to stabilize. Do a search for the Greenhill Formula for a more in depth explanation.
longcruise
70 Cal.
This is an excellent guide for conical shooters. It's not precisely applicable but if it says a bullet will work, it will. It consistently overestimates the twist needed to stabilize any given projectile. It was originally created to apply to artillery.
If you plug a 50 cal with 1:48 twist into Greenhill it will tell you maximum length it will stabilize is 3/4". You can exceed that to a degree but the point being that it will keep you in stability territory.
Some of the BPCR shooters have experimented with bullet length and have come up with modifications to the formula that are more accurate so if your goal is punishing recoil it can be calculated to the max.
1:72” would probably need a whopping powder charge to stabilize a .45 round ball. I use 60 grains FFFG with a 1:56” twist.
Ditt44
40 Cal
I have a 45 cal TC Seneca that is 1:56 and I'm finding that it shoots round balls better than I do. Finally figured out the best load combination and it's doing great. 60g 3F Swiss and an Ox-Yoke .018 patch for 50 cal... bigger cal patch is clearly better than a 45 sized patch.... that was the big "find" with it.
Interesting, my .45cal Seneca does just fine with 25gr. FFFg.for 25-50yds, bump it up to 40gr. For 100yds. I use .020" patch material, cut at the muzzle.
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Ditt44
40 Cal
Plinking or hunting deer? I get good accuracy from 40, better from 50, and best at 60 grains. For hunting out to 50 yards or so, which would be typical for a lot of my hunting spots, I decided on 60g.
A 1:72” twist is what my .62 Rayl barrel has.
Oh, just for matches, paper and sillhoettes.
The slower the twist the larger charges that will be needed to get good grouping. I'm a fan of the 1:48.
Yep, big bores, slow twist. I’ve not seen a .45 with such a slow twist.
the green mountain Kibbler barrel in 45 has a 1-72 this is one of the reasons i asked. i have built several of them and in the middle of one now and have another on the way. this is the SMR i speak of, they shoot good with 55gr. of 3f, but i really have no idea why Jim went with a 1[72 twist in a 45 barrel.
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Interesting! Tha's probably in Woodfill's book, but I don't read every detail in every book! Thanks for the observation!
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