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22-243 rifling twist
Dokey Member Posts: 933 ✭✭✭
edited October 2019 in Ask the Experts
What's the best overall twist for a 22-243 in a 28" barrel?
This discussion has been closed.
Traditional varmint rifles like .22-250 and .220 Swift had 14" twist for bullets 50-55 gr.
If you want high BC for Long Range, you need a faster twist. I have a 6.5 twist .223 for 90 gr bullets which I think I overdid. Frex 8 twist 80 gr seems the sweet spot for National Match 600 yard.
Your big bottle will give higher velocity, higher rpm, so use a stability calculator to see what is needed. Berger has one.
added I have loaded for several rifles without proper dies. 8mm-06 when I was kid in high school - it really shot great with H4895 and Lyman 323470 many running bunnies bit the dirt with that load. After the Army, a 300 Gibbs 'built' on a double heat treat Springfield. That rifle was easily in the top 5 best shooters I ever played with. I made my own cases from 57NM Again I used the same 8mm and 30-06 dies.
Progressive gain twist rifling or rifling of a polygonal nature is needed to achieve the results you desire...
While neither methodology is "common" I happen to own examples of both neither of which is considered "rare"...
Just a different angle of attack for your consideration - a gambit not often considered.
1/12 - 1/13, would be for light, short OAL bullets. My WAG no heavier than 55 grains?
Since it's used. And you don't know the previous shooting history/round count. I would check for throat erosion & do a chamber cast. If the chamber cast verifies, that it is chambered for 22-243. It opens a whole can of worms. 22-243, is a non standardized wildcat round. Going to cost you a bundle for custom made dies. If the throat is badly eroded, from some previous owners handloads. IMHO wouldn't even be worth it. Have it rebarreled, to some modern commercial cartridge that is redilly available.
It is what should be referred to as a 'standard wildcat' since the basic case is simply necked down from the parent case. This allows you to buy a bushing neck sizing die or bushing full length sizing die then get the proper bushing to neck the .243 cases down to accept the .22 caliber bullets. This does entail a little more work since you have to cast the chamber in order to get an exact measurement of the chamber neck diameter. Then do a little bit of math to achieve the right neck tension on the bullet and allow for neck expansion upon firing. There are commercial dies available and there is a large previously owned market thriving on the internet but the bushing dies are simple.
Here is a fairly quick read about the .22-243 cartridge:
Oh, you already have the gun, that is different from knowing what barrel to buy.
Probably a 12 twist, a 13 would be a special order and not really worth the trouble.
That will set you up for anything up to a 60 grain bullet.
People are way too conservative on twist these days.
My 14 twist .22-250 is accurate with some 60 gr flatbase, not others, depending on length not weight, so there is a clear cutoff for the old standard barrel. Yet I have read that a 14 twist is only suitable for 40 grain bullets.
I suggest that you take your data collected from a chronograph and run it through the Berger Stability Calculator:
You might enjoy seeing some of the answers...