22-250 rebarrel - twist rate?


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rbernie
June 15, 2011, 10:56 AM
I have a 22-250 that I am debating having rebarreled to shoot 65gr-75gr bullets. Has anyone done this, and what twist rate is needed to stabilize these heavier bullets in a 22-250? I figure than a 1:9" twist would be ideal, but would prefer not to spend the cash without having some clue as to the likelihood of success. ;)

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joed
June 15, 2011, 12:49 PM
I want to know how long barrel life is with a fast twist like that. I've heard horror stories of 600 rounds for a .22-250, and I just laugh.

ironhead7544
June 15, 2011, 12:59 PM
Im guessing you want to use it at long range. The 75 gr BT would need a 1 in 8 IMHO. A 1 in 7 would be better. I would ask the barrel maker what he recommends. Do a search and you will find some info on 22-250 heavy bullet rifles.

Cemetery21
June 15, 2011, 04:25 PM
I don't have advice on the twist rate - there are others with experience on that.
But if you are a fairly high volume shooter, you might consider using a long blank and leaving the outer profile straight for several inches out from the chamber. That way, you can set the barrel back and rechamber when you get throat erosion. I got 3 lives out of the same 22-250 barrel that way, on light bullets.

dirtyjim
June 15, 2011, 05:58 PM
i would go 1-8 myself because it will stabilize the 75's while the 1-9 most likely will but i've seen a few that wouldn't.
leaving the shank long is also a good idea so after about 1500 rounds you can set it back for a new throat.

243winxb
June 15, 2011, 06:21 PM
Sierra lists the twist for some of there bullet if you click on the bullet number. #9377 .22 Caliber (.224) 77 gr. HPBT Match (500 bullets)

Please Note!! This bullet requires a 1x7" to 1x8" twist barrel.

Berger lists the perfect twist for all there bulllets last time i looked.:)

Jim Watson
June 15, 2011, 06:38 PM
Berger says an 8 twist would get you up to an 80 gr VLD or 82 gr BT.
That might be the sweet spot for a heavy bullet .22-250.

I've got a 6.5 twist 90 gr .223 that may be too much of a good thing.

rbernie
June 15, 2011, 06:54 PM
Its the length, not the weight as i am sure you know.Indeed, but always good to reiterate. :)

Please Note!! This bullet requires a 1x7" to 1x8" twist barrelThe reason that I ask is that most of the barrel twist recommendations for heavier .224 bullets are geared around slower 223 applications and not the faster 220 Swift or 22-250 or 225.

Most 22-250s are set up with 1:14" twists that stabilize the 55gr-60gr just fine, so I'm figuring that the 22-250 runs 2" slower per inch for a given bullet weight than would a 223.

243winxb
June 16, 2011, 07:41 AM
The reason that I ask is that most of the barrel twist recommendations for heavier .224 bullets are geared around slower 223 applications and not the faster 220 Swift or 22-250 or 225.
. Yes, makes a difference. Years ago i run into a guy shooting a Hart barrel in 224/6mm Rem wildcat. The twist was 1-10 using 55 to 65 or 69 gr Sierras. I remember 1 load was right at 4000fps over the chronograph, but showing pressure signs. Groups were running around 1", not great for the amount of $$ he had invested.

NCsmitty
June 16, 2011, 10:12 AM
I would not use any twist faster than the 1in9" due to the velocity advantage of the 22-250 over the .223, causing a potential increase in friction and pressure, and the possibility of skidding the bullet in a very fast twist.
Velocity alone can compensate for slower barrel twist, with higher rotational speed for stabilization.



NCsmitty

Jim Watson
June 16, 2011, 10:42 AM
Ken Waters got good accuracy with 69 gr SMK from a 10" twist .22-250

Calculating from Sierra data, a 10.4" twist .22-250 would give the same rpm as a 9" twist .223.

So I would say that a 9" twist .22-250 would surely handle a 75 gr bullet.
Some but not all 9" twist .223s will, after all. A friend has one that will. It is not quite as accurate as with a 69 in calm air, but the 75 shoots closer to the wind.

It might well get you up to an 80 gr bullet without needing the 8" twist I guessed at above.

rbernie
June 16, 2011, 07:11 PM
Super - thanks. :)

dirtyjim
June 16, 2011, 08:38 PM
it would also depend on what you plan on using the rifle for. if its only a paper puncher go with a 1-8 or 1-9, if you plan on shooting critters with it most of the varmint bullets are in the 45-55 grain range and are meant to be driven very fast so i'd do a 1-12 or 1 -14.

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