TC Custom Shop 22 WMR twist rate

[15xglasser]

Been doing some research on the .22 WMR cartridge, have always like this rimfire cartrige and am considering a barrel in this caliber.  The traditional twist rate seems to fall in the 1-15" to 1-16" range.  Even when you plug all the numbers into the twist rate formula for the .22 WMR, the optimal twist rate seems to come out to between 1-15" and 1-16". 

The TC Custom Shop 22 WMR barrels (as stated in the TC twist rate chart) are manufacured with a twist rate of 1-12" - anybody have any experience with shooting this caiber in a Contender?

Thanks,
15xglasser

[IOWA DON]

They made me a .22 Cooper Centerfire Magnum barrel for a TCR-87. That caliber uses a strait case which is only slightly longer than a .22 Magnum but has a small rifle primer. It will shoot a 40-gr bullet at 2,200 fps. The barrel has a 1-in12 twist. It will shoot 1-inch groups at 100 yards with 40-grain Seirra bullets. With 63-grain Sierra semi-pointed I got the best groups ever at 50 yards.

[DEACONLLB]

Was that made before the fire or after? Was just wondering if they do open back up as they said in December if you could still get a custom TCR barrel in what ever cal. you wanted. I talked to MGM and they will make a barrel but you have to have a doner barrel and that would drive cost up.Ed still comes up with 7mm Rem. mag barrels new but wont say where they come from and they are not in Thompson boxes.
He sells them for 150.00 and they are nice and shoot great.

Deaconllb

[IOWA DON]

That was just before the fire which occured shortly after April 1996. I don't think the Custom Shop made any TCR barrels after that fire. The .22 Cooper Centerfire Magnum (.22 CCM)was listed as an option for custom barrels for the Contender, but not for TCR-83's abd TCR-87's. However they agreed to make a TCR barrel for me in .22 CCM. I suspect it is the only TCR barrel they ever made in that caliber. I was real surprised when I checked with a cleaning rod and found it had such a fast twist barrel. The experiment with the 63-grain Sierra bullets was to see if the longer bullets would be more accurate with the fast twist. I chronographed the load and don't remember for sure but think the muzzle velocity was around 1,700 fps. As I said before, I got the best 50-yard groups ever with those bullets. However, that was for 50 yards and it was also in warm weather. I later shot that load at 100 yards in cold weather. I did not bother to chronograph them again, but suspect the muzzle velocity was lower because of the cold and the bullets would have slowed down even more by the time they got to the 100-yard target. Anyway, the group was very large. I think the bullets were becoming unstable and even entering the target slightly tipped. From what I've read a barrel with a too fast twist was generally an accuracy problem 50 years ago when bullets were not as accurately made as today. However, now bullets are so concentric (center of weight in center of diameter) that they generally shoot well even when spun too fast.

[DEACONLLB]

My 1-12 twist in TC barrels will not handle any thing over 55 Grns including my 223 TCR barrel. They go in at a slight angle. My mossberg SSI one which is 1-9 twist handles all of them well including the 70 grn.

Deaconllb

[Keith L]

Why did this become a TCR barrel?  The OP was asking about a Contender.  The next thread hijacked the barrel type and the caliber.

[IOWA DON]

Sorry about getting a little far off topic, but the .22 Mag and the .22 CCM are very similar ballistically although one is rimfire and the other centerfire, so what applies to one in regard to twist rates appies very closely to the other. When I found out my .22 CCM from the TC Custom Shop had a 1-in-12 twist I was a little concerned that the twist rate was not appropiate for the cartridge, like maybe they had too many 1-in-12 twist barrels laying around and used one in my application rather then get one with the proper twist rate. I still think a slower twist would be better with either caliber. However, I read that .22 Mag ammo is much better than it was 20 years ago and assume that is in part because of better, more concentric bullets. Therefore, better bullets would be less affected by an inappropiate, too fast, twist rate. Also, the fact that my .22 CCM barrel would stabilize 63-grain Sierra semi-pointed bullets at around 1,700 fps shows that a 1-in-12 twist is way more than needed for any available bullet in .22 Mag. That is, I think the heaviest .22 Mag bullet available weighs 50 grain and has a flat point so is much shorter than the 63-grain Sierra. Since, twist rate required to stabilize a bullet is more related to velocity and bullet length than to velocity and bullet weight, I think the comparison shows even more that a 1-in-12 twist is not really the best choice for a .22 Mag.

[15xglasser]

Thank you Keith L. for bringing this topic back around...we tend to go on sidebars when considering technical info regarding firearms, and appreciate all the input that may even remotely relate to the topic...

When considering the "Greenhill equation" as related to barrel twist rate (http://kwk.us/twist.html) it is easy to try to relate the .22 rimfires to the .22 centerfires, at velocities under 2800 FPS.  As the majority of .22 WMR cartridges are available in the 30-40 grain variety in the 2200 FPS range, one intuitively thinks that the same rules apply.  Then why is the industry standard for .22 WMR's twist rate 1-16"?  Because of the shorter bullet length?  ...or because of the quality control on .22 WMR factory ammo? 

There are better minds that have tackled this subject at the bullet manufacturers and industry experts...the subject of accuracy keeps popping up with the .22 WMR, and I'm wondering if the twist rate is one of the factors...and why the different twist rate concerning the T/C custom shop barrel and the majority of other manufacurers barrels chambered for this cartridge.

[DEACONLLB]

Sorry Keith
We did get off subject good that we have someone to get us back on subject.

Deaconllb

[ruger438]

I bought a 22 WMR carbine barrel from ED's this spring, so far I have only shot Rem premium 30grn , and Hornady's 33 grn tipped stuff, and it really shoots IMHO.

So far it prefers the Hornady load, if only by a small margin. Both loads were under an inch.
 
Haven't put 100 rounds through it yet though, so we'll see what else it likes, I wasn't even aware the twist was 1-12.

My position is, if you have a good bullet you can't overstabilize it, at least until the bullet comes apart, so I'm glad to hear the twist is 1-12.
Now I've got to see if I can find some of those old Federal 50 grain loads that never shot well out of my other 22 WMR's, and see if they shoot with this barrel.