Reply With QuoteGotta remember that the twist rate recommendations for heavy .224 caliber bullets are based on .223 Rem velocities. Slower MV = faster twist required. Your 22 CM will be similar in performance to a .22-243AI so a 1-8" twist would be sufficient.
I'm starting to collect parts for a 22 Creedmoor build. The action is a standard Savage 12FV in 6.5 Creedmoor purchased at Cabela's during their sale. $269 after rebate is a no-brainer price for a donor action. I am having the action trued up and will be bedding it into either a Savage laminate stock or an H-S Precision composite stock. My research so far has got me leaning toward a 26" 1/7 heavy barrel. I'm looking for input from members who have been shooting this cartridge. What twist rate do you use and what bullets have you had luck with? I see the new 95gr SMKs call for a twist rate of 6.5, but I'm assuming that is for service rifles at slower speeds. The BCs on the 95s are very impressive. What brass have you been using? I have a decent supply of Hornady 6mm Creedmoor brass to get me started. Alpha Munitions is starting to produce 22CM brass also. I'll just need to pick up a bushing die and appropriate bushings. What size bushings have you been using for forming and loading? Any input will be appreciated. Thank you! -Quigley
Gotta remember that the twist rate recommendations for heavy .224 caliber bullets are based on .223 Rem velocities. Slower MV = faster twist required. Your 22 CM will be similar in performance to a .22-243AI so a 1-8" twist would be sufficient.
"Life' is tough. It's even tougher if you're stupid." ~ John Wayne
“Under certain circumstances, urgent circumstances, desperate circumstances, profanity provides a relief denied even to prayer.” —Mark Twain
I use the Berger twist calculator when exploring the numbers and possibilities. I want a fast twist 22, Ill be watching this.
Running the numbers the 1-7" twist would put you into the stability zone at anything over 3000fps.
"Life' is tough. It's even tougher if you're stupid." ~ John Wayne
“Under certain circumstances, urgent circumstances, desperate circumstances, profanity provides a relief denied even to prayer.” —Mark Twain
I'm interested in this too, would love to throw a 22cm bbl on an old marlin x7 of mine.
I was going to get on here and explain that over stabilization is bad and talk about the bullet "going to sleep", and recommend that 1:8" is probably all you need. ....then I input some data on stability calculators and I really think that a 1:7.0" is exactly you need.
That being said, idk exactly how long a 95gr .224 SMK is. But it's gonna be longer than a 95gr .243 SMK which is 1.180". Let's assume your 22 cal bullet is between 1.20" and 1.24" in length. I also don't know the velocity you can push this heavy of a bullet (or what length bbl you'll end up w) but let's assume you can hit 3000fps, which is mildly generous but perfectly possible.
At 3000fps and a 1.240" length, .224 95gr bullet, you end up w a stability factor of of 1.52. ....which is the minimum you really want. IMO, you don't wanna go over 2.0 and never over 2.5. Just my two cents. But 1.5 at the muzzle is thought to be pretty ideal.
Now if we shorten the length to 1.20" long but keep velocity the same, then your stability factor only goes up to 1.67. That is anything but over-stabilized. This is good stability.
Bottom line is you need to figure our your exact bullet length and expected muzzle velocity to be sure, but I honestly think a 1:7.0" is the minimum you will need.
And I swear I thought a 1:8 wudda been sufficient.
someone correct me if I've made a mistake somewhere.
Btw over-stabilization is true reason (imo) that you can have significantly tighter groups at distance (than at closer targets) after the bullet goes to sleep. Basically, over spinning the bullet causes it to wobble on its longitudinal axis rather than spin cleanly and symmetrically. Litz talks about this in his books, so trust what he says before me. But basically the tip creates a clover leaf pattern about the long axis of the bullet until it goes to sleep, and then settles in such that it spins cleanly without causing the tip and base to wobble around the longitudinal axis. Imagine a football wobbling from too little spin; it's basically the same thing. So you want just enough spin that it's still spinning sufficiently when it gets to its target. Typically, a stability factor of 1.5 is sufficient for this bc it won't drop below 1.0 before it hits its target.
Also, for 99% of us, under stabilization is the only true problem we need to worry about. Over stabilization isn't a practical problem that affects much except those edge cases.
Just my 1/50th of a dollar. Let me know if I'm missing something.
I think a 1-8" would get the job done, but on most calculators it falls into the high end of the "marginally stabilized" range. Of course, I've been shooting 80gr Nosler's out of my 22-250AI for more than a decade with great results where the calculator also says they are just "marginally stabilized." I know others who have run the 90gr SMK's at 3200-3400fps in a 1-8" twist without any issues.
"Life' is tough. It's even tougher if you're stupid." ~ John Wayne
“Under certain circumstances, urgent circumstances, desperate circumstances, profanity provides a relief denied even to prayer.” —Mark Twain
That's good to know, makes feel a lot better about my original thoughts. I would really like to know how this turns out.
The deeper I dig, the more excited I get about this cartridge. I just crunched some theoretical numbers through the Berger Calculator. If the cartridge can launch the 90gr VLD at 3200fps, it will stay supersonic out to 1600 yards!! It will carry 1000 ft-lbs of energy out to 600 yards. This is going to be fun...
The new 95gr SMKs are just plain silly with a B.C. of .600 https://www.sierrabullets.com/store/product.cfm/sn/1396/224-dia-95-gr-HPBT
There's some good info on the 22CM here... https://www.facebook.com/horizonfire...7567401012085/
What is the advantage the 22CM offers over the 22-250?
They who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.
There is none. I would do a 22-250 AI for several reasons. Dies are more available, better brass is available, and it will out perform the CM.
"As long as there's lead in the air....there's still hope.."
That isn't true. Performance wise they're pretty equal.Originally Posted by sharpshooter
Most (smart) people just use 6.5 CM bushing dies,and change out the bushings for 22 CM.
Better brass? Really! I can use 6 CM brass,6.5 CM brass or even 22-250 brass for the 22 CM
As far as twist rate goes,a 1-8 will work for up to 80 gr bullets. If you want to shoot the 90+ gr bullets,go with a 1-7. I've got a 1-8 twist on my barrel,but I have 1200 - 75 gr AMax bullets to shoot,and that will pretty much take care of that barrel's usefulness.
I believe you have missed the point. First of all , I've done both....the 22-250 AI will beat the CM by 200 fps. with 90 gr. bullets. Second of all, the Hornady CM brass is crap. An experienced shooter wouldn't use a 6.5 bushing die to go from 6.5 to .22 because the bushing will not the size the neck all the way down to the shoulder junction when it gets to .22 caliber. There's nothing easier than using Lapua 22-250 brass and blowing it out, and using a standard 22-250 AI full length die to resize. 90 gr. bullets will stabilize in a 1-8" twist @ 2900 fps. If I were to build a barrel for 95's, I would use a 1-7", but not any faster.
"As long as there's lead in the air....there's still hope.."
200fps is a heckuva difference for such a heavy-for-caliber pill. I'm not disagreeing or discounting what you're saying bc I don't know myself. But I'm trying to think how different the cases (or case capacity) would have to be to get such a large increase in MV.
Maybe it's due to COAL? ...i.e. Maybe there's more room in the 22-250ai chamber to load longer pills and keep case capacity fully utilized. Or maybe the gun you were pushing heavy 22s from (in 22-250ai) had more room in the mag than is typical or than is available in a 308 Pmag that folks use for 22CM.
Idk just throwing out ideas.
I know nothing first hand of either cartridge but have been looking into both quite a bit lately.
Lapua is now making creedmoor brass as is alpha so brass options are out there. I think there could be a good argument for both cartridge. I'd be willing to venture a guess that the 22cm could match the 22-250ai in shorter barrels so if one were to build a "coyote buster" or wanted to run a suppressor with a shorter barrel I feel the 22cm would be the ticket. now if one were to build a 26"+ rig to maximize it's potential then yes the 22-250ai should very well outperform it.
as to the 95 smk I read somewhere (want to say snipershide) its .070" longer than the 90gr berger vld approaching 1.3" in length!
ETA: 95 smk length 1.293-1.304"
I am definitely looking to shoot the 90gr and heavier bullets due to the ridiculous high B.C.s. I have read of people using standard 22-250 brass and firing them in their 22CM using max 22-250 data. They are reporting great results and excellent accuracy even during fire forming.
I've read something similar. I agree with a .600g1 those things should really fly especially with with the attainable velocities.
I'm just going to wait for Alpha 22CM brass. Waiting won't be a problem as my barrel is still 9 weeks out. By the way, if interested...Alpha will put you name on their call list for notification as soon as the 22CM brass is available.
#10 G.I. Vietnam. You got anymore ammo?
I recently got my hands on some Prime 6.5 brass. I may run it through the annealer and try necking some of it down for 22CM. I've been hearing mixed reviews on the Hornady brass as far as primer pockets go.
Call Alpha Munitions and ask when they'll be doing another run of 22 Creedmoor brass.
https://store.alphamunitions.com/pro...2mm-creedmoor/
Tom Beckstrand thinks highly of AM and wrote AM makes the best quality brass, no compromises.
Yep. I've been keeping an eye on Alpha as a brass source too.
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