22 Creedmoor twist rate

[jfjohn77]

Well... all I can say is that my Smith is shooting a 22 Creedmoor Improved (40 deg shoulder) with 6.5 tw, and he has no issues 80 gr and up.

 

[B23]

What brand of bullets and at what velocities are you fellows experiencing your bullets coming apart? In checking the Berger Twist Rate Stability Calculator, I don't find any issues even going down to their 80gr with a 6.5 tw at 3525 fps.

That would be a bullet RPM of over 390,000 and that is a lot. Maybe and that would be a big maybe they'll survive the trip on a fresh throat but I'd be very surprised a conventional lead core bullet would survive that kind of RPM once the throat got a little wear on it.

I'm launching 80gr ELD-M's at 3650 with an 8tw 22-243 Improved that puts me at a much less 328,500 RPM and they're making the trip, at least for now they are, but as my barrel gets some wear on the throat that could all change.

I talked to Sierra about those 95gr SMK's and even bought a box when they first came out. The guys I talked to at Sierra told me they weren't really designed for the hot rod 22 cal cartridges because at the higher velocities those cartridges would be capable of added to the very fast twist that was required to stabilize them to get the full BC they didn't think they'd hold together. We talked about using a slower twist to get the bullet RPM down but that would be at the expense of a lowered BC which is kind of the whole point of shooting those 95's.

 

[Thegman]

That would be a bullet RPM of over 390,000 and that is a lot. Maybe and that would be a big maybe they'll survive the trip on a fresh throat but I'd be very surprised a conventional lead core bullet would survive that kind of RPM once the throat got a little wear on it.

I'm launching 80gr ELD-M's at 3650 with an 8tw 22-243 Improved that puts me at a much less 328,500 RPM and they're making the trip, at least for now they are, but as my barrel gets some wear on the throat that could all change.

I talked to Sierra about those 95gr SMK's and even bought a box when they first came out. The guys I talked to at Sierra told me they weren't really designed for the hot rod 22 cal cartridges because at the higher velocities those cartridges would be capable of added to the very fast twist that was required to stabilize them to get the full BC they didn't think they'd hold together. We talked about using a slower twist to get the bullet RPM down but that would be at the expense of a lowered BC which is kind of the whole point of shooting those 95's.

It doesn't make sense, to me anyway, why a high velocity cartridge with slower twist barrel would affect the bullet's BC any differently than a lower velocity cartridge with a faster twist barrel. The bullets RPM leaving the barrel is factor of those two variables.

I would think that a bullet with X RPM would have the same stability and BC regardless of the barrel it came from, unless the velocity itself is the factor...???

 

[jfjohn77]

FYI....
This is where all this becomes confusing and contradictive. I have an article published on loaddata.com dated Sep 13 2022, that gives his recorded load data with velocities from a 1:7 twist bbl using 5 different bullets and 9 different loads per bullet. I used a Bullet Spin Rate Calculator for fastest velocity of each bullet and found the rates between 332229 rpm for the 90 gr Berger and 371931 for the 69 gr RMR. Now he published group sizes for each load, so the bullets obviously made it to the target, and now I'm left scratching my head. I think with my 6.5 twist, as long as I keep my RPMs down below those I calculated from that article, I wouldn't have a problem. Of course the barrel would be different and I would have to find an accurate load in there somewhere below those listed velocities, but that is what I enjoy and why I handload.

.22 Creedmoor Loads Using Peterson Cartridge Small Rifle Primer Brass | Load Data Article​

The .22 Creedmoor is nothing more than the 6.5mm or 6mm Creedmoor necked down to accept .224 bullets without any further changes (necks may require turning or reaming to ensure proper chamber fit/bullet release). The trim-to length is 1.91 inches, like the 6mm Creedmoor. The .22 Creedmoor makes...
loaddata.com

Bullet Spin Rate Calculator - Calculator Academy​

Bullet Spin Rate Calculator Basic Calculator Advanced Calculator Enter any 2 values to calculate the missing variable Muzzle Velocity (fps) Barrel Twist
calculator.academy

 

[Formidilosus]

FYI....
This is where all this becomes confusing and contradictive. I have an article published on loaddata.com dated Sep 13 2022, that gives his recorded load data with velocities from a 1:7 twist bbl using 5 different bullets and 9 different loads per bullet. I used a Bullet Spin Rate Calculator for fastest velocity of each bullet and found the rates between 332229 rpm for the 90 gr Berger and 371931 for the 69 gr RMR (SMK). Now he published group sizes for each load, so the bullets obviously made it to the target, and now I'm left scratching my head. I think with my 6.5 twist, as long as I keep my RPMs down below those I calculated from that article, I wouldn't have a problem. Of course the barrel would be different and I would have to find an accurate load in there somewhere below those listed velocities, but that is what I enjoy and why I handload.

.22 Creedmoor Loads Using Peterson Cartridge Small Rifle Primer Brass | Load Data Article​

The .22 Creedmoor is nothing more than the 6.5mm or 6mm Creedmoor necked down to accept .224 bullets without any further changes (necks may require turning or reaming to ensure proper chamber fit/bullet release). The trim-to length is 1.91 inches, like the 6mm Creedmoor. The .22 Creedmoor makes...
loaddata.com

Bullet Spin Rate Calculator - Calculator Academy​

Bullet Spin Rate Calculator Basic Calculator Advanced Calculator Enter any 2 values to calculate the missing variable Muzzle Velocity (fps) Barrel Twist
calculator.academy

It is an approximation, not a hard line.

 

[wind gypsy]

As others have said, not an exact science. Longer barrel, tighter bore diameter (0.218"), rougher bore/throat, hotter barrel, all increase the likelihood that they go poof.

Edit: Excalibur only had 0.219 bore 6 groove options for 6.5 twist when I looked quick so that is good vs say a .218 bore 3 groove.

 

[HighCascadeHunter]

Ordered a 16.5” McGowen barrel 1/7” twist. 22 creed for a tikka.
Plan to shoot 80 or 88eldm.
Running the rpm calculations it doesn’t seem like I could possibly shoot them fast enough for that combo to be an issue. But reading these threads makes me concerned I should have gone 1/8” twist.
Does anyone see this combo being an issue or recommend a different bullet ?

 

[Stocky]

Ordered a 16.5” McGowen barrel 1/7” twist. 22 creed for a tikka.
Plan to shoot 80 or 88eldm.
Running the rpm calculations it doesn’t seem like I could possibly shoot them fast enough for that combo to be an issue. But reading these threads makes me concerned I should have gone 1/8” twist.
Does anyone see this combo being an issue or recommend a different bullet ?

Should easily be able to hit 3000fps with that combo which is 308k rpm so I'd not say you are guaranteed safe but likely safe depending on rifling type, bore diameter, etc.

Some are fine at 350krpm and some with tight bores, rough throats, certain rifling types have issues under 300krpm (which is what hornady say is the limit).

With a 1 in 7" 2970fps is where you hit the hornady "limit".

 

[HighCascadeHunter]

Should easily be able to hit 3000fps with that combo which is 308k rpm so I'd not say you are guaranteed safe but likely safe depending on rifling type, bore diameter, etc.

Some are fine at 350krpm and some with tight bores, rough throats, certain rifling types have issues under 300krpm (which is what hornady say is the limit).

With a 1 in 7" 2970fps is where you hit the hornady "limit".

Thanks I appreciate the info. Will probably try both 88 eldm and 80 and try not to push it too hard.

 

[Stocky]

Thanks I appreciate the info. Will probably try both 88 eldm and 80 and try not to push it too hard.

For reference a friend here runs 88s at 3350 in a long barrel 22-250ai from a 1 in 7 here in NZ and he hasnt popped one in around 900 rounds. Sometimes you can push them and get away with it. Id be pretty comfortable at 3000fps which would be a lovely result for your short barrel even smidge less would be super effective.

 

[Cbum]

Does anyone have experience with a 1:12? I just got a very good deal from PBB on a 18" 1:12 22CM barreled to a Mesa Summit Ti, and am having a hard time finding load data for a longer twist on a varmaint barrel.

 

[Stocky]

Does anyone have experience with a 1:12? I just got a very good deal from PBB on a 18" 1:12 22CM barreled to a Mesa Summit Ti, and am having a hard time finding load data for a longer twist on a varmaint barrel.

Load data wont change based on twist all it means is you will be shooting stuff in the sub 60 grain weight range. Probably the 53 v max as a good idea to start. May just get a 60TMK stable.

You would be pretty safe to start with the upper end of hornadys data for the 62 ELD VT in the following link

https://static.hornady.media/site/hornady/files/load-data/22-creedmoor.pdf

Personally a 22 Creed loses a lot of appeal with a slow twist to me

Belows the transcript from GRT for what should be max loads at 62KPSI. Don't start here obviously but gives a guideline of potential options with a 53vmax. Id usually start 10% lower and work up. Do so at your own risk.

--------------------------------------------------------------------------------
Gordons Reloading Tool 2021.2030-NIGHTLY
Parametric powder search by generic tolerance synthesis
--------------------------------------------------------------------------------
File : 22 Creed.grtload
Caliber : .22 Creedmoor (.22 CM, 22 Creedmoor)
Projectile : Hornady, V-MAX BT 22265, 0.224, 53.00 grain, 0.8307 in
Seating depth : 0.3008 in
Case : 48.20 grain H2O, 1.9201 in
Cartridge length: 2.4500 in
Initial pressure: 3626 psi
--------------------------------------------------------------------------------
Tolerance-Window : Target Min. Max. Unit
maximum pressure : 62000 61442 62558 psi
Muzzle velocity : - - - ft/s
Barrel Time general (BT) : - - - ms
Bullet Lead Time 10% pmax (BLT): - - - ms
Load ratio : 106.80 75 105 %
burnt propellant : - - - %
--------------------------------------------------------------------------------
A T T E N T I O N - A T T E N T I O N - A T T E N T I O N
--------------------------------------------------------------------------------
Depending on the setting of the limiting tolerance windows, the charges can
exceed the specified maximum pressures, or have no meaningful, or even
a dangerous value. Please check a load prior to use for plausibility.

The order of the list depends on the composition of the powder list.
--------------------------------------------------------------------------------
propellant mass load ratio pmax v0 E0 burnt eff. BT BLT recoil
grain % psi ft/s ft-lb % % ms ms ft-lb
Hodgdon LeverEvolution (2021-01-28) 41.10 86.9 61973 3597.0 1522 100.0 19.4 0.9170 0.8151 13.17 Working pressure close to the maximum permissible gas pressure!

Alliant Reloder TS 15.5 (2021-09-30) 40.28 98.4 61991 3577.7 1506 100.0 20.1 0.8840 0.7965 12.73 Working pressure close to the maximum permissible gas pressure!

Alliant Reloder 17 (2020-02-05) 43.81 97.3 61980 3577.5 1506 91.2 18.0 0.8448 0.7756 13.90 Working pressure close to the maximum permissible gas pressure!

Hodgdon H4895 (2020-12-01) 38.21 87.6 61988 3560.2 1491 100.0 21.2 0.8920 0.7985 11.90 Working pressure close to the maximum permissible gas pressure!

Vihtavuori N550 (2021-09-27) 42.64 99.2 61984 3549.4 1482 92.5 18.4 0.8852 0.8000 13.32 Working pressure close to the maximum permissible gas pressure!

Alliant 2000-MR (2021-03-01) 42.14 98.0 61974 3549.0 1482 97.3 18.9 0.8731 0.7931 13.17 Working pressure close to the maximum permissible gas pressure!

Hodgdon H4350 (2020-12-01) 43.21 96.5 62009 3541.2 1475 88.5 18.3 0.8731 0.7937 13.42 Working pressure close to the maximum permissible gas pressure!

Hodgdon Superformance (2021-10-DEV-2) 47.02 101.9 61968 3538.1 1473 81.4 16.9 0.8593 0.7876 14.70 Working pressure close to the maximum permissible gas pressure!

Hodgdon Varget (2021-10-30-2) 39.88 91.8 61967 3538.0 1473 98.5 19.3 0.8722 0.7904 12.33 Working pressure close to the maximum permissible gas pressure!

Hodgdon BL-C2 (2020-10-02) 41.40 92.0 61967 3537.7 1473 100.0 19.1 0.8814 0.7974 12.82 Working pressure close to the maximum permissible gas pressure!

Vihtavuori N540 (2021-09-30) 39.61 93.1 62002 3528.2 1465 100.0 19.3 0.8869 0.7982 12.15 Working pressure close to the maximum permissible gas pressure!

IMR 8208 XBR (2019-11-08) 38.08 91.5 61964 3525.7 1463 100.0 21.6 0.8627 0.7840 11.65 Working pressure close to the maximum permissible gas pressure!

Hodgdon CFE-223 (2020-03-07) 41.69 94.0 61990 3524.1 1461 96.5 19.3 0.8705 0.7918 12.81 Working pressure close to the maximum permissible gas pressure!

 

[AZ_Hunter]

I have wondered if polygonal rifling would help with blow up as it supposedly imparts less friction on the bullet.

 

[Cbum]

Thank you for taking the time to write this out and getting data for me it's much appreciated. I ended up getting the barreled action mainly for the huge discount and the Mesa Summit Ti on the barrel, but I do have some buddies who go to the dakotas for Prairie Dogs and I'll be building this out for that. When I get it stocked up I'll post what I can from my experiences with it!