Cheetah

[bobinpa]

What is a 22 Cheetah? What did it come from?

 

[Dirtball]

This should help

http://www.reloadbench.com/cartridges/w22chee.html
http://www.reloadersnest.com/frontpage.asp?CaliberID=349
Dave

 

[bobinpa]

Thanks. Makes you wonder why it isn't more popular, now with the interest in small and fast?.?.?.?.

 

[people]

I supose it is hard to come by the 308 BR cassings. I have seen afew 22-243 and a 22-6mm. They are hard on tubes. You can really push a biger bullet hard and fast.

 

[fdshuster]

Many yrs. ago, an old time 'smith suggested I re-barrel with the 22 Cheeta, instead of my planned 22-250. I said "no", I'll stay with the 22-250. That barrel lasted 2500 rds., while the 'smiths personal 22 Cheeta was scrap at 800.

 

[Nailman1]

I purchased a rifle marked 22 Cheetah .251 NK on barrel , which seems to mean that it is not a Mach1 or a Mach 11
but is closest to a Mach11, any ideas how i could form up ammo to shoot in this fine rifle, Any help will be appreciated.
Thks
Causie

 

[284winner]

Thanks. Makes you wonder why it isn't more popular, now with the interest in small and fast?.?.?.?.

It was developed back in the 80s and used a slow twist barrel. Today the 22-243, 22-250 AI and 22 Creedmoor with faster twist barrels have become a more popular design with heavy bullets. Many still use the slower twist with light bullets but heavy bullets with faster barrels have become a favorite recently.

 

[B23]

You don't really hear much about the 22 Cheetah, Mk I or II, anymore. I don't think there is a whole lot of difference between the 22 Cheetah and any of the many variants of 22-243 but you see/hear the most about the 22-243 or a version of.

My dad has a 22-6mm I have a new 224 Terminator aka 22-243 Improved. Both are built on Rem 700 short actions but the 22-243 is a better fit for the SA if you plan to go fast twist and shoot the heavies. Also, brass quality, definitely favors the 22-243.

 

[DaveTooley]

L

I supose it is hard to come by the 308 BR cassings. I have seen afew 22-243 and a 22-6mm. They are hard on tubes. You can really push a biger bullet hard and fast.

Lapua makes the 308 Palma case with a small primer. I seem to remember Jim Carmichael (Outdoor Life)and Kenny Jarrett collaborating on this cartridge.

 

[DaveTooley]

I purchased a rifle marked 22 Cheetah .251 NK on barrel , which seems to mean that it is not a Mach1 or a Mach 11
but is closest to a Mach11, any ideas how i could form up ammo to shoot in this fine rifle, Any help will be appreciated.
Thks
Causie

What reloading dies do you have?

 

[284winner]

L

Lapua makes the 308 Palma case with a small primer. I seem to remember Jim Carmichael (Outdoor Life)and Kenny Jarrett collaborating on this cartridge.

Yes that was the big thing when he developed it was using the smaller primer pocket. Apparently it was much more consistent. At the time Benchrest primers were a fairly new concept. Adaptation of small rifle primers in large cases. I believe the CHeetahs of today are simply the 22/243 improved(40°).

 

[DaveTooley]

Don't think match primers were new. I was shooting them in 1978. The CHeetah came out after that. I stand corrected Jim and Fred collaborated on this. I was one of the developers of the 30 American case(early 80's) and it had a small primer. Once we got past 35 grs. of powder we didn't see any benefit to the small primer. Get 243 Lapua brass and build a 22-243 of some kind. I've got a Middlested reamer and can't remember the last time I used it.

 

[284winner]

Don't think match primers were new. I was shooting them in 1978. The CHeetah came out after that. I stand corrected Jim and Fred collaborated on this. I was one of the developers of the 30 American case(early 80's) and it had a small primer. Once we got past 35 grs. of powder we didn't see any benefit to the small primer. Get 243 Lapua brass and build a 22-243 of some kind. I've got a Middlested reamer and can't remember the last time I used it.

No I guess I meant fairly ( about a decade new) at the time he built his CHeetah.

 

[284winner]

I remember back in the mid 80s reading about Carmichael/Huntington's newest CHeetah build. I wanted one so bad and was determined to build one. I guess that need went away eventually but it always returned occasionally when I read stories of that round. Always thought it would be a great cartridge in a 9 twist build. Best of both worlds. 40-75 grain bullets instead of 40-55s. Back then it wasn't real popular shooting heavy bullets in 22-250. Today having a 22-250AI running 53-80s in an 8 twist, the need for a CHeetah isn't so strong. One day I'll step up to the 22-243 improved and see what the CHeetah really offered. Only difference is it will have an 8 twist barrel.

 

[Ned Ludd]

The ability of small rifle primer .308 Win brass (Palma) to handle pressure is far greater than LRP .308 brass. Loads with 185s in LRP brass predicted by QuickLoad to be running somewhere in between 60-61K psi would trash the primer pockets in maybe 4-5 firings. In contrast, the SRP Palma brass can take pressures predicted to be in the neighborhood of 63-64K psi (or higher) for quite a few more firings. I'd imagine that would be a big benefit for a cartridge like the Cheetah.

 

[284winner]

The ability of small rifle primer .308 Win brass (Palma) to handle pressure is far greater than LRP .308 brass. Loads with 185s in LRP brass predicted by QuickLoad to be running somewhere in between 60-61K psi would trash the primer pockets in maybe 4-5 firings. In contrast, the SRP Palma brass can take pressures predicted to be in the neighborhood of 63-64K psi (or higher) for quite a few more firings. I'd imagine that would be a big benefit for a cartridge like the Cheetah.

According to Carmichael, he stated in the article of his CHeetah build, that the large primer ignites much more case powder upon ignition than the small primer does taking away from the charge used to propel the bullet. Too me it seems as tho once the primer ignites the case powder, it's all burning to propel the bullet anyway. Didn't understand his theory exactly concerning the primer ignition and the powder it ignites in the case. The pressure difference I understand.

 

[Richard308]

The ability of small rifle primer .308 Win brass (Palma) to handle pressure is far greater than LRP .308 brass. Loads with 185s in LRP brass predicted by QuickLoad to be running somewhere in between 60-61K psi would trash the primer pockets in maybe 4-5 firings. In contrast, the SRP Palma brass can take pressures predicted to be in the neighborhood of 63-64K psi (or higher) for quite a few more firings. I'd imagine that would be a big benefit for a cartridge like the Cheetah.

A bench rest gunsmith built me a 22Cheetah Mk 1 on a Remington 40X action and Hart barrel back in the late 80's. The Hart barrel was a 1 in 16 twist using 52-55 grain bullets. Remington URBR (308) brass with the small primer pocket was used to fire form.Using IMR 4350 powder as a final load and Rem. 71/2 primers , I was constantly blowing primer pockets, even after reducing the load, the leaking primers had damaged the bolt face and I decided to re-chamber it to 220 Swift. I have a set of RCBS dies in 22 Cheetah Mk 1 in case anyone is interested.
I believed the Cheetah idea involved Jim Carmichael (benchrest shooter) and Fred Huntington at RCBS. The 1 in 16 twist was used at the start.

 

[284winner]

A bench rest gunsmith built me a 22Cheetah Mk 1 on a Remington 40X action and Hart barrel back in the late 80's. The Hart barrel was a 1 in 16 twist using 52-55 grain bullets. Remington URBR (308) brass with the small primer pocket was used to fire form.Using IMR 4350 powder as a final load and Rem. 71/2 primers , I was constantly blowing primer pockets, even after reducing the load, the leaking primers had damaged the bolt face and I decided to re-chamber it to 220 Swift. I have a set of RCBS dies in 22 Cheetah Mk 1 in case anyone is interested.
I believed the Cheetah idea involved Jim Carmichael (benchrest shooter) and Fred Huntington at RCBS. The 1 in 16 twist was used at the start.

His article only tells of his Douglas 1-14 twist barrel used for his Mark I project gun. His testing was done with 50-55 grain bullets. IMR 4064/4350 were the only two powders used in his article. Charges ran from 40-49. Velocities ran from 3700-4285. Barrel was 27". Carmichael was the designer and inventor and Huntington being the founder of RCBS and friend of Carmichael who provided the reloading components. Initially called the .22 Carmichael-Huntington was shortened to .22 CH but turning out as fast as it was, the speediest of it's breed , it became the .22 CHeetah.

 

[Ned Ludd]

According to Carmichael, he stated in the article of his CHeetah build, that the large primer ignites much more case powder upon ignition than the small primer does taking away from the charge used to propel the bullet. Too me it seems as tho once the primer ignites the case powder, it's all burning to propel the bullet anyway. Didn't understand his theory exactly concerning the primer ignition and the powder it ignites in the case. The pressure difference I understand.

There certainly can be a difference in ignition (brisance) between large and small rifle primers. I guess the most important thing for running brass in the Cheetah would be how high the pressure of your intended load would be. If it was kept below about 60-60.5K psi, the LRP brass should be fine. If the load had greater pressure than that, the Palma brass would have much better life. I would think you could regulate ignition and burn rate to some extent with either SRPs or LRPs simply by choosing a primer with the appropriate brisance for the load, just like optimizing primers in any other load.

 

[Ned Ludd]

A bench rest gunsmith built me a 22Cheetah Mk 1 on a Remington 40X action and Hart barrel back in the late 80's. The Hart barrel was a 1 in 16 twist using 52-55 grain bullets. Remington URBR (308) brass with the small primer pocket was used to fire form.Using IMR 4350 powder as a final load and Rem. 71/2 primers , I was constantly blowing primer pockets, even after reducing the load, the leaking primers had damaged the bolt face and I decided to re-chamber it to 220 Swift. I have a set of RCBS dies in 22 Cheetah Mk 1 in case anyone is interested.
I believed the Cheetah idea involved Jim Carmichael (benchrest shooter) and Fred Huntington at RCBS. The 1 in 16 twist was used at the start.

As I alluded to above, I think Rem 7 1/2 primers fall at the very upper end of the brisance range:

https://web.archive.org/web/2015030...2009/06/primers-small-rifle-primer-study.html

I can imagine that using such a "hot" primer might increase both initial and peak pressures, resulting in exactly the issues you described. Using a primer with lower brisance such as the Fed 205 or the CCI BR4 might have alleviated the problem to some extent.