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DD

The Cheetah is alot of work.
But as has been stated..the fun factor is always there.
You want impacts?
Get a video camera to go along with the Cheetah.
I've flipped 10 lb chucks into the air at 500.The impacts on smaller chucks are even more wild.
You ever decide you want to play I have a formula that will get one to shoot out the gate, without reinventing the wheel.


dave

Thanks Dave, I'll keep you in mind if I decide to play with the Cheetah. I saw my friends rifle the other day and it was a sweet little rife with a 24" barrel. I said to myself, hum, that might be fun.

Sharp Shooters Supply has a chamber reamer for 22-243AI with the 40 degree shoulder. I had them punch out my 26 inch varmint weight Savage 22-250.

The CHeetah requires some volume reducing forming steps, which I consider a PIA, and counter productive to my needs.

I run 243 brass into the sizer to reduce neck diameter and fire form with a 60 gr bullet at 3600 fps.

The next barrel will have a faster twist, currently it is the original Savage 14 inch. So I stick with the 60 gr Hornady spire point. H414, H4350, IMR4831, H4831, and Magnum all work well with this bullet.

From www.loaddata.com:

.224 Texas Trophy Hunter (TTH) / .22-6mm Remington Reloading Data

Following extensive experiments with the 220 Swift, 22/250 and 240 Weatherby cases, the designer settled on the 6mm Remington case as the best balance of case taper, shoulder angle, length and capacity. Necking the 6mm Remington case down to 224 (with the factory's 26-degree shoulder angle), he created a cartridge that would deliver heavier well-constructed, 70 to 80-grain 224 bullets accurately at relatively high velocities. The 6mm case provides optimum capacity for the 224 bore, brass is readily available, and standard actions and magazines require no modification other than a new barrel. Proper rifling twist for the 224 Texas Trophy Hunter is 1:8 or 1:9. Bullet construction is the key to success; it takes a stout, thick jacket, solid or bonded core bullet to hold up to the velocity potential. Stoutly constructed bullets can be driven in excess of 3,500 fps. Dies are available from Redding; Nosler recently endorsed its 22-caliber 60-grain Partition bullet for whitetail deer hunting. (Cartridges of the World 10th and 11th Edition)
Be Alert: Publisher cannot be responsible for errors in published load data.
Wt. Bullet Powder Manufacturer Powder Charge Velocity (FPS)
55 Trophy Bonded Hodgdon H-4831 46.5 3,840
60 Nosler Partition Hodgdon H-4831 46.0 3,780
79 Lost River Vihtavuori VV-N165 45.0 3,520
75 Hornady A-Max Winchester Win Mag Rifle 47.0 3,780

What does that actually mean?

dave

If you build it on a Savage action or a Remington 700 (or better a single shot XR-100 or 40X if one can be found) with a Remington barrel nut and pinned recoil lug, you can swap out the barrels yourself. The Savage allows swapping bolt heads across case families inexpensively, so different cartridges can be experimented with. The CHeeta shouldn't erode barrels any worse than any other overbore .224 with today's powder choices.

There is loading data for the .22 Cheeta Mark II on the Hodgdon loading data site.

To my pea brain I don't see what the CHeeta will do that a .22-250, .220 Swift (especially the Ackley Improved versions with better brass life) or the .223 WSSM will not do without all the hassle. The .22-250 and Swift having the advantage of fitting the .308 Winchester's bolt face.

I don't use .224 calibers for long range varmints, preferring the .243 WSSM. While that is my thing, I still have two .22-250's and I'm building another in the Ackley chambering, one .220 Swift and a couple of .223 Remingtons. The .220 CHeeta would be a good choice for a foray into wildcat cartridges, with the learning experience being a side benefit.

Compare the brass length of 1.986 inches for the CHeetah Mk I vs 2.015 in for the 308, or 2.035 in for the 243.

In the Mk I version of the cartridge, The neck/shoulder juncture is actually moved back and the brass is trimmed, which reduces capacity of the finished cartridge when compared to the AI version of the cartridge. Carmichael's goal was maximum accuracy by bench rest standards, not maximum powder capacity.

In the Mk II version, the brass is left full length. But the 28 degree shoulder does not allow the case as much volume as the AI 40 degree shoulder.

It is much simpler to just neck down the 243 case. Then fire form to the AI dimensions, and have a bit more volume in the case when finished.

The CHeetah Mk I measures 1.647 inches from base to shoulder, the Mk II measures 1.605 inches from base to shoulder. My actual fireformed 22-243AI cartridge measures 1.69 inches from base to shoulder.


MK I




MK II


22-243AI

Compelling. I shoot them all and the CHeetah is easy to pass on and the 22-250AI is where it's at. Much prefer the 223AI,but that is an issue separate. The Swift and Rocket are junk,as are Mouser based goat [bleep].



If/when the fast twist 22-250AI is leaving one shy of a good time,it's time for the 243AI.

So, if I'm reading you right the MKI is the improved version and the MKII is the standard version, correct?

No real reason the MKII couldn't be made from .308BR brass, correct?

If one uses .243 brass to make the MKII than what one has is really .22-243 NOT a .22 CHeetah, correct?

Mk I and Mk II are both "improved" as the original 308 or 243 case has a 20 degree shoulder and both CHeetahs are sharper than that.

Either form of the CHeetah may be derived from 243 brass more easily than from 308BR. Except by definition the CHeetah has a small rifle primer pocket and that can only be acquired through use of 308BR brass.

A 22-243 case would measure 1.560 inches to the shoulder and 2.045 inches overall with a 20 degree shoulder.

Yes the differences are subtle and mostly insignificant, except when ordering chambering reamers, headspace gauges, and resizing dies.

Our friend made a very valid point re 22-250AI. Any case larger than that burns a lot more powder for very little velocity gain.

I knew that very well and had my barrel chambered for the 22-243AI. Nobody ever said this stuff had to make sense.

Might be a pun there.

For us, the unwashed masses, can you identify the members of that lineup?

I'll take a stab at it...

Hornet AI, 223AI, 22-250AI, 243AI.

They all look .22 to me...

K Hornet, 223AI, 22-250AI, 22 Cheetah

I came across this on stevespages.com

http://stevespages.com/jpg/cd22243.jpg

It just says .22-243. It has a 30o shoulder. Is it a Middlestead?

What do you think of a .22-250 with a 30o shoulder?

Based on written descriptions, which I have read, of the 'Middlestead, I would answer "Yes". The drawing you referenced appears to be it.

A 30 degree 22-250? Not for me.

I would go Ackley or leave it as Remington built it. The greatest advantage of the improved cartridge is that the 40 degree shoulder eliminates brass flow and longer or thickened necks, thus eliminating the need for trimming or turning of case necks.

I do not have the experience with wildcats that Paul, or Big Stick, or Steelhead have. I only have two AI cartridges. But I lose very few cases when Fireforming to the 40 degree shoulder of the 30-06AI or the 22-243AI. Just use brand new brass.

If I had a 22-250AI, I would buy 250 savage brass and neck it down to 22 for a good chamber fit when fireforming, to insure proper headspace.

One should be able to fire factory 22-250 cartridges in a properly built Ackley chamber, but I would go the 250 route anyway.

I believe you are correct.



A properly chambered AI rifle will crush fit on a standard case. And you cannot beat Lapua 22-250 brass.

I kinda figured a 30o shoulder wasn't worth it on a .22-250.

Thanks.

The fly in that ointment is the spotty quality of 250 Savage brass. It hasn't been as good as generally available 22-250, and it isn't going to be on the same planet as Lapua 22-250.

Using 250 Savage brass is a backwards approach.

I have been known to run a 243 expander into my 22-250's and neck them back down. But that was to put off doing a rechamber on a rifle which had a "generous chamber".