.22 Super Jet

[Handgun'r]

Hey Guys,

Just thought I'd check and see if anyone had any "dusty data" tucked away for the old .22 Super Jet, (aka .22 Cotterman Jet, named after Dan Cotterman-gun writer, who created the wildcat back in the mid-60"s) The cartridge is basically a .256 Win Mag necked down to .22 caliber...with some slight variations in shoulder angle, etc. It was initially formed by fireforming .22 Rem Jet brass in a .22 Super Jet chamber.....similar in shape to the .256.
It's ballistically very close to the .221FB, (approx. 8% less case capacity), and (as listed by Ackley) runs 45-50gr. bullets up around 3200-3300fps.
It can be easily made from .357 Magnum brass, which I have a ton of, and it's a rimmed case which lends itself to the single action guns much better, thus the reason for making it.

Based on thoughts of the efficiency of the .22PPC, and other fat "shorty cases", it appears to be a good one for the powders and weights used.

As mentioned, I've got some data from Ackley, which was available on the internet, but for the most part, their isn't much else on it anywhere.
I'm currently having a 20" carbine barrel chambered for it now to go on my Encore for fox & coyotes.
Nothing wrong with the Ackley data, but I know he liked to push the envelope a little and was optimistic on pressures.

Anything you guys might have, or can dig up for me would be immensely appreciated......and won't be forgotten....

Thanks gang...

Bob

[Rocky Raab]

I pulled up my faithful Load From a Disk software, and that round is even listed in it (as the 22 Jet Ackley Imp).

For the Hornady 50 SP bullet, it recommends 15.5 grains of H4198 for a tad more than 2700 fps. (their listed "optimal" load.) They go up to 17.4 grains for 3050 fps as max safe load.

Other recommended powders are VVN 120, AA2015 and two hard-to-find ones: Norma 200 and AA2207.

[Handgun'r]

Thanks Rocky,

I figured you'd come through with something....

The load data that I saw on the net showed higher velocity figures (see below), but although not listed, I think the powder weight would be about the same for the 50 grs. with 4198.
Some of the data that I got was from your article on the 256 Win Mag. Although the cartridge is different, I correlated the powder and bullet weights on my computer to give me safe starting loads.
Depending on the barrel length that the loads were tested on, I can see the difference in the reported velocities.
Many of the these velocities listed for the Super Jet are "as good" or better than the .222, encroaching on the .223. This makes me quite skeptical. I think the Super Jet is a great round, for what it is, and I believe it's more efficient than the others for the powder used, but I'm approaching the data with skepticism.

This is the data that I retrieved so far....

22 Super Jet Reloading Data
Bullet (grs.) Powder / (grs.) MV ME Source
45SP IMR-4198 / 17 3300/ 1085 Ackley
45SP IMR-4227 / 16.5 3385/ 1140 Ackley
50 Ball C /21.0 2975/ 980 Ackley
50SP IMR-4227 / 16 3195/ 1130 Ackley


Rocky.....do they have a barrel length listed for the load you mentioned ? I have none for the data listed above, but I'm assuming it's 24-26" for those velocities.

I'll be using some H110, L'il Gun, RL7, 2400, as well as the listed 4198 & 4227.

Thanks,
Bob

[Rocky Raab]

LFD allows you to specify the barrel length, and so I plugged in 20" for your setup.

I'd be very, very leery of those higher loads. Remember that we're working with the 357 Mag case here, and that brass was designed for 35,000 psi working loads. That top LFD load I quoted gets up to 40, and that's starting to push it.

[Handgun'r]

Rocky,

Yeah, thanks......that's about what I figured.

I'm using a nominal 35-40 fps, per inch of barrel deduction from 24 & 26" barrels as a standard.
It comes close to the velocities listed, more or less.

I was looking for something around 3000-3200 anyway, so it should be about right.

Are other useable cases, like the .22 Rem Jet, and the necked .256 Win Mag, any different as far as pressure ?
Based on the same case design, I'm guessing not, but don't know for sure.

I'm assuming that the pressure limits that you're referring to are based on the safe, or working limits of the case head & web.....?

I'm just wondering how much those figures change when the cartridge is necked down, or how differently it reacts to doing so.

Thanks again,
Bob

[Rocky Raab]

It is based on the head/web design, so it shouldn't change much if the case is necked to another caliber.

There's also the gun design, but we're well within the pressure limits for the Contender with a case head of that diameter.

[Handgun'r]

Thanks again Rocky....

Mike Sirois at OTT is building the barrel for my Encore, so it should be relatively stout. Should be here in a couple more weeks (I hope ).
The barrel is a 1" straight fluted matte blue barrel.
Heavy, but short for carrying. More or less a carbine length, but stiffer.
I built something similar several years ago in .17 Rem for a friend and it balances for carrying very well.


Bob