hi all. have ticked up a barrel for a h&r in 22rem.jet am told that there were not very many of these made. any way i supposed the thinking was what good purpose would they serve. that ive asked my self, any way got the barel right and a little elbow grease fitted it to the receiver. passes my gun smiths eye so i did something right. have a small amount of brass this what im told is very hard to find if any one wants to get rid of some p.pm me please and need a set of dies for it also. i can find loads for pistols nothing for a 22" barrel rifle. any help or suggestion here would help. its just some thing to play with more for the grand kids and wife

gat.
Gat,
The 22Rem Jet operates at around 37,000psi and was designed for pistol-length barrels. You can use the recommended Contender loads safely, in your H&R barrel. The (old) Sierra manual I have specifies the following powders/charges out of a 14" Contender barrel, using Winchester small pistol or *CCI550 primers, as noted. I would expect 160-200fps more, out of a 22" rifle barrel.
Sierra 40gr Hornet
Unique 6.1gr - 8.0gr 1800 - 2400fps
IMR 4227 10.0gr - 11.8gr 1800 - 2400fps
*Blue Dot 6.9gr - 9.0gr 1800 - 2300fps
*2400 9.4gr - 11.7gr 1900 - 2400fps
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Sierra 45gr Hornet
Unique 6.0gr - 7.5gr 1800 - 2200fps
IMR 4227 9.4gr - 11.5gr 1700 - 2100fps
*Blue Dot 6.1gr - 7.9gr 1600 - 2000fps
*2400 9.6gr - 11.5gr 1900 - 2200fps
In addition to these loads, I used Quickload to check what Li'l Gun and 2400 might be capable of in this cartridge.
Please note that these loads are in a 22" barrel and are only a reference!
Sierra 40gr Hornet
Li'l Gun 11.5gr - 13.6gr 2612 - 3020fps
2400 9.5gr - 11.3gr 2539 - 2911fps
Li'l Gun seemed to provide the best load density in this cartridge, as it does with so many "Li'l" rounds. As far as formed brass goes, I don't know how to help you, there. I know this round is based on a necked down .357Mag case, and it looks like there are case forming dies to go from 357Mag cases or from 256Win Mag cases. Since the 256WM cases are already about $1/ea, I'm thinking I would buy the dies to go from .357Mag cases...they're much less expensive!
I know I've already rambled on forever, as I am wont to do, but I would delete all of the above and have your gunsmith buddy rechamber your barrel to something a lot easier to work with. There are a ton of options out there, but I would stick with a rimmed cartridge and have him cut the chamber for a 225Winchester. This would give you truly hot 22 performance and commercial brass that doesn't require any case-forming. (Winchester usually makes a run of 225 brass every year or two, so it's really not that hard to find. Midway has it, in stock, right now.)