Just thought I'd add some 22 Jet chronograph data I collected.
Knowing the propensity for flash and boom, then adding in the throat erosion issues caused by the Remington factory ammo I decided that Alliant BE-86 would be a good powder to explore along with some other usual choices. Reports place the BE-86 burn rate between Unique and Power Pistol. The old Speer #9 manual shows 40 gr. bullet data for Unique at 6.0 gr. @1527 fps and 7.0 gr. @1759 fps. With that information I generated this load ladder and results:
5.5 gr. BE-86 1398 fps.
5.8 gr. BE-86 1475 fps.
6.1 gr. BE-86 1510 fps.
6.3 gr. BE-86 1544 fps.
6.5 gr. BE-86 1611 fps.
The loads had all of the blast, but no flash as advertised. Rotating the muzzle upwards, all the cases dropped out without needing the ejector. I might explore going up to 7.0 gr. sometime in the future, but for right now I'm calling BE-86 a success.
The other plinking load I've been using is 7.4 gr. of Blue Dot that delivered 1344 fps.
The last bit of testing involving some handloads I was given without data. I pulled the bullet from one round and found that it used a .223" bullet and 11.2 gr. of powder. I'm all but certain it was Alliant 2400 and 11.2 gr. might be OK in a T/C contender, but it was a full grain over the max listed in the old Speer #8 manual. I decided to pull the bullets and generate another load ladder in the remote chance the handloads were serviceable as is.
9.5 gr. 1393 fps
10.0 gr. 1456 fps
10.3 gr. 1468 fps
10.6 gr. 1579 fps
10.8 gr. 1683 fps.
Until the last load, the measured velocities were below the listed starting load velocity using 2400. One of the 10.8 gr. loads needed a rod tap to extract the case. Clearly way over maximum working pressure. I ended up pulling the bullets from the remaining mystery loads and dumping the powder.