Don't try this it is probably on the order of here hold my beer and watch this.
I have done some stuff like this with .22 Mag before but using .22 Mag brass that I pulled the bullets and powder and just reloaded with different powder and bullets to see if I could get better performance out of handguns. .22 Mag in handguns is not much better than top end .22 LR ammo.
All my testing is in my Ruger Single Six.
I did improve the performance but not enough to be worth the trouble.
This time the motive is a bit different. .22 Mag ammo has always been expensive and now is also hard to find. What I did was combine a couple old experiments. One was a sleeve that lets me fire .22LR in .22 Mag chambers and the afore mentioned performance improvement experiment.
What I have done is use my adapter sleeves, broken down .22 LR and my new powder charges.
The picture top to bottom:
Fired cartridge
Loaded cartridge and fired donor .22 LR case
Donor .22 LR case, sleeve and donor .22 LR bullet
I worked up charges until cylinder rotation was too stiff to cock the hammer but could be rotated with help from my free hand and then back off 10%. It was brass flowing into the firing pin hole that resists cylinder rotation. Dropping down 10% lets the hammer cock and rotate the cylinder but it is a little stiff. Dropping back to my starting loads are as good as factory ammo and don't have cylinder rotation drag.
The donor ammo is Winchester bulk pack ammo. The bullets weigh 36 gr.
The max charge I chrono'd was 1640 fps
The 10% less charge was 1450 fps
I did not chrono my starting load.
My past experiment I used a 35 gr Hornady V-Max bullet in a CCI .22 Mag donor case chrono'd 1480 fps and with a 40 gr. .22 LR donor bullet the velocity was 1310.
In my gun:
Win 40gr. mags 1329 fps
CCI 40gr. Maxi-Mag 1309 fps
Aguila Interceptor 40gr. .22 LR 1114 fps
In other reports:
.22 WMR vs. .22 LR in Ruger Single Six
.22 Mag.
CCI Maxi-Mag 40-gr. FMJ 1360 fps
CCI Maxi-Mag 40-gr. JHP 1315 fps
Federal 40-gr. FMJ 1325 fps
Federal 40-gr. JHP 1308 fps
Winchester Super-X 40-gr. FMJ 1351 fps
Winchester Super-X 40-gr. JHP 1306 fps
.22LR
CCI Mini-Mag 36-gr. HP 1063 fps
Federal Champion Target 40-gr. Solid 970 fps
Remington High Velocity 36-gr. HP 1098 fps
Remington Yellow Jacket 33-gr. HP 1279 fps
Winchester Super Silhouette 42-gr. Solid 953 fps
Tim