Yes, a Jennings J22 will fire without a magazine inserted.
Recommend you ask a gunsmith for help
That's a task best left to a gunsmith.
These retail for about $85 new.
Best to ask a gunsmith for help if you don't have a manual
.22 LR rim fire
They were about $60 new, and now about $100 in good condition at a gun show.
$50 to $75. These were very crude, low cost firearms of no particularly high quality.
Best bet is to find a gunsmith
No, a magazine for a Jimenez J22 will not fit a Jimenez J25 pistol. While both pistols are manufactured by the same company, they are designed for different calibers and have distinct magazine dimensions. Therefore, using a J22 magazine in a J25 could lead to feeding issues and is not advisable. Always use the correct magazine specifically designed for your firearm model.
The estimated value of a Jennings model J-22 pistol is between $80-$150 dollars depending on finish and condition. They are becoming more rare and are going up in value rapidly. They are a part of the Ring of Fire pistols and have a unique place in history as the original "Saturday Night Special", which may ultimately make them a must-have with collectors or "mouseguns".
used about 125 (like new) - 50 (worn) dollars us. New about 150.00 Us.