No, you cannot.

Hi David, no sir, .22lr cannot be fire from a gun chambered in .22 mag, and vice versa.
Stay safe & have a great day!

Hi David and welcome. Unfortunately, no sir. 22 Magnum and 22LT have different case sizes as shown here (Bullet inside the case on 22 Mag and bullet over hangs the case ion 22lr)(2nd picture down): nrawomen.com/content/do-22-mag-snubnose-revolvers-make-sense-for-self-defense ----------------------------- This is why 22 mag/22LR combo revolvers come with two cylinders: budsgunshop.com/product_info.php/products_id/87903/heritage+manufacturing+rough+rider+22lr+22mag+4.75+blued

No. It will not fit. The magnum case is just a few thousands of an inch too big in diameter. Nor should you put a 22 LR in a magnum weapon. It does not make a safe seal in the chamber.