No weaker springs available. I'd buy a stock spring and remove a half coil at a time till you find the right length that will make it work. By the way, common to have sub sonic rounds not cycle in semi auto guns.

Steve, CCI Standard Velocity : budsgunshop.com/product_info.php/products_id/89892/cci+0035+22+lr+40+gr+standard+velocity+50rds -- and Winchester PP for hunting ---- budsgunshop.com/product_info.php/products_id/138144/winchester+100+year+anniversary+22+lr+40+pp+300rd+box

Have you tried CCI's Quite Semi-Auto Ammo? It has a 45gr bullet and is designed for Semi Autos.

Steve, I'm finding extra power springs but no lower power springs. Unfortunately looks like your stuck with using higher velocity rounds. Knows it's a pain but I'd shoot off the rest of the subsonic rounds by racking the slide each time or it always gives you a reason to buy another firearm. Sorry but hope this helps.

I'm unable to find any weaker springs available, unless you purchased quite a large amount of subsonic ammo I would simply just try regular 22LR loads. From a barrel as short as the LCP 22 nearly all loadings of 22LR should be subsonic anyway. I have trouble getting subsonic 22LR to cycle in any semi-automatic firearms and generally only use it with my suppressed bolt action.