most of the problem is due to M21's poor
sights, and trigger overtravel. Draw outline of trigger on paper, clamp its tip in vise, heat with torch, and bend it more, creating less space between it and the frame. Measure space between it and frame before disassembly, so know how much to bend. bend it a bit more rather than less, because easier to reach behind it with dremel remove metal from frame. time is money. Depending upon level of accuracy desired, can either pin down the rear of the popup barrel or not,, drill out the bore and fit 3" of Brownell's barrel liner or not, silver solder a ramped front sight to either the existing band up there, or to the 1/2" long pc of tubing that you thread onto the protruding 1/2" of liner. May or may not want to bother with fitting one of Brownell's generic .22 extractors if pin down the barrel.Fit a Taurus longer mag for a better grasp on the pc.Stipple the front and rear straps. Weld up the top rear of slide (remove firing pin and spring!) and cut a dovetail for a REAL rear sight into the weld. i favor that of the smith 2213, but maybe mmc's little adjustable for ppk would work. I think it's too small and fragile myself. Need Brownell's t handle, hand chambering reamer, and piloted drill bit if doing the barrel liner thing. naturally, other accessories will also thread onto the liner. My design for same makes up into an 8" overall package, with same accuracy. Ideal supplemental pistol to the 357 Sig pocket auto for SHTF. 14 OZS AND 19 OZ= still very lw package,very versatile