since rimfires headspace off the rim, you are asking for trouble; now then, if you get a 17mach 2 rifle, and buy eley or remmy ammo for it, this ammo is hotter loaded than other mach 2 ammo, about 200 fps faster, which brings the speed up to about 2300 fps, even more, in a very well made bbl.
also if you get a mach 2 rifle, ammo is about 1/3 the price, of hmr , especially if you buy a case of it at a time from ammuntitiontogo.com. tell them you are a rfc(rimfirecentral) site member, and want the good deal on eley m2 ammo, and it is yours, for 139. a case, plus real world shipping, which he told me, is less than 15 bucks, all the way to vermont or maine.
Lastly, if you get a m2 rifle, you can fire 17 aguila ammo through it; this is a true 22lr case, but with a longer bullet. not only that , it is a 20 grain, full metal jacket, boattail bullet, that does about 2000 fps from your bbl. this will drill tiny holes through small game, without blowing them up like the other bullets may.
this is good, if you wanna keeps skins, save meat, or the like. they may or may not shoot real accurate from your rifle, you just have to see. I have a ruger in 77/17mach 2, that actually shoots the aggie ammo, tighter than regular mach 2 ammo, and that is sub moa as it is , allready!!! schwing!!!!