Just bought one as a Good Friday impulse purchase. A big Houston gun store was doing a really good storewide sale, which I have never seen there before. 20% all stock in a very early morning window. Anyway, this 60 year old gun (HS SK-100) is having failure to feed issues and I'm sure some of you have this pistol or something very similar. I know the magazine and ammo are critical to smooth feeding and 22 LR rounds can be all over the map on performance and reliability depending on the pistol. There is no feed ramp for this pistol. Long story short. My magazine looks to be pretty old and the rear lips on the magazine likely need some tuning (I have a tool for this process). My rounds are feeding high when I have a FTF. My trial and error process seems to show that copper plated rounds work better than lead. Questions: 1) Would you please recommend a good ammo? I have seen that standard velocity ammo is recommended for these pistols, but my standard velo stuff is all lead bullets which seems to be problematic (they get cut and gouged to easily when going into battery). 2) Is high velocity ammo (1200 to 1280 FPS initial) not a good idea to use on this pistol? The Sport King (version 2) I believe was built in the late 1950s. I don't want to break the gun needlessly, but it seems like the gun is very well built. Copper plated ammo is common for the 1200 FPS rounds I see at the store. 3) Recommended replacement magazines (HS non-military)? I have seen a couple of options out there with Triple K being very available. Is this one good enough or is a there a better option? I have a magazine tuning tool now as well to get it working right. I am not very sure about the manufacturer of the supplied mag I currently have. The key thing here (I think) is having a well built magazine that will perform when it is correctly tuned. 4) The firing pin on this pistol does not appear to be spring driven - it seems to be loose in the slide. Is the firing pin supposed to be that way? Any pointers would be much appreciated!