Jerry, the biggest factor in any ammo in the 1911 is length rather than bullet type. This is where the release point on the magazine comes into play. The farther forward it is the closer to hardball overall length specs the round has to be. If you compare a GI mag to Wilson for instance you will see a big difference in where the mag lips open up to allow the round to rise. But, if you are shooting a 1911 with a barrel throated like a GI barrel it doesn't make much difference how far back the release point is on the mags. It will still likely have feeding problems with anything other than hardball. The guns I work on have to pass a final test before sending them back to their owners. They have to feed hardball, either WW Silvertips or Federal Hydrashoks and my ultra short semiwadcutter hand loads. If the gun will function with all 3 types I'm satisfied that it will work with any comercial ammo. To answer your original question though the most reliable HP ammo I've ever seen was the Remington Flying Ashtray. I don't recall ever having a pistol that wouldn't feed it if it would feed hardball. The most common round that I'm asked to make a 1911 work with is the Federal Hydrashok. Occasionally someone will complain about the Speers also. But as a rule it isn't the cartridge, it's that the pistol isn't set up for it. A good rule of thumb would be the shorter the round the more chance of it not feeding reliably in a pistol out of the box. George