Don't worry what beats up your spring less. You aren't going to be firing thousands of rounds through the gun. You will test the round to make sure it works and then firing it only occasionally. I like the 200 gr. +P rounds at about 1000 fps out of a G36 barrel, either Gold Dot or Hornady TAP FPD. I don't like 185 gr. or lighter rounds out of any length barrel. I don't think the .45 acp has enough sectional density for these lighter rounds to penetrate consistently. The .45 acp was designed for heavier bullets. The 185 and lighter bullets came later. And while people are amazed at their velocities and muzzle energy, those figures mean little if the bullet doesn't penetrate deep enough EVERY time. I carry the Hornady TAP FPD 200 gr. +P in my G36. Nothing shoots better to me, the penetration is great and the expansion is more than adequate. It might not expand as violently as some of the newer rounds, but violent expansion usually limits penetration, which is the most important factor of bullet performance. Remember, you might have to shoot through multiple layers of clothes and/or someone's arm.