Quote Originally Posted by para
MP stands for Pistol Powder, use it in your pistol.

S221 will give you a cleaner burn and you will like it.

MS is also fine but will eventually will shorten the life of your pistol like S121.
If you want the gun to last and you are happy with being 11th in the country in IPSC stick to a heavy head and MP200 or S221.

Well, I'm currently 9th in Std gun on the National log. My gun works just fine (Para frame, .40 STI bull barrel, RHT Slide). It has never broken, jammed, cracked or had any other problem...... ever. I use 180grn Lead bullets (self cast) with S121. The gun feels soft, has little recoil, little smoke and stays flat.

If your powder measure is accurate, S121 should not be a problem in a .40. (I don't like it in a 9mm or .45) The problem I found with S221 in a .40 is the fact that you have to use 2x as much powder to get the same velocity and I had unburnt powder falling out my barrel after holstering. But many people use it, and if it works for them, then good for them. I only use it in my Super when I shoot Open. MP is by far the most stable powder on our market and can be used in most handgun calibres from 9mmK to .45 and everything in between.

But as far as "What is the best competition load" goes: The best load for any gun, is the one the shooter is comfortable shooting with, whilst remaining safe. And it will vary from shooter to shooter.