Originally Posted by
Bigslug
You have two major variables to contend with:
1. You can't seat the bullet out farther than the magazine will allow.
2. You can't seat the bullet out farther than the leade of your rifling will allow. Drop an empty, sized case into your chamber and see where the case head stops in relation to your barrel hood. That's what you want your loaded rounds to do. If it stops farther back than that, you have your bullet's shank too far forward out of the case.
Within those confines, you want the longest C.O.A.L. you can reasonably manage - backed off a little bit so you aren't right up to the ragged edge of failure.
When the feed pawl of your slide hits the rear of the cartridge, the cartridge starts moving forward, but the nose of the round also wants to dive downward. The recoil of the previous shot is also a contributing factor to this, and how much nose-dive you'll have will also depend on how many rounds remain in the magazine. The goal is to have the forward movement of the round place the ogive of the bullet on the feed ramp before the downward movement can collide the nose with the top of the mag or bottom of the ramp, hence the desirability of the longer round.
Magazine styles can play into feeding as well. I mentioned the GI-style tapered feed lips in my last post because they give the 1911 a Mauser-style controlled feed system that allow the nose of a cartridge to rotate progressively upward as it travels forward, and gradually hand off the groove of the case to the extractor. There are parallel-lipped mags and hybrid types out there that will present the round and time its release differently. It's worth playing with a couple different types to see if the mags are your issue.