Among the things I wish I knew before opening my big trap are: What gun are we talking about? What magazine are we talking about? What brand of bullet are we talking about? Do your comments mean the rounds are failing to enter the chamber, or that they are failing to go to battery? And, did you make a dummy round before starting loading to check in your actual barrel?
Anywho, my experience over the past couple of years has suggested that O.A.L. is not a useful piece of datum when it comes to specific bullets in specific barrels in auto-loading pistols. Rather, each bullet design has a different profile for the front part -- the part outside the case. Add to this the matter that barrels are cut with different throats, or often with no freebore whatsoever. Springfields, for example, are known to have chambers that put the bullet up against the lands when the ogive of the bullet begins right at the case mouth. So, you really have to play around with dummy rounds in your actual pistol for a while before committing to proceeding with the loading process.
I use the actual barrel of the gun as a chamber gauge to check bullet seating and other dimensions before putting powder in cases and making working rounds. You really cannot bypass this step with autoloaders in my experience. It's a long trip back from the range when you don't get to put any lead downrange. I have learned this lesson the hard way -- more than once, sadly.
In general terms, 45 acp bullets are designed with a shank, a small step, and then the beginning of the ogive. They tend to do this so that their product will work in a barrel with no throat. This step must be AT OR BELOW the mouth of the case for rounds to go fully to battery. The mistake I made when starting with the a.c.p. was that I didn't seat the bullets deep enough to allow the ogive to clear the lands when the round was chambered. This happened to me because I didn't realize that small step in the bullet was present. It isn't obvious at first because it is only a few thousandths of an inch. We see this problem at every WBAS match with someone who made an assumption about O.A.L. rather than actually testing a given set-up in their barrel before making their ammo. It is very frustrating for the shooter and everyone else at the line responsible for safety.
So, even though a given O.A.L. might fit in the magazine, it won't necessarily run in the gun.
In the absence of answers to my initial questions, I'll go even further out on a limb and suggest the following:
1. Clean your feed ramp and polish it if you haven't already done so.
2. Use only good magazines. The majority of people I shoot with use Tripp magazines. We pay the money for them because they're worth it.
3. Be absolutely certain that the ogive is seated at, or even slightly shy of the case mouth. None of the "shelf" of the shank can be exposed. In other words, the curve of the front of the bullet must start IMMEDIATELY at the the case mouth and taper to the point from there. (this seating may require some adjustment to your powder charge, but probably not).
4. You must make a series of dummy rounds to dial things in before proceeding with loading.
5. Remove your barrel from your pistol and use it as a chamber gauge to check dimensions. If the round won't go to battery here, it won't work consistently in a match.
6. Once things are dialed in, a chamber gauge (Dillon Precision) is necessary for absolute quality control. I consistently encounter brass that is swollen or has a burr at the back end from previous use. A sizing die will not always fix problems at the back of the case. I, personally, use a Lee Bulge Buster on all the brass I intend to use in a match before loading it. At any rate, I've learned I cannot assume consistent results, so a chamber gauge is invaluable.
I hope this helps. Please report back with some more information and your progress.
All the best,
AW