Problem #1
. . . what kind of ammo and bullet type are we talking about?
Good point. I'd also like confirmation that this pistol uses a standard, non-ramped barrel.
FWIW, I use factory 230gr FMJ for initial function testing of all new-to-me 1911s. Of late I've been using Winchester white box because I got a good deal on a case of it.
Any 1911 using quality magazines will run 100% with this ammo and a 14lb recoil spring. If it doesn't, there's a geometry problem somewhere inside the pistol. Often times people will suggest using a heavier recoil spring to fix feeding problems in an effort to overpower whatever is causing the problem. All this is doing is masking the underlying problem. It's a field expedient to get the pistol to run in the short term but it's not a permanent cure.
Also, I'd want to shoot the pistol some and effect some type of break in.
Having to run 500 rounds through a newly manufactured 1911 in order to get it to function 100% indicates poor fitting of the parts at the factory. The pounding of 500 rounds beats ill fitted parts against one another until enough metal is displaced to allow the parts not to hang up on one another. Kimber is famous for doing a poor job fitting lower barrel lugs to slide stops which results in various degrees of barrel bump which, if bad enough, will cause failures-to-feed and/or failures-to-return-to-battery.
In this specific instance the OP's pistol will not feed the top round in a fully loaded magazine. The nose of the bullet is stopped on the feed ramp and the rest of the cartridge is in the magazine. He has not specifically said that this happens with all magazines. He has not said that it only happens with a fully loaded magazine. He has not said that downloading the magazine by one round eliminates the first round feeding problem. No amount of "breaking in" will help this particular malfunction.
The problem may be caused by the ammo, the magazine, an out-of-spec frame ramp, or a couple of other less likely things. We can only speculate since we don't have enough information to make a definitive diagnosis.
The OP needs to focus on one problem at a time and take the time to go through all the steps needed to fully diagnose it. Otherwise, time, effort, and money may be needlessly wasted. I made the mistake early on of jumping to a conclusion and suggesting a possible fix (EGW mag catch). Time to slow down and get methodical in diagnosing the two problems with the OP's pistol.