The chances of getting a Colt LE6920, which is built to USGI specs and standards is vanishingly small.
Lack of lubricant is only an issue after a fair number of rounds are fired and fouling starts to build up.
I think that what you have is a problem with your reloads and a not unusual problem with steel cased ammo..
The key here is that factory M193 Federal and the other factory ammo is all 100%.
When a firearm shoots new factory ammo but chokes on reloads, the problem is the reloads, whether you like to admit it or not.
Even thought the reloads SEEM to be all in spec, obviously they aren't.
Steel cased ammo is notorious for causing problems in American firearms.
Some firearms it works just great in, others of the same brand and model choke on it.
The problem is that steel cases don't expand and contract as well as brass. Combine that lack of elasticity with a chamber that doesn't have the taper of Soviet ammo when fired in American chambers that have less taper, and you get problems.
With steel cased ammo, if it works, great. If it doesn't...don't use it.
That a case fired in one firearm won't chamber in another without being resized is totally normal. All chambers have slight differences that often cause a fired case not to chamber.
Trying to chamber a fired case in another firearm tells you nothing.
Advice:
Forget the steel cased ammo, it just doesn't "like" your rifle and there's nothing you can do about it other then to try another brand and hope it will work. The steel cased ammo is made in former Soviet ammo plants and quality varies, often considerably.
If you can't find a brand that works, just figure on not using steel cases.
Obviously your rifle doesn't "like" your hand loads.
Check your loading system and process, and if possible have a more experienced loader look things over.
Often it's no more complicated then a case die not adjusted perfectly or a bullet going into the case off center slightly.
Bottom line: Your rifle works 100% with good quality factory ammo.
The problem HAS to be with the reloads and the steel cased ammo, not with a lack of enough lubricant.
An AR will work for a while bone dry.