Vltor lower fitment

First of all, sorry if my google-fu isn’t up to some of your standards. I tried searching but was unable to find a direct answer.

I’ve been looking at buying a Vltor lower for a new build. I have read that a Vltor upper wouldn’t fit a LaRue lower and that the upper may have too much beef on the end where the upper meets the lower / buffer tube area.

Does anyone have experience with using a Vltor lower and a standard (BCM in my case) upper? Maybe a gap between the upper and lower between the upper / lower under the charging handle?

I’d think it would fit a standard upper fine or they’d warn you. When you start mixing different brands of beefed up/enhanced uppers and lowers i could see that being an issue.