Opinions on 300blk LMT MRP barrel or dedicated 300blk upper

I own a LMT MRP and would like to make use of the quick barrel change out options. Does any one have experience with swapping out LMT MRP 5.56 barrels for 300blk out barrels? How did it affect your POI? I'm sure there is more drop that needs to be accounted for but is there anything else that you've experienced.. liked or disliked about switching between calibers on an LMT MRP? I currently run an aimpoint pro but may run an ACOG, Elcan Specterdr or something similar in the near future.

I also am building a custom lower and will need to mate it with an upper. Haven't decided what upper I want. I may just make a dedicated 300 black out..

I would make a dedicated rifle, or at least upper, even though you have a modular barrel upper, so that you can have an optic sighted in for it and also because it is quicker to change uppers or rifles.

I liked my MRP because it is a nice rifle, but didn't end up changing barrels on it.

I'd buy/build a dedicated 300BLK complete upper at a bare minimum. If you already have a Form 1 lower then an upper is all that you need. I went with an entirely new rifle (AAC MPW 9") for my 300BLK and I plan to use it mostly for hunting.

Good luck with your decision, there are quite a few really good 300BLK options out there.

The counter-point is a .300 BLK MRP barrel and a dedicated optic in a QD mount will a) be zero'd to the .300 BLK, b) cost hundreds less than a complete upper and c) it is really fast to swap an MRP barrel and a QD optic.

I'd be tempted to get a separate upper in .300 BLK to go shorter than 10.5"

I'll join in with the 2nd upper crowd, I had the same dilemma about 6 months ago.

Wanted very badly to use the barrel change capability but decided against it. My reasoning was for me firstly I have a 12.5 piston so new carrier $$, MRP barrel profiles are gov plus a few ounces so to reprofile at ADCO was $$, then add the barrel $$ and a new Aimpoint T1 $$.

It all just added up and I decided to just get another Noveske upper with the NSR so I luckily found an 8" and haven't regretted it at all.