I have been reading all the MRP threads but either I missed it or read it and it did'nt sink in.  Are MRPs as accurate as a AR in the same configuration?  What I mean is is a 16" QCB MRP as accurate as a 16" with the standard barrel mounting with the conventional screw the barrel to the upper method?  Is a 18" MRP as accurate as say a SPR?  If not can it be made as accurate?
Thanks,
Mike

Sure they are.  Want one?

No actually I have a QCB upper setup and a Rifle setup now I'm thinking of selling a coupla of my other AR's to buy more ammo since I dont use them all.  I was just wondering if I should change out the 16 on the rifle and put a 18" on it for SPR like or better accuracy and put a 16 on the QCB now it has a 14.5 with a permant Vortex.  I will keep my M4ergy and my 16 middy though.

This is a very broad question.  Accuracy is also a very subjective term.  What might be accurate to me, may not be accurate to you.  As for accuracy on the quantative side, that typically depends on the quality of the components that makeup the AR.  For example, a Kreiger match barrel should be more accurate then an off the shelf chrome lined barrel.  So, you need to first compare apples to apples.

As for an 16" chrome lined MRP vs. a 16" chrome lined mil spec AR, assuming that the mil spec barrel is free floated, they should be relatively similar in accuracy.  Roughly 1 to 1.5 MOA accuracy.  Some will be less and some will be more.  Remember, a chrome lined barrel is not designed to be a tack driver.  It's designed to last many thousands of rounds.  

As for a 18" Stainless MRP vs. a true SPR barrel (match grade Douglas), the SPR would probably be more accurate as a general rule of thumb.  The MRP barrels are believed to be made by Mike Rock.  I just don't believe that they were designed to be of the same quality.  That being said, my 16" Stainless MRP will shoot 3/4MOA.  Some have claimed better accuracy.

Currently, you are stuck with LMT barrels since the barrel extension is propriatary.  LMT has not yet released barrel extensions as an individual item to allow someone to mount a different barrel to the MRP.

No actually that does answer a broad question.  What do you do if you want a sub MOA MRP?  I figured the QCB's would be the same.  I'm having a SPR built but I guess I was wondering if I could get as good with a 18" barrel for my rifle model? I bought both of these off EE and was wondering where I would go for extra barrels if I decided to try the sub moa 18"?  Guess LMT solved it for me.  Are there different MRPs?
Thanks,
Mike

Quoted: No actually that does answer a broad question.  What do you do if you want a sub MOA MRP?  I figured the QCB's would be the same.  I'm having a SPR built but I guess I was wondering if I could get as good with a 18" barrel for my rifle model? I bought both of these off EE and was wondering where I would go for extra barrels if I decided to try the sub moa 18"?  Guess LMT solved it for me.  Are there different MRPs? Thanks, Mike

Simply put, the only barrels that will work with the MRP are the ones sold by LMT.  You have your choice of 5.56 barrels in 10.5", 14.5", 16" chrome lined and 16" or 18" stainless steel.  Soon to be released are 6.8spc barrels in 16" chrome lined.  But, that is it... for now.  The barrel extension is the interface between the barrel and the upper.  Since the MRP barrel extension is proprietary to LMT, you can not mount any 'ol barrel to the MRP.  Therefore, until LMT releases barrel extensions to the market, you can not mate a custom match barrel (Kreiger, Douglass, Obermyer, etc.) to your MRP.

As a general rule of thumb, the Stainless barrels will be more accurate then the chrome lined ones.  Most people who have the 16" stainless claim less then 1MOA accuracy.  I haven't seen too many reports about the 18" Stainless barrels.

As for the different version of the MRP, there are only two.  One has a Rifle length handguard and one has a Mid length handguard.  Outside of the length of the handguard, they are the same.  And, either will accept all of the barrels I listed above.

Quoted: Sure they are.  Want one?

Your brother was telling me that you had one that you were gonna sell... I'll tell ya what, since I'm a nice guy, I'll give you $300, a DC metrorail day pass (expired), and a box of Froot Loops (1/2 eaten) for it.

Seriously though, IM me what you've got and what you want for it. I need one to beat up for some tests.

Oh yeah, and there are a handful of MRP barrel extensions floating around. If you want a custom barrel made, I know where at least two of them are.

A better question might be: Does LMT ship uppers with an accuracy guarantee, or not?