Newbie with LMT MRP questions.

[AllanRR]

Hello all,
Well, I finally did it and I'm starting to build my dream AR setup. I started off with a LMT MRP and a 10.5 inch barrel, Aimpoint ML3 on a Larue mount, PRI gas buster charging handle, PWS FCS, Knights 2 stage full auto trigger (yay!!!), Enidine buffer, and a Magpul CTR stock. I also have on order a pair of Troy flip up sights, Magpul MIAD grips, Tango Down vert grip, and a Blue Force gear sling.

http://AllanRomero.smugmug.com/photos/237107966-M.jpg

I'm still in the process of building up my lower though.
Anyway, my questions.

1. Do I need to lube/grease/put anti-seize on the barrel before installing it in the upper?

2. Realistically, what kind of accuracy will I get from a 10.5" barrel?
I know I could've gone longer but I really like the look of a SBR. This AR will be my home defense/range/maybe some competition rifle. Will a 10.5 inch barrel still be useful for plates at around 200 yards?
I was really tempted to get a 14.5" barrel as well but I'm holding out for the piston system LMT is supposed to release in 2008.

Thanks.


A

[Derek_Connor]

Hello all,


1. Do I need to lube/grease/put anti-seize on the barrel before installing it in the upper?


I personally do not own a MRP, but I have shot/installed the barrels before, I dont remember seeing any anti-seize on the barrel extensions. I do not think I would want any anti-seize that close to the feeding "whole" of the rifle. I think a proper cleaning and re-lube with slip/clp/insert choice here would be appropriate.




2. Realistically, what kind of accuracy will I get from a 10.5" barrel?
I know I could've gone longer but I really like the look of a SBR. This AR will be my home defense/range/maybe some competition rifle. Will a 10.5 inch barrel still be useful for plates at around 200 yards?
I was really tempted to get a 14.5" barrel as well but I'm holding out for the piston system LMT is supposed to release in 2008.

A


I belive the LMT MRP barrels come from mike rock blanks? If not, they are made by LMT? Someone can confirm this...

But either way, your 10.5 setup will be VERY accurate with good ammo. For many variables, quality of the blank, barrel stiffness, quality ammo, and proper trigger manipulation, the 10.5 will be very accurate out to 200yards.

If you were to keep an aimpoint or go up in magnification to a 1-4x, you could exploit the quality of the setup even further.

And also remember, you now have the ability to switch between 5.56/6.8 and keep that same accuracy...which is really unique and cost effective since you just have to buy the barrel and bcg assembly, instead of the entire new upper

[l2a3]

I've got a MRP CQB with 16 in chrome lined barrels in 5.56 & 6.8SPC. I asked about anti-seize or any special treatment between the barrel and receiver or on the torque bolts. I was told just a light coat of oil to prevent rusting for the barrel/receiver and nothing on the bolts.

As for the accuracy I can not comment, my 16 in barrels are MOA or less, usually less.

[Spooky130]

You're going to love the MRP. Mine is a rifle length setup almost exactly like yours. I only have 16" and longer barrels for mine (16" CL 5.56, 16" CL 6.8, 18" SS 5.56). And the beauty of the whole concept is that you are just two bolts and a barrel away from a whole different rig!

No lube on the barrel extension or bolts. Just torque them down correctly and you'll be set.

My LMT 10.5" (non-MRP) can hit plates at 200m pretty well.

Spooky

[PaigeB]

I concur there is no anti-seize needed (or mentioned in the instructions). I bring both my 16" 5.56 and 6.8 barrels & bolts to the range. I can fire one caliber, then switch to the other in just a few minutes. To be safe, I wrote the caliber on the base of each barrel with a silver sharpie. I did the same with the bolt carriers and magazines.

The zero is maintained when a barrel is put back on. However, the zero is different for each caliber. I use an ACOG for 6.8 and an EOTECH for 5.56, so I do not have to re-zero for the current caliber. To keep the sights zeroed I have Larue mounts for both.

I have not experimented with this, but I expect the BUIS to not be zeroed for both calibers.

[AllanRR]

Thank you for all the info gentlemen.

I have a few more questions regarding the removal of the flash hider and installation of the PWS FSC.

1. When removing the stock flash hider, should I first remove the barrel from the MRP upper? Is there a danger of bending the gas tube if I don't remove the barrel?

2. I'm assuming that the stock flash hider unscrews counter clockwise, correct? Do I need to use a special tool or would an adjustable wrench do?

3. In installing the PWS FSC, should the barrel be installed on the MRP upper or removed?

4. The FSC comes with a peel washer and I've read on this very forum that the peel washer should be heated with a torch to peel away layers to properly align the FSC. Can I use a normal torch lighter?

5. Is there a proper torque setting for the FSC or does it just have to be hand tight with the top logo properly aligned to the top of the barrel?

Thanks again for any info you guys can provide me. This is my first AR and I'm pretty excited to bring it to the range.

This is what it looks like now and is a work in progress.

http://allanromero.smugmug.com/photos/239860840-M.jpg

I'm just playing around with the lights and mounting positions. I'm also waiting for my Magpul CTR, MIAD, Troy sights and rail covers (all in FDE) to arrive.

A

[Spooky130]

I would leave it in the upper. The way it is secured you would have to break the two bolts and have them fly out to put stress on the gas tube.

Standard directions - righty tighty, leftie losey...

I would keep the barrel installed while installing the PSC.

Not sure about the peel washer thing - which also relates to the torque question.

I've read some folks starting to put the light on the 12 o'clock rail. That part of the gun will pretty much always be "in the line of fire" while lights on the other three sides might be hidden behind barricades, etc. With your X200 or X300 there it should fit nicely on the top rail...

Spooky

[SuicideHz]

For the flash hider- Don't use an adjustable wrench. Use an open end wrench of the appropriate size- 5/8" or 3/4", I don't remember which.

Try the peel washer as is first. Only remove layers if you can't get the flash hider aligned like you want. You'll be able to use a regular lighter if you have to. Hold the SOB with pliers and heat away. Eventually the outer ring will come loose and you can use a knife blade or razor to peel off layers. Take them off one at a time- they are ruined once removed. Get it set up so you can turn the flash hider and get it almost into position- 5 to 10 degrees off is fine. Then use the wrench again to get it the rest of the way. If you can't get it there, peel off one more layer.

Crush washers are easier to use but peel washers look nice sometimes.

[AllanRR]

@ Spooky130: Thanks for the info. And as for the X200, that actually rides on my Glock19. I just put it there for the pic :D . I was thinking of getting a Surefire M900 but since I had a Gladius lying around, I decided to use it instead (and use the SF M900 funds for ammo) and just got a Surefire mount for it. Too bad it does not have a pressure tape switch so I guess it will be "thumb activated" for now.

@ SuicideHz: So the peel washer with lighter method is a trial and error thing? I mean should I heat the peel washer BEFORE I install it on the barrel?
If I'm understanding you correctly (and I can be pretty dense at times;) , I try to install the FSC with the peel washer and if it is more than 5 to 10 degrees off, I remove everything and peel off a layer and try again until I get it almost into position, then tighten with the open ended wrench.

[SuicideHz]

Try installing it with the peel washer. You may not even get it close.

Peel off layers until it can be installed hand tight to within 5 degrees of being exactly where you want it. THEN take a wrench to it. It will give a little, but not much. That's why you have to get very close but you can get very close by peeling off one layer at a time.

You may have to really heat that sucker up to get the outer layer to pop off and for the rest to open up a little. I've had them work different ways.

Don't heat it on the first attempt- only heat it when you want to remove layers.