I ordered 2 LMT MRP gas piston carbines at SHOT last Feb., and the first one arrived yesterday.

In the shipping box


The tag hanging from the trigger guard is a QC form listing all the items tested for fit and function.  After testing each item is initialed and dated by the tester.  This is the first weapon that I've owned with such detailed quality control documentation. The form is dated 9/03/08.



On first inspection the carbine appears well made.  All machine work is very crisp. The anodized finish of the receivers matches perfectly, and there is no slack between the upper and lower.  The buttstock is very tight on the receiver extension tube, so tight it is removing the finish as it slides forward and back.  The trigger is a standard single stage trigger group, although the pull is very smooth without any grittiness or stacking.  The barrel is 16", chrome lined and marked "MP 5.56 NATO 1/7 CB" and has an A2 style FH.  The pistol grip is an Ergo with an internal battery compartment accessed threw a rubber plug in the bottom.  Also provided are (1) 30 round magazine with a "LMT" marked floorplate and a standard green follower, (3) Tangodown rail covers, a simple sling, and a preset torque wrench with a 3/8" torx tool.

I didn't have time to drive out to the shooting range so I stayed home and shot it in the backyard.  Initially I wanted to see how it would group, so I used a laser range finder to find 100 yds. from my target and set out my shooting mat.  Before shooting I split the receivers and gave it a good lubing with CLP.


All testing was shot with the open sights. I shot the first 3 rounds and walked down to check the group.  It was about 2" left of my point of aim, so I adjusted the rear sight.  Apparently the LMT tester zeroed the carbine when he test fired it.

3" 20 round group(minus the sighters) @ 100 yds prone from sandbags with Malaysian ball M193.  The 3 shots furthest left were the first fired (sighters).


After I shot the above group I moved up to 50 yds and shot off hand, sitting, and did some rapid fire drills.  I shot a total of 360 rounds without a failure of any kind, the carbine was flawless and stayed cool.  The carbine balanced very well and the recoil felt about the same as my RobArms XCR or LW/RRA 16" carbine but smoother.  The brass was thrown about 5' to the right and back landing in a 2' circle.



I wanted to see how dirty the carbine got.  Having previous experience with other gas piston ARs(LW converted upper), I expected it to be clean inside the receivers.  I was not disappointed.
Notice how clean the oil is on my fingers.  These pictures were taken right after I finished shooting without any cleaning.  The bolt carrier was cool to the touch also.



The bolt carrier is different from a standard carrier to accommodate the piston rod.  Also note that the lube holes are missing on the side and it is M16 configuration.  The bolt carrier group appears to be finished in MilSpec parkerizing.  At SHOT the sample had a BCG that was finished in a coating that looked almost bronze.  A LMT rep told me that the delay in releasing the piston MRPs was caused by their trying different coatings, looking for durability and appearance.  The bolt is a standard MP tested AR bolt without gas rings.


The gas piston comes out from the front easily, simply push in the plunger, rotate the plug and pull out the assembly.  The gas piston, plug and gasblock are coated with what looks like silicon nitride (as used on high end motorcycle front fork tubes) or something similar, it appears hard and smooth.  The carbon/crud came off easily.  The manual recommends using a bore brush inside the gas block and gas port hole and lubing all parts with CLP.  This system is much simpler than the LW system to disassemble.

Gas Piston and Gas Plug/Plunger


Bolt carrier group and Gas piston group disassembled


The barrel removes easily also.  Remove the front barrel bolt completely and unscrew the rear bolt 3 full turns and pull the barrel out to the front.  To reinstall the barrel reverse the procedure and use the supplied preset torque wrench to torque the bolts to 140 inch/pounds.


The carbine also comes with a H2 buffer as standard.


Disassembled


It was very easy to clean, just blast out with Gunscrubber, run a few patches down the bore, lube and reassemble.  So much nicer than a direct gas impingement AR to clean.

LMT and LW/RRA, both fine weapons.


Overall I'd have to say I'm impressed.  I guess sometimes you get what you pay for.
Even though this weapon system was supposed to be available in June, it was worth waiting for.  LMT wouldn't release it until it was right.  An LMT employee told me they didn't want any "Sig 556" problems.

Tomorrow I hope to "personalize" it and post more pics.

Personalized



New pics

Bump for pics.

dude, awesome shooting with irons.  I wish mine would look anywhere near that with 5 rds...

I need more practice.

Thanks for the great pics and review!

Great review....thank you.

That looks like LMT went to town on improvements.  Great looking rifle.

How's the accuracy?

Thanks for the compliments guys.  

That group was shot @ 100 yds, with open sights from sandbags, not really a great feat of marksmanship.  I shot NRA Service Rifle for several years, and saw many shooters that could hold 12" groups prone at 600 yds all day long.

The group measured at 3 ", minus the sighters.

That is a beautiful peice of work.

How much are they? I am looking at my second AR, and I want AK-like reliability...but with an AR-15...

That is a beauty! Great review and pics. LMT obviously put a lot of design and engineering thought into their gas piston AR. A supplied, preset torque wrench for the barrel? Puhleeze!! I want one!!  

Quoted: Quoted: Very cool. Glad to see these shipping. Those of us who already own MRP's should be able to drop the piston barrel conversion in our existing receivers, right? I believe they will drop right in the QCB MRP's, At least thats what LMT told me when I ordered a piston conversion for mine.

That is what I get from it too. Looking forward to picking up the 12.5 in the future.

I have read that LMT may ask some owners to send their uppers in to fit an aluminum sleeve where the gas tube enters the upper. This is to prevent the piston from stressing the upper. As I understood many of the new ones may have this feature. I haven't checked mine, but I don't plan on buying this just yet.

Quoted: Great review....thank you.

Agree!

new-arguy, the LMT rep @ SHOT told me you would be able to switch from piston to DI and change calibers on any MRP with no problem.  I'm thinking about a 6.8 DI set up.  The 6.8 piston isn't available yet.

forrestallflame- $2000 retail

Any ideas on the price difference between the older barrel packages, and the newer piston equipped ones?

Will the Piston MRP uppers accept the older impingement parts (with the gas BCG)

Really a great report with really great pictures. Like everything that LM&T puts their name on it's a quality product. Give us more Info. as time pass's and you do more shooting.
One item I would like LM&T to address is their use of a cardboard box they send them in as many other AR Mfgs. use a much better type of box for the protection on their ARs.

Yes, I agree about the shipping box.  Everything in the box was wrapped in plastic and bubble wrap though.  Some kind of a hard case would be nice.

SWEET!

nicee..

Great review.  Thanks for taking the time to post it.  My only concern with that system is the potential for flex in that long, skinny piston.  I'm going to let it get some street use before I consider buying one.

Great review.

I was looking at these for awhile now.

I may now consider that offer I got on my Microtech MSAR for one of these.

What are the things on the sides of the gas piston head? They kinda look like gas rings.

BSW

I always have confidence in LMT , thanks for the pics.

Beautiful gun man, hopefully i will have the money to add one of these to my collection before it is too late

, Very nice review. Waiting patiently for mine.

Very nice. I hope it shoots well for you.

Mine came in today!!!!!!!!!!!

Will post pictures when I get time...

Man, that was a loooooong wait!!!!!!!  Looks to be well worth it though!!!

I'm looking at a 1st SBR being their 12.5" upper.....already have the lower. I guess they'll be released towards the 1st quarter of 09.

briansmithtwins-Yes those are gas rings, the manual says don't remove them.

Freakin' awesome rifle!  I have a CQB MRP and cannot wait to get the piston kit.  This maybe a dumb question but I don't really know much about the piston setups.  Where does the gas bleed off from on the LMT piston setup (towards the front...up..to the left side)?

Thanks, great review .


+1 Karma

Quoted: Freakin' awesome rifle!  I have a CQB MRP and cannot wait to get the piston kit.  This maybe a dumb question but I don't really know much about the piston setups.  Where does the gas bleed off from on the LMT piston setup (towards the front...up..to the left side)?

+1. Exactly where does the excess gas vent?

Great question about the gas venting, my understanding is that LWRC dumps the gas into the hand guards . How about LMT?

Quoted: briansmithtwins-Yes those are gas rings, the manual says don't remove them.

So they copied one of the weak points of the DI gas system by moving the rings onto the bolt head? Are they at least standard AR gas rings if you need a replacement?

BSW

The gas vents from the gas block.  The gas rings are smaller than AR bolt gas rings.

Quoted: Quoted: briansmithtwins-Yes those are gas rings, the manual says don't remove them. So they copied one of the weak points of the DI gas system by moving the rings onto the bolt head? Are they at least standard AR gas rings if you need a replacement? BSW

how are gas rings a weak point?  do you EVER know what you are talking about?

Quoted: The gas vents from the gas block.  The gas rings are smaller than AR bolt gas rings.

I assume away from your hand if you had a forward vertical grip correct?  I'm so jealous.

The gas appears to vent from the back of the gas block in front of the handguard,  when the piston moves toward the bolt carrier.  I didn't notice any heat on my hand while firing, but I wasn't doing mag dumps either.  I don't think heat is going to be a problem,  the bolt carrier group stays nice and cool, that's where it counts.  I took a bunch of pictures today,  including close ups of the gas block areas.  I'll try to post them tomorrow.

Fine looking rifle! I don't mean to be a jerk but is that the same model as this one?

https://policeguns.com/catalog/product_info.php?manufacturers_id=137&products_id=6050&osCsid=nla0760f1f8rapte6bbeps0a57

$1500.00 instead of 2K

Quoted: Fine looking rifle! I don't mean to be a jerk but is that the same model as this one? https://policeguns.com/catalog/product_info.php?manufacturers_id=137&products_id=6050&osCsid=nla0760f1f8rapte6bbeps0a57 $1500.00 instead of 2K

That is the original DI model of the MRP.

How do these models differ? Different gas system?

Quoted: How do these models differ? Different gas system?

Ya, the OP has the gas piston system which is supposed to be more reliable, and the cheaper MRP has the standard direct impingement gas system.

Saturday, September 13, 2008

An excellent review of the LMT MRP Gas-Piston (GP) operated upper receiver!  A much better review than the ones that I have read in the gun press!  

I am not surprised by the quality and excellent engineering of this LMT MRP Gas-Piston (GP) operated upper receiver; this is something that LMT owners – like myself – have known for a long time!

The gas-rings on the LMT MRP gas-piston head are not new; the H&K 416 has a similar gas-ring arrangement (H&K part number 205 383).

I have been in contact with Lewis Machine and Tool and the 12.5 inch version is scheduled to ship in December!  

I cannot not wait to try out this bad boy for Christmas!

Quoted: Quoted: briansmithtwins-Yes those are gas rings, the manual says don't remove them. So they copied one of the weak points of the DI gas system by moving the rings onto the bolt head? Are they at least standard AR gas rings if you need a replacement? BSW

Gas rings are not a “weak” point in the Direct Impingement (DI) system!  It is piping the hot and dirty exhaust gas directly into the receiver – bolt carrier group that may, like myself, consider the “weak” point about the DI system!

And no, these are not the same gas rings and yes, according to LMT, spare replacement gas rings are available!

Great work on the review. I'm glad but not surprised of the quality and workmanship that LMT brought to the table.

I'd like to see someone run a future test with different (75&77gr) ammo out to 300yds to see what it can do. I don't have any doubts that it will do the job.