MONOLITHIC UPPER

[payj]

The Mega looks a lot heavier than the VIS.

The MTS-300 (midlength) mono weights 22.9 oz with the dust cover and forward assist.

The Midlength Vis weights 25oz with dust cover and forward assist.


you highlighted "looks" so maybe you already know. If not now ya know!

[variablebinary]

One consideration - the VIS receiver is machined from a 6016 forging while the rail section is made from a 6063 extrusion. This Vltor Rep who provided this info also said the VIS was manufactured in this way "because you cannot weld 7075."

Seems like an odd thing to say? What are they welding, for one?

LMT seem to get things done just fine with 7075-T6 aluminum. There are plenty of first gen MRP's out there that have eaten ungodly amounts of rounds, and have held up perfectly well.

[mark5pt56]

You can't pin a gas block on the Mega. You have to first torque down the barrel nut, and then slide a set screw-type gas block into place and tighten the set screws through the elongated hole machined in the underside of the quad-rail. You have to assemble in this order because the barrel nut wrench will not fit over the gas block. Pinning a gas block would not be a problem with the VIS because the lower portion of the rail is removable as noted earlier.

I had sent my components to Adco to see if they could pin my Vltor low-profile gas block. They did a trial fit and found that they could not properly access the gas block through the holes in the rail for pinning (the angle wasn't right and they couldn't drive a pin straight in). The BCM BFH 16" mid-length barrel I used for my build came with one dimple, so I had them install a second dimple. I was advised by rob_s that Rocksett is less prone to degradation due to heat than Loctite, so that is what I had them apply to the set screws to attach the low-pro.

I kind of knew that, was making a point.

Any idea on barrel nut rotation?

[ALCOAR]

Seems like an odd thing to say? What are they welding, for one?

LMT seem to get things done just fine with 7075-T6 aluminum. There are plenty of first gen MRP's out there that have eaten ungodly amounts of rounds, and have held up perfectly well.

Each chassis is created using a 7lb plus solid piece of Aluminum bar stock and then is precisely machined down to form the completely one piece chassis that captures barrels with one single figure 8washer and 2 bolts. That is simply unmatched and prob. will never be matched....feat of absolute perfection in terms of engineering as well.

Held up well is quite the understatement as Ive yet to see any failures or otherwise wear and tear on Gen I's dating back to the fall of 2004 with as you mentioned simply ridiculous amts. of rounds down the tube. Duffy a fellow member prob. has more rounds logged than anybody I know of through one single chassis. Just for the record I have never seen a Gen I, II, or III ever have a structural problem and for that matter otherwise problem or failure of any kind....and to think that this site has allowed the uneducated to run free with things like the whole "MRP bent rail syndrome" which has occurred to date zero times and is so ridiculous it makes my head hurt.....bottom line is folks by in large have no real depth or understanding on the MRP system even though they "in theory" speak on things like Id rather have a bunch of heavy fully outfitted uppers instead of a mrp system since humping a bunch of awkward heavy uppers is better than just a barrel or two and perhaps a bcg.

[ALCOAR]

I kind of knew that, was making a point.

Any idea on barrel nut rotation?

I knew what you were up to....as you start to see all these things very easily once you own the nasty kit you just brought home...these things start to pop out at you the moment you pick up a mrp. Again, engineering and design wise, its unmatched.

[Hmac]

I knew what you were up to....as you start to see all these things very easily once you own the nasty kit you just brought home...these things start to pop out at you the moment you pick up a mrp. Again, engineering and design wise, its unmatched.

[RogerinTPA]

I want a monolithic upper rifle. I like the look and being able to mount an optic anywhere. Which one do you have and why?
Spider

I have an LMT MRP mid-length with a rifle length rail, for a couple of years now. I went with the LMT due to the their quality and with the notion of converting it to a 6.8 later down the road, primarily for hunting. It is pretty accurate and runs very well. The trade off ? It is heavier in weight compared to a traditional carbine or mi-length with a DD Lite rail 7.0 or even with a 9.0 rail (I have both). Another minus is higher cost when you decide to convert with a new barrel, BCG, Mags and ammo.

[nrose8989]

VIS!!



Why?

Because I wanted a Noveske.....

[St. Dark]

I put a Colt 6940CK on my old SporterII lower.

I wanted to replace the 20" barrel; it got me a 16" free-floated barrel.

[Belmont31R]

Each chassis is created using a 7lb plus solid piece of Aluminum bar stock and then is precisely machined down to form the completely one piece chassis that captures barrels with one single figure 8washer and 2 bolts. That is simply unmatched and prob. will never be matched....feat of absolute perfection in terms of engineering as well.

Held up well is quite the understatement as Ive yet to see any failures or otherwise wear and tear on Gen I's dating back to the fall of 2004 with as you mentioned simply ridiculous amts. of rounds down the tube. Duffy a fellow member prob. has more rounds logged than anybody I know of through one single chassis. Just for the record I have never seen a Gen I, II, or III ever have a structural problem and for that matter otherwise problem or failure of any kind....and to think that this site has allowed the uneducated to run free with things like the whole "MRP bent rail syndrome" which has occurred to date zero times and is so ridiculous it makes my head hurt.....bottom line is folks by in large have no real depth or understanding on the MRP system even though they "in theory" speak on things like Id rather have a bunch of heavy fully outfitted uppers instead of a mrp system since humping a bunch of awkward heavy uppers is better than just a barrel or two and perhaps a bcg.

No one with any sense is "humping a bunch of awkward uppers". Ive never seen anyone do that.

Even if they did I fail to see how thats any worse than 'humping a bunch of awkward barrels, optics, bcg's and a torque wrench' around.

Who would want to mess around taking barrels out, swapping BCG's, and optics around everytime they wanted to shoot a different setup? When I go shooting I usually take 3 AR's with me, and can swap between them in the amount of time it takes me to put one down and pick up another. I had no idea it was so difficult to carry 2 cases (1 pelican and 1 soft case) around or am I missing something? Theres no way Im going to sit there, get the TQ wrench out, pull the barrel out, put a new one in, switch optics, and then shoot. WTF kind of sense does that make? Not to mention you'd burn your hand trying to pull a hot barrel out.


I really don't think LMT had field swapping barrels in mind when they designed the MRP, and certainly not every time you want to shoot a different setup while at the range between strings of fire.