Monolithic Upper AR-10s: LMT, Mega, or ???


April 4, 2012, 01:48 PM
I've been more of an M14/M1A, G3 and FAL kinda guy but I figure all the great new AR technology out there means I should look at putting together a .308 AR. I want this rifle to be capable of something approaching match accuracy, but I don't want a prissy show horse heavy stainless barreled match type rifle... I want a practical battle rifle that might not win at Camp Perry, but I can use in Appleseed shoots and the like and expect the rifle to shoot better than me with milsurp M80 ammo or bulk M80-equivalent reloads.

If I'm going to spend the big bucks on a .308 AR I might as well get something with a monolithic upper, since those seem to offer the best inherent accuracy over standard separate free-float, and remain relatively light and rigid, plus they seem to really work well on the AR-10 platform. Of all the monolithic upper makers, LMT seems to have the best reputation though their prices and lead times are not all that great. I'm also liking the Mega Maten, but its more of a project setup where you have to piece the whole thing together yourself (which isn't a huge deal since I've built both .223 ARs and FALs in the past).

So the question is, do I just buy the LMT rifle which is already tuned out of the box, but isn't exactly what I want, or do I buy myself a Mega Maten matched monolithic upper and lower plus and build the while thing up with exactly the hand-picked parts I want, but suffer through the process of tuning the thing to run reliably? Cost is about the same either way, give or take a couple hundred bucks. Are there any other AR-10 rifles I ought to be looking at?

Also, why doesn't anybody seem to have a monolithic upper AR-10 that has a piston gas system? is there something about DI in a .308 AR that's somehow inherently better than the available piston systems?

How hard is it to headspace an AR, specifically a .308 AR? I've always bought my .223 ARs with complete barreled uppers with matching bolt/carrier but if I go with a Mega Maten, I'm likely to be buying the bolt/carrier and barrel from different manufacturers (specifically a Fulton/Criterion chrome lined barrel and JP bolt/carrier, both DPMS type). I know about the Armalite-type vs. DPMS-type barrel extension difference and the need to match those generally. It seems most people with .223 ARs don't even bother headspacing their rifles and mix/match bolts and barrels without any care about headspace, which seems kinda crazy to me. Excessive headspace is a bomb waiting to go off, but I will admit fiddling with removing the extractor/ejector to get a headspace gauge to work is a major pain in the butt and buying the tools necessary to do this easily seems like a wasteful expense when I'll only be doing it once or twice... but it still seems like such an easy job in general that it would be silly to pay a gunsmith to do it for me.

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April 4, 2012, 03:39 PM
If I were you, I'd just stick with what you got and spend the AR10 budget on ammo.

If you really want an AR10, check out GA Precision, Larue Tactical, or LMT.

April 4, 2012, 03:41 PM
You can never have too much ammo, but lets just say I've got that covered.

April 4, 2012, 03:43 PM

colt sp901 308/223 monolithic rail.

April 4, 2012, 04:33 PM
Les Baer makes a monolithic complete gun and it supposedly shoots .5 MOA.
Pistons add harmonics and dont lend themselves to precision shooting.

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