Grendel Billet upper

[z06man]

I am going to be building a "precision" Grendel and want a billet upper. I'm leaning toward the Rainier Arms UltraMatch Billet Upper. Does anyone have experience with these? Can you tell me any pros/cons that I should be aware of? It's going to sport a 24" Satern barrel when done. I also see a lot of the people on here went with the Mega side charge upper. Is there any good reason I should choose it over the Rainier?

[ss355]

I went with the Mega because I liked that it has really beefy walls, ostensibly to better support a heavy, 24" tube. Also didn't hurt that it was relatively inexpensive as far as billet uppers are concerned.

[Raider1v1]

i would go with the mega as well. a friend has the ma-10 set and i have a billet lower. both are absolutely fantastic and nothing required special fitment during assembly.

[kamrr4437]

Well one of the big pluses of this upper is you not only get the upper receiver but the bolt carrier as well. I dont know if Mega offers it that way but Alexander Arms is where i got mine. And if you try to buy alot of the other billet upper receivers they dont come with a bolt carrier. So you out the big dollars then you have to buy a bolt carrier. So its about the best bang for your buck. But thats taking nothing away from it. Its an awesome piece alot of good thick metal there compared to conventional uppers.

[z06man]

kamr, I don't know for sure if you are talking about the side charge or not, but the Rainier uses a standard bolt carrier(not a side charge) and is much cheaper than the AA side charge, so cost is not really an advantage. I can get a complete BCG for the difference. I do appreciate the input though.

Also on the AA/Mega upper, do they give you something to fill the charging handle hole?

[Drifter]

I have been pleased with Rainier's billet upper receivers. Used 'em in 3 different builds.

[smoke13]

Just noticed that the Rainier ultra match billet upper is on sale right now for $179 from $219. Good time to pick one up. The description says, "We are holding .0003 or better on all of those measurements. Competitor uppers are between .001 and .003 on the perpendicularity and parallelism". This is impressive if they can really hold .0003".
Also, note that on both the Mega and the Rainier Ultra receivers, not only are they beefed up, but the material is billet 7075 vs forged 6061 on mil spec. 7075 is much stronger at about 8300ksi vs, 4500ksi yield strength and has a higher hardness value at 150 vs 95 on the Brinell hardness scale. Although forged vs machined has much better mechanical properties when compared to the same material type, machined 7075 vs forged 6061 will be much stronger.

Bottom line if you're running a heavy match 24" barrel you better get a beefed up upper receiver to support the cantilevered weight or your accuracy is going to suffer from a flexing upper receiver over time. Personally I'm going to go with a Mega just because I like the idea of the side charge.

[ss355]

...
Also on the AA/Mega upper, do they give you something to fill the charging handle hole?

Mine did not come with anything to fill the charging handle hole, but until I purchase a side charging carrier, I'm using a standard charging handle. It's nice to have the choice to use either.

[ARMANIAC]

Negative on the charging handle filler. As far as I know ASA is the only side charger upper doing that. It's pretty slick!

[warped]

I want to make a ASA style AR10 in .260 some day soon.

I think that would rock, of course using parts Bob and or I make.

[z06man]

I've seen the ASA 'door'. It looks pretty nice, but sure is spendy.

[glane5910]

I use AA's billet upper combo. Works great.

[Aquateen]

Rainier arms is the t!ts! I live a mile away from them and periodically donate half my paycheck to them.

[z06man]

LOL. That'd be nice. I like to put my hands on stuff before I buy.