Stealth, MUR or Rainier Arms UltraMatch Upper

[jbsmwd]

I have deceided to built a new upper instead of just rebarreling my upper. So the question becomes which of these 3 uppers is the best one in regauds be true dimensionally and not put any stress/binding/torque on the BCG. I am concernd about the mechanical aspect not the looks of the upper reciever

I have heard good things about the Stealth uppers being vey good, but I don't know much about the other 2 brands other then what I have read at their websites about tolerances.

[Belmont31R]

I'm not aware of any testing that has been done on the 3 that would really show any significant differences.


Im on my 2nd complete Stealth upper, and like them a lot but I don't really think you could go wrong with any of them. Both my Stealths were super smooth right out of the box.

[500grains]

I would add in Sun Devil for a comparison.

LaRue Stealth
Sun Devil billet
VLTOR MUR
Rainier UltraMatch

Isn't VLTOR the only one which is forged in this group?

[jbsmwd]

Isn't VLTOR the only one which is forged in this group?


from there website:

"Prior to machining, the forging is fully stress relieved, heat treated, aged twice and undergoes a proprietary cryogenic treatment"


not sure how one age's steel twice let alone once.

[ROGOPGEAR]

from there website:

"Prior to machining, the forging is fully stress relieved, heat treated, aged twice and undergoes a proprietary cryogenic treatment"


not sure how one age's steel twice let alone once.

aluminum?

[jbsmwd]

aluminum?

Yeah, aluminum is what I meant.

[500grains]

Aging has something to do with hardening.

[benthughes]

I've got a 16" Stealth upper I bought directly from Larue and MUR with a 13.7" Noveske barrel in 6.8. Both are incredibly solid and shoot without a hitch, however, the Larue is a bit lighter. I'd say just pick one and don't look back, you'll just drive yourself nuts.

My Stealth upper with the 1/8 twist will eat any ammo I feed it and still deliver good results. It's amazing to see what good ammo can deliver in terms of accuracy. I started shooting federal 55 Gr with approx. 2" groups, switched to Black Hills 75 Gr and was sub MOA. I can't attest lowest limits of the stealth because, frankly, I don't shoot that well ;).

[pth3k]

from http://www.secowarwick.com/solutionheat.html

Aging is a change in the properties of certain metals and alloys that occurs at ambient or moderately elevated temperatures after hot working or a heat treatment or after a cold working operation. The change in properties is often, but not always, due to a phase change (precipitation), but never involves a change in chemical composition of the metal or alloy.

Artificial aging is aging above room temperature.

Ty Hoeffer
Palmyra, VA

[jbsmwd]

from http://www.secowarwick.com/solutionheat.html

Aging is a change in the properties of certain metals and alloys that occurs at ambient or moderately elevated temperatures after hot working or a heat treatment or after a cold working operation. The change in properties is often, but not always, due to a phase change (precipitation), but never involves a change in chemical composition of the metal or alloy.

Artificial aging is aging above room temperature.

Ty Hoeffer
Palmyra, VA

Thank you for that tidbit of information. It lead me on a 2 hour search on Wikipedia to learn even more about metallurgy. Now I just wish RA and LaRue post the stuff that they do they upper receivers like Vltor does. It's starting to look like a MUR in my future. Just need to call them about the rivits issue that I have.

[Hmac]

No offense meant, but I really think you are overthinking the issue.

Anyway, if you're thinking about a MUR, shouldn't you be thinking about a VIS? In that case, no way is a sling or anything you hang off your rail going to change the relationship of your barrel to your upper receiver nor to the bolt.