Best upper lower matched sets

[Hohn]

I have built at least 50 rifles using Aero parts exclusively , knowing their fit very well I am surprised at what you claim . I guess the extra money for a Daniel Defense is not a wise investment ?

There’s a heck of a lot more to a rifle than how snug the upper and lower fit. I don’t regret the DD at all. Hell and back reliability with match grade accuracy.

 

[dolek]

There’s a heck of a lot more to a rifle than how snug the upper and lower fit. I don’t regret the DD at all. Hell and back reliability with match grade accuracy.

Good to hear you love your Daniel Defense....not sure what the hell the other part meant ? Did I mention anything about how "snug" anything is ? I did not even mention good/bad about Aero . My words were " knowing their fit very well " .

 

[skeeljc]

+1 for Aero Precision.

 

[Walt Krafft]

I add a set screw, to the lower behind the grip, that tightens against the rear pin boss of the upper. It will make the loosest pair rock solid.

 

[338 Mollett]

LES BAER ! Or get a 80% lower and fit your self.

 

[Fuj]

And speaking of Les Baer !! Years back, one of the Larson
boys was under his wing. His brother was a chief Smith for
Springfield Armory. The 2 boys put there pennies together
and formed "Rock River". One brother has since passed. I
have one of the EOP Varmints and a Delta mid DEA contract.
They don't disappoint......

 

[Delfuego]

I have been very happy with Seekins. Very well made, thick walled uppers, tight fit, set screw for tension. They would be my first choice, good people too.

 

[DukeDuke]

I add a set screw, to the lower behind the grip, that tightens against the rear pin boss of the upper. It will make the loosest pair rock solid.

can you please tell us how?

 

[Walt Krafft]

can you please tell us how?

It is a job that should be done in something like a Bridgeport mill. I clamp the lower in the vise, adjusting the angle so the hole I am adding misses all the existing holes and lines up with the rear pin hole. I drill and tap 5/16-24. That size set screw uses the same 5/32 allen wrench as all the adjusting screws on the rifle.

 

[DukeDuke]

great!
thank you!

 

[Mikemontminy]

Here’s another way to remove any play between upper and lower. I used two 5/16” stainless washers stacked together with epoxy between them. I first figured out how much play I had between the upper and lower by using a feeler gauge while driving both takedown pins in. When you figure out how tight you want everything put epoxy between the two washers and place into the recess of the upper. Assemble the upper and lower with the washers and the feeler gauge used as a spacer till the epoxy dries.

 

[vegas]

I'll throw Centurion Arms in for consideration. The owner knows his way around a MK12.

https://www.centurionarms.com/c4-556-billet-upper-lower-set-p/c4-b-556-set.htm

 

[74Bronco]

built 2 nice shooting ar's in 243 Lbc with the cross machine billet upper and lowers, nice fit, very true machining and tight tolerances. used there side charging upper with young machine national match bcg, black hole weaponry/ Columbia river arms barrels.

built another similar in non side charging with a spikes forged upper and lower and good as well , but i do prefer the finish on the cross machines over the spikes