Ultimate AR - which lower

Kinda joking. I have never seen so many great looking parts, but I don't see a need for any of them. Sorry to say, with few exceptions "A lower is a lower"

I agree. Fit and finish have nothing to do with performance.
I understand wanting to build the "ultimate", and wanting it to look and "feel" perfect falls into that category. Just so's everybody knows that it won't make it shoot any better.
 
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Not at all. But asking for updates on a tread was last updated over 6 freakin' years ago may not produce much in the way of information that will be helpful to you. lmao

I never even looked at the date. I did a search, did some reading, and asked a question. Heck, he's had plenty of time to get a photo, right?
 
I agree. Fit and finish have nothing to do with performance.
I understand wanting to build the "ultimate", and wanting it to look and "feel" perfect falls into that category. Just so's everybody knows that it won't make it shoot any better.

That.

Ultimate pretty AR? Can't help but always enjoy seeing what others build.

Ultimate shooter? Matrix, Aero, or Seekins will do. All seem to have very good lower to upper fit. Seekins and Matrix maybe from the same forging house. Aero forges for Boeing, etc. and also makes the AR lowers/uppers. Seekins is holding up to my .458 socom upper just fine. I built a highpower AR on a NES group buy Aero Precision lower. It's a sub .5 MOA gun because of the Krieger barrel and matched bolt, the Geissele trigger, and careful fitting during the build.

Maybe opening up a can of worms here, but if I were picking a lower that my life depended on, I'd pick one of the forged lowers from a trusted supplier. Eventually I want to do a SBR that will be for home defense plus range fun. It will be on an Aero lower and upper. Billet receivers look cool but the thinking that they are automatically better than forged is a myth.

That said, if I won the lottery I'd buy a Noveske, LaRue, or similar with some type of fancy fluted barrel just for the cool factor. On a reality budget I can build off of the 3 above mentioned lowers and spend the saved money for the best barrel/bolt combo and quality components. That will make something that functions as good as anything on the market.
 
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It's a sub .5 MOA gun because of the Krieger barrel and matched bolt, the Geissele trigger, and careful fitting during the build.
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How does one perform "careful fitting during the build"? Do you sand things down after buying them? Really, I understand the concept of "fitting" (I think in car engines, they call it "blueprinting"); but how does one doing that when buying parts online?
 
How does one perform "careful fitting during the build"? Do you sand things down after buying them? Really, I understand the concept of "fitting" (I think in car engines, they call it "blueprinting"); but how does one doing that when buying parts online?


Lapping upper where it meets the barrel extension and a thorough trigger job is most of it. Cleaning trigger and hammer pin holes maybe not necessary but I do it.
 
It will be the best I own to date, quite pretty and most certainly the most expensive. Tolerances are a big concern - especially with the hammer and trigger pins/pin holes as they will be taking a beating. As I said, it will be an NFA item so the option of replacing the lower down the road wont be an option.

NFA as in full auto ? If it's a SBR why so much in a lower?
I always wanted a nice dual side charging non reciprocating upper on a match lower with something cool on it.

I like the JP matched set and I was looking at these before I bailed on a big money AR. Also liked the looks of the Gibbz lower
 
Lapping upper where it meets the barrel extension and a thorough trigger job is most of it. Cleaning trigger and hammer pin holes maybe not necessary but I do it.

Did you by the lapping kit? I wish y o u could lap the barrel extension right to the upper then at least it would be a matched set.
I don't know maybe I think to much. I end up thinking lapping just the receiver is like lapping a head and valve then swapping out the valve with one that's not lapped.
I also don't like the play that's in the barrel to reciever. Be nice if we could do a easy at home fitting. I'm tempted to use a little JB weld on the barrel extension and see just how much tighter I can get the barrel fit.
I'm tempted to have my take down pins on one upper lower combo refitted. They line up ok but there is a slop I don't like on this particular pair.
My RRA matched set is very snug...5 years now it's just beginning to have a bit of looseness
 
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I tried shimming the barrel extension/reciever fit with shim stock all the way around or just on one side if it was tight. Never really saw any difference in accuracy.
 
Lapping upper where it meets the barrel extension and a thorough trigger job is most of it. Cleaning trigger and hammer pin holes maybe not necessary but I do it.

I tried shimming the barrel extension/reciever fit with shim stock all the way around or just on one side if it was tight. Never really saw any difference in accuracy.

Oh. I thought you meant like custom fitting each piece, like a custom made gun. Isn't lapping what you do to the rifling on a barrel? I wouldn't consider that "fitting". Trigger maybe, but I'd just call that a "custom trigger job", not "fitting". I guess I was reading more into it.
 
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