AR-15 slop fix

[bamban]

We had state team shooter back in the 90s who was our top standing shooter. I was in a match with him when he shot 200-8X standing at 200 yards. He cleaned standing one year when he won the state service championship. Back then shooting cleans standing with a service rifle are very few and far between.

He shot standing practice a lot, he said he shot better once he bedded the receivers for no slop. He equates the loose receivers when shooting standing like shooting a bolt gun with loose action screws.. In our matches you can't sling up in the standing event. There are shooters who hold the rifle under the mag. He said whem he tried that position he had aome shots not on call.

None of us on the team questioned his bedding job, our record did support his claim. Besides, he shot standing better than any of us.

Whem you get to the HM (97%) level and going for the win, the ever so slight improvement in standing could determine the winner. As the saying goes, matches are won in standing and lost at 600.

 

[gohring3006]

I looked up reviews on this gun and it shoots better than any review I've seen on an AR-15, they use tension screws under the the upper and lower to take up the slop plus they keep barrel nut and barrel free floated as you would have in a bolt gun in fact that's what they compared it to, ok if slop is fine why are they addressing this issue and it shoots great and if slop is fine I guess I can have all kinds of slip, put way undersize pins in it and it will still shoot the same? Plus with slop the recoil could shift differently depending how you hold it. I just realized my savage AR-15 had that screw to take out the slop, I adjusted it and left accublock in it, nice and tight, been working up a load and gun shot a 6 shot .75 group, best this gun has shot by far, maybe got right load but maybe taking out the slop didn't hurt either.

Anytime you take slop out of the platform your not hurting anything.
There's lots of dynamics happening with the ar platform. You got all the weight being put on the nut/upper interface, you have constant changing pressure on the bolt carrier from each pull of the trigger by the mag spring putting less upward pressure on it. There's not a lot of constant consistent influences on the platform just from the nature of its operation.
I will say, once you put a loaded mag on the well, the upper/lower slop is a lot less.
But it's not addressing the pressure on the nut area, from our face putting pressure on the butt stock, a heavy scope and the constant weight change from less rounds each time you pull the trigger.
It really does shed light on the fact, that consistent form and follow thru is important for accuracy out of the platform.

 

[ntsqd]

I think that the so-called "monolithic" uppers are a step in the right direction. However, most that I've seen online or owned were poorly executed. Their design(s) didn't really address the flex that they were supposed to address. Some appeared to be designed TO flex.

It is enough to make me want to build a billet upper to use something like the Seekins' SP3R hand gaurd w/o any adapter. I.E. like Seekins makes their own upper for the SP3R, but without the steps and notches that promote flex and decrease rigidity. Granted, altering the upper's shape to eliminate flex would very likely make it not legal in NRA comps, but for myself I'm not concerned with that. And this doesn't address the original concern, just one that it triggered discussion of.

A simple change would be to make the take-down pin holes in the lower to be in an eccentric that the user could tighten down after assembly. I should patent that, but now that y'all have read about it, its too late.....

 

[jpfrog]

That was his point. He said he can get a franken gun built with a decent barrel, follow all the torque / grease / locktite specs, and do it all for $800 and have a way better rifle.

Hard to build a decent shooter for $800 today. I just went through this, and though I did opt for some "nicer" options, even $1k would have been tough to stay under if I had gone budget.

 

[Greyfox]

I reinforce my AccuShims by drilling a hole in the base and adding a small section of stiff spring to apply tension. The rubber by itself will eventually fatigue. They last for years with a constant tension.

 

[gohring3006]

I reinforce my AccuShims by drilling a hole in the base and adding a small section of stiff spring to apply tension. The rubber by itself will eventually fatigue. They last for years with a constant tension.
View attachment 338173

Great idea, my problems with the wedges was their eventual degradation.

 

[6pakzak]

I think the problem has been addressed by using tension screws as with my savage that can be adjusted to take out the slop, the saint uses tension screws on the front and back, problem with the accublock is that it can squish from the recoil therefore creating movement, tension screws stop the movement but the accublock can be useful to hold upper up if you bed it some other way.

 

[6pakzak]

Well I think we can say after all this discussion is that sloppy uppers matter.

 

[Ol' Red]

Did not use an Accuwedge on my first AR but did use one on my second AR build. I heard sloppy seconds were bad.

 

[6pakzak]

Did not use an Accuwedge on my first AR but did use one on my second AR build. I heard sloppy seconds were bad.

Regardless, taking the slop out is only gonna help, manufacturer's are now addressing this slop with tension screws or tight fitting uppers and lowers, put a cotter pin in your lower and upper and let's see how good it shoots, sounds ridiculous right, should shoot the same if you believe it don't matter.

 

[Old Rooster]

If I ever do another build I am going to buy the 2 matching upper and lower.That is supposed to be the tightest fit.

AR-15 Combo - Complete Lower and Upper Receiver - Juggernaut Tactical

jtactical.com

 

[6pakzak]

If I ever do another build I am going to buy the 2 matching upper and lower.That is supposed to be the tightest fit.

AR-15 Combo - Complete Lower and Upper Receiver - Juggernaut Tactical

jtactical.com

Or you can get lower like aero precision that uses tension screws so you can always adjust the slop out if it starts to get some after a while.

 

[6pakzak]

I reinforce my AccuShims by drilling a hole in the base and adding a small section of stiff spring to apply tension. The rubber by itself will eventually fatigue. They last for years with a constant tension.
View attachment 338173

Not a bad idea but spring still flexes under recoil, maybe fitting fat pin in there instead of spring and sanding it down till it fits just right to eliminate slop.

 

[Old Rooster]

Bill Wison used to make the AR15 matched upper and lower.They are machined as one peice and after maching they seperate them but there is zero slop.A friend and I built one for his personal rifle and it shot lights out!No slop in many years of competition shootings.
I have not checked in a while but the last time I checked they said no longer available.