New upper and lower impossibly tight

[MarikinaMan]

theres no wedge and the nylon screw is bottomed out, its not even close to the surface

So the question is, where the give? What are you able to squeeze? Thats where you should start.

[coolarthur1]

So the question is, where the give? What are you able to squeeze? Thats where you should start.

Good question, I have removed the bolt, mag, buffer. There's nothing there to impede. The lower has the same problem on other uppers. I'm pretty sure its the lowers fault as its the newest part of the equation and this problem never existed before

After inserting one pin there's an obvious gap between the 2, I squeeze hard and then they finally mate but the remaining pin requires a good amount of force

[MarikinaMan]

Good question, I have removed the bolt, mag, buffer. There's nothing there to impede. The lower has the same problem on other uppers. I'm pretty sure its the lowers fault as its the newest part of the equation and this problem never existed before

Uppers and lowers will fit differently, even within the same brand. Hope u can solve the problem. Good luck.

https://www.ammoland.com/2013/06/tightening-the-fit-between-the-upper-lower-ar15-rifle/

[1911RONIN]

Seekins Precision makes take down pins that are non standard sizes.


Sent from my iPhone using Tapatalk

[heidad01]

Umm, there are things called 1000 grit sand paper and quick cold blue/black.

[coolarthur1]

Umm, there are things called 1000 grit sand paper and quick cold blue/black.

That some neanderthal ****. Ill just deal with it lol

[enorbit3]

This happened on my ar9 build. Spikes lower and upper. Was super hard to push the pins at first and had to use a tool. After shooting it, it loosened up.

[therealnickb]

Tight upper to lower fit doesn't mean squat to accuracy.

[FeuerFrei]

Dancing seems a funny way to put it. Never saw that. To wedgy or not to wedgy?

The barrel nut torqued properly and seated parallel to the receiver does more for consistency than removing any wiggle from upper/lower. The wiggle is part of the design and doesn't affect accuracy. Easy to test when putting a piece of felt or nylon spacer to stop the wiggle. Shoot and see for yourself.

for old discussion about U/L wiggle.

http://calguns.net/calgunforum/showthread.php?t=255876

https://www.fulton-armory.com/faqs/AR-FAQs/AccuWedge.html

[therealnickb]

Dancing seems a funny way to put it. Never saw that. To wedgy or not to wedgy?

The barrel nut torqued properly and seated parallel to the receiver does more for consistency than removing any wiggle from upper/lower. The wiggle is part of the design and doesn't affect accuracy. Easy to test when putting a piece of felt or nylon spacer to stop the wiggle. Shoot and see for yourself.

for old discussion about U/L wiggle.

http://calguns.net/calgunforum/showthread.php?t=255876

https://www.fulton-armory.com/faqs/A...AccuWedge.html

[golfish]

I'll bet that if you get it together and shoot a 100rds through it, thing will line up much better.
I've had the same problem with a couple of my builds.

[FeuerFrei]

Appreciate the links. But Fulton's answer seems to be “depends”. And they actually used the word dancing.

Regardless. I feel like l learned something. Thanks.

I included that Fulton answer to be fair and balanced.

This subject got discussed quite a bit back in the day so I tested using a chunk of felt and switched it in and out. No difference in accuracy.

Everything relating to accuracy is contained in the upper.

[MarikinaMan]

Dancing seems a funny way to put it. Never saw that. To wedgy or not to wedgy?

The barrel nut torqued properly and seated parallel to the receiver does more for consistency than removing any wiggle from upper/lower. The wiggle is part of the design and doesn't affect accuracy. Easy to test when putting a piece of felt or nylon spacer to stop the wiggle. Shoot and see for yourself.

for old discussion about U/L wiggle.

http://calguns.net/calgunforum/showthread.php?t=255876

https://www.fulton-armory.com/faqs/A...AccuWedge.html

All true.

How can a loose lower affect accuracy? Not as much as the barrel and it being free floated, but I would pose its there.

I feel a shaky lower can have the same effect as a loose stock, grip or buffer tube, thats been reported to open up groups

[therealnickb]

So why does Les Baer make them so damn tight? Do you suppose they couldn’t offer the .5 MOA guarantee with a loose upper lower combo?

If you have a rifle shooting 2-3” MOA, then I’ll totally concede that a loose fit won’t make it worse.

[MarikinaMan]

So why does Les Baer make them so damn tight? Do you suppose they couldn’t offer the .5 MOA guarantee with a loose upper lower combo?

If you have a rifle shooting 2-3” MOA, then I’ll totally concede that a loose fit won’t make it worse.

At 19:00 this review of the SCAR talks about movement in the rifle’s lower receiver. It doesnt affect the first shot, but in successive shots, the natural point of aim moves as the parts shift on recoil, hence throwing larger groups with his follow ups. At 26:00, he finds a problem with a loose fastener on the stock.

This POA shift is something that can likely happen to a loose upper lower fit given the multiple forces working on the rifle while its being shot. Recoil, tripod or support, hand grip and cheek weld for starters.

Imagine getting a target in your cross hairs. You are connected to the rifle via the hand grip and your cheek on the stock. The entire upper assembly including the scope and the bipod are separated from you and effectively floats in the loose fit. I’ll bet a tight fit will produce a better group vs a loose fit if asked to create a 5 shot group at 100 yards in 10 seconds.