AR10 upper to lower receiver fit is loose.

[tabberski]

Hello everyone,
Bouncing an idea off of you. Could the take down pin holes be reamed and re-pinned easily? Who would you bring the firearm to to have that done, and what would need to be done about the annodizing that would be machined away? My matched set is matched only in color, and I have had it too long to return. I can put a wedge in the back pin area and the receiver halves are tight, but it's not the solution I want. The firearm is going to be a heavy caliber, probably 45 raptor so any loose tolerances need to be taken care of.

[870TC]

JP has oversize pins called microfit.
https://www.jprifles.com/1.2.7_Receiver ... t=microfit

[tabberski]

I’ve left a message with them, but no response yet. I believe it is going to take a bit more then just pins that are a thousand or two oversized.

[Holland&Holland]

https://www.griffinarmament.com/dimpled-takedown-pin-set-for-ar-15/

Similar option. I would not think reaming would make sense unless you had custom pins made.

[tabberski]

I'm going to use pin gauges to get an accurate diameter of all the holes and see where things are at. With the current pins there is probably.005 gap between the upper and lower. You can literally shake them.

[Rip Van Winkle]

Upper to lower fit on a AR style rifle isn't that critical. Tightening the two halves won't increase strength or improve accuracy. Slop between the two is at worse an annoyance.

Having said all that, the easiest way to eliminate the slop is to bed the lower receiver with something like JB Wield.

[Bearcatrp]

When you lock down the upper to the lower, can you see light through it looking from the side? Does it match up tight when closed? What brand lower and upper? I used a Aero lower for my AR 10 308. Used regular DPMS pins. Wasn't nice and tight and the front pin didn't extrude to the other side. Got ahold of Aero and was told I needed their pins. Worked great since. My upper is a DPMS style I bought as a complete upper from KAK Industries.

[Holland&Holland]

Upper to lower fit on a AR style rifle isn't that critical. Tightening the two halves won't increase strength or improve accuracy. Slop between the two is at worse an annoyance.

Having said all that, the easiest way to eliminate the slop is to bed the lower receiver with something like JB Wield.

What do you use to keep it from sticking?

[Rip Van Winkle]

What do you use to keep it from sticking?

Release Agent on the upper. Failing that tape will work.

[Rip Van Winkle]

I took a picture of my Service Rifle. The bedding starts at about the hammer pin and goes half way up the heal of the lower.

[hammAR]

I've bedded lots of things in my life, but never an AR...........

Will have to give that a try..thanks.....

[Holland&Holland]

I took a picture of my Service Rifle. The bedding starts at about the hammer pin and goes half way up the heal of the lower.

I never would have even thought of that possibility. I will a couple that I might give that a try on.

[crbutler]

Does it make a difference for you accuracy wise?

I have had a couple colts that came with a wedge, which tightens them up, but I cannot tell a difference in accuracy with or without the wedge in, especially with using a scope for accuracy testing.

It will rattle a bit without it, but shoots the same (3/4-1” at 100 yards, about the same as my JP rifle.)

[Rip Van Winkle]

Does it make a difference for you accuracy wise?

No, the only reason I did it was to eliminate an annoying distraction when I'm trying to shoot x's.

[BigDog58]

Upper to lower fit on a AR style rifle isn't that critical. Tightening the two halves won't increase strength or improve accuracy. Slop between the two is at worse an annoyance.

Having said all that, the easiest way to eliminate the slop is to bed the lower receiver with something like JB Wield.

What do you use to keep it from sticking?

Kiwi Shoe Polish also works great. I bedded the action on my 50 BMG using Devcon 10110 and OldmanFCSA suggested we use the shoe polish. It worked well, with nothing we didn't want to stick, getting stuck. And, it's readily available as well as cheap. Pretty easy to clean off as well.