No, lapping the part of the reciever that comes in contact with the barrel extensions so it makes complete contact with the barrel extension. I've found that most of the time receiver are pretty good out of the box but I had one that was really bad. I had really bad stringing on an AR and after a lot of trouble shooting found it was stringing away from the high spot. Lapping fixed the problem and moved the point of impact about 3 MOA from where it was before.
AR-15 slop fix
- Thread starter 6pakzak
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Yes, most of them are pretty good right out the box but you can waste a lot of time trouble shooting it it isn't. I didn't use to do it and I had one that I found out that needed after many headaches. So now I do it with every build.
But one thing to remember...
If you lap the receiver, you better make sure you are using Loc-tite 620. (which I do anyways)
If you lap the receiver, you better make sure you are using Loc-tite 620. (which I do anyways)
Where at?
ntsqd
Well-Known Member
I've used the Accu-Wedge and the JP Ent. Split Rear TD Pin. Both took the slop out and both were a PITA to deal with and I've quit using them with no apparent effect.
IF the grip screw threads do go completely thru the lower (most look like they do but don''t actually go all of the way), then you can use a 1/4-28 plastic tipped set-screw from McMaster.com to lightly load the rear Take-Down pin boss on the upper. You'll need to do this w/o the grip in place, and you need to choose the length of the set-screw such that the grip retaining screw doesn't bottom out on it before the grip is tight. OR shorten the grip screw as needed.
IF the grip screw threads do go completely thru the lower (most look like they do but don''t actually go all of the way), then you can use a 1/4-28 plastic tipped set-screw from McMaster.com to lightly load the rear Take-Down pin boss on the upper. You'll need to do this w/o the grip in place, and you need to choose the length of the set-screw such that the grip retaining screw doesn't bottom out on it before the grip is tight. OR shorten the grip screw as needed.
I have used these on a few ARs and no more rattle.
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Laelkhunter
Well-Known Member
I use the rubber wedge also, got it from Brownell's, I think it is called Accu-wedge. Just inspect it closely while servicing/cleaning your rifle. I have heard where some brands could become brittle and a piece break off which could result in malfunctions. Never happened to me, mine is still as new and I've had it for over 10 years. Just try to buy a quality one (like Brownell's), and you shouldn't have a problem. Knockoffs made out of ??? materials could cause problems.
Thinnly, around the entire extension, as it fits /mates with the upper
Some lowers (aero precision I think) Have a small set screw that can be ran up through the lower and it puts upward pressure on the rear pin/hole in the upper. But I believe (been a while since I've slapped one together) you have to take the grip off if you need to separate the upper/lower, because you'll need to take that pressure off the set screw before you can remove rear pin.
Eric Musgrove
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you can make a shim from a beer can that goes between the upper and lower at the rear right above the take down pin. Cut it bigger than needed and trim with a razor blade. Sould tighten it right up and it was free, plus you got to have a beer first.
Kansaswoodguy
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We occasionally do an egg shoot but we actually use eggs at 400yds using utility marking flag wires bent to hold the eggs great fun
MOOSE39465
Well-Known Member
Here's one of my targets when I was doing load development on my 6.5 creedmoor AR10. There's is tons of slop between the upper and lower. That was 140 grain Speer gold dot and reloaded 16. I was able to eliminate those flyers by simply doing brass sizing.
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MOOSE39465
Well-Known Member
This is a 300 yard group after I settled on a load. Not to bad for a sloppy AR.
