AR upper/lower bedding

[frostfire]

Does any of you use accuwedge, JP tension pin, or do bedding on the upper or lower for a tight-no-flop fit? How do you go about it and which bedding compound did you use?

The wiggle on my AR upper-lower fit is starting to get in my head. The side to side is one thing. But when I hold the rifle by the receiver alone, I can push the upper down by the charging handle ever so slightly and bob it up and down. It makes sound as well I understand there's enough movement from the bolt cycling to be concerned of how the wiggle affects accuracy, but that vertical movement surely hurts sight alignment with iron or optics especially after recoil. I wonder if that's what caused the 0.75 group as opposed to 0.5

Even if it doesn't affect accuracy, a tight fit has mental/psychological effect. So based on master Gene Econ write up on technical, physical, and finally mental stage of precision shooting, it won't hurt to keep the upper-lower dead tight then.

I've perused other shooting forums for input. Some good info:
- Question on accuwedge and bedding at :
odcmp.com/Competitions/USAMU/Equipment_Ammo.htm
- Point 12. Upper to Lower Fit at :
bulletin.accurateshooter.com/2011/10/what-makes-an-ar-accurate-whitley-offers-answers/

I'm thinking of bedding like Post #805589 at:
snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=803703
but with the bedding compound applied to the upper instead. I'm currently trying it with some duct tape and surgical tape and it already eliminates all the vertical and side-to-side wiggle. So I'm planning to make it permanent by bedding. I won't be switching upper so I don't care if the upper and lower can only fit one another. I'd like to solicit some recommendations. Also since I don't need much, if you're local, perhaps I can purchase a small amount from you

[Iraqgunz]

Per the TM when you conduct an inspection of the weapon you are supposed to use a .020 inch feeler gage and do the following;

I personally don't worry much about the wiggle as it has no impact on accuracy. Putting a new upper receiver in place may or may not totally solve the issue. I am not a big fan of Accu-wedges as I have seen them cause issues. I am also not a big fan of making a permanent alteration like bedding.

1. With the upper receiver attached to the lower receiver, and the pivot pin and takedown pins in place,
perform the following test:
(a) Apply hand pressure to push the upper receiver as far to one side as possible.
(b) Attempt to insert a 0.020 inch thickness gage between the pivot pin lugs or the upper and lower
receivers.
(c) If the thickness gage penetrates to the pivot pin at all accessible locations, repair by replacement of
the upper receiver (see (b) below) or replacement of rifle is required.
2. If the rifle fails the above test, remove the upper receiver and install a "NEW" upper receiver and perform
the test again.
3. If the rifle now passes the above test, it shall be considered serviceable and continue in use.
4. If the rifle fails the test with a new upper receiver, this failure shall be considered a shortcoming. This
shortcoming requires action to obtain a replacement rifle. Once a replacement has been received, evacuate the original rifle to depot for overhaul.

[MK262MOD1]

Tight Tolerances are fine. Bedding an AR is not worth the trouble. Frankly the bedding would wear down every time you shotgunned the weapon to clean it and put it back together.

The Accuwedge is not worth the trouble either.

Just my two cents.

[Boomer-61]

I have a CAR-15, and an M4 with the Accuwedge. I also have an M4 with a Barnes Precision lower that has the adjustable tension pin. The Barnes can be set up tight as a tick, no wiggle; and I thought that was great, nothing better. When I needed to break it down and clean it, I initiated the proces like usual, I jammed my nail into the take down pin and it didn't budge. I squeezed the upper and lower together like I do for the Accuwedge guns and still that pin would not budge. I had to take the pistol grip off and loosen the tension pin to get the two halves apart. That concerned me. The tight fit made the gun feel solid (which I really like) but It also made it tough to field strip the weapon without tools. If you're putting together a match gun I think tight is good. The Accuwedge is cheap, takes most (99%) of the wiggle out, and you can disassemble without tools. Seems like the Accuwedge is the way to go for the all around fix.

[Peregrino]

Frostfire - From a friend. TR and I can both verify the accuracy of his comments. If you're hung up on bedding it, get it done right, make sure it's a true "match rifle", and that that's all you're planning to use it for. My service rifle has the rear lug bedded; keeps it from moving, otherwise doesn't do much more than tighten the nut behind the trigger. I use an accuwedge on my carbines that wiggle, again mostly for esthetics, not sure I'd do it for a true field gun. Bottom line - most of the time it does more for the shooter than the gun. Course YMMV. HTH



Peregrino
Mark Gordon was 1 of my students at MCC, look at the glue and trigger mods. He can't get this glue but I can and the bedding works. The pic is right out of the class room and my manual. Gordon left out the pic of the shims on his post. FrostFire is only getting half the story. All my match rifles has had this stuff for the last 30 years. If they think it don't work well you know what my scores have been. (490s and 790s). Wins at Butner and everywhere else. This guy is going to get all messed up with those other posters ignorance.
MSH