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Posted: 9/11/2010 11:05:18 PM EDT
bcm 16" m4 upper/stag lower. Are there any tips or tricks to keep them rock solid? they have a little bit of play between them.
Link Posted: 9/11/2010 11:09:25 PM EDT
foam ear plug, accuwedge, etc if it really bothers you

Link Posted: 9/11/2010 11:20:20 PM EDT
Originally Posted By mvician:
foam ear plug, accuwedge, etc if it really bothers you

http://www.fulton-armory.com/accuwedge.jpg


Accuwedge it and be done.
Link Posted: 9/11/2010 11:23:23 PM EDT
Accuwedge will help giving it a more solid feel but its useless in the sense that the tighter fit it provides does nothing for accuracy..to me its just something that little bits can come off and gum up the works.I dont like anything in the rifle that wasnt necesary for functioning.
Link Posted: 9/11/2010 11:25:06 PM EDT
will a wobble between upper/lower cause accuracy problems? ive only shot 100 rds through mine so far
Link Posted: 9/11/2010 11:42:21 PM EDT
[Last Edit: 9/11/2010 11:43:38 PM EDT by ChromeLined]
No not affected at all upper and lower tightness will not have any bearing on accuracy what so ever.If your issue is about having a solid feel use the wedge if its an accuracy thing then dont use it its useless for that.
Link Posted: 9/12/2010 3:59:11 AM EDT
Most all upper and lower fit's will be loose. It is completly ok .
Link Posted: 9/12/2010 4:31:11 AM EDT
Give this a read.......
Link Posted: 9/12/2010 5:39:45 AM EDT
I've also found that if you put a tight O-ring around the front takedown lug, that can really help with a wobbly upper/lower. 1/2" OD x 3/8" ID x 1/16" thick are what I use. Get a 10 pack of them in the plumbing section at the Home Depot. Just be careful when you pivot the lower/upper together. Also, after you open it up again, you're probably gonna have to replace it as it'll get flat and break.
Link Posted: 9/12/2010 6:04:48 AM EDT
[Last Edit: 9/12/2010 6:25:22 AM EDT by Catman2]
Originally Posted By Eazy_E:
I've also found that if you put a tight O-ring around the front takedown lug, that can really help with a wobbly upper/lower. 1/2" OD x 3/8" ID x 1/16" thick are what I use. Get a 10 pack of them in the plumbing section at the Home Depot. Just be careful when you pivot the lower/upper together. Also, after you open it up again, you're probably gonna have to replace it as it'll get flat and break.


Look on the rack on the plumbing aisle at Home Depot for rubber O rings. You'll want the # 7. My BCM wobbled slightly on my RRA lower. I couldn't get it to do on purpose but it would click in my hand when I wasn't expecting it and although it shot well, like a loose filling, it bugged the shit out of me. I stuck the O ring on the front pivot post and now its a one piece.


eta- as I stated my BCM upper shot great before shimming it but I also know that in accurizing a bolt rifle one of the key rules is to make sure the rear under the reciever is bedded well and the front and rear bolts are tight. Whether that rule transfers over to an AR is debatable but having a solid platform from shot to shot can't hurt.


Link Posted: 9/12/2010 6:18:07 AM EDT
If the play isn't distracting you, then I'd let it be. Play b/w an upper and lower won't affect the accuracy. Adding parts to the rifle just increases Mr. Murphy's chance of visiting.
Link Posted: 9/12/2010 8:28:09 AM EDT
I've used Nylatron washers from Knife kits to get rid of any play in the pivot pin, I've also made a washer out of those juice pouches. Those juice pouches are made out of some type of laminate that is very tough. If there is enough play, you can squeeze the washer in there to shimmy it.
Link Posted: 9/12/2010 8:29:49 AM EDT
Originally Posted By Truth2882:
will a wobble between upper/lower cause accuracy problems?


No.
Link Posted: 9/12/2010 8:38:04 AM EDT
I usually just ignore it. However, I do have 1 Bushmaster upper that fits very very loose with all my other lowers. I put an accuwedge in the lower with a dab of super glue to make sure it stays there. I like the way it "feels" alot better now.
Link Posted: 9/12/2010 9:24:24 AM EDT
Originally Posted By Catman2:
Originally Posted By Eazy_E:
I've also found that if you put a tight O-ring around the front takedown lug, that can really help with a wobbly upper/lower. 1/2" OD x 3/8" ID x 1/16" thick are what I use. Get a 10 pack of them in the plumbing section at the Home Depot. Just be careful when you pivot the lower/upper together. Also, after you open it up again, you're probably gonna have to replace it as it'll get flat and break.


Look on the rack on the plumbing aisle at Home Depot for rubber O rings. You'll want the # 7. My BCM wobbled slightly on my RRA lower. I couldn't get it to do on purpose but it would click in my hand when I wasn't expecting it and although it shot well, like a loose filling, it bugged the shit out of me. I stuck the O ring on the front pivot post and now its a one piece.




If you cant get the right size you can put a bigger one with no worry.

Link Posted: 9/12/2010 10:19:13 AM EDT

Originally Posted By Ben762:
Originally Posted By Truth2882:
will a wobble between upper/lower cause accuracy problems?


No.


Not so fast. The US Army looked at the issue and said based on the fact the iron sights were on the upper, the accuracy SHOULDNT be affected. Once you mount an optic that SHOULDNT gets changed to a MAY, and when you add a magnified optic that MAY changes to a LIKELY. The recoil caused the sight pictire in the optic to move off center from where you were before, so you would gain a slight paralax after each shot.

But all in all...No, accuracy isnt affected to the extent you will see it. Its about the same as a FF vs a 2pc HG set up. Very few will see an accuracy increase with a FF.

I stay away from the accuwedge since it will degrade over time and may jam the FCG. When I found this wobble on an well used A2, I used a small piece of plastic and sandwiched it between the upper and lower forcing an upward pressure. I have seen other guys use tape to build up the inside edges of the lower doing the same thing.
Link Posted: 9/12/2010 12:03:00 PM EDT
The accuwedge is a urethane type material and will not degrade, dry and crumble, or come apart in bits to cause a failure. It will do just fine so thats not a worry. And as others have stated, the wobble will not affect accuracy, accuracy is all in the upper receiver and the lower has ABSOLUTELY nothing to do with it.
Link Posted: 9/12/2010 12:08:37 PM EDT
[Last Edit: 9/12/2010 12:11:58 PM EDT by NorthStaR209]
CWDaco
I stay away from the accuwedge since it will degrade over time and may jam the FCG. When I found this wobble on an well used A2, I used a small piece of plastic and sandwiched it between the upper and lower forcing an upward pressure. I have seen other guys use tape to build up the inside edges of the lower doing the same thing.[/quote]

???To say that plastic or tape is a better choice is rediculous. Plastic drys and crumbles, especially with heat and tape? Come on, tape on an AR? I find it crazy you trusting something homemade out of tape or plastic over a urathane bushing as an accuwedge.
Link Posted: 9/12/2010 12:19:48 PM EDT
I 've used washers like these before. You can put it on the left or right of the lug to adjust accordingly. If the gap is so minor that you can't slide the washer in then you shouldn't give it much thought.
http://www.texasknife.com/vcom/product_info.php?cPath=52_890_554&products_id=2043
Link Posted: 9/12/2010 12:44:58 PM EDT
I agree that a little play is fine, however, in my experience excessive play is detrimental to accuracy. My final qual was with a totally floppy A2. This thing must've seen some hard, long term abuse. My quals were to this point an easily earned, consistent upper Expert. That time was frustrating and I barely made Marksman (made it by 2 points). I felt it may be a problem in dry fire, as the entire upper receiver flopped about; randomly changing the POA/POI when the hammer struck. It was a serious issue at longer ranges. It took my Expert mojo away I couldn't hit shit at 500 yards. I thought about sticking an Accu-Wedge in there (even kept it in my pocket during qual day) but didn't want to risk complete disqualification if caught.
Link Posted: 9/12/2010 1:55:49 PM EDT
Originally Posted By cckw:
Originally Posted By Catman2:
Originally Posted By Eazy_E:
I've also found that if you put a tight O-ring around the front takedown lug, that can really help with a wobbly upper/lower. 1/2" OD x 3/8" ID x 1/16" thick are what I use. Get a 10 pack of them in the plumbing section at the Home Depot. Just be careful when you pivot the lower/upper together. Also, after you open it up again, you're probably gonna have to replace it as it'll get flat and break.


Look on the rack on the plumbing aisle at Home Depot for rubber O rings. You'll want the # 7. My BCM wobbled slightly on my RRA lower. I couldn't get it to do on purpose but it would click in my hand when I wasn't expecting it and although it shot well, like a loose filling, it bugged the shit out of me. I stuck the O ring on the front pivot post and now its a one piece.




If you cant get the right size you can put a bigger one with no worry.



O-rings do work great. If the o-ring cuts when you close the receivers then go down to a smaller cross-sectional size.

Link Posted: 9/12/2010 1:58:12 PM EDT
Originally Posted By Russ4777:
O-rings do work great. If the o-ring cuts when you close the receivers then go down to a smaller cross-sectional size.

http://www.hunt101.com/data/500/medium/IMG_6260.jpg

The only thing I don't like about the o-ring solution is that you'll have to keep replacing them every time they break, so in reality, it's not a permanent solution.
Link Posted: 9/12/2010 2:16:54 PM EDT
I've never tried one, but I like the concept;

http://www.demontactical.com/demon-tactical-quick-pins.html
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