View Full Version : DDM4 Upper meets Bushy lower.
Recieved the upper today. Fantastic fit and finish. #3 for me. This time however I put it on a Bushy lower. It is less than tight for my comport level. Accu-wedge? Or just get a DD lower and move on.
I have always hesitated using different manufacturers for this reason and preference of continuity.
Any input is welcome. Needless to say it's going to the farm in the morning for a prelim.
-C
Blankwaffe
08-18-10, 15:45
If the fit is loose enough to cause function issues,then yeah I'd say its a problem.Otherwise I'd let it rattle.Common wisdom is to avoid the wedges or o-ring fixes.If you want to try and tighten it up a bit,then get a set of Armalite NM pivot and take down pins and see what that does for you.
Otherwise if you have some other lowers try swapping uppers around to get the best fit between the bunch.Pretty much all my rifles are put together with mixed manufacturers receivers.Some fit kinda tight and some are kinda loose,same goes for the factory built guns..
Even rifles from the same manufacturer can and will be loose (hence the perceived need) for Accuwedges. The play between an upper and lower does not affect accuracy or function so I would forget about it and shoot the weapon.
Recieved the upper today. Fantastic fit and finish. #3 for me. This time however I put it on a Bushy lower. It is less than tight for my comport level. Accu-wedge? Or just get a DD lower and move on.
I have always hesitated using different manufacturers for this reason and preference of continuity.
Any input is welcome. Needless to say it's going to the farm in the morning for a prelim.
-C
Well, all good and thanks. Never understood the wedge thing anyway. But, first time iv'e ever married different urg/lrg's. I have 10 hrs of range time at the farm so we'll put it through the paces. I also have one more lonely lower I can sub too.
I'll report later. I really appreciate valuable insight.
V/R
Colin
Canonshooter
08-18-10, 19:19
I just mated a complete BCM 14.5 middy upper to my BM lower and it seems no worse then when I had a BM upper on it.
Even rifles from the same manufacturer can and will be loose (hence the perceived need) for Accuwedges. The play between an upper and lower does not affect accuracy or function so I would forget about it and shoot the weapon.
It affects accuracy a little bit. Feamster demonstrated this in Black Magic.
I would love to see some real proof of this. I am highly doubtful. Obviously if the upper is rocking and rolling all over then I would be concerned. But, this most likely isn't the case. We are talking about a little play.
It affects accuracy a little bit. Feamster demonstrated this in Black Magic.
I would love to see some real proof of this.
I did cite my source.
Sorry, I don't have his book. I also know that other people have tried Accuwedges and other assorted garbage and none of them have reported an appreciable difference.
You'll have to excuse me if I don't believe everything that it published in some book.
I did cite my source.
Sorry, I don't have his book. I also know that other people have tried Accuwedges and other assorted garbage and none of them have reported an appreciable difference.
You'll have to excuse me if I don't believe everything that it published in some book.
He has pictures.
iirc, the method he used was the JB Weld on the upper receiver method.
So what was the difference between the groups he was shooting before and after?
He has pictures.
iirc, the method he used was the JB Weld on the upper receiver method.
kaiservontexas
08-19-10, 09:20
Even rifles from the same manufacturer can and will be loose (hence the perceived need) for Accuwedges. The play between an upper and lower does not affect accuracy or function so I would forget about it and shoot the weapon.
Yep
I think it is hard for some people to understand at the start. Many of us come from the world of bolt action rifles where things are nice and tight. Then we go pick up a Glock or an AR and wonder why we can see light through that very small line between receivers and frames.
Then of course some company comes about to sell gimicks that claim to solve the non-problem. It makes them sleep better at night then so be it, but I would not bother with the gimicks. Go shoot the rifle as stated above and have fun with it.
So what was the difference between the groups he was shooting before and after?
A little dated while not greatly so, sloppy methodology, clown-shoes writing and no editing to speak of(all the !!!!! garbage makes it VERY difficult to take seriously; like if Billy Mays wrote an AR book before his untimely passing).
Results were the kind of difference that only pure benchrest/bullseye shooters would care about. Not a dig on those guys, but it wasn't anywhere near significant enough to even contemplate tightening up lower/upper fit uless you're using a gnat's bunghole as a measuring standard. The info isn't wrong, but it's very, VERY limited in practical application in regard to a working or duty gun.
The US Army Marksmanship Team has/had a page where they dedicated it to debunking the accu-wedge, saying it did nothing to improve accuracy and that accuracy lies solely in the upper...accu-wedges are a solution in search of a problem.....
Unless it's all over the place and sloppy as hell, just forget about it; if you have problems with it, go with another lower; you certainly can't go wrong with DD. Forget about the accuwedge and similar crap.
Too much is made of the upper/lower fit. Unless it causes perceivable degredation in function/accuracy/reliability, there is no problem and thus no reason to give it a second thought.
ForTehNguyen
08-19-10, 10:56
people tend to not see that looser tolerances increase reliability in most cases.
people tend to not see that looser tolerances increase reliability in most cases.
I'm curious; can you expound on this please?
ForTehNguyen
08-19-10, 14:52
I'm curious; can you expound on this please?
Just speaking in general. This is one reason why the AK47 has great reliability, because of loose manufacturing tolerances. With looser tolerances small things like dirt, mud, gunk wont have as big of an effect on operation as some tight tolerance weapon such a German Luger. Luger has high manufacturing tolerances parts but unreliable in the real world. Looser tolerances mean there are less things that can be introduced and screw it up, hence greater reliability. If you have something so tightly manufactured together even the smallest thing can disrupt that more sensitive system. Of course with looser tolerances you lose precision. Its a delicate design balance.
Thanks for the explanation, I see what you're saying now; I thought you meant specifically with the lower/upper mating of the M4/AR; not just in general.
Thanks again.
Jim,
That's what I figured. I did some simple testing years back with my Noveske using an Accuwedge. I could see no practical difference at all when using it.
I Googled his name and when I discovered what type of shooter he was I think I knew all I needed to know.
A little dated while not greatly so, sloppy methodology, clown-shoes writing and no editing to speak of(all the !!!!! garbage makes it VERY difficult to take seriously; like if Billy Mays wrote an AR book before his untimely passing).
Results were the kind of difference that only pure benchrest/bullseye shooters would care about. Not a dig on those guys, but it wasn't anywhere near significant enough to even contemplate tightening up lower/upper fit uless you're using a gnat's bunghole as a measuring standard. The info isn't wrong, but it's very, VERY limited in practical application in regard to a working or duty gun.
Dos Cylindros
08-19-10, 23:23
I will echo everyone else and say the slop does not mean anything. For all the Bushy hating that goes on on alot of sites, they actually make a decent lower receiver. I have a BCM KAC build on a Bushy lower and I have no concerns at all about the reliability and durability of this setup.
I would use one also if I couldn't get a good one anywhere else.
I will echo everyone else and say the slop does not mean anything. For all the Bushy hating that goes on on alot of sites, they actually make a decent lower receiver. I have a BCM KAC build on a Bushy lower and I have no concerns at all about the reliability and durability of this setup.
So what was the difference between the groups he was shooting before and after?
Sorry for the delayed reply. It was 1/4 moa
Well, I had my second day out with the DD and Bushy combo. This time I used the lower from a Varminteer Rifle. I sold the upper off months ago. The lower has a fancy Hogue grip, two stage trigger and actually married to the DD very well. No issues.
The_Hammer_Man
09-17-10, 20:46
Anecdotal reinforcement of what previous posters in this thread have stated...
Slop isn't a bad thing in an AR.
Here in the frozen north , Wisconsin, patrol rifles get iced up a lot!
A "less then perfect" fit allows ice and snow to be knocked out of the receivers and mag well without having to disassemble the weapon.
A "perfect" fit would mean,, to me at least,,, that the weapon could and would potentially malfunction due to ice/snow/rain/dirt under less then perfect range condition.
Heck, could be talkin out my kazoo.. YMMV
I have an older "ban era" Bushmaster 16" that I recently sold off the upper on. I bought a BCM 16" mid-length to replace it. The upper and lower have just a hint of play between them; about what I would term ideal.
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