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Posted: 2/3/2001 5:26:29 PM EDT
I need your advice.

I just got a new PWA lower and tried to put it on a Bushmaster that I recently purchased.  I got the front take down pin in no problem.  When I tried to put the rear takedown pin in, it wouldnt go!  I looked through the hole and it looks like upper and lower align ok.  I couldn't push it in by hand so I took a rubber mallet and tapped it in.  Now its on, but its tight as heck

Is this normal for a new lower?  Will this cause my upper or lower to wear prematurely because of the stress from the tightness?  The reason I am concerned is because I plan on buying a bushy lower in the near future to put on the bushy upper, and I don't want the upper worn out of spec.

thanks, and sorry for the stupid question
Link Posted: 2/3/2001 6:15:25 PM EDT
Link Posted: 2/3/2001 6:35:17 PM EDT
as long as it's not visibly out of line , tight/snug is good, I like 'em that way. just as long as you didn't have to do more than lightly tap on the pin to get it in, the key here is lightly. If it really doesn't want to go you may have a pin that is a thousandth or so too large and that'll make things tough. Make sure it's lubed well and give it a tap, it should then push in with no more than a light tap from a fairly small rubber handled screwdriver, which I commonly use since that way I don't get carried away pounding on something that shouldn't be pounded upon.
Link Posted: 2/3/2001 7:54:07 PM EDT
Tighter is better (just like... oh never mind).  I have an Armalite (AR10) that I have to tap apart and back  together.
Link Posted: 2/3/2001 8:29:08 PM EDT
Thanks for the responses!

I checked the pin before I started tapping. If I put the rear take down pin in first it goes in with no problem, but then the front pin wont go in.

So this tells me that the pins and holes are all the right size (front and back), but one of them will have to be tapped in.

I could get the rear take down pin started (very little bit) but I couldnt push it in by hand. Yes I had to tap the pin pretty good to get it in...I didn't pound it by any means..but I did tap it pretty good. It seemed like It was a little easier the second time after firing the weapon.

Does this mean that I can only use this upper with this lower, because of possible stressing to the upper/lower?

Is stressing out of spec. possible? If it is, which will it happen to...the upper or the lower, or both?

I don't know, I guess since this is my first AR, I'm kind of worried and I have no clue if this is normal with brand new lowers.
Link Posted: 2/3/2001 8:33:34 PM EDT
    I'm just speculating here, but does an accuwedge cause the same stressing on an upper and lower on a normal rifle where tapping is not neccesary?

    I guess not because at least rubber has flexability and its not metal on metal where there is no "give" at all
Link Posted: 2/3/2001 9:03:40 PM EDT
sounds fine to me, fire a couple hundred rnds through and it should settle in. Always take it apart rear pin first, that way you don't stress the frame by an accidental bending the wrong way, that can damage the rear pin lug. Nearly all better grade AR style rifles need the pins tapped in, keeps the fit tight that way and a new gun should be tight, otherwise I would be concerned about the quality of the build.  Not like the 16a1's that sometimes were so loose the pins nearly fell out wher tipped on their side, too loose, not good, tighter is better.[;)]
Link Posted: 2/3/2001 9:36:09 PM EDT

    Thanks, I feel better now [:)] thanks for the advice too!

    Does this mean the specs will be ok if I use an older lower receiver on the new upper that currently has the new PWA on it?

    I guess my real question is:    Once an upper and lower have been broken in, does it change the fit if different lowers are interchanged? ie.  the holes in the upper receiver, lower receiver from the stress?

    should I make a concious effort not to take it apart so often to clean it to minimize wear?

Link Posted: 2/4/2001 2:49:43 AM EDT
Link Posted: 2/4/2001 3:13:55 AM EDT
New should be tight, new lower, new upper or new pins. New everything can be real tight. You were putting new on new and it went together so don't worry about it. Grease the pins and be careful pounding on them.[smoke]
Link Posted: 2/4/2001 5:00:03 AM EDT
View Quote

From the title of this thread, I was gonna suggest either a liberal application of K-Y or Preparation-H...

Link Posted: 2/4/2001 5:16:14 AM EDT
Just a little FYI - the new M-4's in the Army made by Colt - you have to use a damn drift punch or Leatherman with a hammer to take apart the upper and the lower. I know - because I did a work order on an M-4 down in Kosovo. Armament shop told me ALL new M-4's are tight like this. Not necessarily a bad thing - just a big pain to take apart.
Link Posted: 2/4/2001 6:32:58 AM EDT
Mine was so tight that I couldn't even hammer the pin through the back hole.

I actually filed a little around the edges of the rear upper pin hole and now the push pin goes in.  It still takes a lot of force to push it in and requires a punch to get it out but it's aleast do able now.
Link Posted: 2/4/2001 10:47:13 AM EDT
Thank you all so much for the replies!

It sounds like I am ok then [:)]
and that I should be able to switch lowers later without having to worry about proper fit [:D]
Link Posted: 2/4/2001 3:42:19 PM EDT
although ar's are technically interchangeable I don't recommend that you play swap meet with your arms all the time. they do get somewhat set to the components, upper & lower, and the less you take em apart the better. Thats not to say don't take it down and clean it, but there's no reason to field strip the thing every other day for no reason unless you're really using it hard, even then I've know match shooters that very seldom take down their guns except for the patch down the bore and some oil on the important parts.  Also, sometimes the detent pin is too pointy and a little filing to smooth the point can make it go in much easier, a somewhat rounded pin works much better than one that is really pointy. Thats the detent pin on the takedown pins I'm talking of here in case you were lost.
Link Posted: 2/4/2001 3:51:34 PM EDT

    Thanks for your advice!  I learned alot just from your last post[:D]

    How about rounding off the hard edges on the rear take down pin itself?  Do you think that would help, or would you advise against it?

    I guess, I should go ahead and take this lower off and wait until I get the bushy lower to permenantly install it on my current upper.

Thanks Again!
Link Posted: 2/5/2001 6:16:41 AM EDT
If you have a telescoping butt stock that is turned in one revolution too much, this will cause the same problem you are experiencing.  If you unscrew the butt stock one revolution, lock it back down, and your receiver closes easily....there's your problem.
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