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Posted: 11/10/2013 12:53:35 PM EDT
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Ok guys braceman just sent me my 656 upper last week which is stunning and now i'm just waiting on the fsb.
anyway i tried to put it on my 604 lower just to try the fit and it wouldn't seat. I then tried on every lower I have and it's the same problem. Before i get down to my findings I am in no way suggesting anything braceman did caused the prob i'm just looking for a solution. Basically after looking closely it looks like the front take down pin hole on the upper is sitting about 1-2mm too far forwards. So simple question...what is the solution? I only need the hole to come back a tiny bit. I really don't wan to drill the hole out to be larger as that will equal sloppy fit. Is there a way i could maybe hammer the area back just a touch? Any advice is much appreciated can upload pics if you guys think it will help. p.s. i am about a week away from coating the upper so i'd like to get the repair done now before I get a good finish on it :) |
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Off the top of my head...put the upper and lower together, install the take down pin, wrap masking tape to the front to hold the thing together, use a rat tail to remove just enough material from the 'upper' to allow the insertion of the pivot pin. Smooth out the file marks with some sand paper on a small dowel or nail.
That is what I'd do, others may have another ideas. |
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Check to see if the back take down lug is hitting the back of the fire control pocket. I just checked the two 656 uppers i made and they all fit . Will do and yes i'm sure they do to be honest with you this is my own fault for not checking the upper before sending it to you. am sure that the problem already existed before sending it. |
If it makes you feels any better, I have a PM upper I bought (complete upper  ) that I finally tried on a lower - just won't fit. My original XM16E1 upper is also VERY tight on the same NDS lower, but other Colt uppers fit perfectly. You would think everyone would be on the same page by now, but shit happens. It'll be okay I'm sure.
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Thanks Morg,
On the NDS Lower front takedown pin goes in fine...the rear one won't seat. If i put the front pin through the upper then there is about a 2mm crack between the upper and lower that gets bigger the further back you go. I took some pics: On my S&W lower however the rear takedown pin goes in fine and the front one won't go lol. As the NDS lower is the one this is destined for that's the one i will be tinkering with. The lower pic shows the problem pretty clearly btw. You can see the rear takedown lug doesn't reach the the bottom of the pit area in the lower. 
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Since you are refinishing the upper anyway, a little careful CAREFUL filing on the very back of the upper seems like it would allow it to drop in. A dab'll do ya.  Little at a time, check, recheck. You can take it off, you just can't put it back. The file will 'loadup' with aluminum, so clean it with wire brush as you go.
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the hole on the rear lug should be slightly elongated. i had a PM one that wasn't and was drilled to fit that 1 upper. heatnbeat opened it up for me so it will fit others. i'd modify the rear hole if possible and leave the front alone. +1 - leave the front alone. I'd look through the hole and see if you see any material - looks to me as though a high point at the very rear of the upper is preventing it from dropping down. If not, then I'd ream the hole slightly. |
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Hello. Now that I see pictures of the upper I realize what it is, how was it made? Was it welded? I had a friend weld the markings on the right side of a lower and it did warp a little bit.
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Thanks Morg, On the NDS Lower front takedown pin goes in fine...the rear one won't seat. If i put the front pin through the upper then there is about a 2mm crack between the upper and lower that gets bigger the further back you go. I took some pics: On my S&W lower however the rear takedown pin goes in fine and the front one won't go lol. As the NDS lower is the one this is destined for that's the one i will be tinkering with. The lower pic shows the problem pretty clearly btw. You can see the rear takedown lug doesn't reach the the bottom of the pit area in the lower. http://imageshack.us/a/img812/3273/tfzy.jpg http://imageshack.us/a/img35/1900/yq3e.jpg |
The upper had welding done on it but not the lower, the lower is from NDS and generally has a 604 style upper on it, which fits and functions fine. However the the welding was done well away from the takedown lug i doubt it warped but who knows. Either way I think with some careful filing of the upper and slight tinkering of the pins by myself and my local GS tomorrow i should be ok. Will report back if not, probably with less hair! 
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can you close the upper with a little more than normal force (hate to say slam, but...) and get it to close?
if so (even if not) whwn you open you should be able to see marks where the problem lies. wait i just saw its a Nodak lower, the pocket the rear lug goes in should be ok, i was thinking 80% er. you can use the dollar bill trick between mating surfaces and see where the tight spots are if the uppers touching the lower way up front it'll keep it from closing. put a dolllar bill between the upper and lower and see if its free all the way. (no FCG) as to modifying the " least expensive/easiest to replace " rule applies |
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Minus 1 on the dremel...in this case I'd recommend a round file on the back lug and go SLOW. Aluminum doesn't take much and a little tight won't hurt. I would bet you Nodakspud would probably fit it for you, they are very customer satisfaction oriented and they mention doing this on their website.
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Minus 1 on the dremel...in this case I'd recommend a round file on the back lug and go SLOW. Aluminum doesn't take much and a little tight won't hurt. I would bet you Nodakspud would probably fit it for you, they are very customer satisfaction oriented and they mention doing this on their website. That's why i'm not taking my dremel to it ;) lol... doing to try a file then GS if that doesn't work and then if the guys at NDS would fit it i might try them i'm pretty sure my local guy can hook me up though. |
| I would start with a very well used pivot pin,,even roll the pin with emory cloth. Get the pin to make the upper and lower work,,then start shooting and allow everything to settle in. Filing uppers or lowers should always be the the VERY LAST COURSE of action. |
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I would start with a very well used pivot pin,,even roll the pin with emory cloth. Get the pin to make the upper and lower work,,then start shooting and allow everything to settle in. Filing uppers or lowers should always be the the VERY LAST COURSE of action. This. ^^^ a voice of reason. |
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I would start with a very well used pivot pin,,even roll the pin with emory cloth. Get the pin to make the upper and lower work,,then start shooting and allow everything to settle in. Filing uppers or lowers should always be the the VERY LAST COURSE of action. M1 shot you an im ref pins...my only concern in trying this is that (and i can't get the pic to show very well) is that the rear takedown lug is nowhere near seating correctly. If i get the rear pin to fit (with the front one in place it would need to be about 2/3rds the diameter of a standard pin. If i reverse it (bare in mind i can't get the rear pin all the way in anyway) then the front pin would have to be similarly filed down. I might get a couple of pins from you anyway sniper in case i bork this pair. I have some spares sitting in a parts kit in the garage i can try out tomorrow also. Thanks for the tips guys this is why i post here. |
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M1 shot you an im ref pins...my only concern in trying this is that (and i can't get the pic to show very well) is that the rear takedown lug is nowhere near seating correctly. If i get the rear pin to fit (with the front one in place it would need to be about 2/3rds the diameter of a standard pin. If i reverse it (bare in mind i can't get the rear pin all the way in anyway) then the front pin would have to be similarly filed down. I might get a couple of pins from you anyway sniper in case i bork this pair. I have some spares sitting in a parts kit in the garage i can try out tomorrow also. Thanks for the tips guys this is why i post here. Quoted:
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I would start with a very well used pivot pin,,even roll the pin with emory cloth. Get the pin to make the upper and lower work,,then start shooting and allow everything to settle in. Filing uppers or lowers should always be the the VERY LAST COURSE of action. M1 shot you an im ref pins...my only concern in trying this is that (and i can't get the pic to show very well) is that the rear takedown lug is nowhere near seating correctly. If i get the rear pin to fit (with the front one in place it would need to be about 2/3rds the diameter of a standard pin. If i reverse it (bare in mind i can't get the rear pin all the way in anyway) then the front pin would have to be similarly filed down. I might get a couple of pins from you anyway sniper in case i bork this pair. I have some spares sitting in a parts kit in the garage i can try out tomorrow also. Thanks for the tips guys this is why i post here. If the upper and lower are that misaligned, would the bolt carrier be a running fit in the buffer tube????? probably not??? If I had it in hand, I would take some measurements and know exactly what the situation was before I started sanding/filing willy nilly......but that's just me. Hopefully, your GS has a surface plate or some other suitable surface for checking the surfaces on the receiver that needs to be checked/measured, etc to determine what needs to be done. |
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If the upper will lay flush and flat on the lower when NO pins are installed, but cantilevers when the front is, it's pinching at the front.
This will keep the back end from coming all the way down. You will need to adjust the bottom flat on the upper before it's anodized. ETA: I just looked at your pics again. Check the rear radius to see is there is daylight between the back of the upper and the leading edge of the buffer tube area. You can check for pinch with a piece of paper. |
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M1 shot you an im ref pins...my only concern in trying this is that (and i can't get the pic to show very well) is that the rear takedown lug is nowhere near seating correctly. If i get the rear pin to fit (with the front one in place it would need to be about 2/3rds the diameter of a standard pin. If i reverse it (bare in mind i can't get the rear pin all the way in anyway) then the front pin would have to be similarly filed down. I might get a couple of pins from you anyway sniper in case i bork this pair. I have some spares sitting in a parts kit in the garage i can try out tomorrow also. Thanks for the tips guys this is why i post here. Quoted:
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I would start with a very well used pivot pin,,even roll the pin with emory cloth. Get the pin to make the upper and lower work,,then start shooting and allow everything to settle in. Filing uppers or lowers should always be the the VERY LAST COURSE of action. M1 shot you an im ref pins...my only concern in trying this is that (and i can't get the pic to show very well) is that the rear takedown lug is nowhere near seating correctly. If i get the rear pin to fit (with the front one in place it would need to be about 2/3rds the diameter of a standard pin. If i reverse it (bare in mind i can't get the rear pin all the way in anyway) then the front pin would have to be similarly filed down. I might get a couple of pins from you anyway sniper in case i bork this pair. I have some spares sitting in a parts kit in the garage i can try out tomorrow also. Thanks for the tips guys this is why i post here. I still think you can file this to work, but based on your description above, a picture of the front pivot pin hole (straight on) assembled to the lower with the rear take down pin inserted partially or completely would help. If we are talking a 1/16 of an inch or so were good to go. Do not remove material from the rear contour of the upper. Where did you get this upper originally????? Have you ever had this upper on a lower that fit correctly???? |
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What brand of upper was used as your base? I've had multiple Rock River uppers that required filing on the chamfered corners of the rear lug to fit into the lower.
You can check for this by looking to see if the upper corners are wearing in that spot when you try to close it with a front pin in place. This is an easy fix, and is actually a benefit because you can get a nice tight fit if you want to. |
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If the upper will lay flush and flat on the lower when NO pins are installed, but cantilevers when the front is, it's pinching at the front. This will keep the back end from coming all the way down. You will need to adjust the bottom flat on the upper before it's anodized. ETA: I just looked at your pics again. Check the rear radius to see is there is daylight between the back of the upper and the leading edge of the buffer tube area. You can check for pinch with a piece of paper. Actually took this to my local "expert" and then the GS i use regularly and the problem is the upper is out of spec so yes mike you are right that is exactly what the problem is. Unfortunately my local GS just moved locations and doesn't have the set up in place yet to fix the front end of the receiver. His idea was to mill the front end down ever so slightly instead of enlarging the takedown hole or messing with the pins. We did talk about the other two options but i don't want to have anything that results in a sloppy fit. My options now are to try another GS in my area who is currently away or look for someone else that knows what they are doing and can help out. So if anyone has any recommendations i'd appreciate them. To answer someone else's post it was a RRA upper i bought from someone on the EE but i stupidly didn't check it for fit before shipping it out to braceman. Lesson learned there. Overall i'm feeling pretty stupid right now but I can't say thank you enough for the help! |
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Best option. Buy a "new" upper on EE or GB. No muss no fuss no bother. (Just a Franklin and a few Jacksons) are you forgetting that this is a 656 upper and after the Franklin and couple Jacksons he'd still have to send it out to be reworked into a 656? |
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are you forgetting that this is a 656 upper and after the Franklin and couple Jacksons he'd still have to send it out to be reworked into a 656? Quoted:
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Best option. Buy a "new" upper on EE or GB. No muss no fuss no bother. (Just a Franklin and a few Jacksons) are you forgetting that this is a 656 upper and after the Franklin and couple Jacksons he'd still have to send it out to be reworked into a 656? Sure did Stoner! 
I used to be a stoner too! A different kind of stoner though. I didn't know how much I would miss those fallen brain cells. 
I got 3 or 4 left. I hope they last. |
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OP, here is some good discussion on what I think is your problem:
http://www.ar15.com/mobile/topic.html?b=3&f=66&t=282974 I hate to hear about anybody taking something to the "local gunsmith". Maybe I've just read too many horror stories about that. |
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I have never had any luck with local gunsmiths, at least when it comes to retro.
I would try to talk them about this and that pertaining to retro and their face Goes blank . They don't want to do anything custom , But they are more than happen to instal some Magpul or A rail |
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The gs is going to mill the receiver down? Coulndt m60joe fill and redrill the holes? That was my thought too.........if it were mine.........but I could do the machine work myself. I've never had need of m60joe's services, but I understand it doesn't come inexpensively. I understand too, being a mchinist, that custom work is expensive. Not knocking him at all, but it would be a last resort method for me. |
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That was my thought too.........if it were mine.........but I could do the machine work myself. I've never had need of m60joe's services, but I understand it doesn't come inexpensively. I understand too, being a mchinist, that custom work is expensive. Not knocking him at all, but it would be a last resort method for me. Quoted:
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The gs is going to mill the receiver down? Coulndt m60joe fill and redrill the holes? That was my thought too.........if it were mine.........but I could do the machine work myself. I've never had need of m60joe's services, but I understand it doesn't come inexpensively. I understand too, being a mchinist, that custom work is expensive. Not knocking him at all, but it would be a last resort method for me. Well if you guys can recommend someone i'm all ears. I just hate to trash bracemans hard work and start all over. The local GS i was going to use made me feel a little better when i sent him a pic and he said "is that a 656!?!?" so at least he knows his proto ar's. I've seen work he has done before and it's good. I mean i'm seeing a lot of people posting on here saying don't use a local GS but i'm not really sure what other option i have at this point. |
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Aeneas,,,,,,,,I wouldn't say just because he's your local gs that I would be concerned. I mean........m60joe is considered someone's local gs, as probably John Thomas, Heatnbeat or any of the other well respected guys on this list are.
I do believe that bushing the frt pin hole and redrilling/reaming it may be the least "invasive" surgery for your problem...........but I haven't had your receiver set in my hands.......so that is just an opinion. (and we know what opinions are like) |
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Well i might drop JT or braceman an email this evening then and see if i can ship them the upper for some tinkering. I do appreciate the ideas guys. Its just annoying to have such a minor problem become a major one. at least it was before sending it off to get refinished.
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at least it was before sending it off to get refinished. Quoted:
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Well i might drop JT or braceman an email this evening then and see if i can ship them the upper for some tinkering. I do appreciate the ideas guys. Its just annoying to have such a minor problem become a major one. at least it was before sending it off to get refinished. This. The Great Spirit was looking out for you IMO. Like I said, it'll work out. |
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I think someone already mentioned this, but a trick I do on tight rear pins is to sand the middle and / or ends of the pin to get a little more clearance or to make up for slightly misaligned holes. You could try sanding down the middle of the bottom side of the pin and see if you can get enough clearance to allow the upper to close. If it doesn't work you are only out the replacement cost of a pivot pin.
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Actually took this to my local "expert" and then the GS i use regularly and the problem is the upper is out of spec so yes mike you are right that is exactly what the problem is. Unfortunately my local GS just moved locations and doesn't have the set up in place yet to fix the front end of the receiver. His idea was to mill the front end down ever so slightly instead of enlarging the takedown hole or messing with the pins. We did talk about the other two options but i don't want to have anything that results in a sloppy fit. My options now are to try another GS in my area who is currently away or look for someone else that knows what they are doing and can help out. So if anyone has any recommendations i'd appreciate them. To answer someone else's post it was a RRA upper i bought from someone on the EE but i stupidly didn't check it for fit before shipping it out to braceman. Lesson learned there. Overall i'm feeling pretty stupid right now but I can't say thank you enough for the help! Quoted:
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If the upper will lay flush and flat on the lower when NO pins are installed, but cantilevers when the front is, it's pinching at the front. This will keep the back end from coming all the way down. You will need to adjust the bottom flat on the upper before it's anodized. ETA: I just looked at your pics again. Check the rear radius to see is there is daylight between the back of the upper and the leading edge of the buffer tube area. You can check for pinch with a piece of paper. Actually took this to my local "expert" and then the GS i use regularly and the problem is the upper is out of spec so yes mike you are right that is exactly what the problem is. Unfortunately my local GS just moved locations and doesn't have the set up in place yet to fix the front end of the receiver. His idea was to mill the front end down ever so slightly instead of enlarging the takedown hole or messing with the pins. We did talk about the other two options but i don't want to have anything that results in a sloppy fit. My options now are to try another GS in my area who is currently away or look for someone else that knows what they are doing and can help out. So if anyone has any recommendations i'd appreciate them. To answer someone else's post it was a RRA upper i bought from someone on the EE but i stupidly didn't check it for fit before shipping it out to braceman. Lesson learned there. Overall i'm feeling pretty stupid right now but I can't say thank you enough for the help! |
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