Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 24

Thread: Fitting an upper to a lower receiver?

  1. #11
    Join Date
    Mar 2009
    Posts
    24
    Feedback Score
    0
    Quote Originally Posted by bkb0000 View Post
    there's another recent thread where a guy had some fit issues and took a caliper to his takedown pins. there's some inconsistencies in size, and if your pins are took big it'll be hard to get it closed/opened, too loose and you'll have excessive play. the numbers he gave for the ones he measured were .248 on the large end, and .2435 on the small end, but i'm sure pins probably vary even more than this, as this was just his sampling.
    Thanks for the suggestion, already checked pin diameters before I even put the new upper together. You can literally look in the pin hole from the left side and see that the receiver is I'd guess 1/64" or less from going all the way down and you can see the bottom of the pin hole on the upper isn't low enough. And taking the striped receivers and look at them from the sides with the light behind it and you can see the spot that it hits, not very much and not real long a spot.

    I'll be truthful with you have haven't done any serious AR work in better than ten years. This is actually on my own personal gun which I had another A1 upper on when I got it. That was well I guess a while back because I converted the A1 upper into a flattop before the AWB of 94. All that was available then was converted upper where they cut the handles off and pinned a rail on them. I went a slightly different route and found I guy that knew how to weld on T7075 aluminum and had the rail welded on.

    I know what I have to do, its hitting on the rear corners of the upper as you look at it from the side about a quarter inch up. Trim it down slightly and it will fit and lock up quite tight. I ran into this once before with a varmint barreled flat top I built for a guy back in 97. Both DPMS upper and lower and it took just a couple thousands off the back corner and it fit tight and ran like a charm (shot under 1/2 MOA out to 200 meters too. That gun shot well!)

  2. #12
    Join Date
    Jan 2008
    Location
    AZ-Waging jihad against crappy AR's.
    Posts
    24,902
    Feedback Score
    104 (100%)
    Another reason not to own DPMS. I would make them fix it. It's the only way these companies are going to stop pumping out crap.



    Owner/Instructor at Semper Paratus Arms

    Facebook: https://www.facebook.com/SemperParatusArms/

    Semper Paratus Arms AR15 Armorer Course http://www.semperparatusarms.com/cou...-registration/

    M4C Misc. Training and Course Announcements- http://www.m4carbine.net/forumdisplay.php?f=141

    Master Armorer/R&D at SIONICS Weapon Systems- http://sionicsweaponsystems.com

  3. #13
    Join Date
    Mar 2009
    Posts
    24
    Feedback Score
    0
    Quote Originally Posted by Iraqgunz View Post
    Another reason not to own DPMS. I would make them fix it. It's the only way these companies are going to stop pumping out crap.
    Well that is alfully strong, what do you prefer out of curiousity?

  4. #14
    Join Date
    Jun 2008
    Location
    Edmonds, WA
    Posts
    1,845
    Feedback Score
    1 (100%)
    Quote Originally Posted by duramaxtech View Post
    Well that is alfully strong, what do you prefer out of curiousity?
    Demanding that a company make parts within a blueprinted specification to fit together with their own branded parts is "alfully strong"? Other people seem to be capable of it and have been for years. Having to modify the receivers to get them to mate is unacceptable. Period.

  5. #15
    Join Date
    Mar 2009
    Posts
    24
    Feedback Score
    0
    Quote Originally Posted by spamsammich View Post
    Demanding that a company make parts within a blueprinted specification to fit together with their own branded parts is "alfully strong"? Other people seem to be capable of it and have been for years. Having to modify the receivers to get them to mate is unacceptable. Period.
    Well to answer your question, yes I think that it is a little strong. Keep in mind the lower receiver I'm using now I got back in either 92 or 93. Having a upper receiver that I got this year being off that little doesn't bother me in the least. I was just curious if anyone else had run into this.

    Do we know if DPMS is using the same equipment to manufacture this part they did in 92? Are they using the exact same methods and materials? Fact is the last time I ran into this it produce a very accurate rifle, with my old A1 upper this one shot pretty good but was just ugly as can be and thats the only reason for the change. If it doesn't perform as I want it to I'll switch back and not be concerned.

    I may not have the experience some have with these guns but I have put together just over a dozen of them between 91 and 97 and all have worked well. Its just I'm surprised at the reaction to the DPMS name being mentioned.
    Last edited by duramaxtech; 03-30-09 at 13:03.

  6. #16
    Join Date
    Jun 2008
    Location
    Edmonds, WA
    Posts
    1,845
    Feedback Score
    1 (100%)
    If a firearms company cannot produce parts that mate together without me having to modify them and refinish them, I will have nothing to do with them. Who knows what other details the skip in their process if they can't get the fit right? If they can't make them right, I'll find somebody that can. This is not too much to ask from a company with access to CNC machines. Having to modify the receivers to get them to mate is unacceptable.

    Are you sure you don't have your receiver extensions screwed in too far, causing them to contact the upper receiver?

  7. #17
    Join Date
    Mar 2009
    Posts
    24
    Feedback Score
    0
    Quote Originally Posted by spamsammich View Post
    Are you sure you don't have your receiver extensions screwed in too far, causing them to contact the upper receiver?
    100 % positive.

  8. #18
    Join Date
    Jan 2008
    Location
    AZ-Waging jihad against crappy AR's.
    Posts
    24,902
    Feedback Score
    104 (100%)
    It's not awfully strong, it's the way it is. DPMS has a history of producing weapons that are out of spec, use crappy parts, etc...etc.. Read the DPMS horror stories here. Someone recently bought a DPMS that was missing a buffer and buffer retainer. Yes, the dealer should have caught that when he received it, but it should never have left the factory like that.

    Their chambers are also not 5.56 either. Personally I would save the money and get a good gun or at a minimum build one myself. But, that's just me. YMMV.

    Quote Originally Posted by duramaxtech View Post
    Well that is alfully strong, what do you prefer out of curiousity?



    Owner/Instructor at Semper Paratus Arms

    Facebook: https://www.facebook.com/SemperParatusArms/

    Semper Paratus Arms AR15 Armorer Course http://www.semperparatusarms.com/cou...-registration/

    M4C Misc. Training and Course Announcements- http://www.m4carbine.net/forumdisplay.php?f=141

    Master Armorer/R&D at SIONICS Weapon Systems- http://sionicsweaponsystems.com

  9. #19
    Join Date
    Feb 2007
    Location
    AZ
    Posts
    2,626
    Feedback Score
    0
    Often when new you may have to push down on the top of the back of the upper and on the lower to get them to go together.

  10. #20
    Join Date
    Mar 2009
    Posts
    24
    Feedback Score
    0
    Quote Originally Posted by Iraqgunz View Post
    It's not awfully strong, it's the way it is. DPMS has a history of producing weapons that are out of spec, use crappy parts, etc...etc.. Read the DPMS horror stories here. Someone recently bought a DPMS that was missing a buffer and buffer retainer. Yes, the dealer should have caught that when he received it, but it should never have left the factory like that.

    Their chambers are also not 5.56 either. Personally I would save the money and get a good gun or at a minimum build one myself. But, that's just me. YMMV.
    OK one thing for certain I shouldn't post before coffee, thanks for correcting my spelling. Don't say a word about grammer

    I see your point, as I mentioned before I have been out of it a while. I've got another lower I'm working on for a coworker that I'm going to check against mine (this one is Bushmaster) and I'll see which is the problem, upper or lower. No fears on the barrel not being chambered 5.56 because for the most part I shoot and reload .223 brass, but the barrel is Bushmaster anyway. I junked the OE pencil barrel years ago along with the carbine handguards and such. This gun isn't meant to be a M4 just a accurate carbine.

Page 2 of 3 FirstFirst 123 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •