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Posted: 2/9/2016 9:06:08 PM EDT
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So this is my issue:
Have a DD 10.3 MK18 Upper for my SBR. Thing is TIGHT fitting to my lower. Tight enough that I need to use a brass hammer to get the rear pin to go in/hammer + punch to get it out. I can take another upper I have, put it on the SBR lower, fits like it should without tools. I can take my DD 10.3 MK18 upper, put it on a different lower (pistol) and it fits fine. For whatever reason the SBR lower and the MK18 upper do not love each other. It runs fine shooting wise, but I dont like having a setup that I cannot break down without needing tools. Possible solution? (want input) I spent some money on this DD 10.3 upper and ive shot it so im looking to make it work. If I got a different upper reciever that fits fine with my lower, swap out the DD upper reciever with a different one then keeping my DD barrel, handgaurd, etc. (lower is a psa blem: but ive ruled out it being a bad lower because it fits other uppers just fine, only blem being a scratch that came with it) I was thinking about using a new DD upper reciever but was weary about that not fitting, so my thought was using BCM upper reciever? Can get one from AIM for 120 + free ship. Wondering if you guys forsee any issues mixing brands like that or what? Or if you have any other good ideas, open to input, just wanting to find a solution because this has been bugging me the past few weeks. Thanks. |
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Quoted:
This or contact DD. Quoted:
Quoted:
Do you have a shop near you that stocks stripped uppers? If so take your lower and see if they will let you do a trial fit before you buy an upper from them. V This or contact DD. I thought about contacting DD but wont they just get it from shippment, attach it to one of their lowers and say "it worked for us so we shipped it back to you." Ive had experiences like that when it comes to gun service in the past from manufacture companies so I was trying to think of a at-home fix. I may try the first suggestion for looking up a local stripped upper and doing the trial fit. Quoted:
So you're complaining about the fit being too tight? Most people try to find ways to make their rifles tight. Just wondering. My reasoning for it was just based on I dont want to always have to have tools to remove the top from the bottom. |
| I have a DD upper that fit the same way and contacted DD who sent me a pair of their takedown and pivot pins, which were slightly smaller. I would post this in their Industry forum and Caroline will take care of you. They have some of the best customer service in the business. The other option is they could ream out the upper slightly. I would definitely not want an upper so tight that requires a hammer to break open. |
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I've had 2 builds That did the same thing to me, not dd. one was a spikes blem upper that would not fit any lowers I had, so it's now fitted to a lower without any slop whatsoever, I had to ream out the front takedown pin holes to fit.
The second was an aero precision upper and Anderson lower, however it wasn't the fit of the recievers, but a bad front takedown pin in a radical arms lpk. Swapped the front pin with an old colt one from a m16a1 parts kit I have and it works fine, but Both receivers fit extremely sloppy still, so maybe just a extreme case of tolerance stacking for this one. |
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Had the same issue previously. BCM 11.5" upper way too tight on a specific lower. That upper on a number of other lowers was perfect fit. That lower on several other uppers was a perfect fit. That upper and lower combo just had some tolerance stacking issues. I had to use a punch and mallet to break it down. I purchased some B.A.D. Enhanced Pins, and that went a long way to alleviate the issue. Eventually, with the new pin set, and shooting it a decent amount, it now has the perfect fit. Since then I've had the same issue again. Solution was the same B.A.D. pins and shoot it. |
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Quoted:
I thought about contacting DD but wont they just get it from shippment, attach it to one of their lowers and say "it worked for us so we shipped it back to you." Ive had experiences like that when it comes to gun service in the past from manufacture companies so I was trying to think of a at-home fix. I may try the first suggestion for looking up a local stripped upper and doing the trial fit. My reasoning for it was just based on I dont want to always have to have tools to remove the top from the bottom. Quoted:
Quoted:
Quoted:
Do you have a shop near you that stocks stripped uppers? If so take your lower and see if they will let you do a trial fit before you buy an upper from them. V This or contact DD. I thought about contacting DD but wont they just get it from shippment, attach it to one of their lowers and say "it worked for us so we shipped it back to you." Ive had experiences like that when it comes to gun service in the past from manufacture companies so I was trying to think of a at-home fix. I may try the first suggestion for looking up a local stripped upper and doing the trial fit. Quoted:
So you're complaining about the fit being too tight? Most people try to find ways to make their rifles tight. Just wondering. My reasoning for it was just based on I dont want to always have to have tools to remove the top from the bottom. I had a couple of rifles that had this problem that didn't loosen up after awhile. I solved the issue by removing the take down pin and butt stock off and putting the upper and lower in my vise and squeezing them together and inserting a 1/4" drill bit through them. Then I ran the drill a few seconds, left the drill bit in and took it out of the vise and ran the drill for a few seconds while pushing it back and forth. After it loosened up a little I removed the drill bit and re-inserted while drilling a few times. I never had an issue again. |
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OP: Try this. Squeeze the upper and lower together as hard as you can while using a round/punch/Glock tool to push the pins. I typically hold mine with the top of the upper against my palm with my fingers around the buffer tube & against the back of the pistol grip. I have a setup very similar to yours in that respect and have found this trick to make it possible to take apart "in the field" without a hammer.
Quoted:
Just keep shooting it and it will loosen up after a few hundred rounds. Quoted:
Just keep shooting it and it will loosen up after a few hundred rounds. Quoted:
Try it on a different lower, maybe your lower is out of spec. Shooting it should loosen it up. Otherwise, DD CS. Quoted:
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Just keep shooting it and it will loosen up after a few hundred rounds. This, my 11.5' BCM upper was the same on my spikes punisher lower.. a year and a half later and its still tight but I can take it off by hand now no tools needed. I have not found this to be the case. I have the same issue with my Noveske lower and Vlt0r upper on my 300BLK SBR. It has not loosened up in the slightest after 1-2k rounds. |
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Quoted:
OP: Try this. Squeeze the upper and lower together as hard as you can while using a round/punch/Glock tool to push the pins. I typically hold mine with the top of the upper against my palm with my fingers around the buffer tube & against the back of the pistol grip. I have a setup very similar to yours in that respect and have found this trick to make it possible to take apart "in the field" without a hammer. This was going to be my next suggestion. I have to do this with my AAC. |
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I've had the same problem with an older olympic upper (tried it with Stag and Spikes lowers), turns out that the rear takedown lug was longer than spec (or made to use with low shelf lowers, not high shelf lowers)..
either way. a little 180 grit sandpaper on the bottom of the takedown lug on the upper receiver and they are MUCH easier to separate now. I used aluminum black to clean up where I removed the material. |
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You wont know what DD is going to do until you talk to them. My understanding is that they have exceptional customer service; on par with their products.
I say giv DD a call. Sounds like tolerance stacking making the tight fit. Other than the take down issue, is there a performance issue? Quoted:
I thought about contacting DD but wont they just get it from shippment, attach it to one of their lowers and say "it worked for us so we shipped it back to you." Ive had experiences like that when it comes to gun service in the past from manufacture companies so I was trying to think of a at-home fix. I may try the first suggestion for looking up a local stripped upper and doing the trial fit. My reasoning for it was just based on I dont want to always have to have tools to remove the top from the bottom. Quoted:
Quoted:
Quoted:
Do you have a shop near you that stocks stripped uppers? If so take your lower and see if they will let you do a trial fit before you buy an upper from them. V This or contact DD. I thought about contacting DD but wont they just get it from shippment, attach it to one of their lowers and say "it worked for us so we shipped it back to you." Ive had experiences like that when it comes to gun service in the past from manufacture companies so I was trying to think of a at-home fix. I may try the first suggestion for looking up a local stripped upper and doing the trial fit. Quoted:
So you're complaining about the fit being too tight? Most people try to find ways to make their rifles tight. Just wondering. My reasoning for it was just based on I dont want to always have to have tools to remove the top from the bottom. |
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Before you ream, polish, or drill anything, just try swapping out your takedown pins. I have found that to work in some instances.
If not, try polishing the pin, not the hole. Always modify the least expensive, most easily replaceable part first. Modify the lower as the last resort. |
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I just sanded my rear pin. Cheapest fix I could think of. Easy to swap out if you need to later. Very good advice. I didn't start the drilling process until they didn't loosen up after repeated disassembly. It didn't occur to me to sand the takedown pin though. I'll save that bit of advice for the next one. Thanks! |
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