Kingchooser Posted November 3, 2015 Report Share Posted November 3, 2015 After the bolt catch wouldn't hold the carrier back Friday night, I broker her down completely yesterday and found some really rough spots in the bolt catch buffer spring recess. Some 1500 sand paper around a toothpick and the problem seems to be gone. Stopped on the way home for 30 to test fire and she ran good. After 4 shots to zero, I fired 3, 3 shot groups. The one marked Z, is the ZQi stuff from walmart. The 2 marked F, is 168GMM. Definately happy with this start, especially since I didn't do a proper assembly. Besides torquing the barrel to spec, I just slapped it together, no loctite or anything. I might shoot another ten rounds in her once my SD-E trigger gets in, but then I am going to break it down and send the upper to mike at Dtech for truing. Then I will properly reassemble, 620 loctite the barrel extension in, and have at it. Specs:AP M5 upper/lower AP LPK, heavy trigger, but not as bad as fearedAP forward assiststrike industries dust coverodin works 15.5" kmod Fulton Armory 18.5" ss rifle gasFulton Armory BCG and gas tubeSLR sentry 9 clamp on ebay birdcage (for $10 I'll postpone specwar muzzle brake until xmas)mega arms ambi charging handledavid tubb flatwire buffer spring (I feared it to be sluggish, but ran real soft)DPMS rifle bufferA2 stock, homemade kydex cheek piece and ergo gripscope is just a weaver K4 I slap on stuff to test. 40+ years and still holds zero pretty good. Anyone ever reloaded this ZQi brass?i think so far so good, what about yall?thanks guys Quote Link to comment Share on other sites More sharing options...
planeflyer21 Posted November 3, 2015 Report Share Posted November 3, 2015 I like it! Quote Link to comment Share on other sites More sharing options...
survivalshop Posted November 3, 2015 Report Share Posted November 3, 2015 Why the LocTite on the Barrel Extension ? You think its going to move with the Barrel nut torqued to spec's ? Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted November 3, 2015 Report Share Posted November 3, 2015 I have always understood that you use a real light coat of oil on the extension, and aero grease on the barrel nut???????? Quote Link to comment Share on other sites More sharing options...
blue109 Posted November 3, 2015 Report Share Posted November 3, 2015 What sort of truing are you having done? If she runs, she runs. Not too much to gain from breaking it down and putting it back together. Quote Link to comment Share on other sites More sharing options...
washguy Posted November 3, 2015 Report Share Posted November 3, 2015 King as the members said...leave it alone...no need for locktite...it will be fine Wash Quote Link to comment Share on other sites More sharing options...
Kingchooser Posted November 3, 2015 Author Report Share Posted November 3, 2015 I want to true the upper just because it's only $30, and it eliminates a variable. Same with the loctite. If this was a Mega that I had to heat up just to get the extension seated, I wouldn't do it, but if I can eliminate any play whatsoever with a little loctite 620, then I do it. It isn't used as an adhesive, more as a gap filler. I want to try and push as many of the variables to the reloading bench as my budget allows, just part of the game. Once I get it set up, I don't want to mess with anything. Of course I run the risk of ending up with looser groups, but I don't think that'll happen. If all the groups were touching, I would reframe. Quote Link to comment Share on other sites More sharing options...
guruofhotrod Posted November 4, 2015 Report Share Posted November 4, 2015 (edited) We use a lot of 609 and 620 where I work and when something has to be disassembled you have to take a torch to it to loosen it up or forget it, it's not coming apart! I'm not too sure I like the idea of using it on a barrel extension? Nice Rifle BTW! Edited November 4, 2015 by guruofhotrod Quote Link to comment Share on other sites More sharing options...
ChaseFan9 Posted November 5, 2015 Report Share Posted November 5, 2015 I think what KC means by truing is he's getting the barrel extension collar on the upper lapped to increase contact surface, like with scope rings. As for the loctite on the barrel extension, it SUPPOSEDLY helps keep groups tight by keeping the extension from moving when it heats up, not that it sticks, but the loctite seals up the tiny gap between the two.Or something like that, I've never been too worried about it myself.... Quote Link to comment Share on other sites More sharing options...
survivalshop Posted November 5, 2015 Report Share Posted November 5, 2015 The Barrel Extension flange seats on the Upper Receiver's Barrel seating face , once the Barrel nut is tightened to spec's , there will be no play , hot or not . Its a Mechanical weld . I have never seen Barrel extension fit in an Upper Receiver ,that was so loose you would need a filler , if you do ,send it back where it came from & get one that's to spec's . By filling in that fitment of the Barrel Extension , to the Upper Receive , you may also run the risk of defeating your purpose of making it a better shooter , too tight & expansion from heat of repeated firing , may cause different issues .Fitment of components & their tolerances are there for a reason. Your call , its your rifle . Quote Link to comment Share on other sites More sharing options...
Kingchooser Posted November 6, 2015 Author Report Share Posted November 6, 2015 The trueing is squaring the face of the upper where the flange meets the receiver. It can't hurt. Rarely are they perfect when forged. The loctite is filling any void, however so small. There is a reason high end Megas usually require heating to get extension in. I thought it wise to get some loctite 246, which is high temp but blue, so it's not semi perminent. it will remove without heat. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted November 10, 2015 Report Share Posted November 10, 2015 The Upper Receivers Barrel's extension flange seating area is a machined surface & any imperfections are the result from Finnish coating on the Upper , I see no problem lapping it to make sure there is no coating material on it . I lap all of mine lightly . I have never seen a Barrel extension that had to have the Upper Receiver Heated to get it to accept the Barrel . Where are these coming from ? Quote Link to comment Share on other sites More sharing options...
ChaseFan9 Posted November 10, 2015 Report Share Posted November 10, 2015 The Upper Receivers Barrel's extension flange seating area is a machined surface & any imperfections are the result from Finnish coating on the Upper , I see no problem lapping it to make sure there is no coating material on it . I lap all of mine lightly . I have never seen a Barrel extension that had to have the Upper Receiver Heated to get it to accept the Barrel . Where are these coming from ?The uppers I've used all accepted the barrel extension easily, but I've heard from a couple people that the barrel extension flange on their MATEN uppers is excessively tight and had to be heated for assembly. It has been a while, though.... Quote Link to comment Share on other sites More sharing options...
washguy Posted November 10, 2015 Report Share Posted November 10, 2015 " The uppers I've used all accepted the barrel extension easily, but I've heard from a couple people that the barrel extension flange on their MATEN uppers is excessively tight and had to be heated for assembly. It has been a while, though."Nah....not here anyway Wash Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted November 10, 2015 Report Share Posted November 10, 2015 " The uppers I've used all accepted the barrel extension easily, but I've heard from a couple people that the barrel extension flange on their MATEN uppers is excessively tight and had to be heated for assembly. It has been a while, though."Nah....not here anyway WashCan you chase the threads to ease the assembly ? Quote Link to comment Share on other sites More sharing options...
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