first AR15 build: need help with upper

[isplice]

You got yours started in further than I could with mine. I couldn't even start mine. Surprisingly, I have a JD upper from about 2011/early 2012 and the barrel would slide right in just like it should!

[onegtalon]

I got a feeling I may have this issue as well. I don't have the barrel yet but I plan to throw that in the freezer and heat up the upper with a propane torch for about 10 seconds. If it looks like a real tight fit before I heat up the upper then I'll prob take some scotch brite to the upper's inner ID before I do the heat/cold thing.

[RemMax]

Im not familar with that brand upper but the thing that has already caught my attention here is the mention of PAINT
AR's should be parkerized and if they put a heavt layer of paint inside the hole then the barrel aint gonna fit
Of my current 13AR15's I have right now in assoted calibers and not one of then has ever been tight like that
If its got paint start by sanding that off and I bet your barrel fits rught in
If you were closer I would tell you to stop by and I would check it out and fix it for you but kali is a long frive from Indiana
try sanding the paint out first then see what happens
RemMax

[isplice]

Where is the mention of PAINT? Receivers of most AR's are anodized (not Parkerized, as this only works for steel, not aluminum), unless they have been painted. The receivers in this thread are anodized to thickly. This is a problem that JD Machine has had in the past, and it appears that it is again a problem. Before, the company that was anodizing for them was leaving the receivers in the tank over night, or at least that is what I was told.

[hava982931]

Just a quick update: ordered the brake hone and will take another whack at it this weekend. Will post progress to this thread.

[RomanDad]

I built a JD machine upper last night... Very tight... A little lithium grease on both parts and a few hits on the flash protector with a rubber mallet and it popped right in.

Lube, lube, lube... From the photo above, I dont see any grease there!!! I usually spend more time cleaning excess lube out of the nooks and crannies than anything else... Heat and cold work as well... barrel in the freezer overnight, take a torch or heat gun to the receiver for 10 seconds or so... They should pop together EASY.

[uxo2]

Problem solved..

PAINT.

[isplice]

Now paint has been mentioned. Thanks much. As for the work on my upper. Sometimes a barrel must be installed so other things can be worked on/alined, then the barrel must be removed so work can be finished. Then, the barrel must be re-installed and torqued. My DD barrel wouldn't start more than 1/32nd or so. No way was I going to drive it on, only to spend a long time driving it back off, risking damage to the barrel extension/upper assembly.

[hava982931]

Just a quick update on this. Tried the brake hone and it worked flawlessly. Maybe it was just the paint, or maybe it went a little deeper than that. Don't really know. Barrel is nice and snug now. Had to tap it in with a rubber mallet, and it's all good.

Thanks for all your help guys!