I have a MUR-1 upper on an Anderson Mfg. lower receiver. The MUR is extremely tight and it’s very difficult to push out the take down pin without a bullet/screw/push pin to start the job. I didn’t have this problem with my old PWA lower (which I sold because it’s pre-ban and I don’t need a pre-ban in my new home :)). Is the Anderson receiver out of spec or something? or is it more likely that the problem is with the take down pin? (note: The LPK was Midwest, not Anderson)
Look at your take down pin detent and make sure it is pointed and not flat or nearly flat.
-Jax
It could be the lower as well. Do you have a spare pin? If so run it through the holes and see if it moves freely.
Often times when things are new they will in fact be a little tight due to the anodizing.
There is always a tolerance, positive or negative, on anything man made. At times, those differences can add up to make parts fit tightly, or very loosely. You have three components going together with possible variations in final dimensions. I can count on one hand how many ARs I have assembled that fit “perfectly”.
Don’t sweat it. Don’t over think it. Let it be and usage over time will get you squared away.
Thread drift…
Where are you in Montgomery County? If you just moved and aren’t familiar with the area, I could give you some suggestions of places worth spending your time and money. Feel free to PM if you don’t feel like responding in public.
Back on topic…
I had the same with my recent Noveske/Vltor setup; just needed a little use and now it is near perfect.
Good to know. Sounds like it just needs some use and wear. I was worried it was damaging the receiver with how tight it is. I guess I’ll just play with it for now and if I notice any unnecessary wear I’ll find a local armorer to take a look at it.
I guess on the bright side, the thing is not going to have the slightest bit of rattle!
I have a similar issue.
http://m4carbine.net/showthread.php?t=136202
Update: I treated all parts in question with Froglube and pushed the pin in and out a few times with a (electric tape covered) punch. Part is still tight but I can pull the pin in and out without tools now.