Ive noticed that my upper reciever isnt completly straight when my handguard is attached. The handguard has a VERY slight rise. So i thought i would try out one of the reciever face lapping tools. This got me to my next point.
What if anything do yall put on your barrel extention when its inserted into the reciever? On one hand i can see how a antisieze type substance may be useful and would somewhat make the barrel to reciever fit tighter. I can also see how it could turn into a gummy mess and be a nightmare. It could also defete the purpose of me lapping the front of the reciever if you put the substance on the barrel extension vs the inside of the upper.
Some substances i have on hand are: Super Lube (synthetic grease), permatex Anti-sieze Lubricant (i normally use this on the uppers threads), Sta-lube Engine Assembly Lube (extreme pressure, anti seize with moly graphite), Locktite :eek: (seems like this would just cause more problems than good. even in the blue flavor) , Then there are the various gun oils (miltec-1, machinegunners lube, gunbutter, firepower fp-10, mobil 1 10w30.)
So what do yall think and do? Do you have any other tricks of the trade that work good for building uppers? How about a method for aligning upper to a handguard? Ive heard using a scope mount but then you have the how do i fit the strap wrench issue. That is if the mount will clear the handguard retaing nut.
When I install barrels I use molybdenum grease when available or most often C5-A anti-seize. There are no issues with an “guming” or anything else.
I am slightly confused by your post. Are you talking about methods of installing the handguard slip ring and lining up the gas tube or mounting a free floating rail system and lining it up with the upper?
i’ve usd a light coat of bearing grease on tight fits, but i wouldn’t “pack” it at all if it’s not a super tight fit. having grease leech into your receiver probably wont hurt anything, but i guess i’m such a control freak that i can’t stand the idea of my receiver self-lubricating…? heh. i usually just oil it and slide it in.
as far as getting the handguard straight- what kind of handguard are you using? the only guards i’ve had to eyeball straight are the float-tube type without rails, and those dont really need to be dead-nuts-on, if you’re just mounting a bipod or something. if you’ve got a good railed guard, it should have nut alignment pins or receiver lock screws or something that does the work for you. in my experience anyway- i certainly haven’t used everything out there.
Sorry about the lack of focus on my part. Once i started typing i kept coming up with questions.
The issues at hand are:
-To lube or not to lube the barrel extension or inside of the reciever where it slides in. Further if you do lube what do you use?
-I didnt intend to ask this but did type it so…On the upper threads what lube or antisieze do you use?
-I have a Larue forend that i have a flip up front sight mounted to. What i need to do is line up the handguards rails with the recievers rail. The problem is the only way i can figure out how to make sure its flat is to use a gage block laid on the not as accurate wide and long side. In typing this i just thought i could use a digital protractor if the resolution was high enough.
-To add another question; Do any of you use anything under the gas block to give it a buffer or seal? You just couldnt have it in front of the gas port but then again it may just blow out after a shot or few.
As for lining up the gas tube holes i use a gage pin. Ill update the post with some sizes since i have two different uppers stripped. Most of the time the pin is too small for the barrel nut holes but you can eyeball the center. This was the best method ive found to line the holes up.
The substances i listed were just some things i had on hand and could use if they would work out good.
Thanks for the replies so far.
Sorry for not adding the update.
The gage pins i use to align the barrel nut are:
Vltor MUR: .182"
LMT: .180"
RRA: .182"
The gage pins i have are 2" long and to use them i do the following:
-
Before putting the barrel nut in place try to find the largest pin that will fit without binding.
-
Attach the barrel nut and once you are close to lining up the hole with the barrel nut in the recomended torque rangestart trying to insert the pin through the barrel nut and into the reciever.
-
Once you have it where it will pass through the barrel nut and the reciever push the pin into the reciever so it sits there but is still out of the barrel nut. You can then fine tune the alignment to make the gap even around the pin. I ushually leave the pin in place and only fine tune it by tightening the barrel nut.
- Every barrel nut ive tried this on has had a gap around the pin so the reciever is the tight point atleast in the installs ive done.
Hope that was useful for some of you.