Need Input Smoothing my Action AR-15

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socalbeachbum

socalbeachbum

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So I decided to assemble an AR-15 and along the way have learned a few things. My end result looks nice, BUT.... I'm not happy with the smoothness of the action and fitment of a couple parts.

Mainly, racking the bolt seems to be much more effort than it should be. Not sure if I should use the slipperiest teflon or silicone grease on the buffer, tube, spring, bolt and upper or start looking for surfaces to polish? On a trip to the local weapons store I handled several new AR's some pretty stiff, and none really smooth. I tried a used Stag Arms that looks like new, and the action was oh so very silky smooth, half the effort to rack the bolt open.

So I'm asking. What should I do? Go shoot it and break it in? Buy an NIBx coated bolt carrier? Buy a roller cam pin? Polish and then test different lubes? I looked for teflon coated buffers and springs and buffer tubes, and found nothing. I did see NiBx coated uppers.

About parts fitment, the Badger Ordnance charging handle does not fit the CMMG Upper. Borrowing parts of my kid's MP-15, I found a S&W handle fits the CMMG upper just fine, and the Badger Ordnance handle fits the MP15. Not sure if the BO handle is too wide at the rear or the CMMG upper is too narrow. So I'm not sure if I should lose this upper and grab another or lose this charging handle. Is there a place to look up the mil-spec tolerances? :banghead::banghead::banghead:
 
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Clean it, lube it, and shoot it. CLP or some form of it will work fine. During the break-in period use lots of oil. You can also use 320 grit oiled paper and smooth out the upper but that's probably not necessary.
 
It feels stiff because it's a new spring. Just lightly oil the buffer spring with a good gun lube and shoot it.

When you say the Badger charging handle doesn't fit is it the handle fitting inside the upper in the gas key groove, or is it the handle latch that's causing a fit problem?
 
socalbeachbum said:
what are the best lubes to use?
Click to expand...
Oh now you've done it. Asking a gun forum what the best lube for an AR-15 is, that's like asking how many angels can fit on the head of a pin.

Have you performed a function check and know everything is peachy except for being difficult to charge? If so, keep it simple at this stage - get some plain jane CLP and lube it per the army M16 "comic book" pamphlet. Get some decent quality brass ammo and go shootin'.

There is a 96.75% chance you will start feeling the tight spots loosening up as you go. I would check to be sure it's going into battery for the first few rounds just to be sure the drag on the charging handle isn't an actual problem.
 
Some comments:
I had a tight CMMG upper that would't fully close after cycling. Between range visits I lightly lubed it and hand cycled it dozens and dozens of times. Probably a few of these treatments. Cleaned it up, re-oiled and it worked fine at the range next visit. Go spend 20 mins 3-4 times with it and then see what you think.
I do have a Ranier handle in my CMMG upper and it seems to work just fine. Mine is a Revo upper though. Not sure if that is the difference.
All AR uppers (or most) when compared to fine machines (e.g. bolt and lever rifles) feel like they're grinding chalk dust in their actions. I've always disliked that aspect of the design, with rough coated parts engaging others. But it works and with ear protection on you don't hear that scraping sound.
B
 
Oil it with whatever you have, even motor oil. If it functions well, dont worry about it. Its a military rifle, not a finely fitted euro piece.
 
Jackal said:
Oil it with whatever you have, even motor oil. If it functions well, dont worry about it. Its a military rifle, not a finely fitted euro piece.
Click to expand...
I just oiled up my build with Mobile 1 synthetic 5W-30...runs great.

I'd been meaning to try this after multiple recommendations. Wife's SUV needed to be topped off and the shop used Mobile 1 at the last oil change. When I topped off her oil, it just seemed like a good time to give it a try.

If I hadn't had the oil, I would have used the Slip 2000 EWL (Extreme Weapons Lubricant) that BCM shipped with my upper
 
Jackal said it right - lube it and shoot it... don't ask what kind of oil/lube to use. :) You'll get every answer possible. Any of them will work and you'll eventually settle on the one you want to use for whatever reason.
 
Some bolt carriers are smoother than others. It really only matters on the rails that contact the inside of the receiver. You can lightly smooth out the rails with fine sandpaper and make sure plenty of lube is along the path of these rails. I like to do this to minimize wear inside the receiver. Pretty soon yours should be as smooth as that broken in Stag.
 
First, don't take sandpaper to anything unless you know exactly what you're doing and why you're doing it. Just go shoot the darn thing, and use lots of CLP. The friction you're feeling in a brand new gun is mostly coming from the charging handle. Put some wear marks on it, it will smooth out.
 
Another suggestion:

Inspect the inside of the upper receiver for any scratches or marks that may indicate any abnormal rubbing of parts. If something is not in spec, you may be able to see marks or scratches to indicate this.

Otherwise, you probably just need to break in the rifle.

Like others said, lube it and shoot it. If you are not having any malfunctions, then its probably not an issue. Lube the BCG very well and run at least 200rds on your AR to see if it smoothens out over time.
 
Power operated machinery cannot be rated by hand cranking it.

The AR is a dynamic gas cycled machine, not a luxury hand fitted mechanism. Nobody much talks about how nicely their daily driver feels hand cranking it over to start it. They don't - they punch the button and hit the throttle.

The AR doesn't hand cycle, therefore, how it feels being hand cycled means nothing. It's gas cycled by the ammo, that is what counts. Thousands of pounds of gas pressure will cycle it, they hand fit manual actions because humans are lame in comparison and can only reliably get them working with less than tens of pounds of effort. It why we don't hand crank cars. We pull triggers with 2- 6 pounds of effort, a flying full auto bolt carrier will trip an auto sear and chamber a cartridge with plenty to spare. Not even in the same league.

Load the first one, after that, it's power operated. Things go wrong if you get in the way, it's a gas pressure cycled machine.
 
ugaarguy, the width of the charging handle itself interferes with the width of the CMMG slot. the portion of the handle that is enlarged at the rear wedges tightly into the upper.

my supplier is going to swap the CMMG upper for me to a new DPMS upper. Once I get the DPMS upper, if the handle fits tightly, the handle is going de la vista baby, adios.

yes, I'll avoid any abrasives, lube it well, bang out a couple hundred rounds, clean, lube, shoot, clean, lube, and shoot some more.

I'm very anxious to try out my Lothar Walther 223 Wylde barrel. Thanks for the tips!
 
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