Drag in BCG

[wideopen231]

Helping a buddy with his build. Test firing rifle and does not cycle. Swapped his BCG for mine and fires fine. Only thing I have found is when bolt is rotating back it has quite a bit more drag than mine. Now his is new and mine few hundred rounds used. Pulled it apart and cleaned,reassembled and same thing. Not sure who's BCG,was bought as complete assembly. He bought from few different sites against my advise.

 

Ideas?

 

[Matt.Cross]

17 minutes ago, wideopen231 said:

Helping a buddy with his build. Test firing rifle and does not cycle. Swapped his BCG for mine and fires fine. Only thing I have found is when bolt is rotating back it has quite a bit more drag than mine. Now his is new and mine few hundred rounds used. Pulled it apart and cleaned,reassembled and same thing. Not sure who's BCG,was bought as complete assembly. He bought from few different sites against my advise.

 

Ideas?

 

Buy the same bolt you have.

[wideopen231]

more looking for way to use this one.Plus one I have came with rifle we took it out of and no idea who's.

[wideopen231]

To add to confusion. His BCG cycles in my upper and mine cycles in his upper,but his will not cycle in his upper. You all follow that. LOL 

[Matt.Cross]

32 minutes ago, wideopen231 said:

To add to confusion. His BCG cycles in my upper and mine cycles in his upper,but his will not cycle in his upper. You all follow that. LOL 

With your working bolt, his BCG won't cycle?

[wideopen231]

no. Swapped his assembly into my rifle and works fine.Put mine into his worked fine. Put his back into his upper and will cycle.

 

My thinking right now is his combo if all new stuff is just.000_ tight somewhere

[Matt.Cross]

1 hour ago, wideopen231 said:

no. Swapped his assembly into my rifle and works fine.Put mine into his worked fine. Put his back into his upper and will cycle.

 

My thinking right now is his combo if all new stuff is just.000_ tight somewhere

That's why general diagnosis step #1 around here is to ask, "Are you running it with the BCG soaking wet with lube?".

[wideopen231]

no.  disassembled and wiped it down. reassenble with lite lube.

[Matt.Cross]

28 minutes ago, wideopen231 said:

no.  disassembled and wiped it down. reassenble with lite lube.

Go heavy and liberal with the lube, I'm talking motor oil and soaking wet on the carrier body. After 300 - 500 rounds, light lube will do fine.

[Rsquared]

^^^^Agree. You can't hurt these things by lubing them up.

And I'll wait for all the smart-ass responses.

[98Z5V]

New ones need to be almost like this - dripping with lube...

[Sharpshooter]

Now that's damned near pornographic ... as well as being instructional!

[98Z5V]

54 minutes ago, Sharpshooter said:

Now that's damned near pornographic ... as well as being instructional!

The message won't be taken seriously, unless it has impact.  That's the best way to learn a lesson.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Magwa]

Ok I got the lesson where is that finger headed?

[Cliff R]

Take a black magic marker and "paint" the BCG on the outer friction surfaces.  Cycle it a few dozen times and look for "witness" marks or light areas, scratches, etc.

There may simply be a "tight" spot or burr inside his upper someplace.  Don't forget to check the charging handle as well and make sure there isn't something in that part of the upper pushing it down, or miss-alignment, etc.

Don't forget about the buffer and tube, any dents, dings or tight there will effect cycling as well.......

[RedRiverII]

When threading pipe in a machine and there isn't enough cutting oil on the threads you can hear the shrieks from the surfaces.  The threads chip and crack.  Use the same setup with a heavy application of oil and you get a smooth cut,  crisp threads,  and no shrieks or squeals.  Oil that BCG,  heavy duty style.  It'll smooth out just fine.  I remember first learning about gun care and it being said don't over lube because of the dirt and grime that will accumulate.  I think Larry Vickers does a goof video on over lubing a firearm.  He dunks the whole gun in a vat of motor oil and then has at it.  Boom,  boom,  and boom.   The break in period is real.  Let the parts mate and then get meticulous with the placement of oil and lube.  Best of Luck to you and your friend.

[Cliff R]

Forgot to comment on interchangeability above.  Everything related to this deal has a specification and in theory many parts should drop in from one weapon to another.  But like anything else components range from low to high for specs, and no two are exactly the same despite the best efforts of those building them. 

Don't even want to go into "Googling" up parts and looking for a few dollars savings one supplier over the other.  I've had next to ZERO luck with that deal no matter WTF I'm working with, so I er toward top of the pile even when it empties my wallet a little more. 

Anyhow, IF the fix is nothing more than dropping in a different BCG, and/or some super-lubing, etc,  then really no need to put the entire assembly under a microscope, change the part, the gun runs, go have fun with it......

Edited May 9, 2020 by Cliff R

[PaddyMac]

Quick question and not to step on the thread. My .308 build is waiting on parts so I'm not there yet. But on my AR15 I lube the bolt with Valvoline Japanese, Chrysler, multi-vehicle grease. Its red and light. I dunk the assembled BCG in Mobil 1. I wipe a little to not make too much of a mess, install, and put the rifle in the safe with a cloth underneath for the drips. I got the technique some a respected armorer on another forum. Never had a FTE or FTF on the rifle. 300 round count (I know I baby it).

I planned on the same treatment for the .308. Any issues?

 

[Rsquared]

56 minutes ago, PaddyMac said:

Quick question and not to step on the thread. My .308 build is waiting on parts so I'm not there yet. But on my AR15 I lube the bolt with Valvoline Japanese, Chrysler, multi-vehicle grease. Its red and light. I dunk the assembled BCG in Mobil 1. I wipe a little to not make too much of a mess, install, and put the rifle in the safe with a cloth underneath for the drips. I got the technique some a respected armorer on another forum. Never had a FTE or FTF on the rifle. 300 round count (I know I baby it).

I planned on the same treatment for the .308. Any issues?

 

Nope. Nothing wrong with that. I do something similar for any of the rifles that I run suppressed. Except that I use the red, high temperature wheel bearing grease.

All BCG's get a bath of mobil1. You can't go wrong with that. On new builds, I'll let them soak for a day or two. Once again, it can't hurt.

[Cliff R]

LOTS of opinions on lubricants for AR platforms.  Everyone has their own favorite "snake oil" of some sort and I'm sure they have had great success with it.

Personally for civilian use I really don't think it makes much difference what you use as long as it has enough to keep the parts sliding nicely against each other.  The problem with using  EXCESSIVE amounts of lubricant on the parts is that in the field the weapon will be subjected to dust, dirt, debris, water, mud, sand, silt and if you are running a lot of mags thru it powder residue.  Excessive lubricant at this point becomes a dust/dirt/powder magnet and can create a thick and gooey residue as well.  You may or may not have the opportunity to clean the weapon effectively till the mission is completed.

I've always found that just a few drops of whatever lubricant we were issued (used to be CLP) on the metal parts then wiped clean was adequate for most scenarios.  Of course this refers to Military grade weapons built to Military specifications with the correct coatings on the associated parts.

I am NOT a big fan of using any type of grease on the BCG and related upper parts.  Probably OK but grease is thick and sticky and gets even worse in really cold weather.  A dab of grease on the hammer/trigger isn't a bad idea as those parts would be the only ones in the lower not parkerized, blued or coated where the surfaces meet each other......FWIW......

 

 

[98Z5V]

15 hours ago, Cliff R said:

Personally for civilian use I really don't think it makes much difference what you use as long as it has enough to keep the parts sliding nicely against each other.  The problem with using  EXCESSIVE amounts of lubricant on the parts is that in the field the weapon will be subjected to dust, dirt, debris, water, mud, sand, silt and if you are running a lot of mags thru it powder residue.  Excessive lubricant at this point becomes a dust/dirt/powder magnet and can create a thick and gooey residue as well.  You may or may not have the opportunity to clean the weapon effectively till the mission is completed.

This is typically not how you'd run your weapon, everyday.  The Heavy Lube recommendations are for breaking in new .308AR rifles.  Break it in, make sure everything is mated and fully functional, break it down, and clean it up.

After that, normal lube practices apply.

You wouldn't break in a new engine rebuild with just a little bit of assembly lube in critical places, and nothing in the oil pan.

Run new .308ARs heavy with lube, until you're positive that the function as they're supposed to - if they don't function as they're supposed to, at least you know it's now from a lack of lube on all those new, unmated, huge parts.

[Cliff R]

Correct, but even with that said I would NEVER under any circumstances use heavy "grease" of any sort.  If you are doing a "break-in" and apply heavy thick lubricants like grease they can induce additional "drag" in he components especially in cold weather.  Quick "break-in" would favor lighter lubricants to let the moving parts "bump and rub" a bit and move freely in the assembly.

As far as what to use otherwise, I really don't think it matters much.  I've had folks tell me than in lieu of buying expensive weapon specific lubricants they just use full synthetic motor oil like 0W-20.  I had this discussion recently with a guy who builds a decent amount of these weapons and he uses Dextron type 6 full synthetic transmission oil claiming it helps clean and minimizes powder build-up, etc.  Keep in mind that with direct impingement vs piston operated a decent amount of powder is blown into the receiver when you fire the weapon. 

Anyhow, with most any "modern" lubricant the film strength will be excellent so I tend to agree that it probably doesn't matter what you use for the most part just have something there so it's not "dry" and creating excessive and unwanted friction.

I actually hate to make specific recommendations with this sort of thing.  Just go to any Automotive or even a Forestry Forum and you'll get a ZILLION opinions of different types of lubricants for engines, transmissions, 2 cycle power equipment, etc.  It's not much different with weapons stuff from what I've seen.

I still use CLP simply because I have pretty much a lifetime supply of it as I ran the Armory at every duty station I was assigned to and did all the weapons training, weapons maintenance, etc for each of my units.......

[98Z5V]

I use this for Engine Assembly Lube, and I also use it for lubing a new .308AR gun that I'm gonna shoot.

About 6 years ago, I met my local Justice Brothers rep. After seeing the demonstration he laid out, I was sold, and tried it for myself.  Worked wonders.  After that, I found out that he was into guns, as I was, and started talking to him about using his products for breaking in new Large-Frame ARs...  he was intrigued - and I found out that he spent 10 years on the US Shooting Team as a shot-gunner... 

Wow, how worlds collide. 

That conversation led to he and I working on a gun-specific formulation of lube.  I think we/HE perfected it about 3 years ago.  All this info is available in the new section to you - you just have to check it out.  All the years of documentation, tests on this board - it all there, Cliff. 

@JBMatt, you rock, brother... 

[Cliff R]

I haven't seen it, but really haven't looked around much on this board. 

The problems associated with oils is that they tend to run-off when things heat up.  Problems with grease is that they get thick when things cool down and have poor penetration properties.  Probably why the Military went with a product that cleans, lubricates, penetrates and sticks around to protect parts from rust, oxidation and corrosion.

In any case I'm sure that you put the R & D needed to come up with a good product, and I'd be interested in reading about it if you can provide a link to it........tks.....

[98Z5V]

16 hours ago, Cliff R said:

In any case I'm sure that you put the R & D needed to come up with a good product, and I'd be interested in reading about it if you can provide a link to it........tks.....

There's an entire thread about all the testing that we did here, and the progress of the lube - I'll send you a PM about it.

Edited May 13, 2020 by 98Z5V