Running "wet" or else!

AR/M4 AR Technical Discussion
1

I am having issues with my M4 “kit” gun. I have a RRA complete factory lower, with a LMT upper and BCM BCG. My gun only seems to run well when it’s pretty wet with lube. Once the lube gets blown off, and the BCG appears “moist” (not dry), i start having 2 issues. one is where the bolt doesn’t lock back on the last round. the other is where i get a misfeed where the round has been partially picked up and the BCG hits the partially loaded round. is this a bolt issue? or am i not seating my mags securely?

furthermore, being the winter, i shoot more indoors. the range i goto frequently have a fine layer of metallic appearing dust on the bench, and i feel that this may be getting into my action as well.

i’m using the Weaponshield lube and Mil-comm TW25B grease.

i’m trying to figure out if my malfunctions are environmental, procedural, mechanical, or a combination of the 3. your suggestions and help would be appreciated.

2

That lube is great stuff, even when(if) it gets blown off it leaves a barrier film that prolongs the “lubiness” of it. It’s better than FP-10 (the guy who invented FP-10 invented WS) so it has the same stuff as FP-10 in it and more.

It’s the only stuff I use now…so the brand of lube likely isnt the issue.

I know the owner of that company if anyone thinks his input would be valuable to the discussion…just met him last week but we’ve been talking online for some time now.

3

Are you using an H-Buffer? This might explain some of your issues. What type of ammo are you using? What kind of mags are you using? These could be issues as well. The more info you provide the more help you’ll get.

4

What kind of ammo are you using? I don’t think its a lube issue. Your gun should run for a few hundred rounds even dry. I’m thinking since LMT tends to have a smaller gas port than some other manufacturers your ammo is just too weak. Although it should still function with the weaker stuff. Maybe a possible gas leak somewhere? Even monkeys fall from trees, so its not impossible for LMT to mess up however unlikely. Also which buffer are you using, regular CAR I assume? And are you using the standard buffer spring and not some extra power Wolff, Tubb, or Sprinco one?

Also I would talk to whomever runs your range and get them to clean that shit up. Could that ‘metallic appearing dust’ possibly contain lead? Not something I would want to be exposed to and could possibly get them shut down if the right person walks in and notices that.

5

Couple questions:

  1. Type of mags and how old are they?
  2. Type of ammo used?
  3. Do you use the oil and grease at the same time?
  4. How many rounds are your going through before you start to notice issues?

My thought is that you are using weak, underpressured ammo along with a stiff buffer spring and an H/H2/H3 buffer.

C4

6

sorry guys, forgot to include the much needed background info

  1. i’m using Magpul PMAGs. i think they’re the 2nd gen mags as they were purchased in the last year.
  2. i’m using remington UMC ammunition, 55gr. , marked .223 and not 5.56
  3. i primarily use the oil, in areas where i see high wear, i use the oil with the grease.
  4. i’d say about 400-500 rds thru the gun now.

I am using the stock RRA buffer spring, with a H buffer (which i read was a good idea for carbine systems)

LMT 14.5" upper was purchased from BCM, PWS FCS556 permanently attached by Adco.

7

Remington UMC is certainly underpowered IMO.

8

So your weapon short strokes after 400-500rds (without re-lubrication)?

UMC is under pressured ammo (fyi).

C4

9

the malfunction are occurring maybe 40-60 rounds into a range session. so is that what’s happening? short stroking?

thanks for the heads up about underpowered UMC ammo. i just want to correct any errors if it was my technique or specific gun mechanical problems.

10

Sounds like a short cycle. Do you have another bolt carrier you could try?

Have you checked your gas key?

11

While I understand that some folks have experienced issues with UMC, my dept has sent thousands of rounds downrange without issues. The 55 gr ball has ran in a variety of Colt M4’s, as well Mini 14s and a variety of individually owned ARs.

Does it reliably lock open after the last round?

12

no it sometimes does not. it probably does not lock back on the last round maybe 20-30 percent of the time during the range session. when i throw alittle more lube on my BCG, it goes away.

what should i look for at the gas key? it appears to be properly staked…

13

Try and wiggle it on the BC.

14

Sounds like it (short stroking).

Let’s try some simple things first. Drop the grease and ONLY use the lube. Also drop the H buffer and go with the car buffer.

Clean the wean (specifically the bolt and carrier). Check that the gas rings are good (by doing the bolt test).

Lube the bolt and cam pin (like they fell into a bucket of oil).

Report back what you get.

C4

15

Is that something that you should always do?

-DM-

16

Yes. The bucket of oil comment is a bit of an exaggeration, but not by much.

Your AR burns oil. Plain and simple. A dirty gun that is lubed, will run. A clean gun that is dry, will not.

As a general rule, after about 200-300rds, you will want to add some lube to your bolt. It is raining, you will want to add lube sooner.

C4

17

Since I contracted the BRD, I have always run my BCG&A very wet but wondered if I was just using too much lube.

BTW Grant. Thank you for being the only one who had the items I needed in stock

-DM-

18

More lube is better than less lube.

Glad we could help with what you needed.

C4

19

If you want to keep runnning weak ammo, I agree fully- but would also recommend switching ammo to something a little more appropriate to the platform.

I think that Wolf is pretty much the lowest acceptable ammuniton. In my opinion personal weapons should be able to perform with everything from 55gr Wolf to Mk262. I bet that if you simply switched to M193 the issue would disappear without having to alter anything else.

Keep in mind that the higher-end companies port their barrels to work correctly with NATO pressure rounds. The larger ports of other manufacturers are made to work with lower pressure since common users of those brands aren’t using higher end ammo- thus leading to all sorts of band-aids to the system when more relevant ammuniton is introduced.

20

I understand what you are saying about wanting your gun to run with all ammo. The problem is that when you pick a barrel with a mil-spec gas port, you cannot always get away with cheap ammo.

C4