AR-15 and "the cold" ...magazine-feed action issues

M

MUDGOAT

New member
Need some insight from AR-15 owners/shooters. I recently purchased a Bushmaster Varminter AR-15 with 24 inch heavy fluted barrel, Harris Bipod, standard stock and grip. The gun was used with the former owner stating not more than 200 rounds were through it--also a "breakdown" inspection by my FLL seemed to confirm the rifle had only a couple hundred rounds through it. After purchasing the rifle, I ran only 25 rounds through at an indoor pistol range to ensure the rifle worked, which it did.

This weekend I mounted a Nikon Gold Monarch 2.5-10X50mm scope on it--primarily for coyote and bobcat hunting. I went to an outdoor rifle range this weekend (yesterday 1/15) to dial in the scope.

We just had a snowstorm in Minnesota, and the temperature was 8 degrees outside at the range with windchill taking it down below zero. The first 25 rounds went through the gun with no problem with a standard Bushmaster 5 round steel magazine.

Sometime in the next 50 rounds, the magazine seemed not to be feeding the rounds correctly, and turned my AR, basically into a bolt action, where I had feed only one to two rounds rounds into the mag and physically manipulate the bolt and feed to get the rounds to chamber correctly. Towards the end I had to use the "Bolt charger" every couple rounds to close the bolt.

After the problem started, I oiled up the bolt mechanism the magwell, and even the five round magazine. I switched to a 30 round mag, and still had the same "feeding issues"...so a couple questions to you seasoned AR-15 shooters...

1 What could be my "feed" problem?

2. How many rounds can you fire through a AR-15, before needing to do a complete field strip, clean and oil?

3. Will below freezing temperatures impact the feed operation of an AR?

Thanks guys--any help/wisdom appreciated...

PS, I was able to dial in some 1/2 to 1 inch groups at 125 yards with the new scope eventually, but it took some time as I had to monkey with bad feeds...The ammo I was using was UMG .45 grain .223 semi jacketed hollowpoints-
 
Just a quick question. What kind of lube or oil are you using. It almost sounds to me that oil was the problem and not the mag. As the gun started get colder the lube may be freezing. The barrel gets warm, but the actions usually don't heat up enough.
 
Sportsman-n-1,

I originally oiled the gun with Hoppes #9 oil. When I started having trouble at the range, I used a Berreta gun oil in a small blue tip bottle. The Beretta oil seemed light both in color and was fluid--

Also I did not "gun grease" the gun after cleaning, I only do that when storing firearms...so there was no gun grease in or on the AR15 at the range--just gun oil.

Thanks.
 
It does sound like an oil problem not a mag problem. Me and my brother just went to wyoming. We started shooting rabbits with no malfunctions from the ar. It was a low of -25 and a high of 1 degree. To much oil or the wrong oil in the cold is going to lead to problems.
 
I would recommend using Breakfree CLP, same stuff that is issued to the Marines for use on their rifles around the world. I have never had any problems with it.
 
I have had some problems with oils as well, they will get sticky. If you get a chance, take some gunscrubber or break cleaner and clean the upper and bolt out completely. Then take Break Free (comes in a black can) it is a dry lube and give that a shot. I use that here in cold weather on both semi auto shotguns and AR's with very good results.
 
Sportsman-n-1,

Thanks amigo-- good advice I will break it down pull the bolt out, and clean that and the upper completely. In the indoor setting the gun performed well--maybe I did not oil it enough after the in door range--the temps could have impacted the performance.

One more question, are there any AR mags or mag replacements that are preferable-well rated?-- and what replacement mags should AR shooters stay way from.
 
I would say that you standard Colt, Bushmaster, Mil surplus with green follower. There are a few out there like Triple K that are crap. A good replacement part for most mags would be the Magpul Anti tilt follower. Other then that I don't do much to them.
 
Quote:
Sportsman-n-1,

--maybe I did not oil it enough after the in door range--the temps could have impacted the performance.



I think everyone is trying to tell you that you probably oiled it too much. That's what it definitely sounds like to me, too....and with the wrong oil.

Like someone suggested, get some CLP and oil it lightly only where recommended per AR maintenance guidelines (maybe check AR-15.com if in doubt as to "guidelines")

Too much oil in an AR can gum up the works very quickly, especially in cold weather. I've shot one AR over a thousand rounds several times without cleaning and finally cleaned it just because I was feeling guilty.

-BCB
 
I started using militec on my AR's my son and his buddys used it in iraq and it worked very well for them i just got back for hunting temps that hung around zero no problems at all.

Gary
 
I just started having feed issues with mine too. I use Outers Tri-Lube which is synthetic and good to -50 degrees. The rifle will not chamber a new round after the shot. I don't think it's the cold since it started doing it a few days ago when it was about 20 degrees. I thought it might be the ammo being under powered but I just tried some hotter rounds and it did the same thing. I cleaned the rifle last night and took it out in my yard just now and fired 6 shots. The gun was warm from being in the house but it only chambered one round by itself. I had to use the charge handle to put in a round. It seems as though the bolt doesn't go back far enough to pick up the round in the clip. This is my first AR so I'm not really up on their problems and how to remedy them.
 
If you don't have prior experience with the AR you might want to get a good video on assembly and cleaning. I bought the AGI AR-15 Armor's DVD from Midway and it showed me all the stuff that I wanted to know.
Instead of using oil you might want to lube the carrier with high temp synthetic bearing grease. You can get some that is rated for very high as well as very low temperature. I got a small tube at the auto parts store for about $4. It just takes a small amount on the four contact areas where the carrier and the upper receiver rub as the carrier moves back and forth. The oil seems to run off and collect into crud as it combines with the blowback gasses and gets gummy inside the upper receiver to clean off.
The down side of the grease is that because it doesn't run off like oil it might pick up some grit once in a while. I normally wipe it off after every trip to the range and put on just a bit of fresh. The amount you use is very small.
 
duxndog:

Several things you might check real quick:

1. Are the three gas rings staggered so the openings aren't lined up?

2. Is the gas tube open completely? And the barrel bleed hole open?

3. Any evidence of gas leaks around the gas port/front sight/sight block or around the carrier key n the bolt carrier?

4. Did you just start reloading for the AR and are you sure the rounds will cycle it?

Using a powder that burns too fast will do the same thing you are seeing - short cycling - which happens if the pressure spike in the round occurs too fast in duration. Or it simply could be not enough pressure to cycle the action because of low pressure/not enough powder even with an adequate burning rate powder.

Wow!! there seems to be a rsh of AR problems lately..... that's not typical...

HTH - BCB
 
Another alternative would be to use Eezox Gun lube. It is tested down to -95F according to the company. It has the consistency of WD-40. Just spray it on lightly and wipe off any drips. The light coating will seem to "dry off" but the protection is still there.
I've used it with great results in both my AR and Benelli SBE in below 0 conditions several times.
Make sure you de-grease the gun thoroughly with a good solvent before appplying the Eezox.
 
I live in Minnesota and when I go hunting in extremely cold temps I run the AR action dry, no lube. Reliable cycle is what you need. It isn't like your shooting a ton as would at the range. Oil does get thick at low temps and what looks to be a magazine issue IMO is oil guming up the action not allowing the mag to feed.
 
my read on your problem is that you have WAY too much oil on your bolt and carrier and it is freezing.

clean it thoroughly and take all the oil off of it, you should only have to put a few drops of CLP inside the bolt and carrier.

clean the chamber while you are at it too. no oil, no grease etc..

I think the cold weather was "freezing" your bolt and slowing or stopping it.

I suspect the powder residue was mixing with the oil and coagulating and freezing.

make sure your mag springs are oil free too.
 
Been having similiar problems in my Bushy Predator. When it occured the temps were in the 30's and it was only lightly oiled (closer too dry). NOw she is well oiled in Breakfree CLP and I'll get some time in at the range in the current 0 degree temps before going into the field.


Bayou City boy,
Would H335 be a powder that may cuase problems? I'm running 22.9gr under a 60gr v-max for this load. Guess I'll have too dig around and find some factory loads and see if they function better.

Thanks!

MAhamari
 
My new Bushmaster Preadator wouldn't feed, I changed mags checked the rings and it turned out to be that the gas block was lose. Tighen it up and it chambered fine.
 
Anytime I think the extreme cold will affect my action, I just throw another log in the fireplace. It got down to 30 degrees here last night /ubbthreads/images/graemlins/confused1.gif I wish it would warm up so I could go hunting /ubbthreads/images/graemlins/smile.gif
 
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