[OC455]

Hey guys,

Maybe you can clue me into what is going on with my 5.56. I setup my AR for patrolduties because I don't have one in my patrol yet, even though it's setup for one, (that and I don't care for ours).

I set it up witha CMMG 16 M10 barrel with a mid length gas port, a YHM low profile gas block, using a Colt bolt & carrier. I had my Dept. armorer build it for me. I had a Noveske H2 buffer in the with a standard carbine spring it. When I went to test fire and zero it in, it did not cycle and function as it did previously when I had the 20incher on it. It would fire, push the bolt back, without ejecting the spent round, and re-chamber the empty round. It turned into a very expensive single shot.

I was thinking the buffer is too heavy and was going to change it out to a standard weight buffer. My other thought was the gas block was not aligned correctly and is not providing enough gas to cycle it properly.

My other thought is that the bolt is causing a problem and is not unlocking quick enough when it is being fired and is causing the malfunction.

Am I on track here or is there something else I should be checking?

Thanks for any info,

Chuck

 

[rushca01]

I know the experts will come along here in a minute with better info. I think you are on the right idea.

What kind of ammo were you using? Sounds like a gas leak to me somewhere or a misaligned gas block.

I was thinking the buffer is too heavy and was going to change it out to a standard weight buffer. My other thought was the gas block was not aligned correctly and is not providing enough gas to cycle it properly.

I agree with what you are thinking here.

My other thought is that the bolt is causing a problem and is not unlocking quick enough when it is being fired and is causing the malfunction

This sounds to me that not enough gas is coming back to force the bolt open.

I would have your dept armor take the barrel off and check the gas block and then reasemble and check it again.

 

[marinesg1012]

I would use the standard carbine buffer first, and if you can take the handguards off and look around the gas block for any carbon deposits....

also what ammo were you using?

 

[shooter_gregg]

I would borrow a standard buffer and try it with that first. I think the H2 is for a carbine length gas system. The bolt may be tight also. Lube it up and while watching your favorite TV show, hand cycle the action about 1000 times. It sounds like a lot, but it goes fast with a good show. Just remember to put a drop cloth under it and put the muzzle down on or over it. Don't want to upset the wife. Even if the buffer is the problem, hand cycling the action wears off the rough edges that slide over each other.
You don't want to mess with your gas block unless you have eliminated all other possibilities. Remember! always try the simple things first. Some of our minds run to the worst possibility first. Eliminate the easiest causes first.

Hope this helps.

 

[OC455]

I was using Federal XM193 55gr., FMJ's 1st and then tried Winchester 55gr. ballistic silvertips and the same thing occurred.

 

[OC455]

I'd have to cycle it downstairs in the basement, I would drive my wife nuts.....and she dont tolerate me & my toys that much these days )

 

[paulosantos]

To rule out the buffer, I would start with a regular buffer, but I doubt that is your problem. If it isn't ejecting, it most likely is the ejector. Try a regulat bolt and regular bolt carrier and make sure that the carrier key is staked properly. If that doesn't work, then check the gas port.

 

[OC455]

I forgot to mention that I was with my friend when I was shooting and he said when he was watching me shoot, that the bolt carrier was not coming far enough back to clear the round from the chamber completely, making it re-chamber the spent cartridge and not ejecting and stripping a fresh cartridge from the magazine. I should have made that clearer in the original posting.

 

[paulosantos]

I forgot to mention that I was with my friend when I was shooting and he said when he was watching me shoot, that the bolt carrier was not coming far enough back to clear the round from the chamber completely, making it re-chamber the spent cartridge and not ejecting and stripping a fresh cartridge from the magazine. I should have made that clearer in the original posting.

That sounds more like short stroking. Midlength barrels don't need the Heavy buffers or the heavier BCG's.

 

[OC455]

The bolt carrier is the half circle semi version. Or as I heard others call it the nuetered carrier

 

[infidel\crusader]

m16 carrier

so's it wouldnt be reccomended to use a m16 carrier on my 6.8?
if not i can swap it out with my m4gery

 

[paulosantos]

so's it wouldnt be reccomended to use a m16 carrier on my 6.8?
if not i can swap it out with my m4gery

Only if it is severely overgassed. If you have a 16" with a midlength, I would use a regular BCG.

 

[biglucky]

What kind of oil are you using?? You might want to make sure first and foremost that it is properly lubed.. Properly lubed for most AR's means dripping oil. On the suggestion of a master gunsmith and 3 gun shooter who runs' 5k+ rounds through his AR's I have switched to using fully synthetic motor oil to lube my bolt. I was having some short stroking issues with my 6.8 and this fixed it. Make sure you put plenty of oil on the gas ring on the bolt.

 

[ArtFWTx]

What kind of oil are you using?? You might want to make sure first and foremost that it is properly lubed.. Properly lubed for most AR's means dripping oil. On the suggestion of a master gunsmith and 3 gun shooter who runs' 5k+ rounds through his AR's I have switched to using fully synthetic motor oil to lube my bolt. I was having some short stroking issues with my 6.8 and this fixed it. Make sure you put plenty of oil on the gas ring on the bolt.

True. There are still many AR owners who do not understand what "wet" means as far as lube goes. That may not apply to this rifle's issues, but it's worth mentioning.

 

[biglucky]

True. There are still many AR owners who do not understand what "wet" means as far as lube goes. That may not apply to this rifle's issues, but it's worth mentioning.

Very true. I just thought I would bring it up because it fixed my short stroking issues.

 

[marinesg1012]

breaking in the action by hand cycling and making sure your weapon is lubed very well (you can never have to much lube unless your storing it in dusty conditions and or freezing temps) will probably help most short stroking issues.... lighter buffer wieght and making sure you use quality ammo is also going to help....

 

[ArtFWTx]

Very true. I just thought I would bring it up because it fixed my short stroking issues.

breaking in the action by hand cycling and making sure your weapon is lubed very well (you can never have to much lube unless your storing it in dusty conditions and or freezing temps) will probably help most short stroking issues.... lighter buffer wieght and making sure you use quality ammo is also going to help....

Hopefully it's something simple and easy to fix like breaking in the action, some extra lube, or a buffer change.

 

[OC455]

Hi, guys, my armorer friend checked the alignment of the gas block and it was slightly off a hair, so he re-aligned it, I changed it to a standard buffer. Oiled it up and cycled it a few hundred times with a different bolt that was a spare. My friend said that the other bolt felt like it was dragging as well and changed it out.

Unfortunately I was working the street and I let my buddy go out and rip with it. He was getting some good three shot groups with it and then had a malfunction and discovered that the ammo we used before, the XM193 55gr., a couple of those rounds had the primers come out. One jammed the gun up getting lodged somehow in between the reciever and the carrier. He got that out and he had another malfunction where the hammer would not lock back and stay back. He checked the lower receiver and discovered a piece of primer from the first test shoot lodged in the lower receiver causing the problem. My bud John has done tours in Bosnia, Somalia and Iraq and said he never seen ammo do this before. I think it was a bad lot number that they produced.

Anyhoo, he gave it another try using the Winchester 55gr., ballistic silvertip duty ammo I had and it went good and then the bolt stripped one round out and pushed the bullet deep into the casing causing it malfunction again. I had another spare bolt and told him to try that one and see if it would work better. He changed it out function tested it, and then ran a full 30 round mag through it in under thirty seconds without a malfunction or hang up. He said that the last bolt did not drag and it ran smooth as silk. He was running a body armor drill with it. There is one ragged hole that is about an inch and quarter in size dead center of the target. He was at 25 meters while doing this. Everything is now copacetic.

Anyway, if any of you guys re using the Federal XM193F 5.56mm M193 ball ammo, Lot #: Q49Z474, I have had at least 4 primers end up coming out of the cartridge case out of 35 to 40 rounds of that specific lot. I have run Federal XM193's from different lot numbers without a problem in my gun and my armorer's AR without a problem. Maybe it is this Lot that has some issues.

As my friend said as well, some times these things(AR's) are picky.

Thanks for the advise and the help guys.

 

[paulosantos]

Does he have a 556 reamer to check the chamber to make sure that it is a true 5.56 chamber? If you guys need one, I can let you borrow mine. Also, try some PMAGS. They should help with the feeding problems.

 

[jasonpeterson]

I would check the chamber before I shot anymore 556. Seems like extreme pressure signs with blown primers.