LMT Failure to Feed?

tjhjunk · #1 03-10-08, 16:02

Just took possession of my new LMT carbine. The rifle consists of LMT BCG, CTR stock, Daniel Defense Omega rail, Aimpoint C3 in a LaRue cantilever mount. The rifle was purchased with a standard buffer but was replaced with a H-buffer.

I loaded a new P-Mag up with 30rds. of Hornady TAP 55gr. practice and took her out for a test run. I only had enough time for one magazine but experienced 4 failure to feeds

I know that the gun is new and tight but 4 FTF in one mag seems a little much. I had to have knee surgery so have not had a chance to shoot it again.

I guess my question is do you think that the heavy buffer is the problem? I know that 30rds. is not a good representation of reliability but for the money I spent I was hoping for better.

Tim

markm · #2 03-10-08, 16:16

There has to be something wrong. "New and tight" isn't it. You shouldn't have any failures.

That said It's hard to diagnos without seeing it in action. Especially since you're using premium mags, ammo, and a premium rifle.

I wouldn't get too crapped out. There has to be an explanation.

RD62 · #3 03-10-08, 16:46

Can you give more description of the FTF? That may help in diagosing the problem. Empty chamber? Hang up on a feed ramp? Round hang up in the mag? Etc....

-RD62

tjhjunk · #4 03-10-08, 17:05

I guess I should say that this is my first AR and that I have zero experience with the platform. That being said I am not new to firearms. been around them all my life mostly sporting arms.

The problem seemed to occur when I tried quick double taps. If you slowly fired a few rounds no problem. One of the failures was a round that just did not feed at all. The others I had to operate the bolt to clear the lodged round from the chamber.

If the bolt was assembled incorrectly could that be my problem as I stripped the BCG for a quick clean and lube before shooting. But my thinking is that if it was it would not fire at all.

As I stated I have never shot a AR before so operator error could have be some of the problem.

Tim

The Archangel · #5 03-10-08, 17:28

You didn't mention what lengthn barrel (10.5" / 14.5" or 16"). Also what ammo are you using? I'm assuming that you have either a 16" or 14.5" with Perm FH since this is your first AR.

If it is the 14.5" or 16" then I would try the standard buffer first. I had the same issue with an 14.5" Colt upper that had never had a FTF/FTE issue with over 5000 rounds. I got lazy one day and was playing with my SBR and decided that I didn't want to clean two rifles so I just took the 14.5" upper with me to the range along with the SBR. The 14.5" upper had FTF issues every round and I narrowed it down to the heavier 9mm buffer in my SBR.

Try the standard buffer first and let us know.

By the way, great choice in weapon parts & optic.

Other suggestions if you have not done also:

1. Magpul PMAGS are excellent magazines to use. They are inexpensive and seem to work like magic.

2. Use a generous amount of lubrication (not so much that it drips out of your rifle, but make sure the bolt & carrier gets some decent lubrication). There are so many lubricants out there. CLP has worked well for me, but now I'm switching over to Mobile 1 Synthetic 15w50 and it seems to work better (doesn't burn off with suppressor use as fast as the CLP).

tjhjunk · #6 03-10-08, 17:42

Thanks, I tried not to skimp on anything as I installed a Troy BUIS and a Vickers sling also. That's why I'm kinda disappointed, but as was stated it's probably something simple like the buffer.

Oh yeah, 16 inch barrel.

Tim

nmscuba · #7 03-10-08, 19:34

Isn't the Hornady TAP 55gr. practice ammo lower velocity? With new rifle that isn't broken in and firing that ammo could be the problem.

Did you try any other ammo?

ErnieB · #8 03-10-08, 19:47

Quote:

Originally Posted by tjhjunk

Just took possession of my new LMT carbine. The rifle consists of LMT BCG, CTR stock, Daniel Defense Omega rail, Aimpoint C3 in a LaRue cantilever mount. The rifle was purchased with a standard buffer but was replaced with a H-buffer.

I loaded a new P-Mag up with 30rds. of Hornady TAP 55gr. practice and took her out for a test run. I only had enough time for one magazine but experienced 4 failure to feeds

I know that the gun is new and tight but 4 FTF in one mag seems a little much. I had to have knee surgery so have not had a chance to shoot it again.

I guess my question is do you think that the heavy buffer is the problem? I know that 30rds. is not a good representation of reliability but for the money I spent I was hoping for better.

Tim

Just my opinion. Put in the original buffer and run some more ammo through it. Lube the bolt properly. I bet your problem will disappear in another mag or so.

tjhjunk · #9 03-10-08, 20:25

No just the TAP, had to have my knee scoped the next morning and have been laid up. Hope to shoot again later this week. I've put the standard buffer back in and re-lubed and cleaned.

Tim

Jerm · #10 03-10-08, 20:28

i have the Hbuffer in my new 16" LMT...sounds like we have the exact same set-up other than optic(i have the TR21).

havent had a single failure in over 1,000 rounds.

various ammo from 50gr to 75gr...in .223 and 5.56 loads.

i wouldnt think it was the Hbuffer...most said that was the best way to go.

Shihan · #11 03-11-08, 03:53

LMT recomends the H Buffer in their carbines. Where are you located?

AR-15A3 · #12 03-12-08, 01:45

I don't think that your H buffer is the problem, in my case my H buffer helped.

I've got a similar LMT carbine like yours except mine have KAC M4 RAS rails, EOTech and LaRue mount, and it started out when I first put it together with a standard semi auto LMT BCG and the factory standard carbine buffer.

When my carbine was new I had random failure to feed the first round when I released the bolt release, then I upgraded to the LMT M16 BCG but still had the problem, next I used a LMT H buffer and the problem went away.

I'm also using a BCM extra power CS extractor spring and it improved the extraction in my opinion.

Lately now that my carbine is broken in I tried my semi auto BCG and no problem, but I'm still going to run my M16 BCG.

Robb Jensen · #13 03-12-08, 05:47

Next time at the range since you started with the H buffer reinstall it use a few known good mags. Measure your buffer spring, it should be between 10 1/16" & 11 1/4".

Load 1 round per mag and fire the one round, it should lock the bolt back every time.

If it doesn't lock the bolt back then reinstall your CAR buffer and try the one round per mag.

If it starts to lock the bolt back, which I think it will then you were over buffered.

hellbound · #14 03-12-08, 14:47

Quote:

Originally Posted by tjhjunk

The problem seemed to occur when I tried quick double taps. If you slowly fired a few rounds no problem. One of the failures was a round that just did not feed at all. The others I had to operate the bolt to clear the lodged round from the chamber.

so that's one failure to feed
three failures to extract?
you are confusing terms here.

the failure to feed may just be a loose mag catch or the mag not fully seated... i've had it happen on lowers i've built myself... tightening the mag catch an extra half of a turn solved it... or since it happens during rapid fire the spring or follower could be hanging up...

as for the three FTEs, you pulled the trigger, heard it go BANG, and the bolt never unlocked?
you had to pull the charging handle back and then the empty brass was thrown from the rifle?

you are saying "lodged round" which is a little confusing b/c it could also imply that you are double feeding (which means the extractor is not holding tight to the case)...

C4IGrant · #15 03-12-08, 19:26

Quote:

Originally Posted by nmscuba

Isn't the Hornady TAP 55gr. practice ammo lower velocity? With new rifle that isn't broken in and firing that ammo could be the problem.

Did you try any other ammo?

No, it isn't.

C4

tjhjunk · #16 03-12-08, 20:32

After talking with someone very knowledgeable with the platform I think my problem is going to be not enough lube. I guess I'm just used to handguns and sporting rifles were you oil and wipe the excess.

I plan on shooting some tomorrow with H buffer and a generous amount of lube applied to BCG.

Probably should have done some reading before I posted my question.

Will give a report on my next range session.

Forgive me for the confusion and thanks for the response.

Tim