Missing bolt lugs AR 15

Niko-PG

Niko-PG

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Back from the range, cleaning the toy and WTF, I'm missing 2 lugs on the bolt !!!

Can someone explain me what happened ?

Rifle is a Bushmaster 11.5", approx 3000 rnds in in, at the range I shoot a little more than 250 rnds of American Eagle 55 gr without any malfunction or strange noise/sensation.
My guess is an ammo problem but I'd like to hear your opinion and also how 'unsafe' it was to shoot with two lugs missing

Pictures as soon as I can

thanks
 
DO NOT SHOOT IT UNTILL YOU GET A NEW BOLT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Thats about 55,000 psi of preasure coming at your face at a very high rate of speed should that bolt fail.

When you get a new bolt, have the headspace checked and also have the barrel extention checked.

Scott
 
I would definitely not shoot it.

I would contact the dealer it came from, or if purchased second hand, the bushmaster dealer here in Canada, which I believe is Freedom Ventures.

Sounds like a manufacturers defect. Heat treat issue??
 
How much lube did you have on the bolt.... I know of problems with lugs when people don't use enough lube. Bolt acts sluggish and shears lugs. (Mainly a problem when people use sonic cleaners and don't re-oil properly).

As mentioned... could also be a defective bolt.....

Not the greatest/safest to shoot but as you found out the gun still functions. :eek:

just my 2 cents...
 
is it the 2 lugs near the extractor?

if so thats the "normal" spot for them to shear on the m16/ar15 bolts BUT not at 3K rounds

do NOT fire it
 
CAR type rifles seem to have a shorter life expectancy on their bolt-heads. (KevinB could explain this better than I)

3K does seem short, but it depends on a lot of things, how hot is the ammo, how well do you clean things, what were the conditions? Many variables, no good answers without more info.

DO NOT FIRE UNTIL YOU REPLACE THE BOLT-HEAD.

NavyShooter
 
I don't know if it has anything to do with the length of the barrel. I saw the same thing happen to a C7 A2 right in front of my eyes. Colt M16 bolt in the rifle CF IVI ammo. I thought it was extreamly wierd and had never seen it before.

I agree with the above mentioned; Don't fire it and get a new bolt
 
Shorties are tougher on bolts because of the higher operating pressures/shorter dwell times. IIRC the recommended M4 bolt replacement is ~5K rounds, 3K is definitely premature but I think you know that. Why did it fail? Without a lab analysis, who knows?

Long barrel, short barrel, whichever, a broken bolt lug on an ar-15 isn't unheard of, that's where spares and warranties come in. If you have a warranty, contact your dealer, if not, pick up a TWO new bolts (1 spare) and get back on 'er. I'd recommend a MP tested bolt, then you at least know there are no defects to start with.

Don't shoot it as is!


Good luck,
DT
 
Well, that's why you buy MPed bolts that are proofed, but on the other hand, Bushmaster will most likely replace it at no charge.

3K should not break it - unless your firing schedule is very intense.
 
looking for new bolts right now and I'll write Bushmaster and my retailer, not to complain ( too much fun with this thing) but to let them know.

I'm really surprised how the rifle keeps shooting, and good, even missing two lugs ! What were the odds that a piece of metal went in the barrel and KABOUM ?

How much lube did you have on the bolt
Click to expand...
Standard green machine SOP : oiled with a brush then wipe the extra :rolleyes:

unless your firing schedule is very intense
Click to expand...
I dunno if it can be qualified as intense for an AR15, but I was shooting as fast as I could, still hitting the target , 10 rounds in approx 8 sec, 260 rounds total this day.

Thanks for your answers, I'll post pics this weekend
 
yup thats where they all break usually under FA fire or really intense prolonged semi dumping 30 rnd mags after another us target shooters with 10 rnds mags should never break one Ive got several K thru some of my ar's and not problems

armalite semi bolts and colt m16 bolt/carriers
 
Savage said:
Thats Bushmaters for you
Click to expand...

Bushmaster doesn't MP their #### - so not mil spec. The only makes for sale in Canada that are mil spec is Stag, LMT and Colt (Colts available this week only;)). Buy mil spec and the problem goes away or errrrr... gets delayed.;):ar15:
 
Course I've dumped 30 rd mag after 30 rd mag through MY bushmasters (+ 1000 rds in a day) and have yet to break anything......

I guess that's bushmaster for you....

jl

btw...an MP'd bolt doesn't last longer...it's just guarantied to have no flaws.
 
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