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keyholing after 2000+ rounds of milsurp. wtf???


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never had this problem with my bulgy until today.

 

 

before this happened, it had a tapco double hook fcg, with a standard wire guide recoil assembly, and wolff xp recoil spring. no keyholing, though sometimes the carrier did jump the rails every few hundred rounds or so. its done it about 8 times now.

 

so i added a milled romanian rpk guide rod, an arsenal single hook trigger, arsenal disconnector, and tapco g2 hammer. went and shot it today at the 50 yard line and loaded 30 rounds, first few rounds were ok, then it started to keyhole! i shot another 60 rounds though it, and they were innacurate as well, but the ones that did hit the target were very low (50 yard target aiming at center mass the whole time with sights set to 'battle'), and one keyhole on the target.

 

i dont know what is going on. could it be the guide rod or the fcg? i doubt its the ammo, ive shot nothing but spamcan milsurp out of this thing.

 

i am always careful to clean the gun, and have shown no signs of rusting anywhere on it.

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Those typically wont cause keyholing - deflection sure.

 

Don't know why it just started the keyhole. That is a barrel ID or twist rate typically.

 

First remove what you replaced and install the original parts (shouldn't make a difference) - if it still keyholes you haave a gyroscopic stability problem, not a burr contrary to what.many will tell you.

Edited by jeep45238
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Nicks to the crown or flaking chrome... anything that looks out of the ordinary and would potentially cause the bullet's path to deviate. Do you have a brake on it? That would be most likely to cause keyholing if the bullet is nicking it on the way out.

 

I don't see how anything you may have done to the FCG or guide rod would affect the bullet's path.

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i have a zigzag brake installed but its on permanently for state compliance. there are no signs of deflection nor flaking. i always clean with foaming bore cleaner and remoil, just run patches down until it shines. i dont use brushes to scrub the bore. so its wierd

Edited by m1lk
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Man, that sucks. I gotta say I'm kind of stumped if all you did was switch out receiver components.

 

Stupid question--but are you sure it wasn't keyholing to begin with? Are you shooting at the same distances you were before? One thing about those small light rounds is they sometimes take a short distance to stabilize fully. If the barrel or the ammo is a bit out of spec it might show up at short distances but chances are at 100 yards you won't see keyholing anymore. Also, re-reading your first description it doesn't sound like all of your rounds keyholed, just a couple, which is promising.

 

Don't rule the ammo out, try some from a different batch or better yet a different brand and see if you get the same results.

Edited by rob-cubed
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m1lk,

You have just pooched your self Big Time Rem oil contains Teflon ,Teflon has no place in a barrel ,it should Never be used in a barrel because every time you fire it ,it melts the Teflon into the grain interstices and starts building up .

That build up will ruin a barrel Forever because it cannot be removed by any method .I have had very expensive Match barrels come back to me with strings of Teflon coming out of the bore with the shooter complaining "it shoots like a shot gun ,it will not group, it was great when i started and then got worse and worse " .

 

If you value your barrel Never use any lube containing Teflon in the barrel !!!!!

 

It was almost as bad when Moly coated slugs were available but at least you could remove it mostly !! Notice that there are very few Moly coated bullets are now on the market today , there is a reason why !!!

 

every Match shooter worth his salt knows that a little moly is ok but Teflon is Never to be used in the bore of any rifle !!!!

 

Lets hope you have not gotten enough build up in your barrel to screw the rifle totally and irreparably !!!!!!!!!

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no, it has never keyholed before. ive shot it at 50 yards with very acceptable results, much so that i started shooting 100-150 only with this gun. the day this happened, i just happened to feel like shooting at 50...

here are the pics. both times i was aiming with the irons set to the lowest setting, at the red center mass:

 

the first picture is the first few shots. notice the keyholing. do not mind the other holes, those are from a shotgun.

 

WP_000051-1.jpg

 

 

this is the 2nd run. 60 shots. a few i intentionally shot into the giant dirt mound so i could see the bullet splash the dirt, because i did not know what was going on at the time, so not all 60 are there. but as you can see, even at 50 yards aiming at center mass it was hitting very low. notice the one keyhole this time, but who knows how many keyholing bullets there were that ended in the dirt mound...

 

WP_000052.jpg

 

 

 

suppose it was this fucking rem-oil. how do i get as much of this shit out of my barrel without firing it? you mentioned repair, how exactly would that go about? and if i have to send this out to have the barrel swapped out, whom do i send it to, and how much would it cost?

Edited by m1lk
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m1lk ,

 

There is no known way to remove Teflon from a barrel without destroying it , don`t add any more to it use just straight oil in bores

 

i have tried every thing from Butch`s bore shine to fire lapping and nothing works , it chemically inert so no chemical wash will work either,in short there is no repairing what may have happened

 

the only solution is complete replacement of the barrel !!! as for cost i have not a clue i do not work on AK`s ,check with a few of our vendors Pauly comes to mind

 

Just do not use any oil with Teflon or PTFE listed on the ingredients in the barrel ,any were else is Ok just not in Hot sections of a weapon

 

read this http://en.wikipedia.org/wiki/Polytetrafluoroethylene#Properties

 

there is a reason the US military quit using CLP Break Free !!! it contains PTFE also .

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Several smiths have warned that Grandad's WD-40 cleaning regimen will build up into an awful lacquer but this is the first time I've heard CLP will do the same. Which is a shame, it's always done me good as a rust inhibitor and "bore treatment" before storage. But it makes complete sense that Teflon will not shoot out like oil and can be baked into the barrel. Never again.

 

OP, before you give up hope I'd continue to shoot her a bit more. If the difference in accuracy went from great to keyhole city overnight, and buildup on the bore is the issue, then we're talking about just a tiny fraction of thickness to create such a huge difference in performance. I'd run a few jags through, shoot it some more, and still try different ammo before calling a good Bulgy barrel toast.

Edited by rob-cubed
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For giggles I would remove the brake to make sure there isn't an obstruction... I shoot only 200 rounds and my brake has carbon baked all over it... No telling what yours looks like on permanently (hopefully by a reversible solder job) and 2000+ rounds shot outta it. That would also give you a good look at the crown and see if its been mauled after ramming a cleaning rod down it repeatedly.

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I will let you all in on a secret this is the stuff to use http://www.fluid-film.com/ it is only lanolin and micro crystalline wax , it burns off/out cleanly (no carbon build up ), as a storage medium there is none better (one application will last for years or about a year or so if you handle it), it literally stops rust dead in it`s tracks (cuts off all access to oxygen ) and no matter what finish you have from park, blued to BBQ paint it has no effect on any of them !!!!!

 

we use it exclusively in the off shore industry to stop and control rust in direct sea water washed applications .

 

for weapons just spray or finger rub it on (a little goes a Loong way ) let it sit for a few minutes and wipe dry ,once you have done that even the dreaded Acid finger (i have it ) will not leave a mark (not even fingerprint oils ) and once the lanolin has evaporated you still have the wax coating protecting it and that wax is deeply embedded into the surface ,let me tell you it Works and it does not attract dust either !!!!

 

Oh and any weapon coated with it is Not slippery it is also fantastic for IBW carry pistols no sweat will ever reach the metal and allow rust to start !!!!!

 

I use it because a few of my rifles have to "swim" in salt water on the way in and out . a little trick learned long ago 30+ years more or less .

Edited by belt fed frog
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well, holy shit...

 

checked the crown again, no flaking. though a bit of cake is starting to build up around it.... crown is still visible.

 

took a closer look at the muzzle brake, the outside part right after the zigzag ports, and found a nice shiny notch that wasnt there before. i think the bullet was hitting the brake and causing this.

 

now, question is...why?? it definitely did not do this the last time i shot it. how to fix this?

 

ill post pics of it tomorrow...my battery is dead

Edited by m1lk
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The barrel jumps up, and inertia holds the brake. It has developed enough wear move the slight amount to nick the round. Try to wiggle the brake up and down. any motion at all is too much.

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its silver soldered on for compliance, it does not move at all. i have never had any issues until now. and i doubt its the ammo. its either the carbon buildup, the crown or the barrel doing this. so starting wirh the simplest and hopefully the right solution, how do i get rid of all the crap in there without destroying the crown?

 

 

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a flat nose end mill sized to the ID. of your muzzle device with only a few .010-.015" of clearance loose . you turn by hand only ,this will scrape the carbon loose ,then i would use a ball nose end mill using only fingers lightly if you feel a stop dont push it !! it might be a rifling land ! if your bore is Chrome lined by hand you would be hard pressed to put a scratch in it even with the cutters i have suggested !

 

you can get them from MSC Grangers even E-puke and it is one time expense it is the some method i use to deal with 1919A4 boosters and they carbon up quick and deep

Edited by belt fed frog
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here are some pic and vids of the inside of the brake. took it with my phonecam, and shined a small keychain flashlight to each one of the side port holes.... what do you think, could this be the culprit? it looks like the martian landscape in there...

 

WP_000065.jpg

WP_000063.jpg

 

 

couple pics of the chamber:

WP_000074.jpg

WP_000076.jpg

 

 

and just to confirm, here is a pic of a 5.56 sitting in the chamber, and how the 5.45 sits...

WP_000077.jpg

WP_000079-1.jpg

 

 

and heres a vid of the brake for more detail:

http://s189.photobuc...nt=IMG_0000.mp4

 

 

 

 

finally here is where the bullet was hitting.

keyholing.png

 

notice that its at the top part of the brake. putting it together, the crap in the brake caused the bullets to exit fucked up, and after the bullets wore off enough from the brake, it started grazing and hence why it was shooting low.

 

well besides going in there with drillbits to gash everything up and risk fucking it up even more, isnt there some carbon cleaners i can soak the brake in for a day or two that will at least get rid of enough so that this doesnt happen?

Edited by m1lk
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Good old carb cleaner from your local automotive shop will do the trick as well as any gun-related product. Man you have some buildup in there.

 

Looks like you have a pretty big nick on the inside of the brake, but unless the barrel was threaded poorly the bullet is already off-course by the time it hits the brake. Make sure you clean up the muzzle really good. Sucks that you can't remove the brake to clean properly and test shoot... is it blind pinned or welded on?

 

After you get the brake clean, if there is bare metal hit it with a black Sharpie. If the bullet is still nicking the brake, it'll take the sharpie off and make it easier to see.

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Good old carb cleaner from your local automotive shop will do the trick as well as any gun-related product. Man you have some buildup in there.

 

Looks like you have a pretty big nick on the inside of the brake, but unless the barrel was threaded poorly the bullet is already off-course by the time it hits the brake. Make sure you clean up the muzzle really good. Sucks that you can't remove the brake to clean properly and test shoot... is it blind pinned or welded on?

 

After you get the brake clean, if there is bare metal hit it with a black Sharpie. If the bullet is still nicking the brake, it'll take the sharpie off and make it easier to see.

+1

Also try a .30 cal brush, either brass or stainless in a drill to clean the brake.

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managed to get alot, but not al, of the carbon shit out. also opened up the hole where the brake was hitting. then put 30 rounds of silver bear, 20 rounds of wolf mil classic, and 30 rounds of milsurp. still keyholing but not as bad, though still wildly innacurate...

 

 

found a way to check the bore headspacing with the welded brake attatched.

 

took a pulled 5.45 and 5.56, superglued them to the back of ink pen cartridges, and painted them white with enamel paint pen, put them in the front of the bore and spun them around lightly.

 

here are the results:

 

in the problem rifle:

 

SavedPicture-2.jpg

 

left is the 5.56, right is the 5.45. notice how the 5.56 stops right before the crimp.

now look closely at the 5.45 and see how it goes all the way to where the red lacquer begins.

 

 

 

i repainted the bullets, and then i did the same thing to my other bulgy with original barrel, this one currently has no issues:

 

SavedPicture-1-1.jpg

 

notice how this time the 5.45 stops just right before the red lacquer starts.

 

 

my hypothesis is ive had a 5.56 barrel all along. but if that truly is the case, then why did i not have keyholing issues in the beginning?

Edited by m1lk
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Hmm... Is it possible you shot out the barrel after 2k rounds?

 

 

ya theres always that...

 

im going to make one last attempt and counterbore or cut & re-crown, if that doesnt help then new barrel it is...

 

 

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You could just hone the end of the brake out with a honing tool. But before I would even attempt that, I would first clean that god aweful crown with a CAREFUL scraping using a flat head (the one that comes with the cleaning kit I use). Fire the weapon w/o the brake and see if you get keyholes. If that's the case, then best bet its the brake or barrel. 2000 rounds is an awfully small amount of rounds for this weapon to have a shot out barrel.

Edited by WhoDat504
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punched the pins of the fsb, pulled it out along with the brake, cleaned it up, cut and crowned,saw that the barrel really is worn to shit. test fired it yesterday and the keyholing issue is gone but its innacurate. 15 rounds aimed at center mass with sights on battle at 50 yrds, barely any hit. let my friend shoot it to confirm. though according to him it started to get a bit better after 90 rounds. 120 rnds milsurp total.

 

ordered a new bulgy barrel from whatacounty, guess ive got no choice now

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