7.62x39 CAR upper build = problem child??
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Thread: 7.62x39 CAR upper build = problem child??

  1. #1
    Gunco Addicted for life j427x's Avatar
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    Postak 7.62x39 CAR upper build = problem child??

    well i finally got my del-ton 7.62x39 CAR barrel. aside from it being horrindeously dirty in the bore is has been problematic from the get go.

    after much much cleaning i assembled the barrel to an upper. and it is having problems right off the bat.

    problem #1 steel cased ammo likes to stick in the chamber!

    problem #2 steel cased ammo sometimes fails to eject and or extract!

    problem #3 steel cased ammo sometimes fails to allow the bolt to close fully on the breech!

    i disassembled the upper and re-checked the head-space the bolt--the gas tube and can't see a darned thing wrong. the chamber has a rather dark finish and there are some rough looking finishing marks in the chamber--nothing severe. but if i can see them with my old eyes there certainly there!! if you put a round in by hand it fits fine and drops with gravity if you tilt the barrel up. the sticking only takes place when the round is rammed home wy the bolt &cg under pressure of the recoil spring.

    the same set up seems like it wants to run the brass ammo fine--although due to expense of the brass 7.62x39 i haven't fired enough of it to see if it is 100% on the brass stuff.

    now my other AR's/m4's and middies have no problems with the steel cased stuff in 5.56/5.45x39 and my 6.5G which is based on the 7.62x39 also runs fine although all its ammo is brass cased. my old colt 7.62x39 also runs the steel ammo well so somebody must have missed something here--but what is it??

    this barrel came with a red tag saying it can have malfunctions firing steel cased ammo--don't use it yada-yada-void warrenty and so on.

    all my other 7.62x39 rifles have little if any problems running it--so whats up with this barrrel??

    any ideas on how to get this turd into a diamond??--LOL!

    i think the extraction/ejection problem is fixable with a spring swap--

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    gunco irregular moleman's Avatar
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    You might try putting an o ring around the extractor spring and polishing the chamber since it sounds like its not a gas issue. Are the cases getting stuck in the neck area?

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    Gunco Addicted for life j427x's Avatar
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    all ready got the 0-ring!! i don't leave home without one!

    i am considering polishing the chamber a little bit. all my other del-ton barrels even though they are not chromed had very bright bores and chambers. this one is sort of dull looking and there are some tooling marks. a light polish might help. what is bad is it feeds and fires brass ammo pretty well--just like the red-card said it don't like steel cases!!!

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    gunco irregular moleman's Avatar
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    The o-rings are a lot cheaper aren't they than the d-finder rings, especially when you buy a bubble pack of them at home depot for $3. You might try getting one of the steel cased rounds that won't chamber and coloring it with a sharpie marker to see where its hanging up in the chamber. I wonder if they did a "semi match" tighter chamber on them, which would be stupid because you know most people are going to shoot the steel cased ammo in it. Keep us posted I'm kinda curious as to whats causing it.

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    Gunco Maniac sjohnson's Avatar
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    Take one of those fired steel cases, pop the primer (might be tough to do). Then center drill a hole for some threaded rod and double-nut the rod to the case. If you can't pop the primer, just center drill through it.

    Add some rouge or tripoli mixed with oil to the chamber and spin that case in the chamber at low to medium speed just enough to polish the chamber. Of course, that'll void your warranty as sure as using steel cases .

    Lacquered steel cases like a clean, smooth chamber wall, else they stick.
    I have a daughter. I tell her, "911 is what you dial after you're raped. 1911 is what you should have before they try."

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    Gunco Addicted for life j427x's Avatar
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    sounds like a good idea--


    Quote Originally Posted by sjohnson View Post
    Take one of those fired steel cases, pop the primer (might be tough to do). Then center drill a hole for some threaded rod and double-nut the rod to the case. If you can't pop the primer, just center drill through it.

    Add some rouge or tripoli mixed with oil to the chamber and spin that case in the chamber at low to medium speed just enough to polish the chamber. Of course, that'll void your warranty as sure as using steel cases .

    Lacquered steel cases like a clean, smooth chamber wall, else they stick.

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    Gunco Regular bsouthnow's Avatar
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    Did you look at the spent case to determine if there were any scratches on it? Just making sure you don't have a burr problem.
    Bill
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    Gunco Addicted for life j427x's Avatar
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    i think i got the problem nailed. the 7.62x39 CAR is looking like it is wanting to run now.

    the problem was -GET THIS!!-the extractor was over sprung!--now tell me when have you ever seen too much spring there? my 5.56s and my 5.45 seem to love the extra pressure of the 0-ring but not this 7.62x39!!!

    and ironically it also seems to have solved the ejection problem. it has went away after i took the o-ring off the extractor spring.

    before i had polished the chamber, no luck, but after firing a few rounds of wolf polymer and getting several jams --so i started swapping ammo , golden tiger works for a few rounds then get a failure to close the breech, brass yugo fire a few rounds but get a couple fail to ejects, put some wolf laquer cased ammo and jam,fail to eject, fail to extract, and fail to close breech--other words--fail-fail -fail!! with the chamber clean and shiny and no burrs visible i had to look elsewhere.

    i picked up the empty cases and the rims looked a little mauled by the extractor, pulled the bolt out and looked up into the barrel-extension lugs and saw a few little tiny flakes of metal there brass and steel from the rims of the ammo.

    took the 0 ring out, cleaned out the metal flakes, put her back together and started pop-ing off 7.62x39. so far so good. i still got a little finish work to do but but the turd is starting to shine up a little bit!!

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    gunco irregular moleman's Avatar
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    I had a similar problem with one extractor in 5.56/223. I finally traced it down to the front edge of the extractor wasn't beveled enough to let cases with more squared off rims to slide over them as well. I didn't notice it until after I replaced it and was comparing it to the new extractor. I beveled the old extractor the same ammount as the new one and it worked fine. I didn't remember about it until you said it worked better without the O-ring, which I agree is a first.

  10. #10
    Gunco Addicted for life j427x's Avatar
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    it is odd. the only one of my AR types that don't like/need the 0-ring.

    but it is up and running now--with the 0-ring it was one FTF after the other.

    these 7.62x39s are some strange cats.

    i have seen other people that were constantly breaking extractors on the 7.62x39 AR types. being over-sprung well something has to give!! i don't know that ALL 7.62x39s are like this but i'll bet a number of them are. if you got an extractor eating up the rim it would be a good idea to see if there is too much pressure on the extractor.

    ironically my old colt 7.62x39 will run either with or without the 0-ring. i am thinking it also will run better without one but it don't seem as "critical" as it does with this Del-ton/m1 sales stuff.

    could it be just this type of bolt/extractor combo that has a tendency to be over-sprung??--a possibility i am thinking??

    i may try the 5.45x39 upper with the 0-ring removed. it is running like a champ now but it throws the brass in my face a little. strangely removing the 0-ring from the 7.62s39 also solved the ejection problem. it now tosses all the empty's clear. maybe this will help get the empty's out of my left-handed shooting face!!--lol

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