Deep scars on Casings/projectile from Bolt passing over??? (Pics inside)
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Thread: Deep scars on Casings/projectile from Bolt passing over??? (Pics inside)

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    Deep scars on Casings/projectile from Bolt passing over??? (Pics inside)

    Having issues with the right feedlip of new AK Pmags binding against my Bolt & Carrier and lower portion of Carrier of my "SAM7", so I tested 3 tight fitting Polymer mags in my SAM7 (M3 Pmag, Tothtool, and Circle 10) with 29 rounds. I stopped at 29 so that the top round would be on the Right Side where the follower issue is with Pmags in this AK.

    **I ONLY charged the handle to the rear so the Bolt passed over the mag/rounds, then removed the mag to checked casings**

    The Bolt scars on the casings show how the bolt rode very close to the feedlip on the M3 and then "Curved" (bolt must have twisted at the "rough spot" where it binds against the feedlips.)

    The scratches were straight on the Tothtool and ((10)) tho.

    This brings me to question my Mag Height in the receiver and if my mag catch is out of spec etc (Even tried a looser surplus mag, charged much smoother as if the rounds weren't pushing upward on the bolt as hard but still created scars on those casings IIRC.)

    Seeing these deep scratches just from the Carrier/Bolt passing rearward over the top round (the scratches can easily be felt with a finger nail being deep) and the front edge of the casing that holds the projectile gets marred also....

    IS THIS 100% NORMAL FOR AK's???


    M3 Pmag -Tula ammo (Tried with rounds on both sides, which explains scars on the left/lower round in mag)












    Tothtool (Brown Bear or WPA....Mix...Barnual symbol on them all.)









    Circle 10 (Potato Pics, had Golden Tiger and it scratches ALOT deeper into the coating...Also, the edge of the rim of the casing around the projectile gets damaged easier, but light created a Glare on the lacquer coating so badly that I couldn't get a good pic!)




    Never thought this was bad, just showed pics to someone (maybe a novice) and they acted as if the scars were not normal and said they should only be on the projectile if it were chambered and removed (which adds alot more I will say from tests Ive done on ejection, but these casings ONLY experienced a "rearward handcycle".)
    Last edited by train; 12-24-2015 at 10:43 PM.

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    Wasn't expecting to even view this as a big deal until someone made it out as if my bolt was ruining the rounds before they were even chambered due to the gouges i the projectiles or that the scratches are burr related etc etc etc (likely a noob, atleast I hope.)

    The other night, in attempt to find the M3 mag "Binding Issue", I Put some red lipstick on the inner edge of the "Right Feedlip" of an M3 Pmag to see where it smeared... Also have a big silver scuff on the lower corner of the lower rounded portion of carrier that lines up with the feedlips. I tried to re-create it in the pic below being I didnt take a pic of where the Lipstick ended up on the "Carrier & Bolt!"

    Didn't take a pic when I did that test but re-created it in "Paint"...

    Not sure if it's the mag alone, or a mix of my SAM7's specs AND the magpul design....

    I personally think the lack of "Slants" on the inner edge of the feedlips is creating a "Clearance issue" being every other AK mag has those 45 degree slants and the Pmags are rounded on the inner edges.

    http://i41.photobucket.com/albums/e2...ick%20test.jpg
    Last edited by train; 12-25-2015 at 02:01 AM.

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    A copy and paste of what I sent a pm, saw this thread after:

    You are going to have something, even if only rearward. The bolt has nowhere to go, in that it can't go up or twist. The bolt is what pushes the round into the chamber. On rear ward travel it drags across the top round but has nothing to grab, because the cartridge is arrow shaped. In doing so the bolt pushes down slightly on rounds in mag. Once bolt gets behind the top round, cartridges spring up slightly, and bolt falls below the upper edge of top round, behind the back of steel casing. So as it moves forward it now can catch the casing and drive the round into the chamber. The bolt only twists at the very end of forward travel. Also most bolt carriers drag across the top round as well. If you shoot brass casings [at least a mag], then pull bolt and bolt carrier out, you will see the contact points, because bolt and bolt carrier will begin to get a brass coloring on them from where they are contacting.

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    The rounds dont look bad but I already pmd you. In my opinion pmag is no go for me for ak.

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    Understood.

    I always thought it was normal, and I'm sure looser/lower fitting mags may have marks that aren't as deep, but I understand the process. This mag having an issue that it doesn't in other AKs made me question my mag height via some tips from others.

    My Bolt has some slop inside of the carrier in the outmost position (it droops down about 2mm, and can be twisted to the side, when I insert a mag it rises up and twists away from the ejector) so that's what I meant about it having play to shifting when passing over that Pmag due to the mags specs being odd in this AK and it hitting a rough spot and the Bolt shifting a tad.

    As long as the Casing/projectile scaring is 100% normal and the scratches being deeper in person (which they are) is normal also, then everything is good to go! (I've saw the brass colored stains on the left and right sides of the Bolt also, wiped it off with some CLP the other night actually which made this scratches less aparent due to a sheen of light CLP rather than being bone dry, although I try to keep it as dry, yet as protected as possible on the areas that pass over the rounds.)

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    Could you 2 do this same test with 29 rounds and take a pic?

    Gunplumber (very experienced smith) says it seems my mags are sitting too high an should not have scratches like that on casings, with would explain what made my bolt loosened up, and peened so quickly against the ejector (and the fact I can feel the bolt hit the casing's neck when charging the handle.) Bolt does its job and pushes them down, but you can tell the rounds push the bolt up first so its like it takes double the effort.

    Have some other AKs and cant even tell when it passes over the mag, there is friction but its one solid pull, this has a 2 stage feel even when going fast that I've gotten used to.

    Not expecting anyone to solve this, just wondering if similar pics could be taken for comparison and see if its a "Sam Thing"!

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    Well, like i mentioned in another thread. I won't use polymer mags in an ak. Aside from the strength of tabs and such, it seems like there is too much friction and too much effort needed to load the mags. It just doesn't feel right to me. I can pop rounds into a steel surplus mag like im popping popcorn in my mouth, real easy. I got 10 of these yesterday, you may want to check some out:
    Polish Steel AK47 7.62x39 30rd Magazine

    There's a thread on them here:
    https://www.theakforum.net/forums/20-...steel-aim.html

    All 10 lock up nice in my sam7r, as all my surplus do. Nice spring and follower action. pretty good deal.

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    On my sam7r my bolt has always had free play inside the carrier and the bolt peened the carrier when it was brand new until about 500 rounds later and stopped, just the nature of the beast..something I wouldn't worry about.

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    Part 1 due to pics: Fully loaded Hungarian surplus mag. Silver Bear 125gr SP. Pulled Charging handle to rear. Removed mag. Did this on sam7r-66, 1800 plus rounds, and sam7r-61 maybe 200 rounds. Pics 1 and 2 are the 66. Pics 3, 4, & 5 are the 61. I do have scratching from both rifles on the rounds. On the cases its more of a visible line than a scratch but I would not call it deep scarring. The bullet itself is scratched harder, being its softer, and scratches the soft point pretty well.

    SAM7R-66:

    1.jpg2.jpg


    SAM7R-61: Note the coloring on bolt and small piece of bullet material as you get close to the top of the slope on the bolt in pics 4 & 5.


    3.jpg4.jpg5.jpg
    Last edited by texasgunsmith; 12-26-2015 at 10:07 PM.

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    Part 2: Now in reality, its not something I'm worried about. All things being equal I'd prefer not to have that though. I do think it can be corrected or at least softened. And can be done without affecting head space or function. Looking dead center of the following pics, I think the intersecting point of the 3 lines at top of the slope could be softened with a file or emery cloth or dremel if you are careful. Plus softening the single line that you can see in center of pic 10, it moves forward toward bolt face. Softening these areas LIGHTLY on both sides, because rounds in mag alternate which side of bolt it rides against. Again I would not remove too much material, just soften the point edge and the one line edge on both sides of bolt. I'll probably do it for shits and giggles to see how it goes.


    6.jpg7.jpg


    The last pic, 10, shows the line going forward in dead center of pic, Its that line I would slightly soften also.

    8.jpg9.jpg10.jpg
    Last edited by texasgunsmith; 12-26-2015 at 10:11 PM.

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    Quote Originally Posted by texasgunsmith View Post
    Part 1 due to pics: Fully loaded Hungarian surplus. Silver Bear 125gr SP. Pulled Charging handle to rear. Removed mag. Did this on sam7r-66, 1800 plus rounds, and sam7r-61 maybe 200 rounds. Pics 1 and 2 are the 66. Pics 3, 4, & 5 are the 61. I do have scratching from both rifles on the rounds. On the cases its more of a visible line than a scratch but I would not call it deep scarring. The bullet itself is scratched harder, being its softer, and scratches the soft point pretty well.

    SAM7R-66:

    1.jpg2.jpg


    SAM7R-61: Note the coloring on bolt and small piece of bullet material as you get close to the top of the slope on the bolt in pics 4 & 5.


    3.jpg4.jpg5.jpg
    AWESOME!!!

    And I an assume this is your used SAM....Isn't it above the 1k mark?

    I can tell by the bolt that alot of the underside of the bolt gets worn down over time (another thing Arsenals finish shows.)

    I assume your scratches aren't quite as deep (My higher fitting Poly mags likely make mine worse) but sure the ridges wear down during "Break-in" also, although I can see that the patterns are the same.

    Btw, Can you feel the scratch with your fingernail on the projectile & casing, or is it mainly discoloration in the casing finish? (if put up already, no worries)

    Thanks for comparison pics, some were saying it was normal, and some acted as if it were absurd so I was baffled and mainly wondered about the "Projectile" scars the most and if it affects accuracy.

    This worry has been put to sleep just from seeing a comparison!
    Last edited by train; 12-26-2015 at 10:14 PM.

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    I'm thinking you were replying to my part 1 post before i got part 2 posted, lol. So you may want to check that if you didn't see it. Anyway i've got my stuff out and am doing some late night tinkering, so i'll polish those edges a little and see what it looks like.

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    Quote Originally Posted by texasgunsmith View Post
    I'm thinking you were replying to my part 1 post before i got part 2 posted, lol. So you may want to check that if you didn't see it. Anyway i've got my stuff out and am doing some late night tinkering, so i'll polish those edges a little and see what it looks like.
    Yea, hadn't saw Part 1 yet.

    If yours cant be felt by fingernail, they're not as bad as mine.

    I would use sandpaper if anything, just so it smooths it but doesn't reshape it, but if you are a smith, you likely know what your doing.

    I'm gonna just run mine and see if it lightens up, just wanted to make sure it was normal. Most people don't have tight mag catches like the "SAM" so one reason some others thought it wasn't normal (likely).

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    I did gently and lightly soften the places i mentioned. In looking at it closer, it seemed to me the outer edge of the lug itself my be coming into play. So i carefully used a dremel with a emery cloth cylinder shaped bit to go around the upper edge of lug on all 4 sides, not really taking meat off, just softenting the edge a bit. I did get some marginal improvement, the scratches appear lighter to me and less defined as i run my nail across it. But with the force it takes to shove the rounds down a fully loaded mag, well there's always going to be something.


    11.jpg12.jpg13.jpg14.jpg

 

 
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