HP feeding
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Thread: HP feeding

  1. #1
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    HP feeding

    Took my build out for a test run, and it jams once in awhile with hollow points. I have read about this here, so I wasn't too surprised. I have also read here I can modify the feed ramp to cure this. Anyone have pictures or advice on the best way to do this?

    Thanks

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    let me guess, nodak receiver?

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    Some feed ramps lack a chamfer at their back edge. With no chamfer there, a HP round can hang up on that edge like a hang nail caught it.

    An easy solution is a 1/8" diamond burr in a Dremel tool. Go through the magwell and gently kiss the burr to the back edge of the feed ramp in a back & forth motion to knock down the hard edge. Don't just do the bottom of the ramp! These are double stack mags and need the whole surface from side to side chamfered. You don't have to get crazy and grind it down to a 45 degree angle! Just chamfering half the thickness is enough.

    Compare the one that hangs up to one that does feed HP ammo and you'll see what I mean. Just a little chamfer all along the top edge back & forth will fix it.

    Good luck with it!
    "Whenever I feel blue, I start breathing again."

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  5. #4
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    Thanks, I will try that. Its a home built receiver. Thing runs great with FMJ.

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    is the bullet catching on the bullet gude or the barrel?? if its hitting the barrel you can add some weld to the bullet guide at the edge of it to raise the bullet higher. I raise the gude and extend it back as far as possable. I do this on all my builds that will shoot HP and soft point ammo. it also helps stop bullet deformation on solid points. a very light champher of the barrel wont hurt, just be sure not to go very far into the chamber. I run almost any ammo including heavy bullets with this mod.

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    HDI romG on a NoDak feeds 7.62x39 wolf mc 124 gr HPs just fine so far with metal com bloc mags.

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    Quote Originally Posted by GreenEye
    let me guess, nodak receiver?
    how would the type of receiver make any difference?
    "Yes, you really can build a gun with bolt cutters......"

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    Quote Originally Posted by RomG78
    Quote Originally Posted by GreenEye
    let me guess, nodak receiver?
    how would the type of receiver make any difference?
    I was wondering that as well since the feed ramp is riveted to the trunnion.
    RIN (Remember in November)

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    Quote Originally Posted by gundoc
    Quote Originally Posted by RomG78
    Quote Originally Posted by GreenEye
    let me guess, nodak receiver?
    how would the type of receiver make any difference?
    I was wondering that as well since the feed ramp is riveted to the trunnion.
    Inquiring minds want to know :roll:

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    Quote Originally Posted by RomG78
    Quote Originally Posted by GreenEye
    let me guess, nodak receiver?
    how would the type of receiver make any difference?

    It doesn't. As already covered, the ramp is in the trunnion. The ramp is what allows or doesn't allow HP ammo to feed.
    Out of the dozen AK's I built from kits, only two lacked enough chamfer on the ramp to feed HP's. Easy fix to both. It was interesting though to see just how perfectly the HP tip would snag the non chamfered ramps though. Just like a hang nail.
    "Whenever I feel blue, I start breathing again."

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    In a related thread, someone suggested moving the bullet guide. If the round is jamming low into the chamber face, then you move the bullet guide slightly towards the magazine and the bullet will be propped up slightly as it passes. I think this has the same effect as a bead of weld on the bullet guide, but it looks nicer.

    I wouldn't do anything to the gun until I had tested it enough to know exactly how it is failing, and then choose the solution that seems to address your particular problem.

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    It doesn't. As already covered, the ramp is in the trunnion. The ramp is what allows or doesn't allow HP ammo to feed.
    Out of the dozen AK's I built from kits, only two lacked enough chamfer on the ramp to feed HP's. Easy fix to both. It was interesting though to see just how perfectly the HP tip would snag the non chamfered ramps though. Just like a hang nail.

    Wrong

    the reciver has a lot to do with feeding. mag angle is a major contributing factor to feeding. were the bottom of the reciver is in relation to the upper rails impacts this. if you lower the rear of the mag slightly the tip of the bullet will be higher as the angle changes. it dosent take very much to affect feeding. most builds I have encounterd the bullet tip clears the ramp just fine but the ramp is not high enough to get the angel required to make the bullet enter the chamber with out hitting. If the bullet is hitting tip is hitting the actual bullet gude then the back of the mag may be to high. this can also be adjusted at the selector stop. if the bullet tip is hitting the barrel and not catching the guide then champering the guide will make matters worse as removing material from the gude will lower the feed angle.

    I have spent a lot of time messing with this stuff as I am big into accuracy. it dosent do much good to spend hours doing perfect hand loads when the bullet hits the edge of the barrel and damges the tip or worse pushes the bullet back. not all trunions are identical were the mag lugs engage the trunion can be off as well I have seen one trunion feed just fine and a difeerant one in the same reciver have a issue the same can be said for mags not being the same also.


    In a related thread, someone suggested moving the bullet guide. If the round is jamming low into the chamber face, then you move the bullet guide slightly towards the magazine and the bullet will be propped up slightly as it passes. I think this has the same effect as a bead of weld on the bullet guide, but it looks nicer.

    I wouldn't do anything to the gun until I had tested it enough to know exactly how it is failing, and then choose the solution that seems to address your particular problem.
    welding a bead onto a bullet guide properly grinding it and polishing it is have going to have virtualy no impact on the looks of the gun. On most of my builds I doubt you would notice it at all. Im not sure how you would move the guide back or up with out affecting how it was riveted in place it would require welding the rivet hole and redrilling it and also moving it would likley affect the bolt rotating in as the ramp that rotates the bolt is built into the bulet guide. you really cant shim the guide up for the same reasons
    you cant move the guide back much or it will hit the mag. I try to set my builds up so hollow points just clear the edge of the guide.

    I do agree you need decide what is wrong before attempting any fixes. pull the covers and work some dummy rounds carefully watching what is going on. find out if its catching on the barrel or on the ramp. I champher all my barrels regardless and on 7.62 x39 builds I add weld on rivet build first just in case I need to adjust the feed doing it before assemply makes it easier to weld in cleanly. on the screw build I just pull the trunion and fix it if there is one. almost all AKs ding up HP,s some in stock trim most will feed but the bullet damage does affect acuracy.

    On my 223 varmit build I can see the differance in groups from Hand loade into the barrel and auto loaded with traditional HP,s I use the plastic Vmax or Nossler balistic tips so its not a problem but recently I have started shooting the heavy match hollow points and I may have to rework my bullet gide some more.

  14. #13
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    here is picture of a bullet guide that has been welded up and back slightly and then adjusted with a sand paper roll.
    its almost undedectable. this gun will feed any thing including 180grain soft points. note that the bullet gude is litteraly touching the mag. I check every mag I own to be sure they all fit. also note that the bullet tip is still way above the edge of guide. this is a bent tapco reciver BTW. the barrel has a slight champher as well.


 

 

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