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Discussion Starter · #1 ·
While drilling out the revits in the front trunnion, I hit the barrel on two of them. Just how deep is too deep? :sick: I figure i'm into it about .075 inch. Did I trash it or is it serviceable?
 

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I agree , I see no problem here.
I have thought about this a lot , now I admit I have not made any lab studies on AK barrels drilled to differant depths, BUT I have worked with metal a lot and done more fab work than I care to rember. Here is what I come to, It would take an amazing amount of pressure to blow through the small hole even if all that was left is 1/8" . If you drilled 1/2 way through I can not imagen the gas pressure blowing through I just cant see it happening. I do not know how much pressure is back their behind the sholder but any gass pressure their could follow along the side of the case and blow out the back to the bolt face, it is not realy contained. It is not like the pressure up in the front of the case driveing the bullet. dont this make sence?? honestly I am not convinced that a hole all the way through realy would be all that bad back their, some gasses would flow through it but with no hole they are just following a short distance and passing rite out of the back to the bolt face anyway. rite?? If the fear is the barrel cracking or totaly failing because of the small hole ,, again I just cant see it, it is very strong back their and I just do not see a small hole weakening it enough to rupture. . . I have even thought about dooing some testing with drilling deeper and deeper fireing rounds at each depth and see if gas pressure ever blowes out any undrilled part and through the hole.. and fireing it with a hole drilled rite through. .. you know I should have bought another AMD65 for $59 and screwed the front to alow me to take it appart as often as needed. I am reminded of the photos of the front trunion held in with tooth picks,, only one way to find out,, build a test and fire it!!! rite?
Keep in mind as I said my oppinion is based on generalized experiance NOT first hand for this issue "yet" .
Other guys MUST have thought long and hard about this too, I would love to hear what thoughts you have come up with,
 

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Discussion Starter · #3 ·
Cephus, I'm doing a mix. Because I'm leaving the barrel in the trunnion, I'm going to use screws in the two front holes and revit the third hole. The rear block will all be revits, and I'm not sure about the trigger guard, yet. I may have to fill the screw heads so it doesn't look goofy with a mixture of fasteners. What do you think, I read about a rivet build and a screw build, how about a hybred.

Hot barrel, I'm thinking along the same lines as you are, on the hole. It's not full size, as the hole was made with the first (smallest) drill in a set of three that I used to step up to the full diameter of the rivets.

Thank you guys for your responses and I look forward to hearing any and all others.
 

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This is an interesting thread. I did the same when drilling. Don't know how much, but I did hit the barrel. Barrels are proofed at much greater pressures than a fired cartridge produces, so I would say that we are safe. I still will tie that thing to a tree first though!!!
 

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I also built a kit that has 4 screws and 2 rivets holding the front trunion in . works fine .
 

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On my very first attempt at a amd kit, I drilled completely through the barrel when I was drilling the rivets out. I had just chucked in a new bit after the first three holes and the stop setting on my drill press had vibrated loose. I was through it before I knew it. I welded the hole in the barrel and I also welded the reciever onto the trunion. It held up for over a thousand rounds and one day I was firing it and a puff of smoke came out the side of the receiver that I welded the barrel. After closer examination I realized that the gases had broke the welds on the side of the reciever and bent the side a quarter inch away from the trunion. I was lucky. It could have blown up in my face. I promptly took a torch to the gun and shitcanned it. I could have cried, all the work I had into it and it was really a sweet looking build. ak'sr4me
 

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well now we have someone with some first hand experiance.
Did the actual weld brake out of the hole?? what did you use to weld the hole up with?? did you weld up from the out side, or get inside too? did you countersink the hole before welding to get deeper penitration and more surface area? when you were welding how did the steal of the barrel end look when you were welding? did it flow smooth or did it boil and spatter? how deep penitration do you think you got?
If you welded the reciever to the trunion , ware did you weld? what did you do with the rivet holes? did you put in screws, rivets, or weld through them to the trunion?
Please do not take me as critisizeing,, it is just I have never read anyone with first hand results. so as you see I have a lot of questions for you. this is the first oppertunity for me to get actual facts not oppinion. :thankyou:
well if the pressure blew back the side of the reciever, I think wehn I do my testing I will leave the screw out of that hole to let the gas strate out and hoplfully prevent reciever the damage.
 

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Discussion Starter · #8 ·
OK, so after working to pick out the back of the rivets and not being sucessful, I decided to try and remove the barrel after all. Useing the suggestions from all you good folks, I pushed the retaining pin (drift punch & heavy hammer, trunnion laying on my anvil) and drove the barrel out (set front of trunnion on the vise jaws and used a large brass bar with the 5 pound hammer). It worked, no damage to the pin, barrel or trunnion. Getting it back in might be another matter. Anyway, turns out I nicked the barrel in three places while drilling out the rivets. (yea, I know, should have pulled the barrel before drilling. Next time I will) The deepest hole is .075" , which is less than half the notch for the retaining pin. So, my question is, should I have a pro welder tig the holes or just leave it? Is the heat from the welding, gonna do more damage than I've already done, by over drilling? Also, now that I have the barrel out, should I go ahead and do a rivet build, instead of the screw/rivet build I was planning on? I have many more questions, but they can wait for now, little by little, I'll get there. Thanks for all the help guys.
 

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new guy questions are allways welcome here. I honestly believe you should just forget about the holes. and move forward with the build. As you say it is less than the depth of the pin notch. just my opinion keep on building.
Also read the answers to my questions here they may help
 

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I agree. If the hole is less than half of the depth of the notch you have no problem, just leave it. When I welded my barrel I put a shell casing in the barrel so I would not get any spatter inside the barrel. I mig welded the hole in the barrel, it flowed smooth and I got good penetration, however I didn't want to totally fill the hole and muck up the bore. I then plug welded the reciever to the trunion and also welded it very well underneath in the area where the handgrip fit's into. When the welds broke loose on the one hole that went all the way through, I am assuming that the gases blew the weld right out of the hole and the force broke the other weld on that side of the reciever bending the reciever away from the trunion. At this point, I would have just got another barrel, but since the reciever was welded to the trunion I decided to just toss it and chaulk it up to a learning experience. Now I pull the barrel on all my builds before drilling the trunions and I bolt the reciever so I can remove the reciever if I need to. I could easily do rivet builds, I have a 12 ton press, but I like to be able to easily disassemble my builds if I need to.
 

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Discussion Starter · #12 ·
Page two.
I took the barrel, with the holes, to a machinist, a welder, and and a master gunsmith. They all told me the same thing. It's not bad enough to worry about, go ahead and build your rifle. So I ordered the rivets and the US gas piston w/ retainer pin, from K-Var. I already have a G2 FCG. When they and the reciever (OOW) arrive, I'll have everything I need and can get started. Now to start researching how to do the riveting...
 

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Discussion Starter · #14 ·
My K-Var rivets and gas piston arrived today. Only waiting on Joeken for my OOW reciever.
 
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