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Posted: 6/3/2013 7:09:06 PM EDT
| My Romy is overgassed. The BC hits the rear trunion and leaves a nice dent in it. Luckily I have been running a buffer in it since I bought it. Is there any good way to fix this problem? I know about the Wolf extra power springs, I was hoping someone had experience with these. |
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My Romy is overgassed. The BC hits the rear trunion and leaves a nice dent in it. Luckily I have been running a buffer in it since I bought it. Is there any good way to fix this problem? I know about the Wolf extra power springs, I was hoping someone had experience with these. had the same thing happen.. there is no easy answer.. at a bare minimum change the spring and see if that helps |
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Yeah I was considering a ported gas tube but then upon further reading, I found some sources claim the ports are only there to remove debris...doesn't make sense to me. let this topic die here.. check with the guys on ak files.. ported gas tube is moot.. the best i found was a regulator in the gas block.. i f*ucked up the gas block.. F8ucked up the barrel trying to remove the gas block.. sold the rifle for a loss.. win win.. shoot it over gassed fwiw.. |
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Mr. Graham thank you for responding. I have read other posts from you on other forums and I believe you're an expert in this area. The barrel is original on a matching number rifle; typical Century import. I am using a Wolf extra power spring (which does nothing) and a bj buffer, the bc still hits the rear trunion. Not sure how to find the diameter of the gas port. I have a port reamer but I don't use it for obvious reasons.
Can you help me with my M70? Its undergassed with a new gas valve from CNC warrior. I hate the M70 system and I was hoping to send it to you at ARS for work. How much to replace the pos gas block with a standard bulgarian? |
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I hate everything about Yugos.
Pin gauges through the gas chamber into the barrel to see the port size. I suspect the gas port could be welded in and redrilled smaller. But if it is correct already, then I don't know what. It is not a defect for the carrier to strike the trunion, but if it is deforming, then there is a problem. What kind of brake do you have on it? Putting a brake that creates back pressure like the Krink 4-piece can cause this. |
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There are those who say that it induces malfunction, but they simply cannot give any reasonable explanation as how.
I recommend a buffer tech buffer only to work around the much more complicated fix of carrier jumping the rail. The blackjack buffer is a piece of shit and I'd be embarrassed to put my name on such a joke of a product. I can see that if the carrier is not hitting the trunion, then adding the buffer will make it hit the trunion (albeit with the buffer in between) so it is dubious as to whether its really any help. But I just can't see where it hurts. I bought a bunch of them years back and haven't used them - so if anyone wants to buy several, I can give you a decent quantity discount. |
| Good question, I I was thinking it was the muzzle brake as well. I was running an AK 74 type brake on it and figured it was the problem. It functions the same with the slant brake I have on there now (still hits rear trunion). I will switch to the muzzle nut to see if there is any difference. There is no deforming in the rear trunion or receiver for that matter. |
| Mr. Graham, how did you get to where you are in AK world? The reason I ask is I want to do what you do. I want to be up there with Mark Krebs and Will Hayden and eventually produce my own AKs. I understand this is pretty much impossible because the fed gov will probably permit me out of business. I have books and magazines on the ak platform but none mention little details on how to perfect the system. Did you go to school somewhere? |
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Back in the late 80s, Chinese AKs were under $200. Ammo was a penny a round.
How could I not? But I had no skills at working on them, other than threading barrels. So I studied what every other person I could find had done, acquired a dozen factory manual in several languages, got help with the translations, and then made the gauges so that I could measure the factory specifications. Early 90s, the thumbholes were coming in to get around the Republican Import Ban. So I did a lot of retrofitting/deneutering, and worked with two friends of mine who were starting their own little companies - Matt Shuster at Ironwood Designs, and Harold Shinn at First Son Enterprises. There was this weird thing called 922 and everyone was terrified of ending up in jail over a non US part. Then in '94 the AW Ban passed, and all the imports switched to parts kits. AKs, not so much just yet because there were still tons of the Romy SARs, and 5.45 was just coming on the scene. Then I bought a bunch of kits and built them and rebuilt them until I got it right. Then I bought another 500 Romy G kits and built those. Then another 300 Bulgy AK74s. I knew how to build them, but now I needed to make money at it, by refining my technique and streamlining it - time was money. Even today I scour the internet daily for more information, or new techniques. For me, my "surfing" is the same as my dad reading the WSJ over breakfast - continued education and professional development. The most important thing, which it seems 90% of the people out there never grasp, is that I realize Mr. Kalashnikov and the Kalashnikov Design Bureau, have people who are smarter than me and smarter than them.. So I don't presume to change their dimensions without really good reason and careful thought. I learn the specs so that with each part I can determine "in spec" or "not in spec". I am not a brilliant artist or designer.. I am simply an educated and experienced technician. And so I do not randomly file part A to fit part B. I measure part A, and part B, and determine they are both correct. Which then leads me to part C, which I learn was designed to be adjusted. And so I adjust it, and now part A and B fit perfectly. 90% of the people out there are too lazy or stupid to learn "in spec" and "not in spec" so they start randomly filing away, chasing symptoms and ruining guns. Me - I just read the books. So I can do it "right" - and there is "right" and "wrong" and there is not "equally viable alternative". And because I do it the Kalashnikov way, and not "my way", the guns work every time and people begin to think I'm some kind of magician. No - I JUST FOLLOW DIRECTIONS. And - gratuitous plug - I've taken all the armorer manuals from several countries, plus my own experience, and combined them into an 8 hour DVD set and 200 page shop manual, that I am offering for sale. Just e-mail me. |
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Mr Graham,
Your statement- "I can see that if the carrier is not hitting the trunion, then adding the buffer will make it hit the trunion (albeit with the buffer in between) so it is dubious as to whether its really any help. But I just can't see where it hurts" This statement had a lot of very interesting points. I finally understand buffers purpose/function now, thank you. I installed buffer tech recoil buffer when my A47 SGL-20 was new, thinking it needed it. Ran thousands of rounds no malfunction. After reading your explanation on buffers, I thought, why didnt Arsenal Las Vegas or , for that matter Mr Kalashnikov install a buffer? Not needed as my gun is in spec I presume. I took my buffer tech out after reading your post today. As you stated " then adding the buffer will make it hit the trunion (albeit with the buffer in between) " Yes, thats about the thickness of the buffer, to fill the gap in rearward travel (as seen in video below). Although you said " I just can't see where it hurts" If the gap is filled by buffer, wouldnt the force of the carrier hitting the rear trunion be the same as hitting it with a rubber hammer each shot, eventually loosening rear trunion?? Im not at all saying this in a negative way, I hope its not perceived as such. This video shows the AK recoil without dust cover(no buffer). The carrier comes about an inch +/- from rear trunnion from what I can see. Truly an AK in spec barely, if at all , hits the rear trunnion very hard. * Looks as if the rear sight block is the place where a buffer would be needed as seen in video- front of carrier hits it pretty hard. SLOW MOTION AK VIDEO LINK |
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In your video, the bolt carrier soes not seem to be striking the rear trunion. In some, it does.
In cases where the bc does not strike the trunion, the installation of a buffer will cause the carrier to impact the buffer and transmit through the buffer to the trunion. As you said, kindof like hitting it with a rubber mallet. But how hard is it getting hit. Is it enough to make any difference? The nature of the material - also used in automotive suspensions - is to dissipate the impact. Know anyone with an accelerometer? It would be interesting to test. Now in cases where the carrier is striking the trunion, the buffer will dissipate the impact. F = M x A, The carrier is decelerating at impact, but A will be increased by reducing the distance - less deceleration has occurred at impact. But even though F is increased (M is constant), it is dampened. Is the net result greater or lesser? I suspect that it is still less. What if one cut the buffer tech unit in half? Oh, and for the other part, I think you meant the front trunion, not the RSB, and yes, it does impact. The AK carrier impacts on the R side. Combined with the R rotation of the bolt and the R rifling, this created rotational force to the R. The piston above the axis of the bore imparted upward force on the muzzle. To counteract these somewhat, on the AKM, they added the slant brake and changed the bolt carrier impact to the left side. As for drilling and tapping the port - why? If it is oversize, weld it in and drill it the right size. |
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Mr Graham,
Thanks for the reply. The idea of cutting the buffer tech in half is a great idea. If I was to reinstall the buffer tech , i will hotknife it in half , as an experiment of such, if my carrier strikes the rear trunion too hard, next time I shoot it without it.( I suspect mine will not strike, hopefully) I did inspect the buffer tech and it has a circular slight imprint on the bottom from carrier. I suspect this is from me hand cycling carrier after lubing to distribute the lube , re-assembly, etc. As you explained the buffer will dissipate the impact, carrier on buffer is better than carrier on rear trunion directly. I understand now."I suspect that it is still less" Thank you for sharing your knowledge and ideas! |
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