bubbamauser Posted May 27, 2006 Report Share Posted May 27, 2006 Does anybody have .308 semi barrel chamber dimensions available. I need a few dimensions to see if a yugo AK barrel has enough meat to rechamber to .308 Thanks in advance Link to comment Share on other sites More sharing options...
tomme boy Posted May 27, 2006 Report Share Posted May 27, 2006 Does anybody have .308 semi barrel chamber dimensions available. I need a few dimensions to see if a yugo AK barrel has enough meat to rechamber to .308 Thanks in advance Are you planning on using the 7.62x39 barrel to do this? And are you going to use this in an AK? If you are, the 308 AK's have a 3rd locking lug on the bolt and they also use the RPK trunnion because of the greater mass of the trunnion. A friend of mine already did this, but he started with a 308 Saiga. The swapped out the barrel with a straight fully chambered blank from Shaw. He then turned it down to the contour of a original RPK barrel and faced the chamber end to HS it. Here is a pic of it. It is on the green tarp in the middle.it is not a very good pic. Link to comment Share on other sites More sharing options...
bubbamauser Posted May 27, 2006 Author Report Share Posted May 27, 2006 The 8mm yugos use the same bolt as the m70 yugos (what I'm using) the 308 galils use 2 lugs too. The yugo m70 lugs are a lot thicker than romanian ones Link to comment Share on other sites More sharing options...
sonic1 Posted May 28, 2006 Report Share Posted May 28, 2006 go to clymer reamers and look up .308 win. http://www.clymertool.com/cgi-bin/reamer.cgi or here http://www.reloadbench.com/cartspec.html Link to comment Share on other sites More sharing options...
bubbamauser Posted May 28, 2006 Author Report Share Posted May 28, 2006 I probably worded it wrong but I meant how much steel should be left around the case in the chamber area after its reamed to withstand the pressure. Thanks, Roy Link to comment Share on other sites More sharing options...
sonic1 Posted May 28, 2006 Report Share Posted May 28, 2006 roy the yugo barrel shank is .910 ..so you get into the same question as the small ring turk mag. just what is safe.. many small shank rifles chambered in .308 and there threaded as were the ak is pinned... if you only shot nato .308 it would slightly safer because of the lower pressure... sounds like another test gun. Link to comment Share on other sites More sharing options...
tomme boy Posted May 28, 2006 Report Share Posted May 28, 2006 The M75 8mm uses a larger and longer trunnion to encase the barrel of the 8mm round. The 39mm barrel is not going to have enough meat around the barrel to safely handle the 308. The barrel stepps off too fast to a smaller diameter for the 308. When you run a reamer into the 39 chamber, you are probaly going to run right into the pin to lock the barrel. Hence the larger trunnion, and barrel diameter. Does the Yugo use the longer RPK rec.? You are going to need this as the 308 round is too long to work out of a normal AK rec. Also you will have to know what size of gas port to drill, and where to drill it. It takes some tricky math to get it drilled in the grove and not on the land. Link to comment Share on other sites More sharing options...
bubbamauser Posted May 29, 2006 Author Report Share Posted May 29, 2006 I'll take both of your suggestions on this one, no actual data on wether the bolt or trunion will take the pressure, and the barrel does follow the contour of the case (reduces in thickness at the case mouth) a little too close for me. I guess I'll be doing an AK pistol out of this one. (it is a dark bore yugo milled kit with a decent barrel) I just need to weld up the cut out for the g3 mag now. Thanks guys for the info Link to comment Share on other sites More sharing options...
R.Neumann Posted May 30, 2006 Report Share Posted May 30, 2006 Something I know about! I have been building aks for about a year now and I can say without a doubt that the yugo is a great donor for a 308 conversion. The problem with rechambering an original barrel as has been stated is that the barrel shank thins out too fast and the bore is .311 to begin with. However! The Yugo stamped kits use an RPK trunnion and it is plenty beefy to take the 308 round with a new barrel. It is a pretty simple rebarrel as well if you have a lathe to contour the barrel. You simply fully chamber your barrel and then press it in on top of a go guage that is placed in a bolt in the lugs. I have done this conversion 3 times and each one functions flawlessly. I would suggest going with a heavier recoil spring and a buffer though. Let me put the Caveat here. I have not done extensive pressure testing on this and I know a milled kit will be a pain in the buttox. You Will have to mill out the rear of the trunnion to accept the front of your new mag. I did this very slowly with a milling machine and I kept it cool. Some people say that this weakens the gun to the point of danger. I disagree because the part being milled does not even come close to touching the area around the barrel. This is the same trunnion that they use for the romanian FPK in 7.62x54r. Any other questions? Link to comment Share on other sites More sharing options...
tomme boy Posted May 30, 2006 Report Share Posted May 30, 2006 The 54R round opperates at 46K PSI. It is a low pressure round. I can't remember the PSI for the 308. I thought it was 58K or 62K PSI. That is a big jump on the pressure. That was why when my bud decided to do his, he went with the Saiga 308 as it was all ready proven. Link to comment Share on other sites More sharing options...
R.Neumann Posted May 30, 2006 Report Share Posted May 30, 2006 The 54R round opperates at 46K PSI. It is a low pressure round. I can't remember the PSI for the 308. I thought it was 58K or 62K PSI. That is a big jump on the pressure. That was why when my bud decided to do his, he went with the Saiga 308 as it was all ready proven. I built my conversions using a saiga 308 as a template. The trunnion and bolt is identical to my 308 saiga. minus a few wierd shaped cuts for m1a mags. I forgot to add here that the Saiga does indeed have a 3rd lug on the bolt. However I have noticed no contact wear between my 3rd lug and the trunnion. I BELIEVE it might be like a safety lug on a mauser 98 bolt. Just in case. You will have to open up the bolt face just a little to get a 308 round to chamber. so far as I know none of my conversions have gone kaboom. My personal gun has 500 rounds SA surplus through it with no problems or signs of stress. I have a wilson combat barrel that is real nice that I am going to build. I might do a step by step of the process with pics. I plan to make the parts needed to keep it an actual heavy barrel. Link to comment Share on other sites More sharing options...
bubbamauser Posted June 2, 2006 Author Report Share Posted June 2, 2006 I may give this a go with the stamped kit, I aready decided to turn this one into a pistol, I made a sheetmetal receiver (home depot) and copied the rails but set the ejector back farther. I hope it will still eject the 7.62 russian. I bent it so the milled parts barrel trunion, rear trunnion are drilled and tapped in, I just need to fill the g3 size mag well back to normal Link to comment Share on other sites More sharing options...
Doble Troble Posted June 2, 2006 Report Share Posted June 2, 2006 What kind of accuracy are you guys getting out of these? These projects sound like a lot of fun (as if I need more fun). P.S. What is a trunion? R. Neumann - please do document your next project. For some reason I think I need an AK in 8 x 57, and If I could build one...maybe I could figure-out a way to actually have one (or maybe I can finally find a way to blow myself up which I haven't been successful yet with those darn, safe M98s...maybe my first one should be a 7.62x39...it might be really cool to make a wildcat in 6.5 x 39...). P.P.S. I think this thread is entirely 100% on topic. Link to comment Share on other sites More sharing options...
R.Neumann Posted June 2, 2006 Report Share Posted June 2, 2006 A trunnion is a milled piece that allows the barrel to be mated to the sheet metal receiver. It is held together with rivets. I have honestly been mulling over the 8x57 conversion. I am thinking mg13 mag for the feeding. 25 rounds of pain!. Please be careful when choosing a kit to work off. I would suggest ONLY using the Yugoslavian AB series of ak-47 as they have the 1.6 mil receiver and the heavy trunnion. The romanian kits will not handle the stress of firing a full rifle round. Also the barrel accessories are set up for a heavier barrel contour with the yugos. And the wood is teak! As to accuracy it depends. I built mine off a barrel that was originally on a mauser and had been used. I get 2-3 inches at 100 yards in semiauto fire. when I turn the gas valve off the group size drops slightly but then you have a bolt action anyway. Link to comment Share on other sites More sharing options...
Clemson Posted June 2, 2006 Report Share Posted June 2, 2006 I'll take both of your suggestions on this one, no actual data on wether the bolt or trunion will take the pressure, and the barrel does follow the contour of the case (reduces in thickness at the case mouth) a little too close for me. I guess I'll be doing an AK pistol out of this one. (it is a dark bore yugo milled kit with a decent barrel) I just need to weld up the cut out for the g3 mag now. Thanks guys for the info Just to keep you out of the pokey, bubbamauser, it is a Federal crime to turn a rifle into a pistol. You might want to rethink this one...... Clemson Link to comment Share on other sites More sharing options...
sonic1 Posted June 2, 2006 Report Share Posted June 2, 2006 well this really makes this off topic...but because the receiver he made from sheet metal is a new receiver that was never a rifle...it is legal to make it a pistol... once the mil.surp rifle was cutup it is no longer a gun only parts and because its a pistol federal law 922r does not apply meaning it need not have any u.s made parts http://www.ar15.com/forums/topic.html?b=3&f=122&t=245366 Link to comment Share on other sites More sharing options...
bubbamauser Posted June 3, 2006 Author Report Share Posted June 3, 2006 Sonic is right, I can use any parts even from a rifle to make a pistol as long as I make the receiver , I am going to stamp it pistol just to be safe though even though its not required. also there cant be a way to attach a stock or a forward pistol grip on it. DT these are fun, just check out some of the ak boards to get compliance info, for one with a muzzle brake you would need 6 us made compliance parts. PM me if you wanted any of the info mailed over. Roy Link to comment Share on other sites More sharing options...
R.Neumann Posted June 3, 2006 Report Share Posted June 3, 2006 Hey Bubba I got good news for you. Sec 922r applies only to rifles my friend. You need NO compliance parts for a pistol build. You can use the original fire control group and everything. I suggest cutting off the disconnector though. Happy pistol building! I love making those flamethrowers. Link to comment Share on other sites More sharing options...
bubbamauser Posted June 4, 2006 Author Report Share Posted June 4, 2006 Thanks R. this will be my first pistol. I included the compliance info for DT just in case he will be doing a rifle. The first rifle I did I didn't know how many suppliers for the compliance parts were out there and ended up paying too much for parts that didn't look authentic, some of the cheaper guys out there's parts are pretty damn close to the originals and quality is nice. I'm still going to do one in .308 but I have one rifle that is "experimental" that I have to wait until I head up to my cabin in New York to test, next week. I don't want another one that has to sit for months until I go up again. Link to comment Share on other sites More sharing options...
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