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Starting a guide rod build.....

5K views 61 replies 9 participants last post by  gwailo 
#1 ·
Okay so i finally cleaned out some more junk bins. found a 7 inch romy chrome bbl i had from a disastrous learning experience from years ago. figured id try my hand at being a human lathe and turning it down to fit a Bulgarian gas block.

......aaaaaand i did it.


Put it in an AMD trunnion and headspace..


GO!


No-Go..


and im using a polish 80% blank.


and that is as far as i have gotten today. I have been reading and reading and reading on guide rod builds, and still have some questions...

1. Do i need to drill through the gas block? or just drill an indent so to speak for the guide rod to rest in?

If anyone could post some pictures of the internals of their own, and how the rod attaches, where the spring goes, etc, i would REALLY appreciate it!!!!

More to follow. going to get a pistol trunnion from AK-builder for the back part. still throwing some ideas around. Thanks all!:)
 
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#27 ·
That looks like it'd work. I like that idea too. I have a bunch of aluminium rails, no steel ones so i cant weld any to it, but I want to 'bolt' a section of picatinny rail to the top of the RSB section i cut up. It has about 1/8-1/4" of clearance between it and and the bolt carrier. It cleared the line of sight of the HK ring sight on there. So, still playing around. anyone got a small section of metal/steel section of picatinny rail? :)
 
#28 ·
Played around a little more this morning. turned the end of the bbl down a bit more with a bench grinder and a file, enough to get a die on it.








Put a fake silencer on it from AK-builder to test the threads.. threadin' worked!


Now after the kids go down for a nap i'm either going to get started on working the modded RSB, or try some other options. maybe even say what the hell and see what the tide looks like and go catch another dinner, last night's was taaaasty!

 
#34 ·
BF,

dont want to sidetrack his build thread but what made you think gas escaped everywhere was wrong?

its supposed to escape everywhere the second that the action is initiated.. these are impulse driven system....

so as long as the gas isnt going out the guide rod hole in the front then its escaping exactly as it should.

depending on your length that should be at teh front site base, or thru the FSB or thru the edge of the gas block.

the only thing you DONT want is all the gas escaping back into the top cover area as lots of people make this mistake and it leads to crap in yoru face and top cover in your face.


another question in this thread was on gas port size:

on my super shorty AK's 47's my gas port is .1875 this is a major size port and you only need it for the 3" and smaller barrel as gas port is 2mm from the end of the barrel so it HAS to be bigger at this length.

on the 1" & 3" ak74's? my gas port is .1406 & .1250 respectively to length.

these function flawlessly when you have it all in line and a smooth flow with no rough edges.
 
#31 ·
Found a piece of 1/2" iron pipe. ID was a bit tight, so i used a dremel and some crafty drill bit work to open it up. stepped the end at the gas block, measured, filed and welded it to the piece of RSB i used. Im hoping this will help minimize gas leakage when firing. also thinking of making some kind of 'telescoping/sectional' guide rod, so that i can close up the hole in the gas block by plugging it with a section of rod, that will stick out far enough for a shorter piece t meet up with it from the dust over retaining button. that way no gas is lossed out the GB. Still a work in progress, ideas coming and going... Fun to tinker tho!





Put the barrel section on after cleaning up the welds (sort of)





Mocked up, no lower rails, no rear trunnion, no FCG holes yet.







Enough for today, took the kids to the beach, worn out. Time for a beer and some Shade :)
 
#32 ·
hmmmmmmm I sure would not have put that amount of hear on the trunion. that barrel pin holds as much thrust as the lugs an there is likely no way the teamper is not changed significantly. others will disagree but i simply will not weld on a truion.

I hate to say it but I honestly would be concerned with the safety of it.
 
#33 ·
Looking good Posthumous!!!! Keep the pics/reports coming.
 
#35 ·
another question in this thread was on gas port size:

on my super shorty AK's 47's my gas port is .1875 this is a major size port and you only need it for the 3" and smaller barrel as gas port is 2mm from the end of the barrel so it HAS to be bigger at this length.

on the 1" & 3" ak74's? my gas port is .1406 & .1250 respectively to length.

these function flawlessly when you have it all in line and a smooth flow with no rough edges.
good to know on the port sizes. an that is a huge port .
 
#36 ·
lmao........ you must mean on the 47 version... hee hee it is a huge port... BUT as i said its ONLY 2MM from the end of the barrel.. so it has to be that big to get anything up thru it as we are talking micro seconds of gas being there.

if you have a longer barrel then you can go back to the standard size as it gets some back pressure. :)
 
#38 ·
A 90 DEGREE BLOCK WILL ALLOW THE PORT TO BE FURTHER BACK FROM THE MUZZEL.

I GUESS WITH SOIMEHTING LIKE THIS IT REALLY DOSENT MATTER AS LONG AS IT CYCLES AN THERE IS NOT LEAD COMING OUT THE PORT. LOL

NOT SURE IF MOVING THE PORT BACK A 1/2" WILL ALLOW A SMALLER PORT. IMO THE LESS GAS COMING BACK AT YOU THE BETTER.

IM LOOIKING AT MY PILE AN TRYING DECIDE IF I REALLY WANT ONE OF THESE. WITH PARTS WHAT THEY ARE THESE DAYS IS NOT SUPER CHEAP ANY MORE. I SHOULD HAVE BOUGHT MORE OF THOSE RUSTY KITS BACK IN THE DAY FOR $45. IM THINKING IF IO DO ONE IT WILL BE A 223 OR SOMETHING MADE FROM 223 BRASS. THAT WAY I CAN USE MY MANY FIRED VARMINT CASES UP IN IT AN NOT WORRY ABOUT SAVING THEM.

HAS ANY ONE TRIED A FASTER POWDER IN ONE OF THESE REALLY SHORT BUILDS???
i RELIZE MOST DONT RELOAD FOR THESE. SEEMS LIKE A FAST PISTOL POWDER MIGHT WORK BETTER WITH A 3" BARREL.

THE 7.62X39 USES A PRETTY FASST POWDER ALREADY. IM WONDERING HOW MUCH PRESSURE A 3" BARREL IS MAKING?? ID THINK GOING BLUE DOT OR SOME OF THE OTHER SLIGHTY FASTER POWDERS MIGHT WORK. THERE ARE 357 LOADS THAT USE 4227 THE SAME POWDER AS THE X39.
 
#39 ·
1bg: im not a reload guy... but what ive found out is that the x39 3" barrel set up doesnt leave near as much unburned powder as the 5.45 does.. you'll find unburned/ignited powder in the flashhider area and all over the place in the 5.45 builds.

and if you look at my video you'll see that there is lots of it flying past your head and everywhere else.

something you mentioned that i didnt touch on... i make very sure that there are no burs or edges on my gas port hole and also use a very small ball end bit on my rotozip to kamfer that edge a little. :)

while i wouldnt hesitate to shoot an intruder with one of these, they really serve no purpose other than to say you can and for the ooooohs & ahhhhs that people give when you roll one of these out with a drum on it.

sdk
 
#40 ·
while i wouldnt hesitate to shoot an intruder with one of these, they really serve no purpose other than to say you can and for the ooooohs & ahhhhs that people give when you roll one of these out with a drum on it.

Shoot, im just making one in the hopes that one day i can do the "sliding sideways on a motorcycle pulling the super short AK from a keg holster and spraying zombies and anything else in the way before lobbing a molotov at them and speeding off again" thing.

I need to rework the piston on mine. thinking about basically extending the carrier a bit in that area and blocking it off with a piece of round stock, (drilled for guide rod) and going that route, vice using an actual piston.

Like 1bg said tho, im just using 'scrap' pieces from around to finish this. Its a hobby build of convenience, not something im investing a ton of money on!
 
#41 ·
I SEE NO REASON THAT THE GAS BLOCK COULD NOT BE EXTENED AN HAVE THE SHORT TUBE AS PERMINATE WELDED PART. I SEE NO REASON TO REALLY EVEN NEED A RSB OR ON THE BARREL OR ATTACHED TO THE TRUNION. THE GB IS CAPIABLE OF SUPPORTING A SHORT TUBE LIKE THIS.

THE X39 HAS A PRETTY FAST WORDER AS IS AN THAT LIKELY ACCOUNTS FOR LESS UNBURNED POWDER VS A 5.45 AN LIKELY A 223.

I STILL THINK A FASTER POWDER WOULD BE OF BENIFIT IF YOU HAND LOAD. ANY POWDER THAT IS NOT BURIONG IS SIMPLY WASTED POWDER. imo BETTER TO HAVE IT ALL BURN AS IN A PISTOL TYPE POWDER.

THE DOWN SIDE IS THOSE HAND LOADS MIGHT BE PRETTY DANGERIOUS IN A LONGER BARREL AN IT WOULD BE SUPER EASY TO MIX SOME UP.

IM LOOKING AT THE 357 AR ROUND THAT WOULD USE CUT 223 BRASS AN WOULD NOT FIT ANY OTHER GUN. CAST LEAD BULLETS WOULD BE REALLY DOABLE HERE. iD OVE TO CRONY ONE OF THESE AN SEE HAT ITS REALLY DOING ???? I WONDER IF A 3" build in 7.62x39 is faster than a 7.62x25 tokerov round in a 6" barrel ??????
 
#42 ·
im also wondering if the gasses from a muzzel break could also not be channeld into the rsb some how to reduce port size????? might also quite the gun some ntot sure the legalitys. a muzzel device desigend to cycle the gun might be cionsidered a supressor if it were to quiet the gun. then again if it part of the design to makle it work its not there to suppress. Im jsut thinking most guys but some sor tof zombie killing muzzel devive ont he gun. why not make it direct gas to help make it cycle?????? I looked at the idea ona accuracy build but never tried any thing.
 
#43 ·
ANYTHING that changes or influences the sound can be called a suppressor IF THEY WANT IT TO......

been there, done that, had that conversation before. thats all about if they need justification to snag you. if they do? that would be a suppressor. :)

one thing i want to tell you is to not worry about the port size, its no problem at all... there are lots of builds out there that have larger ports than this.

the port size is only like this due to its location and lack of barrel after the port for the pressure to do its job.

think of it this way:

1" snub nose saturday nite special..... except that its in a semi auto with a drum! :)

essentially we are just making snub nose assault weapons, not something these were never designed to do or be.
 
#45 ·
oh this is where i bow out of the conversation. LMAO....

my visit went well, but other people on this board and WG did not fair so good. your really at the mercy of the inspector & what THEIR interpretation of the law is pertaining to you at the instant they are at your place.

if ya need any help on the build give me a yell.
 
#46 · (Edited)
Ok... had some more time today.

Got the dust cover latch and guide rod itself welded and in place:


Fitted some of the spring, will most likely need to trim some more coils, but for now it works:


And with a set of digital calipers, a drill, some schematics, and my MkI Eyeball...



Ooohhh that lined up nice didnt it??? I would like to thank the metal band "Nightwish", and their cover of the 1989 hit single, "Where were you last night?", which got stuck on repeat for about 5 beers.

Still needs the lower rails, FCG holes to be heat treated, and the center support rivet... but its looking like it wants to go bang eventually! woo!



Edit: I approve of this, my 1, 000th post on Gunco!! CHEERS!
 
#48 ·
oh this is where i bow out of the conversation. LMAO....

my visit went well, but other people on this board and WG did not fair so good. your really at the mercy of the inspector & what THEIR interpretation of the law is pertaining to you at the instant they are at your place.

if ya need any help on the build give me a yell.
I HOPE I DIDNT CAUSE THIS ????? I WAS BEING A SMART ASS ABOUT THE 100 PORT GB LOL. I HAVE NO INTENTION OF MESSING WITH THE ATF.
 
#49 ·
Dude when do u suppose some one will cut one off at the trunion
I HAVE SEEN THEM SHORTER THAN THIS . LITTERALY THE BULLET WAS ALMOST STICKING OUT OF THE BARREL. A BLOW BACK IN PISTOL CALIBUR COULD BE SHORTER YET IF YOU MOVE THE BREACH BACK A INCH OR SO ALONG WITH THE TRUNION . I INITALY HAD PLANNED A GUIDE ROD 7.62X25 WITH HOME MADE TRUNION AN BOLT/CARRIER THE RECIVER WOULD HAVE BEEN AT LEAST 2" SHORTER MAY BE MORE. WHEN AMMO GOT SCARCE AN THEN DOUBLED IN PRICE I HELD OFF. DECIDED TO SAVE HWAT i HAD FOR MY M76 YUGO TOKEROVS .
 
#50 ·
look at my super shorty ak74s' there is literally 1" of rifling on these and they are still a closed bolt standard issue lock system...

without the flash hider on the end you can definitely SEE the bullet..... if you want to look in the end of a loaded gun... lmao
 

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#52 ·
The part of the RSB there is where it would be on a normal build setup. I have the steel pipe going from it to the gasblack, so there is no gap between the RSB section and the trunnion.

Basically, square RSB, round pipe for gastube. Welded all the way around where they meet, to make it one piece with no gaps. the pipe and gas block are not joined, i just fitted the pipe to the proper length so that when the barrel was pressed in, it would mate up like a regular gastube and gasblock would.

I see you just slid the rsb back. how do you fill in the gap were the dust cover dosent reach the truninon. do you just notch the dust cover ???
 
#55 ·
so jumping a ahead a little bit.. what you planning on doing for your forward handgaurd? or are you gonna have one?
 
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