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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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#6 ·
all my guide rod builds are posted here at GUNCO....

i do drill thru the gas block housing.. & i leave that hole as tight as possible so that you dont loose gas out the front.

i keep the rod as short as i can so that my forward travel to release it usually stops at the end of the front site.

the most important thing here is being on center in drilling the piston, the gas block and then installing the rod to the rear nub.
 
#7 ·
does it even need a guide rod???? looks like it might be long enough for just a slight trim of the csrrier an a piston weLded to the carrier. you said the barrel was 7" is it now???

Ditigaf is the guy in these he can likely tell you what will an will not work.

SO HOW SHORT CAN A BARREL BE AN STILL RUN A PISTON AN NO GUIDE ROD??

WHAT ABOUT A ROD WITH A THIN BUSHUN ON IT THAT GOES INTO THE gb BUT DISENT NEED TO GO THROUGH???? JUST GET IT BEHIND THE PORT ???? NOT SURE IF IT WOULD BE ANY BETTER BUT YOU WOULD NOT NEED TO DRILL A gb THAT WAY.

TO DRILL THE GB CENTERED MAKE A BUSHING WITH A HOLE TO CENTER THE BIT.

IM GOING TO BUILD ONE OF THESE SOME DAY. LIKELY A 7.62X25 OR 9MM I ALWAYS LOOK CLOSE AT THESE BUILDS.

I HAVE A FEW PARTS LAYING HERE MY SELF FOR SUCH A DEAL :)
 
#9 ·
cut down to 5" now. Im experimenting with alternatives to a guide rod or having to drill through things.

the rod is there to keep the carrier on track as it travels rearward after the shot, and back into place on the way forward. There is no RSB on this, so im thinking out loud here....but what about making a 'guide groove' so to speak, cut or grind a slot for the needed length on the top of the carrier, and using say... a piece of cast iron gas pipe, halved and welded to the top of the trunnion, weld something to that, that would rest in the groove/slot on the carrier, but fit under the dust cover? it would keep the carrier and piston in line during travel.

have to go play in the garage more this weekend, see what i can come up with.
 
#10 ·
I have had a few ideas in the past but all of them were likely harder than a gude rod/ the hole drilling should be pretty simple just drill out the piston for the carrier before hand. make a drill pit guide for the RSB an use the rod to dictate were the hole inthe recoil assembly anchor would need to go. I think all that other stuff would not bea s good as a simple rod an three holes drilled.

just a custom dust cover keeping every thin in place with close tollerances would likey work. Or a sloted cover an a tab weded to the carrer would possably work. you would have to make some mods to the cover . maybe make it hinge an be attached more securaly in the rear. I envisioned milled cover that attached on a hinge on an extended barrel pin an m70 type locking system in the rear. a slot miled intot he cover as well as the rail attached to he cover. a tap or gude welded tot he top of the csarrer to goi inot the cover/ rail. I dont see how the thing could move. just thinking out loud here. A guide rod is simple an works .
 
#12 ·
couple of things to throw in for you....

ive done tons of 9" builds with no guide rod and no problem.

its all about the cycle distance and keeping it all on track. if the stroke is long enough to get the round on the boltface while keeping the piston in the FSB housing??

then you dont need a guide rod.

ive never done 7" builds..

my builds go from 9" and drop right to 5" & then 3" & 1"

but there are several different set up s for this & yes you could use a denial bar style set up in the top cover to keep it all in line.

only reason i never went this route was the covers are so thin and they have a lot of variance in them in there with the spring wanting to ride up and so on..

when i drill the gas block from the front i actually do it with the piston on the carrier and a dummy round locked into the barrel..

so it IS where its gonna be. this is the poor mans way of guaranteeing your alignment.

lots of your super machinists will measure and measure and measure.... but all you really need to do is have it where its gonna be and then keep the holes tight.
 
#13 ·
once i drilled the piston i left it on the drillbit and used that to center the bit in the gasblock. If you find another way to guide the bolt you still need a guide for the spring
brilliant on the piston to align the hole an DUHHHHH why didnt I think of that.

good point onthe spring. I was up all night one time thinking of ways to move the pistion to one side as well as the reciol spring an asssmble to bea ble to get a scope lowere to the barrel. I hade idea like springs in a AR buffer tube lower down a GB with a carge bar running onthe LH side. dust cover guides for more consistant bolt lock up for accuracy issues an every thig in between. I ende dup designng a m14 oit of it at one point an even considered gas impengment. then I woke up an said screw it KISS. It works good like it is. Id still like the cneter to the piston an the center of the bare closer together. i even had a idea fore a circular piston that went around the barrel an used the barrel to guide it an a gas tube tht went arong the barrel an the pistion an worked as a forend /tube like on a AR. a lot can be done.

THANKS FOR SHARING HOW YOU BUILD THESE WHEN MY TIME COMES ILL BE ASKIG YOU QUESTIONS SO i DONT HAE TO REINVENT THE WHEEL .

I HAVE 3.25" BARRELD BULGY 5.45X39 TRUNION SITTING HERE AN HAVE BEEN THINIKING WHAT CAN I DO WITH IT ????? LOL WANTED A 7.62X39 SO I COULD USE A DRUM ( YOU NEED A DRUM TO KILL ZOMBIES RIGHT )
 
#14 ·
lots of your super machinists will measure and measure and measure.... but all you really need to do is have it where its gonna be and then keep the holes tight.
__________________

VERY TRUE .

THEY SAY JOHN BROWNING COULD EYEBALL A PART HAVE A WORKER TAKE A MIC AN MEASURE BETWEEN IS FINGERS FOR THE SIZE WITH A MIC AN GO MAKE THE PART AN IT WOULD FIT.

THE HUMAN EYE IS A VERY PERCISION INSTRUMENT.

i DONT KNOW HOW AMY TIMES IM PUTTNG SOME THING INT HE MILLING MACHINE VICE AN LEVEL IT BY EYE AN WHEN A CHECK IT WOITH A DAIL INDICATER ILL BE .010 OVER 8" . IF IT DONLT LOOK RIGHT VERY OVFTEN IT IS.

A PERSON CAN SEE A PICTURE FRAM OFF BY LESS THAN A 1/16" ON ONE CORNER ON A TWO AN HALF FOOT FRAME. TRUST ME MY EX WIFE COULD. I REHUNG THAT DAMN THING 3 TIMES AN WHEN IT WAS WERE SHE SAID IT WAS PERFECT THE LEVEL AN EVEN THE LAZER LEVEL WAS DEAD ON. i ALIGN ALL MY BARREL PARTS BY EYE AND HAVE YET TO HAVE ANY NOTICABLE CANT.
 
#15 ·
now thats funny. my "current/only" wife is that way now! :)


on the stubs... the way people measure barrels throws a lot of these off.

do you have a 3" stub TOTAL or 3" of rifling? HUGE difference.

my ak74 pistol build in my avatar is done on a 3" STUB.. thats overall length! so thats about 1" of rifling. :)

ive got a tutorial on the design i came up with for that posted, but will help ya if ya got any questions.

sdk
 
#16 ·
do you have a 3" stub TOTAL or 3" of rifling? HUGE difference.
ITS JUST OVER 3" TOTAL LENGTH . GOOD POINT ON HOW LITTE LRIFLEING THERE IS MADE ME THINK SOME LOL.

I STARTED POKING AROUND AGAIN ON WEAPONS GUILD AN THERE IS SOME GOOD STUFF GOING ON THERE.

I WAS KIND OF THINKING OF DOING A CUSTOM MILLED ONE PIECE RSB/GB THAT MATCHED THE CONTURE OF THE DUST COVER SORT OF. MAYBE IN ALLUMINUM.

NOT SURE HOW ALLUMINUM WOULD LIKE HOT GAS OR A PISTON WEARING ON IT. MAYBE A SLEAVE FOR THE PISTON. AR GB,S ARE ALLOY SO IM THINKING THE PORT WILL BE OK.

I HAVE A FEW POLISH (CIRCLE 10 IS POLISH RIGHT) 5.45 FRONT ENDS WITH CUT BARRELS THAT ARE AROUND 3.25" WITH BOLTS AN CARRIERS .

I CAN EASLY DO ANY OTHER CALIBUR BUT WAS KIND OF EYEBALLING THEM FOR A FUN BUILD. ID LIKLEY HAVE ABOUT $100 IN THE WHOLE GUN .

WOULD BE A EASY BUILD IF USED AS IS JUST CUT STRAIGHT AN CROWNED .

ID RATHER DO A X39 BECAUSE IF IM GOING TO KILL ZOMBIES I WANT A DRUM AN A BRASS KNUCLE PISTOL GRIP AN A BAYONET ATTACHEMNET AN MAYBE A GERNADE LANCHER OR FLAIR GUN ON THE BOTTOM . OH YEA A LAZER AN A FLASH LIGHT WITH A RED DOT....

OK iM SERIOUS ABOUT THE RED DOT AN THE BRASS KNUCKLE GRIP lol

I HAVE A X39 REAMER SO I CAN MAKE WHAT EVER I NEED JUST LOOKING AT SIMPLE AN FAST.

WERE IS YOUR TUTORIAL ? i KNOW I HAVE SEEN IT.
 
#18 ·
ID RATHER DO A 7.62X25 IN BLOW BACK BUT ITS A LOT MORE WORK. I BOUGHT ALL THE TOOLING AN STUFF TO MAKE A BLOW BACK CARRIER FROM SCRATCH HAVE THE REAMER NEVER GOT IT DONE. SPENT ALL MY TIME MAKING BARRELS IN X25 FOR OTHERS. NOW AMMO IS SKY HIGH SO I HELD OFF.

I COULD LIKELY BUILD ONE OF THE 5.45X39S IN A DAY. OR A HOUR IF I WANTED TO DO A WELD BUILD ON A 100% RECIVER.

I WONT DO A WELD BUILD BUT I CAN SEE HOW YOU COULD TAKE A CUT BARREL KIT AN HAVE A PISTOL IN A HURRY. CUT THE CARRER ADD A GB DRILL A PORT MAKE A GUIDE. SOLDER OR WELD ALL THE STTACHMENTS ON. I DONT ROLL THAT WAY BUT IT WOULD BE A EASY CHEAP DOWN AN DORTY WAY TO MAKE A GUN GTHAT GOES BANG

NOW HERE IS A QUESTION OF THE STANDARD RIFLE ROUNDS 5.45, 5.56 OR 7.62 WHICH ONE IS THE BEST IN A 3" BARREL. I RELIZE THIS IS NOT GOING TO BE VERY ACCURATE. IM THINKING THE 223 ON 5.45 MIGHT HAVE LESS RECOIL AN BE MORE MANAGABLE?????? WAS THINKING THAT 357 AR ROUND ON CUT DOWN AN NECKED UP BRASS MIGHT BE A GOOD ROUND. A 223 WOULD BE THE CHEAPEST TO RELOAD. 5.45 THE CHEAPEST TO BUY OUT RIGHT. 7.62 EASEST TO BUILD FOR ME AN MAKES A BIGGER HOLE IN STUFF BUT MORE RECOIL . SCREW IT ILL GO 308 WIN LOL ;)

I HAVE A CHEAPO DUST COVER WITH A 22LR TYPE RAIL ON IT THAT WOULD WORK GOOD FOR HOLDING A RED DOT AS A SITE OR JUAT ADD IRONS TO IT.

IM ALSO WONDERING IF A GUY COULD GET ONE OF THESE TO CYCLE WITH A REDUCED LOAD SHOOTING CAST LEAD BULLETS??????? OR EVEN SUPPRESSED IF WITH SUBSONIC IF I EVER GET OFF MY ASS AN GET THE TAX FORM/STAMP.

SPEAKING OF WHICH HOW MUCH PORT DID A 7.62 NEED WITH A 3" BARREL AN HOW FAR BACK WAS IT????? ILL BE RUNNING A BREAK IF I DO THIS . MAYBE A BIG PORT AN A ADJUSTABLE BLOCK MIGHT BE A GOOD IDEA. I LIKE THE IDEA OF LEAD BULLETS IN ONE OF THESE. MAYBE LOAD WITH PISTOL POWDER TO GET AS MUCH VELOCITY AS POSSABLE FROMTHE SHORT BARREL.
 
#20 ·
Circle 10 is Bulgarian.

I cut the RSB up so it would still be usable as the dust cover retainer in the front, and cover the guide rod/piston between the cover and the gas block. I will post some more pictures of the build progress as i go along, too.

Wont have much time in the garage for a month or so. Having a 'procedure' that a grown up will have when both he and his wife have the amount of kids they want, and dont want any more. Wish me luck. Any advice from those that have gone before?
 
#21 ·
some how I got it in my head they were polish . likely becasue my polish hunter build.

I have a reciver sitting at a FFL I might just do a quicky screw build on in 7.62x39 as that what the ejector tip will be length wise. I can always unscrew it an sell it as a pistol kit if i dont like it or need the reciver.

I was thinking I could make a simple block to house the tube an GB front sight all in one piece. basicaly just need three holes bored into it one not clear through. I have stainless tubing that fits a piston perfect press the tube in the hole an a allen or pin to hold it an add piece on the rear to take the dust cover. should be pretty simple. maybe even make the bottem of it a integeral hand guard/ finger stop. I would not need to buy a rsb, gb or a front sigth block or a gas tube. an I could go aluminum to reduce some weight. Just thinking out loud.
 
#22 ·
Having a 'procedure' that a grown up will have when both he and his wife have the amount of kids they want, and dont want any more. Wish me luck. Any advice from those that have gone before?
i hear the recover time is not to bad. had a buddy do that . I went with the divorce meathod it was only $300,000 an has about a 25 year recovery time. condoms are $5 a dozen LOL
 
#24 ·
I like the sight idea.

if I do one its getting a LH charge handel so i can hold it in my right an an contrl it as I charge it.

what about cutting away most of the front of the RSB so just the dust cover has a place to go???????? I keep thinking you dont need the rsb. I have a 223 galil tube I was looking at to try to get on a standard trunion.
 
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