Up to 60% Off Daily Deal Products. Palmetto State Armory
The Ultimate Gun Belt, US Made, Lifetime Warranty, Free Shipping. Shop Now.
Gorilla Ammo Free Shipping when you order 10 Boxes or more.
Shop all the current Lone Wolf closeouts here

Go Back   The AK Files Forums > General Forums > Gunsmithing & Build It Yourself

Notices

Reply
 
Thread Tools
Old 07-14-2018, 09:41 PM   #1
timhogan427
I am the one who knocks!
 
timhogan427's Avatar
 
AKaholic #: 178465
Join Date: Jan 2015
Location: morrow/cinci, ohio
Posts: 5,109
Default gas port size on 11" barrel

i had a mishap today. i noticed my 762x39 galil gas block was canted. so my dumbass tried to press it off this afternoon. i forgot it was seized. i tried heat too. basically the barrel bent when i whacked the press with hammer. IT WENT BOING! CRASH! it bent in front of the block about 25 degrees! grrrrrrrrr. then i was like wait, PISTOL! i ended up slitting the block and saw the barrel had galled going on due to a raised area in the block. long story short i am the proud new owner of an 11" barrel x39 galil pistol with a 4" shortened piston and shortened tube. good thing i have a lathe and welder! i left on just enough room to allow my handguard retainer to move to get the guard on. its all assembled and i like it better as a pistol actually! will paint it again tomorrow.

so, what gas port size do i run? 11" barrel and the block is about 1.5" from the muzzle
timhogan427 is online now   Reply With Quote
Old 07-14-2018, 09:43 PM   #2
1biggun
Curio & Relic
 
AKaholic #: 6541
Join Date: Sep 2006
Posts: 6,504
Default

the 12.5 AMD 65 is the same size as a AKM what ever that is . I dont have my note book here .

Ill hold off on commenting on your painful screw up LOL
1biggun is online now   Reply With Quote
Old 07-14-2018, 09:46 PM   #3
timhogan427
I am the one who knocks!
 
timhogan427's Avatar
 
AKaholic #: 178465
Join Date: Jan 2015
Location: morrow/cinci, ohio
Posts: 5,109
Default

dont care, its cool as a pistol. first bent barrel ever. my god that somebitch was tighter than a ticks ass, it wouldnt move more than half way. my press bed shifted or spread part when i hit the top of the press. so 1/8"?
timhogan427 is online now   Reply With Quote
Old 07-14-2018, 09:56 PM   #4
MIG*7.62
Curio & Relic
 
AKaholic #: 192572
Join Date: Apr 2017
Location: Shop or Lake
Posts: 2,416
Default

Pistol build I just posted other day is 11-3/8" with a 7/64 port, runs like a top and not overgassed/undergassed at all.

Course im running a booster so maybe a hair bigger for you.

This one http://www.akfiles.com/forums/showpo...32&postcount=1

Port distance from muzzle changes things a bit too

Last edited by MIG*7.62; 07-14-2018 at 10:01 PM.
MIG*7.62 is online now   Reply With Quote
Old 07-14-2018, 09:58 PM   #5
timhogan427
I am the one who knocks!
 
timhogan427's Avatar
 
AKaholic #: 178465
Join Date: Jan 2015
Location: morrow/cinci, ohio
Posts: 5,109
Default

may do 109 to start, then work up to 1/8" if it short cycles.
timhogan427 is online now   Reply With Quote
Old 07-14-2018, 10:21 PM   #6
MIG*7.62
Curio & Relic
 
AKaholic #: 192572
Join Date: Apr 2017
Location: Shop or Lake
Posts: 2,416
Default

Cool, pics of new pistol when finished
MIG*7.62 is online now   Reply With Quote
Old 07-14-2018, 10:48 PM   #7
1biggun
Curio & Relic
 
AKaholic #: 6541
Join Date: Sep 2006
Posts: 6,504
Default

Quote:
Originally Posted by timhogan427 View Post
dont care, its cool as a pistol. first bent barrel ever. my god that somebitch was tighter than a ticks ass, it wouldnt move more than half way. my press bed shifted or spread part when i hit the top of the press. so 1/8"?
yea some times tight things dont like to reverse direction .

I about destroyed a GB once as well . It got a little thight and I said oh no and it got a lot tighter going the other way .

Id start a little small if you can like suggested above .
1biggun is online now   Reply With Quote
Old 07-15-2018, 01:57 AM   #8
islandfocus2
Guns & Coffee
Contributor
 
islandfocus2's Avatar
 
AKaholic #: 159575
Join Date: Dec 2011
Location: United States, Bellingham, WA
Posts: 8,039
Default

I used a #30 drill bit for the 11” barrel AK pistol that I just built. Shoots great!

islandfocus2 is online now   Reply With Quote
Old 07-15-2018, 08:34 AM   #9
timhogan427
I am the one who knocks!
 
timhogan427's Avatar
 
AKaholic #: 178465
Join Date: Jan 2015
Location: morrow/cinci, ohio
Posts: 5,109
Default

thanks
timhogan427 is online now   Reply With Quote
Old 07-17-2018, 04:35 PM   #10
T_AZ-AK_BOY
Member
 
AKaholic #: 183899
Join Date: Jan 2016
Location: Queen Creek, Arizona
Posts: 158
Default

In all of my AKM barrel stubs I have Russian, Hungarian, East German, and Romanian all the gas ports a (.1495)#25 drill will fit in them perfectly which makes me think they used a 3.8mm drill on Original AKM barrels after assembly. On milled AK barrels I’ve had an (.1719) 11/64 drill will fit in perfectly. That’s quite big for a gas port on a 7.62x39 AK. The Russians must’ve though we don’t need a gas port that large for the AKM. On AK’s that have a gas block that’s not 90 degrees I use a drill that perfectly fits in the gas port hole as my drill bit size to use. I found starting the gas port hole with a #25 drill get a good spot drill divot then use a smaller size drill to finish the hole. I’ve had little to no tool breakage using that method. I’m not a fan of drilling gas port holes I’ve broken tons of drills doing that operation before I started using that other method I just mentioned having the hole “spot drilled” with a drill that fits perfectly in th has block hole.
T_AZ-AK_BOY is offline   Reply With Quote
Old 07-17-2018, 04:50 PM   #11
timhogan427
I am the one who knocks!
 
timhogan427's Avatar
 
AKaholic #: 178465
Join Date: Jan 2015
Location: morrow/cinci, ohio
Posts: 5,109
Default

i just did mine 1/8" to start. it should ok as is. the piston fits really well in the block. before the port drilling, it would develop a suction almost. i could hear it when dry cycling. plus drilling with fast speed with a hand drill is as its breaking through is the only way i do it. let off when the bit feels funny, thats it breaking through, increase speed and reduce pressure considerably. i never messed with spot drilling. never needed that extra step. dont know if i matters for cycling, but i ported my tube with 6 2.5mm ports total in the front like it was before i shortened it. it may just keep my action a tad cleaner. i think thats what those are for, venting excessive gas.

Last edited by timhogan427; 07-17-2018 at 07:44 PM.
timhogan427 is online now   Reply With Quote
Old 07-22-2018, 06:19 AM   #12
timhogan427
I am the one who knocks!
 
timhogan427's Avatar
 
AKaholic #: 178465
Join Date: Jan 2015
Location: morrow/cinci, ohio
Posts: 5,109
Default

well 1/8" is too small. almost comes back far enough. i got pissed and went to 4mm. gas block seals perfect. piston fit is very nice. headspace is spot on. ill find out this morning if its big enough. off to the range at 10am
timhogan427 is online now   Reply With Quote
Old 07-22-2018, 07:54 AM   #13
marktc223
Veteran Member
Bronze Contributor
 
marktc223's Avatar
 
AKaholic #: 156271
Join Date: Feb 2011
Location: USA, Florida, Largo
Posts: 1,288
Default

Are you using a muzzle device? A muzzle device, depending on what type/model, will increase gas pressure through the gas port.
Also, if you were ever considering the use of a suppressor, that increases the gas pressure considerably.
__________________
01 FFL Dealer/Gunsmith 45+ years
My company motto: "Quality is the Best Policy"
marktc223 is offline   Reply With Quote
Old 07-22-2018, 08:11 AM   #14
timhogan427
I am the one who knocks!
 
timhogan427's Avatar
 
AKaholic #: 178465
Join Date: Jan 2015
Location: morrow/cinci, ohio
Posts: 5,109
Default

Just the stock galil hider. I don't want a booster on this. If I have to, I will. But the galil Mar and ace doesn't use one, so I won't either. The port was just way too small. I'll find out soon enough shortly
timhogan427 is online now   Reply With Quote
Old 07-22-2018, 12:51 PM   #15
timhogan427
I am the one who knocks!
 
timhogan427's Avatar
 
AKaholic #: 178465
Join Date: Jan 2015
Location: morrow/cinci, ohio
Posts: 5,109
Default

It shoots fine now. 4mm was it. Big fireball. Boom. I brought 5 guns in 2 huge cases to the range. After going through my first mag, I turned around and saw 3 grown men huddled around a window starring at me hard like a teenager watching their first porno. It was like something out of a cartoon. They were pretty entertained to see 5 different ak variants lol. Needless to say they were all over my stuff when I was done. It made me feel good.

Last edited by timhogan427; 07-22-2018 at 04:05 PM.
timhogan427 is online now   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -4. The time now is 09:24 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
©1998-2018 The AK FIles