User Panel
User Panel
User Panel
|
Posted: 5/11/2017 1:06:54 PM EDT
[#1]
I looked into doing this many years ago. That was the option suggested, w/ the addition of throwing a gas block on top so it couldn't back out.
|
|
|
|
Posted: 5/11/2017 1:10:59 PM EDT
[#2]
I've plugged gas ports in front sight bases for 22 builds with such screws. To do the barrel itself, just choose the correct length so it doesn't protrude into the bore and is sunk below the journal for the sight base.
The specific diameter of your gas port will determine which screw and threading to use. I used a #10 tap and screw on the gas tube hole of the sight block, but that's much bigger than your gas port is likely to be. #2 through #4 are likely candidates for plugging a gas port. |
|
|
|
Posted: 5/11/2017 1:40:40 PM EDT
[#3]
Quoted:
I have a unique barrel that I want to reuse in a blowback build and I need to plug the gas port. for a 22? no need to plug it, just leave or cut down a gas block |
|
|
|
Posted: 5/11/2017 1:41:41 PM EDT
[#4]
Quote HistoryQuoted:
I looked into doing this many years ago. That was the option suggested, w/ the addition of throwing a gas block on top so it couldn't back out. I was thinking to red loctite it. That's good for up to 550 deg. |
|
|
|
Posted: 5/11/2017 1:42:22 PM EDT
[#5]
Quote HistoryQuoted:
I've plugged gas ports in front sight bases for 22 builds with such screws. To do the barrel itself, just choose the correct length so it doesn't protrude into the bore and is sunk below the journal for the sight base. The specific diameter of your gas port will determine which screw and threading to use. I used a #10 tap and screw on the gas tube hole of the sight block, but that's much bigger than your gas port is likely to be. #2 through #4 are likely candidates for plugging a gas port. |
|
|
|
Posted: 5/11/2017 1:43:05 PM EDT
[#6]
Quote HistoryQuoted:
for a 22? no need to plug it, just leave or cut down a gas block |
|
|
|
Posted: 5/11/2017 1:47:37 PM EDT
[#7]
Quote HistoryQuoted:
What did you use to secure the grub screw, if anything? |
|
|
|
Posted: 5/11/2017 1:54:53 PM EDT
[#8]
Quote HistoryQuoted:
Since I was doing the gas block, I used a cap-head screw to both secure the handguard retainer and plug the port. It's just torqued on. that's a much better idea than a grub screw since it's under the handguard anyhow. thanks! Why make this hard on myself, DUH 
|
|
|
|
Posted: 5/11/2017 2:15:38 PM EDT
[#9]
I wouldn't feel comfortable threading and leaving a set screw in it. One with a head to keep it from creeping in maybe. I personally would just tig weld over it with maybe a er308 filler. If the barrel is thin at that point you could use a tight fitting piece of soft copper wire .1" longer than the bore diameter of the rifle inserted through the gas port before welding to keep the weld puddle from obstructing the bore. Then you could just drive the copper out of the barrel. Just watch your heat input and try to keep the heat affected zone to a minimum.
The easiest way would be just use a gas block or hose clamp over it though. |
|
|
|
Posted: 5/11/2017 2:31:31 PM EDT
[#10]
Quote HistoryQuoted:
I wouldn't feel comfortable threading and leaving a set screw in it. One with a head to keep it from creeping in maybe. I personally would just tig weld over it with maybe a er308 filler. If the barrel is thin at that point you could use a tight fitting piece of soft copper wire .1" longer than the bore diameter of the rifle inserted through the gas port before welding to keep the weld puddle from obstructing the bore. Then you could just drive the copper out of the barrel. Just watch your heat input and try to keep the heat affected zone to a minimum. The easiest way would be just use a gas block or hose clamp over it though. i think a button head screw torqued and loctited should do it fine. loctite goes to 550 deg. |
|
|
|
Posted: 5/11/2017 2:35:06 PM EDT
[#11]
ADCO can plug the barrel for you if you desire to go that route.
|
|
|
|
Posted: 5/11/2017 3:55:52 PM EDT
[#12]
Quote HistoryQuoted:
ADCO can plug the barrel for you if you desire to go that route. 
|
|
|
|
Posted: 5/11/2017 4:13:08 PM EDT
[#13]
If it were me, I would find someone that has done it before who would let you be there to show you how to do it. That way if it ever comes up again in the future, you will at least have a basic understanding of how it needs to be done.
|
|
|
|
Posted: 5/11/2017 4:30:47 PM EDT
[#14]
you guys are overthinking this.
all you have to do is to turn your gas tube 180 degree. problem solved. knock the gas tube roll pin out. remove the gas tube. cut it. turn the gas tube 180 degree, the gas hole on tube is now facing up instead of barrel. put gas tube roll pin back. when i did mine, i also cut the gas tube. gas tube are cheap, so if u had to return it into original configuration, just buy a new gas tube. |
|
|
|
Posted: 5/11/2017 4:38:35 PM EDT
[#15]
I would think a cheap low-profile gas block would work here, heck, put it on backwards so the gas port is blocked and doesn't line up with the gas block. The fear I would have with the screw is the screw working its way into the barrel at all. I've seen pics of high-round count cutaway barrels on here before, and there is a TON of erosion at the gas port, in your case, that erosion is going to eat away the material that the screw is holding on to. with two possible worst case outcomes. 1, screw falls into bore just enough to block or possibly even stop a round, causing a kaboom. Or, 2, screw under pressure blows out, hopefully this just hits your handguard and stops, but, I wouldn't chance it.
|
|
|
|
Posted: 5/15/2017 12:36:39 PM EDT
[#16]
Quote HistoryQuoted:
you guys are overthinking this. all you have to do is to turn your gas tube 180 degree. problem solved. knock the gas tube roll pin out. remove the gas tube. cut it. turn the gas tube 180 degree, the gas hole on tube is now facing up instead of barrel. put gas tube roll pin back. when i did mine, i also cut the gas tube. gas tube are cheap, so if u had to return it into original configuration, just buy a new gas tube. |
|
|
|
Posted: 5/15/2017 12:52:44 PM EDT
[#17]
Set screw and tig weld.
|
|
|
|
Posted: 5/18/2017 7:39:31 AM EDT
[#18]
Quote HistoryQuoted:
Set screw and tig weld. |
|
|
|
Posted: 5/18/2017 7:49:26 AM EDT
[#19]
Quote HistoryQuoted:
no. 7.62 tokarev had one of those, you running a m16 lower? use a socket cap screw, did that on my tok barrel, (same close ass gas port-had to move 3 times) |
|
|
|
Posted: 5/18/2017 10:49:18 AM EDT
[#20]
Quote HistoryQuoted:
I think that may be the best, but I'm trying to do this myself. I have a MIG welder, but I don't have Tig. Quote HistoryQuoted:
Quoted:
Set screw and tig weld. |
|
|
|
Posted: 5/18/2017 1:09:59 PM EDT
[#21]
Quote HistoryQuoted:
Just a little tack weld from your mig will do. I think i'm just going to thread the port and use a low profile button screw with loctite 2620. that's got a release threshold of 650F. semi-auto firing temps on the M16 with M193 get to around 600F. M193 has about 27 gr of powder and milsurp Tokarev has about 17 gr. It should be enough. I may look into getting someone to tig it later. |
|
|
|
Posted: 5/18/2017 1:12:22 PM EDT
[#22]
Quote HistoryQuoted:
ah had one of those, you running a m16 lower? use a socket cap screw, did that on my tok barrel, (same close ass gas port-had to move 3 times) |
|
|
|
Posted: 5/18/2017 1:45:29 PM EDT
[#23]
Use rocksett instead of loctite.
|
|
|
|
Posted: 5/18/2017 1:56:33 PM EDT
[#24]
Quote HistoryQuoted:
Use rocksett instead of loctite. thanks for the tip |
|
|
|
Posted: 5/18/2017 2:02:28 PM EDT
[#25]
Google the Nutnfancy review of Larue rifles.
Lots of tips there. |
|
|
|
Posted: 5/18/2017 2:20:10 PM EDT
[#26]
Quote HistoryQuoted:
Just a little tack weld from your mig will do. |
|
|
|
Posted: 5/18/2017 3:11:44 PM EDT
[#27]
Quote HistoryQuoted:
I have a 5.45 barrel that I need to plug. I'm going to use a soft copper slug as a chill, weld the hole, then drive the slug out. It *should* make the weld filler conform to the rifling engraving. |
|
|
|
Posted: 5/18/2017 3:14:03 PM EDT
[#28]
Quote HistoryQuoted:
Google the Nutnfancy review of Larue rifles. Lots of tips there. |
|
|
|
Posted: 5/18/2017 3:20:06 PM EDT
[#29]
Quote HistoryQuoted:
googled and found about 40 different links to different Nutnfancy reviews of Larue rifles... anything more specific? |
|
|
|
Posted: 5/18/2017 3:30:38 PM EDT
[#30]
Quote HistoryQuoted:
Where is yoru gas port? Mine is only about 1" from the delta ring. I don't think 2mm of missing rifling will matter much there, but I'd love to hear about your results. I also have a 7.62x25 upper from Heavy Metal that has a similarly positioned gas tube, so I sympathise. If it's constructed like mine, the tube is basically stabbed into the barrel. If I were to convert to blowback I'd cut the tube and crimp it. |
|
|
|
Posted: 5/18/2017 3:40:50 PM EDT
[#31]
Quote HistoryQuoted:
hmm. i've never weld stainless before. not sure i want to try this. I think i'm just going to thread the port and use a low profile button screw with loctite 2620. that's got a release threshold of 650F. semi-auto firing temps on the M16 with M193 get to around 600F. M193 has about 27 gr of powder and milsurp Tokarev has about 17 gr. It should be enough. I may look into getting someone to tig it later. Quote HistoryQuoted:
Quoted:
Just a little tack weld from your mig will do. I think i'm just going to thread the port and use a low profile button screw with loctite 2620. that's got a release threshold of 650F. semi-auto firing temps on the M16 with M193 get to around 600F. M193 has about 27 gr of powder and milsurp Tokarev has about 17 gr. It should be enough. I may look into getting someone to tig it later. |
|
|
|
Posted: 5/19/2017 11:09:21 AM EDT
[#32]
Quote HistoryQuoted:
He's joking. Nutnfancy did some parts swapping on a Larue rifle, installed the new parts incorrectly, turned his rifle into a single shot, and blamed Larue.
gotcha! UPS just dropped off the final parts. I should be able to do the tap this weekend and once I get the rocksett, I'll start the build. |
|
|
|
Posted: 5/20/2017 9:19:25 PM EDT
[#33]
I just realized it may not be possible to use the barrel after all--
Is it possible to use a regular gas type barrel with the standard locking shoulder in a blowback AR with a Colt SMG type bolt? I think I may be in a pickle here. Blowback barrel chamber: 
This is the standard gas AR15 chamber: 
|
|
|
|
Posted: 5/21/2017 9:18:21 PM EDT
[#34]
Quote HistoryQuoted: I just realized it may not be possible to use the barrel after all--
Is it possible to use a regular gas type barrel with the standard locking shoulder in a blowback AR with a Colt SMG type bolt? I think I may be in a pickle here. Blowback barrel chamber: http://cdn2.bigcommerce.com/n-biq04i/9s3jnna5/products/8/images/482/GM_M4_9_combo__64506.1421257199.1280.1280.jpg This is the standard gas AR15 chamber: https://www.pewpewtactical.com/wp-content/uploads/2016/02/AR-15-Chamber-300x200.jpg 1) Remove the bbl extension, and have a machinist mill a custom bbl extension for you, spin it on, and pin it. This is the most straightforward solution, using a standard mass-delayed blowback bolt. 2) Create a custom blowback bolt, either by cutting and pinning a standard bolt into a standard bolt carrier, or cutting down a blowback bolt carrier. 3) Copy this design: http://www.ar15.com/forums/t_6_48/477575_CMMG-Guard-45-Carbine-PDW.html |
|
|
|
Posted: 5/21/2017 10:22:25 PM EDT
[#35]
Quote HistoryQuoted:
Duh. All of us missed it. You have 3 options for semi-auto w/o gas w/ this bbl: 1) Remove the bbl extension, and have a machinist mill a custom bbl extension for you, spin it on, and pin it. This is the most straightforward solution, using a standard mass-delayed blowback bolt. 2) Create a custom blowback bolt, either by cutting and pinning a standard bolt into a standard bolt carrier, or cutting down a blowback bolt carrier. 3) Copy this design: http://www.ar15.com/forums/t_6_48/477575_CMMG-Guard-45-Carbine-PDW.html |
|
|
|
Posted: 5/21/2017 10:53:24 PM EDT
[#36]
Quote HistoryQuoted: Thanks... none of those seem ideal and it may be cheaper to just get a new barrel cut. it's the same as a 762x39 bore with the tok chamber... |
|
|
|
Posted: 5/22/2017 11:14:37 AM EDT
[#37]
Quote HistoryQuoted:
You are correct, though the rotary-delayed blowback may prove to be ideal for your application once it gets some traction. |
|
|
|
Posted: 5/22/2017 11:34:31 AM EDT
[#38]
You'd probably have to use their bolt carrier, and then cut angles on the lugs of the bolt. That's pretty much it, I think. What is the proper angle for your application? Who knows!
|
|
|
|
Posted: 5/22/2017 12:08:50 PM EDT
[#39]
Quote HistoryQuoted:
You'd probably have to use their bolt carrier, and then cut angles on the lugs of the bolt. That's pretty much it, I think. What is the proper angle for your application? Who knows! |
|
|
|
Posted: 5/22/2017 1:14:18 PM EDT
[#40]
well crap
this is making me rethink the whole thing. i've had this Tok-AR now for about 2 years and it runs great -- until the gas system gets clogged. Plus I have to clean it crazy well after shooting because the ammo is so dirty and corrosive. I've had the bolt freeze in the chamber with rust even after cleaning it. A blowback setup is much simpler. I really wonder how much people with these gas Tok-ARs are shooting. Mine clogs up after 200-300 rounds. I may just sit on the ammo and sell it, I bought a skid of it. |
|
|
|
Posted: 5/22/2017 1:26:04 PM EDT
[#41]
Send your parts off to get nitrided. That will at least help with the corrosion, may help with the reliability as well.
|
|
|
|
Posted: 5/22/2017 1:58:31 PM EDT
[#42]
I may have to go that route. I don't know. Seems like there should be some way to do this.
A bit part of the issue I think is that the gas port is so close to the delta ring. Like 1.5 inches. IT's a catch-22, the port needs to be that close to get enough impulse, but putting it that close allows a lot of powder to go up the port. The Tok rounds have about half the powder of an average 5.56 round, but putting the gas port so close to the chamber means sludge |
|
|
|
Posted: 5/22/2017 2:53:26 PM EDT
[#43]
Quote HistoryQuoted:
I really wonder how much people with these gas Tok-ARs are shooting. Mine clogs up after 200-300 rounds. I may just sit on the ammo and sell it, I bought a skid of it. 
was a pita ass to get going-needed a short gas system and light buffer, ran 20k or so, didn't have a problem with the corrosive ammo but i was living in a dry climate. sold 15-20k extra ammo I had a coupl years ago covered the cost of the original buy and the barrel, I would do it again if the price was right, and I would use a aluminium carrier |
|
|
|
Posted: 5/22/2017 3:08:41 PM EDT
[#44]
Quote HistoryQuoted:
was a pita ass to get going-needed a short gas system and light buffer, ran 20k or so, didn't have a problem with the corrosive ammo but i was living in a dry climate. Either way... this round would work much better in blowback of some kind. |
|
|
Win a FREE Membership!
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.
