My buddy shot out his bull barrel .223 and wanted me to do something with the old barrel. At first I was going to just cut it and put some really aggressive looking muzzle idea on it. Then I thought why not let him build a pistol? It's a shot out .223/5.6 I think 1/7 twist bull barrel. the current gas port would be out further than I want it. Turning the barrel, adding a new gas port, threading it and making a fun looking muzzle end are not a problem. Accuracy is not an issue but safety is. I guess there are standards for the length. I want to keep it short. Gas port size and location are questions. Length I think is a standard for twist? Anyway, Thoughts?
.223 pistol from a rifle barrel
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Dave DeLaurant
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Interesting idea. A few clarifications please.
Since you are talking about gas ports, assume you mean the barrel was originally for an AR-15 of some flavor -- true?
What kind of pistol action do you have in mind? Another AR?
Is the receiver you have in mind legal to use as a handgun? (a paperwork issue)
Have you run a bore scope through it to check condition over its full length?
Since you are talking about gas ports, assume you mean the barrel was originally for an AR-15 of some flavor -- true?
What kind of pistol action do you have in mind? Another AR?
Is the receiver you have in mind legal to use as a handgun? (a paperwork issue)
Have you run a bore scope through it to check condition over its full length?
edwardware
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If a receiver started life as a rifle, it may never be a pistol. It may only be a rifle, or an SBR. If you build a 'pistol' with a receiver that started as a rifle, it's an undocumented SBR, not a pistol.
Get a stripped receiver, assemble as a pistol first, and carry on.
CarJunkieLS1
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Guys the lower receiver is what's considered the firearm. The upper receiver doesn't matter what length barrel was screwed into it. You have a 16" barrel it's a rifle upper, you screw in a 10" barrel it's a pistol upper.
Now the lower if it was "registered" as a rifle lower then it can never be considered a pistol lower.
Now the lower if it was "registered" as a rifle lower then it can never be considered a pistol lower.
edwardware
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You were good right up until the word "registered". If there is a registry on which a receiver is registered as a rifle, that registry might serve as evidence, but such registration is beside the point. The configuration of the first assembly of the lower is the point:
-first a rifle, always a rifle
-first a pistol, and you can reconfigure at will
CarJunkieLS1
Member
I used registered in italics for lack of a better way of saying it. It was a short way of saying when it was purchased at an ffl and the 4473 application was filled out and signed.
Dave DeLaurant
Member
The pistol AR reuse could get expensive if you don't already have a BATFE-blessed handgun receiver. An alternative suggestion for your barrel would be a rebore job to something like .30 Apache, but suitability would depend on the condition of the chamber and the original manufacturing techniques -- rebore shops usually turn down work on barrels that have been hammer forged. Chrome lining could also be an issue. Also a good rebore/rechamber job almost always costs more than a new barrel, so there's that.
Yet another suggestion would be to weld the gas port shut and see whether there is enough good bore left to shorten from the breech and continue using in a rifle. There's also the SBR route, if you know someone with a NFA-papered lower.
Yet another suggestion would be to weld the gas port shut and see whether there is enough good bore left to shorten from the breech and continue using in a rifle. There's also the SBR route, if you know someone with a NFA-papered lower.
Here's what it looks like after turning. I'm looking for the size of gas port and where I should put it. Ideas? The lower I don't have. Its work for a friend. He tells me that his interest will be to get the rest of the parts at a local gun show. With some of the left over barrel I plan on making him some sort of menacing looking muzzle brake. Just finished everything but the blue. My buddy says he will try it on another pistol he has. I guess if it didn't shoot straight as a worn out rifle I shouldn't expect anything as a pistol.
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Varminterror
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You have the journal cut, how did you place your shoulder if you didn't know where the gas block needed to be? Idea out ran your feet?
CarJunkieLS1
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Now how is one supposed to make a .22 caliber bore made a .30 cal bore...interested minds want to know.
Varminterror
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Rebore... welcome to the party.
CarJunkieLS1
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Wouldn't it be much more cost effective to buy a barrel with the correct bore already.
But where's the fun in that!
While I had the same question in my head, it does appear he could move it 3/4" or so back if need be.
Varminterror
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It used to not be so, but now, certainly is.
I can put the port anywhere. Im interested in location and size for the operation. Its not an idea that lost control as its a study of concept matching its operational design. A .09 port just seems too much. I'm gonna go with a .075 and whish I had an adjustable block. I do but the one I bought was a wopping $18. This is just for fun guys. THe barrel was toast when this started. I like the idea of re-boring would be fun but I don't have the tooling. There is no reason to buy a new bore because that was never a consideration of this post. Cost is an issue as there should be basicly none. This is a just for fun project.
Varminterror
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Are you making your own gas tube? Are you making your own gas block? If not, then no, you cannot put your gas port just anywhere.
It seems as though you’re not familiar with AR-15 designs. As I asked in my first above - What guidance did you use to cut the gas block journal and shoulder in your profile?
You SHOULD have chosen a gas length, which would dictate port location and size, as well as your gas block journal and shoulder position. If that shoulder is at an arbitrary length, you’ll have to cut, flare, and sewage your own custom gas tube length. AR’s have standard gas lengths for a reason. Your gas port should be placed accordingly, then your gas block shoulder cut based on the port position. The port should be placed according to your desired gas system length, then the shoulder placed 0.295” +/-0.005” behind the center of the port. The port size is dictated by the cartridge and gas system length.
The entire enterprise is kinda misguided. What you SHOULD have done is pull the extension, set the barrel back, and rechamber to cut out the old, obviously burned out throat and leade. Sure, it’s gonna go bang (if you can resolve your gas length issues), and if you have no performance expectations, it’ll be fun, but you kept the worn out part of the barrel.
Since it looks like the old barrel was a straight profile, I would have kept the old gas journal and shoulder, and cut the barrel out of the middle, such I would totally eliminate the old chamber, throat, and leade.
But here we are, what’s turned is turned - what’s your length from the gas block shoulder to the end of the extension?
It seems as though you’re not familiar with AR-15 designs. As I asked in my first above - What guidance did you use to cut the gas block journal and shoulder in your profile?
You SHOULD have chosen a gas length, which would dictate port location and size, as well as your gas block journal and shoulder position. If that shoulder is at an arbitrary length, you’ll have to cut, flare, and sewage your own custom gas tube length. AR’s have standard gas lengths for a reason. Your gas port should be placed accordingly, then your gas block shoulder cut based on the port position. The port should be placed according to your desired gas system length, then the shoulder placed 0.295” +/-0.005” behind the center of the port. The port size is dictated by the cartridge and gas system length.
The entire enterprise is kinda misguided. What you SHOULD have done is pull the extension, set the barrel back, and rechamber to cut out the old, obviously burned out throat and leade. Sure, it’s gonna go bang (if you can resolve your gas length issues), and if you have no performance expectations, it’ll be fun, but you kept the worn out part of the barrel.
Since it looks like the old barrel was a straight profile, I would have kept the old gas journal and shoulder, and cut the barrel out of the middle, such I would totally eliminate the old chamber, throat, and leade.
But here we are, what’s turned is turned - what’s your length from the gas block shoulder to the end of the extension?
Varminterror
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Why do you think .090” seems too big, and think .075” will suffice? Most pistol length barrels I have bought are still .081-.083”. Is your shoulder position and port position going to be shorter than standard pistol length?
Verminterror, That's really a handful of the best information I've ever got form this site! Thank so very much. Not sure where to start other than I wish I could start over with your tutelage. I went to a couple of gun stores and watched a few youtubes. Form this I gathered that .90 was going to spit brass and dirty things in an overwhelming fashion. I copied a 10.5" of my own for position. I did not build my own block or tube. With the info your providing I'd like to try this again. Thanks again. I really appreciate you.
Verinterror, please help me understand a bit more about gas tubes. 1. can I take his old longer tube and reuse it? In that can I punch out the roll pin and will it fit a different block? 2. how is sewage done? How do adjustable blocks work? 3. What is your thoughts about a .075 port. 4.What is the rationale for where they put the ports? Thanks for help with any of this.
Varminterror
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1) Kinda. Yes, you can cut the overlength tube to fit the new length, but you’ll note, there’s a bit of a bulge on the end where it seats into the gas key. The diameter, pin bore, and port position will be the same for all tubes, only difference is length.
2) There are different means to flare and swage the end, I can’t say I like any I have tried better than others - other than to say I don’t like any method I have tried.
2B) adjustable gas blocks have a screw positioned to occlude the gas port. The port is just a bore hole from the ID face of the block outward to meet the gas tube bore. You may even be able to drill, bottom, and tap an adjustment screw into the gas block you have, since you obviously have access to a machine shop. Or make your own adjustable block.
3) An adjustable gas block can make an oversized port act like a smaller port, but an undersized port can never be made to act like a larger port. I would rather over port and run an adjustable gas block, instead of being stuck pulling the block later and reaming a larger port if the .075” bore didn’t work.
4) I couldn’t say myself why the different EXACT lengths were chosen, other than to say it is a balancing act between bullet dwell time in front of the port, the diameter, volume of the gas tube behind it, volume of the gas piston formed between the bolt and carrier, and the mass of the BCG. But for us mortals who aren’t equipped to produce our own custom gas tubes (hydro flare/swage, precision bend, etc), or at least those of us not silly enough to create a couple hours worth of work to produce a $7 part, complying with known and proven gas system lengths sure keeps life easy.
So what’s your shoulder length from the extension?
2) There are different means to flare and swage the end, I can’t say I like any I have tried better than others - other than to say I don’t like any method I have tried.
2B) adjustable gas blocks have a screw positioned to occlude the gas port. The port is just a bore hole from the ID face of the block outward to meet the gas tube bore. You may even be able to drill, bottom, and tap an adjustment screw into the gas block you have, since you obviously have access to a machine shop. Or make your own adjustable block.
3) An adjustable gas block can make an oversized port act like a smaller port, but an undersized port can never be made to act like a larger port. I would rather over port and run an adjustable gas block, instead of being stuck pulling the block later and reaming a larger port if the .075” bore didn’t work.
4) I couldn’t say myself why the different EXACT lengths were chosen, other than to say it is a balancing act between bullet dwell time in front of the port, the diameter, volume of the gas tube behind it, volume of the gas piston formed between the bolt and carrier, and the mass of the BCG. But for us mortals who aren’t equipped to produce our own custom gas tubes (hydro flare/swage, precision bend, etc), or at least those of us not silly enough to create a couple hours worth of work to produce a $7 part, complying with known and proven gas system lengths sure keeps life easy.
So what’s your shoulder length from the extension?
I'm trying to get a pic with measurements to download. In the meanwhile, thanks for the assist. Can I tape the roll pin and reuse the old tube? Or can you tell me the cuts to make on the gas block end, if I just harvest the old tube to keep the swaged end? Pic still not in. Here's another thing that I've often wondered about. I have glassed three rifle stocks and the idea was always to be able to slide a dollar bill along the barrel. The idea being that anything that touches the barrel directly affects accuracy. Then I look at gas blocks. I'm told that the vibration from shells detonation travels up and d
own the barrel many times prior to the bullet ever leaving. This makes me think that the gas block should greatly affect the accuracy. Now I see JP Enterprise with guns stated to be sub .5 MOA. Why does the gas block not make more of a difference? BTW, I took three semesters of a night gun school class. More of a free for all but tons of fun. Then when I retired with my Wife, she bought me a lathe and mill. Guess I know just enough to know that I really don't know much. Great learning though. Pic still not in. I post when it does. Thanks again Varminterror. Pics loaded. I could have been hyper critical of any of the locations. I was, however, quite ignorant of why.
own the barrel many times prior to the bullet ever leaving. This makes me think that the gas block should greatly affect the accuracy. Now I see JP Enterprise with guns stated to be sub .5 MOA. Why does the gas block not make more of a difference? BTW, I took three semesters of a night gun school class. More of a free for all but tons of fun. Then when I retired with my Wife, she bought me a lathe and mill. Guess I know just enough to know that I really don't know much. Great learning though. Pic still not in. I post when it does. Thanks again Varminterror. Pics loaded. I could have been hyper critical of any of the locations. I was, however, quite ignorant of why.
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