223 ai

midwestpredator

Active member
Once again I am revisiting the topic of a 223 ai ar15. Once I get an idea in my head I usually need very compelling evidence that it is a bad idea and so far all i can find is peoples "claims" that it wont feed. Now on the other hand, i cant find anything solid that shows me it will feed and function.

During my search last night I came across a couple of articles on rifles built by lee mosher of Insight Shooting Systems inc. (ISSI)

http://www.smallarmsreview.com/display.article.cfm?idarticles=1557

https://www.tactical-life.com/firearms/insight-shooting-systems-coyote-hunting-ar/

https://www.thefreelibrary.com/Pumping+u...y...-a098124201


A small excerpt from the last link:

Other Details

In the course of firing some 200 rounds of standard 223 Rem. and 300 .223 AI cartridges the ISSI unit functioned perfectly.

"The AR-15 is almost perfectly suited to feeding the 40-degree case," Mosher commented, "better than most bolt guns."

Something I like to see with any semi-auto, rifle or pistol, is a consistent ejection pattern. Wanting to recover the cases while shooting the .223 AI unit from the bench, I noted where the first case lancteci, then set a range bag on the spot. From then on, just about every case ejected from the ISSI unit went spinning neatly into the bag.

Mosher does a lot of tuning and fitting to ensure smooth functioning. He found that the bolt locking lugs at the 1:30 and 3:00 positions tended to scratch cases. Relieving the edges of the lugs not only stopped the case scratching but led to a more consistent ejection pattern.

Latest Developments

Although both prototypes functioned reliably, Mosher felt the feed/ejection cycle could be smoother. On current models he slightly reduces the gas port diameter, and he now uses a Les Baer bolt and bolt carrier (1/4 ounce heavier than standard), and a chrome silicon recoil spring buffer from David Tubb. The result, he says, is superbly smooth operation.



So, anyone know where I can go to find video or actual first hand experience with a 223 AI ar15?
 
I've got a 223ai ar15. Been running it for several years now. No issues with feeding. Run ASC mags with no mods. Hope nobody tells mine that it can't feed. I know of at least 1 more on here that has a couple. I'm sure there are more of us rebels.
 
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Originally Posted By: tj66I've got a 223ai ar15. Been running it for several years now. No issues with feeding. Run ASC mags with no mods. Hope nobody tells mine that it can't feed. I know of at least 1 more on here that has a couple. I'm sure there are more of us rebels.

Where did you get your barrel? Specs on it and loads/velocity? thanks


Originally Posted By: steve garrett22 nosler Don’t monkey around

No interest in 22 nosler
 
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What’s the speed of a 223ai? I have been really watching the 22 nxs Ritch has. Wouldn’t a 22x6.8 be faster then a 223ai?
 
That middle article is mine. It was at the editors for years before it go published. I really like mine but if you're getting a new setup I'd go with Valkyrie or Nosler instead. The AI chambering requires some work fireforming, and honestly my buddies 8T 223 is just as effective as my 9T AI, and maybe better. We've often thought of a 22-204 Ruger setup using a VLD magazine which would have even a bit more capacity, and easier to form. AI nets you maybe +/-100 fps more vel. than 223.
 
Originally Posted By: midwestpredatorOriginally Posted By: tj66I've got a 223ai ar15. Been running it for several years now. No issues with feeding. Run ASC mags with no mods. Hope nobody tells mine that it can't feed. I know of at least 1 more on here that has a couple. I'm sure there are more of us rebels.

Where did you get your barrel? Specs on it and loads/velocity? thanks


Originally Posted By: steve garrett22 nosler Don’t monkey around

No interest in 22 nosler

My barrel was built by local gunsmith. Shilen 22" 12 twist, 0 freebore, rifle gas .750 @ muzzle. Currently running 50 NBT's ~ 3450 Have had them faster but groups fell apart. IMI brass, Benchmark powder on these. Can usually necksize 2 times before bumping shoulders back without any chambering issues.
 
sscoyote said:
That middle article is mine. It was at the editors for years before it go published. I really like mine but if you're getting a new setup I'd go with Valkyrie or Nosler instead. The AI chambering requires some work fireforming, and honestly my buddies 8T 223 is just as effective as my 9T AI, and maybe better. We've often thought of a 22-204 Ruger setup using a VLD magazine which would have even a bit more capacity, and easier to form. AI nets you maybe +/-100 fps more vel. than 223. [/quote

I haven't tried a straight 22-204. Last winter I ran a 223ai reamer deep and made a 22-204ai in a savage 9 twist factory tube. It shoots Ok, but I haven't really pursued it much as it didn't gain much over a 223ai. Accuracy on that barrel was best around 3450-3550 which is easily done with 223ai. I thought it would have better return than it did, but it could have been different with a higher quality tube.
 
monkeying around with AI brass over 22 nosler...... interesting. what you should do is go read PO ackley's book, you know the guy that invented the AI in the first place. since your asking about doing it in an AR, I would just say this. when an ackley invented the idea and to set up an ackley chamber correctly they shorten the headspace by 4 thousandths, That way when you chamber the brass you get a crush fit on the brass when closing the bolt on a bolt action. a crush fit isn't possible with an AR 15 and do so reliably. I think you could do an AR, AI but it would be best if you fireformed the brass in a bolt action chamber or bought preformed brass. Why do you need crush fit? well if you don't have it the brass expands and sticks to the chamber walls during the firing process. because you are moving the shoulder forward without the crush fit you are stretching the case to the rear instead. That could dangerously weaken the case and lead to case head separation. If you are going to the trouble of doing an ackley round, I have 2 BTW you want your brass lasting as long as you can. because isn't the point not to keep having to firefrom?

a poster named DAA probably would be the guy to ask about this more than me. maybe he will chime in.

YES 22 nosler, 22 DTI whatever. for what it would cost to have a decent gunsmith cut a chamber you might as well get a new barrel and in a cartridge that really offers a benefit. its your money.
 
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Originally Posted By: zr600What’s the speed of a 223ai? I have been really watching the 22 nxs Ritch has. Wouldn’t a 22x6.8 be faster then a 223ai?

22x6.8 will be faster, but 223 is by far easier to find quality brass if you want to run hard. I'm not really pushing mine as it really has a sweet spot where I'm at.
 
Originally Posted By: steve garrettmonkeying around with AI brass over 22 nosler...... interesting. what you should do is go read PO ackley's book, you know the guy that invented the AI in the first place. since your asking about doing it in an AR, I would just say this. when an ackley invented the idea and to set up an ackley chamber correctly they shorten the headspace by 4 thousandths, That way when you chamber the brass you get a crush fit on the brass when closing the bolt on a bolt action. a crush fit isn't possible with an AR 15 and do so reliably. I think you could do an AR, AI but it would be best if you fireformed the brass in a bolt action chamber or bought preformed brass. Why do you need crush fit? well if you don't have it the brass expands and sticks to the chamber walls during the firing process. because you are moving the shoulder forward without the crush fit you are stretching the case to the rear instead. That could dangerously weaken the case and lead to case head separation. If you are going to the trouble of doing an ackley round, I have 2 BTW you want your brass lasting as long as you can. because isn't the point not to keep having to firefrom?

a poster named DAA probably would be the guy to ask about this more than me. maybe he will chime in.

YES 22 nosler, 22 DTI whatever. for what it would cost to have a decent gunsmith cut a chamber you might as well get a new barrel and in a cartridge that really offers a benefit. its your money.

Im still waiting for you to build yourself a 6br. The parts are out there. As for me, ill monkey with whatever I want to. For now its research but might lead to something.

As far as crush fit, how well do your dti cases form?
 
The thing about 0.004 crush from my understanding, is partly to aide in blowing the shoulder forward but mostly has to do with shooting factory rounds in the virgin form.

I doubt I can crush fit 4 thou but I know for a fact that I can crush fit to some extent and that should be sufficient to fork brass. The problem becomes manual ejection of a live round which I'm not terribly worried about as I'd probably form at the range or prairie dog town. Somewhere that ejecting a live round is not common.

Originally Posted By: zr600Instead of the crush fit couldn’t you just neck it up then neck it down to create a false shoulder?

Yes, you just need a zero or slightly negative headspace value. However you get it shouldn't matter.
 
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Originally Posted By: midwestpredatorThe thing about 0.004 crush from my understanding, is partly to aide in blowing the shoulder forward but mostly has to do with shooting factory rounds in the virgin form.

I doubt I can crush fit 4 thou but I know for a fact that I can crush fit to some extent and that should be sufficient to fork brass. The problem becomes manual ejection of a live round which I'm not terribly worried about as I'd probably form at the range or prairie dog town. Somewhere that ejecting a live round is not common.

Originally Posted By: zr600Instead of the crush fit couldn’t you just neck it up then neck it down to create a false shoulder?

Yes, you just need a zero or slightly negative headspace value. However you get it shouldn't matter.

I agree with the zero value. False shoulder works also. Question is on factory brass how many brands measure the same? They vary all over the place. As long as the brass is held tight against the bolt they will fireform. Then measure your shoulders and don't knock them back excessively and the brass will be fine. No different than forming Dasher brass or DTI as you already pointed out.
 
Lucky, my rem 700 bolt rifle in .223 AI hardly feeds. I am waiting on detachable mag bottom metal and a center feed magazine. Everything I've read is that is a way to get the bolt rifle to feed well. Never thought about a .223AI in an AR. That's cool.
 
Originally Posted By: sscoyoteThat middle article is mine. It was at the editors for years before it go published. I really like mine but if you're getting a new setup I'd go with Valkyrie or Nosler instead. The AI chambering requires some work fireforming, and honestly my buddies 8T 223 is just as effective as my 9T AI, and maybe better. We've often thought of a 22-204 Ruger setup using a VLD magazine which would have even a bit more capacity, and easier to form. AI nets you maybe +/-100 fps more vel. than 223.

What do you mean by just as effective? What is your load? Any feeding issues ever come up or fireforming issues?

I'm not going for the "223 is inadequate" thing. 223 is just fine but Im just interested in trying new things. Never had an Ackley anything and to play with bolt guns costs too much for me. With the ar, I can pull my 223 barrel and put on an ai and if need be 8 can get Lee dies for less than $40.
 
I have 3 such chambered ar's, and none of them have any problems. I had a feed issue for a while, but slightly more chamfer on the bottom of the chamber mouth solved that. No issues fireforming, I do seat bullets long to kiss the lands on the latest one when forming to eliminate any stretch. All of mine were done for me locally and from take off Remington barrels, 12 twist.
 
I also have one of Lee Mosher's 223AI, I would have to do some research to see when I had him build it. The one thing that stands out is that Lee used a modified reamer, it had a little bit of a radiused shoulder that helped them feed. 10-12% more capacity is probably accurate, Lee provided some targets that he had shot with mine, it was crazy accurate. Lee built them to shoot factory ammo to fireform brass.

His favorite powders were the 2460 and the 2520. I pressure tested his action, accidently put a different powder in it, it blew the upper apart, the bolt was ruined and the housing was spread, blew the bottom out of the magazine as well. I tried to contact Lee and was not able to find him, I believe he might of passed away by then. I put the barrel on another upper and shot if for a little bit. The different chamber caused me problems as I had several other 223AI's built with a different style reamer, the AR wouldn't chamber the ones from the later reamer, due to the difference in the shoulder. I decided to build a straight 223, so I took the barrel off and put it away.

I have been looking at it sitting in the cabinet thinking it should be shot as I have traded away all the other bolt 223AI's I had. Mine is a 24" 14 twist, Lee didn't like the idea of the shorter barrel but I wanted a pickup gun. I also think mine maybe a Hart barrel as well. Lee Mosher could sure build a shooter.
 
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Originally Posted By: 204 ARI have 3 such chambered ar's, and none of them have any problems. I had a feed issue for a while, but slightly more chamfer on the bottom of the chamber mouth solved that. No issues fireforming, I do seat bullets long to kiss the lands on the latest one when forming to eliminate any stretch. All of mine were done for me locally and from take off Remington barrels, 12 twist.

So the round would get past the extension but hang up on the bottom of the barrel? At the end of they day, do you like them and would you do another? Barrel length, bullet and velocity?
 
Originally Posted By: midwestpredatorOriginally Posted By: 204 ARI have 3 such chambered ar's, and none of them have any problems. I had a feed issue for a while, but slightly more chamfer on the bottom of the chamber mouth solved that. No issues fireforming, I do seat bullets long to kiss the lands on the latest one when forming to eliminate any stretch. All of mine were done for me locally and from take off Remington barrels, 12 twist.

So the round would get past the extension but hang up on the bottom of the barrel? At the end of they day, do you like them and would you do another? Barrel length, bullet and velocity?

Basically yes. As it would feed, and the bullet had entered the chamber, the bottom of the case about 1/4" back from the shoulder would bind on the bottom of the chamber mouth, and the force of the bcg would cause a sort of half-moon dent in the case at that spot. Not nearly every time, more like once out of 20 or 30 rounds. But often enough that it could be a concern. This was on one build, the other two were flawless from day one. And this one is also now, no more problems after I had the chamber mouth beveled slightly more.

So two are 26" bulls, and one a 24" pencil. All are real tackdrivers, the two bulls not picky at all and the pencil slightly more picky on bullets. My load in the bulls is a 40 gr vmax at 3850 fps with my decade old load with A2230. I have no doubt I could beat that speed accurately with 8208 now, and when I run out of 2230 will probably try it. The 24" uses the same load but with 40 gr nbt at 3750, and I've worked up a 53 gr vmax load with 8208 at 3450 fps. These have always been with Remington brass which is notoriously soft but I have a good pile of it so I use it. I'm sure LC would support stiffer loads yet, but I'm pretty happy for now with these speeds I guess.

And yes, I'd do it again, in fact one of the bulls was just done this last summer as my hobbyist smith had a brand new take off and I think he sold me the barrel with all the work done for like $140.
 
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