I am playing with the idea of reaming an existing 14.5" barrel (1:9) to .223 AI to give the caliber a try.
Or, may be, to turn a removed Rem 700 barrel to an AR profile and to ream it to .223AI.
Does anyone ever tried an Ackley Improved chamber in an AR-15 ?
223 AI, from what I’ve seen, will put loads over mag length.
In a long barreled bolt gun you might gain 150 fps if you are lucky. If you get any more speed out of a 14 1/2" gas rifle it’s not going to be enough to justify the hassle. Converting the old bolt barrel to fit an AR IMO wouldn’t be worth the effort. There’s more to it than you think.
I’d prefer if ammo had stayed at 223 level and there was no 5.56, for safety margin and parts life. Not sure why anyone would want to increase the pressure with the AI.
My main concern was, first, the risk of overstressing the bolt lugs and to badly shorten the bolt life.
I thought the .223AI overall length was OK for the AR-15/M16 magazine but, anyway, I will probably do something else. Still, I think there is something interesting to do with the removed Rem 700 barrel. It could be probably turned to do a stupidly long 24" barrel, even if the 1-12 twist is somehow a show stopper.
If you get a quote for setting up the old barrel you will probably abandon the idea of using it for anything other than a tent stake. Why was it taken off of the bolt gun anyway??
I removed it from a customer’s Rem700. He wanted a 1-7" twist barrel but was unable to get it here…the Remington importer only stock 1-12" models.
So, I turned him a new barrel and kept the original that may be fired 50 rounds.
Got it. If you are capable of setting up the barrel yourself and want to shoot lightweight varmint bullets go for it. I still wouldn’t do it unless I already owned the reamer.
We have 2 AI bolt action rifles in the family. The benefits of AI chambering include:
I am not sure how the AI would behave in the semiautomatic rifle. I would speculate that the decrease in brass taper could reduce reliability.