Thread: .223 Ackley Improved

Anyone been down this road?
I am thinking about compensating for the velocity loss of a shortened barrel by getting greater speed with an AI.
Looking to go fast twist and heavier pills as well.
Donor will be a 788 .222

224 Valkyrie if your bolt face can handle it

better option for heavier pills

Yip one of my favourite cals..
I have a Rem 700P LTR in .223 AI. 20" 1-9" twist factory barrel rechambered.

I run 69gr TMKs at 3200fps and it is crazy flat and hard hitting.
The cases are easily fireformed by just shooting std .223 in your new improved chamber. .223 AI makes the most of the .223 rem case by blowing out to an almost straight walled case and pushed the shoulder forward a bit at the same time as forming the 40 degree angle. It extends case life and will give you a few hundred more fps too.









Im not sure how well it will go in your 788 asa they have quite a short mag. you need to load them long and hve quite a long throat cut if you want to make the most of the call. Ideally you'd run the heavier bullets, 65gr to 90gr pulled out really long to get the most from the cal but you could load them to 788 mag length and use 40gr to 55g for varminting or well placed shots on larger game.

Ive just added an Atlas works bottom metal and AI mag to mine for additional COAL to really get it singing and its devastating on critters. Hitting goats with it sounds like a grenade going off.

1/2 MOA at 200y

Yeah mag length is an issue with around 58.25 mm OAL available. I could rely on single feed for long OAL bullets and keep 55 / 60 grainers stacked up in the mag for cou de gras. @ebf i will have to look into the Valkyrie. And any others that come up in discusssion.
For now I think I will chop it back and run it as god intended (.222) with a supressor. @Wingman is there a difference between AI and the .223 40' or is that the same beast?

Had one a few years back and it was one of the easiest and most accurate 1/4 MOA rifles I’ve had to shoot, even the fire forming loads shot 1/4 MOA.
But now if I wanted the extra speed a 22 Terminator would be well worth considering over the 223ai.

https://www.nzhuntingandshooting.co....rminator-5607/

Originally Posted by johnd

Yeah mag length is an issue with around 58.25 mm OAL available. I could rely on single feed for long OAL bullets and keep 55 / 60 grainers stacked up in the mag for cou de gras. @Wingman is there a difference between AI and the .223 40' or is that the same beast?

Yes I was single feeding mine up until a few weeks ago when I did the detachable mag mod. A Tikka T3 would be a better donor for that cal, long mags and the .223 Rem comes in a 1-8 twist option. A .22 terminator could be considered on that platform too as you will have the same issues with your 788 mag in that cal too.

There were about 4 versions of the .223 Imp chamber ream with slight variations in neck lengths and dimensions but once brass is fire formed to your chamber you should anneal it and just neck size regardless of chamber variant used. The brass lives a very long life.

I could load mine hotter as there is plenty of room in the case still with my 2206H loads im limited with a 20" barrel so basically maxing out what the 69gr will do in my tube.
Improved chambers all benefit from longer mags and barrels as well as faster twists to make it a worth while mod.

Your bolt face and action strength will cope with a single feed 224 Valkyrie but again your mag wont. It wont be wide enough for the fatter case even if you modded the feed lips.

stick to the trebly....it has good reputation for a reason..... plenty of other rifles to cut up and change around without ruining a classic.....
had a very brief play with the terminator version (.204ruger necked back up) and had to laugh as its really close to reinventing the wheel
the .204 ruger is basically a necked down .222 magnum.....
the couple of loads we did werent mind blowingly faster than my std .223 ....used a fair bit more powder to do so.....

@gimp had one. Probably even before he became a gimp.

Originally Posted by Micky Duck

stick to the trebly....it has good reputation for a reason..... plenty of other rifles to cut up and change around without ruining a classic.....
had a very brief play with the terminator version (.204ruger necked back up) and had to laugh as its really close to reinventing the wheel
the .204 ruger is basically a necked down .222 magnum.....
the couple of loads we did werent mind blowingly faster than my std .223 ....used a fair bit more powder to do so.....

Sorry Micky this one is due for the chop, I sold my Sako 'cause I couldnt bring myself to cut that down or even put a thread on it.
First step will be to remove 6 inches off its barrel and rethread it ( its all ready supressed but is a bit long ).
It will remain as a .222 for now as i too love the caliber .... if it doesnt perform I will get a stainless barrel put on it as the 1 /14 twist it has now may well limit the projectile weight.
My thoughts were if i go to the trouble of rebarrelling then i should really explore the other avenues that exposes.

fair enough...a nice handy short trebly sounds great LOL.

Originally Posted by Wingman

Yip one of my favourite cals..
I have a Rem 700P LTR in .223 AI. 20" 1-9" twist factory barrel rechambered.

I run 69gr TMKs at 3200fps and it is crazy flat and hard hitting.
The cases are easily fireformed by just shooting std .223 in your new improved chamber. .223 AI makes the most of the .223 rem case by blowing out to an almost straight walled case and pushed the shoulder forward a bit at the same time as forming the 40 degree angle. It extends case life and will give you a few hundred more fps too.









Im not sure how well it will go in your 788 asa they have quite a short mag. you need to load them long and hve quite a long throat cut if you want to make the most of the call. Ideally you'd run the heavier bullets, 65gr to 90gr pulled out really long to get the most from the cal but you could load them to 788 mag length and use 40gr to 55g for varminting or well placed shots on larger game.

Ive just added an Atlas works bottom metal and AI mag to mine for additional COAL to really get it singing and its devastating on critters. Hitting goats with it sounds like a grenade going off.

1/2 MOA at 200y

Could you provide a run down on your fire forming. Seriously thinking of doing this with a T3. Thanks.

he has already...just shoot std .223 through rifle and it does the rest for you.... same as most ak imps

I have a spare unused Remington 700 SPS Tactical lying about. 223 1:9. Where could i get it rechambered to 223AI and what would be the rough cost. Am in Wellington area.

If the new imp chamber was cut correctly you will have a bit of crush fit when you close it on a loaded std .223 round. A new case headspaces on the neck/shoulder junction. You'll want to feel some pressure - 'crush' - closing the action. It's the case sealing tight against the chamber in front and pushing hard against the action in back. Against popular fire forming belief, seating a bullet into the lands accomplishes nothing, lubing the case also accomplishes nothing. Lighter loads and some factory loads dont form these .223 imp cases well, think about this: The AI chamber is larger than a std. .223 chamber. Your .223 load is X amount of powder and the formed AI case holds a couple gr more, so why on earth be fire forming with only 85% of your regular .223 load like most people will tell you? Some of the advice people give out so freely about this stuff is just nonsense. When fireforming, start with your std .223 load and go up from there, stop when you find nice sharp shoulders.

Heres a case next to a std .223 rem load that was loaded with too light of a charge with a 55gr vmax and failed to blow out to the new Imp chamber's full dimensions.



I have also had good success with light loads of pistol powder and topping the case off with corn tumble media and a candle wax plug. This saves on projectiles and barrel life.
Its a good idea to anneal brass first if it is older used .223rem brass to stop neck splits. Once fully fireformed, anneal it again and your good to go.

Originally Posted by Robojaz

I have a spare unused Remington 700 SPS Tactical lying about. 223 1:9. Where could i get it rechambered to 223AI and what would be the rough cost. Am in Wellington area.

Give Robbie Tiffen at Gunworks a call, he has the ream that did my chamber and he will do it right.
To get a chamber that's right you'll want to at least set the barrel back one thread which will realign your factory barrel markings and give enough room to clear your new IMP chamber. it is a fairly quick and easy job so wont cost a lot. The new dies will likely cost more.