brant89
Well-Known Member
Anyone here have any experience with a short barreled .223AI? Considering building one in the 16-20" range for a nice, compact pack rifle. Anyone have any idea what kind of velocity could be expected with a 75gr ELD?
Shorty .223AI Velocity
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J E Custom
Well-Known Member
My 223 AI will break 3000 ft/sec with a 22 " barrel and the AI is normally an average of 150 ft/sec faster than a standard 223. I would think that a 20"barrel should come in around 2750 to 2800 ft/sec.
J E CUSTOM
brant89
Well-Known Member
You think a 223AI will lose 200-250fps going from 22" to 20"? I would not have expected losing 100fps per inch of barrel.
Spot on...7-8yrs ago I had a 223AI Kimber Montana with the factory barrel cut 20". With the 75 Amax, I got around 2800fps.
hunter67wa
Well-Known Member
I'm running 18" but with lighter bullets. Seems like there is more gain with lighter bullets and it diminishes as you go heavy. Oh ya 53gr vmax 3394fps
flyinstroke
Well-Known Member
What a coincidence. I was about to start building one of these. In for some more responses. I am thinking about going 20" also possibly 22" haven' decided yet.
brant89
Well-Known Member
Have you ever run heavier bullets out of it? It just seems like you should be able to hit around 2900 with a 75gr bullet out of a 20" barrel since there are factory 5.56 loads doing it. I would think a 223AI should at least keep up with the higher pressure NATO round given the increased case capacity. Maybe I'm mistaken though, hence the post.
B23
Well-Known Member
My 223AI has a 22in Hart 9tw barrel and it loves the 53gr Vmax and that's pretty much all I ever shoot in mine. With my 9tw, I doubt I could shoot the 75's even if I wanted to.
The little 223AI case with it's minimal taper will take a lot of abuse and sometimes do so without showing obvious signs of pressure and you'll read/hear about alllllll kinds of crazy velocities from these things so keep that in mind when you talk to people and they tell you about velocities that sound to good to be true.
The speeds JE posted are reasonable pressure type loads. Be leary of velocities that are well above that.
The 223AI is a very fun little cartridge and they always seem to shoot very well.
The little 223AI case with it's minimal taper will take a lot of abuse and sometimes do so without showing obvious signs of pressure and you'll read/hear about alllllll kinds of crazy velocities from these things so keep that in mind when you talk to people and they tell you about velocities that sound to good to be true.
The speeds JE posted are reasonable pressure type loads. Be leary of velocities that are well above that.
The 223AI is a very fun little cartridge and they always seem to shoot very well.
J E Custom
Well-Known Member
If the pressures are held to SAMMI spec. they can be shot in the AR platform without trouble. If the pressures are higher, a bolt action is needed/Recommended. If you use the Lapua cases they are stronger and pressure signs are slow to show up. but excessive pressure is possible because the Lapua cases normally have less case volume than other cases except for the Mil Spec cases
The loads/velocities I listed are within SAMMI pressures and should be adhered to. Most 223 AI loads are hand loaded and therefore on the high pressure side because they are normally custom bolt rifles and some liberties with pressure can be taken (But not to much). So if someone want's to over load his rifle/cartridge, he is the one that has to live with the effects.
Most of the available load data for the 223 and the 223 AI are based on 24" barrels and the velocities are elevated from a 20 Inch barrel. So if these loads are used in 20" barrels, the velocity loss should be very close.
J E CUSTOM
brant89
Well-Known Member
This would be a bolt gun. I only referenced the NATO loads because they are generally fired from shorter barrels so short barrel information is a little more readily available, and most .223 data is tested in 24" barrels as mentioned. I understand that NATO and SAMMI are different and that many people push the Ackley's pretty hard. I was hoping I could get 26" 223 velocities out of an 18" 223AI but it sounds like that would not be the case.
hunter67wa
Well-Known Member
I have not shot heavies in my 223. Well i should say it will stabilize a 69gr MK thats as heavy as Ive shot. Its a 9 twist. The 53 vmax shoots so good that the load I settled on was all about the accuracy. I was actually surprised when I screened it.
I have a 22-250 with an 8 twist for 75 gr pills and it shoots them very well!
I have a 22-250 with an 8 twist for 75 gr pills and it shoots them very well!
brant89
Well-Known Member
My 9 twist throws 75gr pills like a champ. Just want something shorter since I have a YHM Turbo in NFA jail.
Ernie
SPONSOR
I have a 15" 223 (Not a AI), that has a 1-7 twist barrel, if that can help in any way.
It seems to me that building a short barrel rifle in a speedier cartridge might be a little counterproductive when it comes to velocity preform, kinda like having a thoroughbred racehorse in the race then putting a 300 Lbs jockey on him with a roping saddle. It would seem as the barrels started coming down in length perhaps the original cartridge, in this case, .223 Rem would work just fine especially when going under 16" inch barrel length. But... if you just like the looks of the horse and the jockey is your brother-in-law why not? 
