Need a few 223 AI cases

[Jethro]

I am about to do a re-barrel on my CZ-527, and thinking of having the new barrel punched out to 223 AI instead of the standard 223. Before I do that though I want to make up a few dummy rounds and make sure they are going to feed right in my rifle before I take the plunge. The extra performance would be nice, but not at the cost of feeding issues.

Anybody got a few wore out cases they can send me to so I can make some dummy rounds to play with?

[sendit]

I have some but they are are at the ranch and it will be a few day before I get there.

[Jethro]

That is fine, I have some time on this project. It is on my daughters rifle and I am not doing anything with it until after she shoots her buck this season. She can keep shooting it as-is until I decide.

[sendit]

I assume you are going to run a fast twist barrel to some heavies through it?

[Jethro]

The rifle is a little cut down CZ-527 n 223. My daughter shoots it for everything from jackrabbits to deer. The original barrel was a 12 twist, she would shoot 40's or 50's for varmints, and then I would have a deer load using the Nosler 64 bonded or similar. Kind of a PITA switching loads back and forth though, and any heavier bullet I shot I would have to keep with something pretty short and stumpy to stabilize.

That rifle has been shot a bunch, and the throat is gone. A couple years ago, as the throat started going away, I bought a brand new factory takeoff barrel to replace it with from James Calhoon for $125. Same contour, but a 9 twist 223 instead of a 12. The plan is to step up to something like the 65 SGK and shoot it for everything. That will give her a good deer load, yet something with a pretty decent BC that she can start shooting some moderate distance with.

I had the original barrel cut back to 18" since she has a Specwar 556K on it. The shorter length helps to keep it easy to handle for her. I would like to keep this barrel the same length. I was thinking the AI conversion would help to make up for the shorter barrel.

Main thing is it has to feed good though. Since it is her primary hunting rifle I don't need any hiccups out in the field. I want to make up some dummy rounds and play with it, make sure I am satisfied with the way it feeds. If not, I will just keep it a standard 223 and roll with it.

[McClain]

If sendit is unable to follow up with some, I could send you a couple Lapua (or Lake City) brass next week. Mike Bryant chambered a 9-twist barrel for me according to my specs using Lapua brass and 69 SMK that also shoots the 65 SGK very well. No feeding problems at all with the older style HS Precision DBM.

[SabreKiller]

Tagged...

for further reference. I've got the same rifle in .223 with a 12 twist. I've had good luck with the 50 gr. Nosler BT, but not so much luck with heavier fodder.

It's a tack driver with the 50 gr, but I like shooting critters with a little heavier bullet. I shoot 64 gr. Winchester out of my AR, but any of the heavier bullets like this aren't very accurate in my rifle. Handloaded 62 gr. Barnes TTSX's are donig OK, but nothing like the 50's.

I keep hearing Ackley Improved on this site and it's got my curiosity up. Once a GS reams the chamber can you just fire-form regular .223 brass to make the new round?

Jethro, once you get those dummy rounds built and have time to play with it and make a decision, let me know how it works out. I'm interested in this big time.

[Jethro]

No need for Lapua brass, LC is fine. Like I said, just trying to make some dummy rounds so I know it will feed fine before I jump in. If Sendit doesn't find any I will holler at you McClain. I appreciate it. My sons 270 was built by Mike Bryant. He can sure build a rifle, no doubt.

I think, being a center feed magazine, that the CZ won't have any problems with it. A guy just doesn't know until he tries though. Trying to do my homework before I commit.

Honestly I think it might net me 75 fps or so in the shorter barrel. Not much I know, but maybe it will help offset some for the short length, and help give her a bit more FPE on deer or hogs.

I love that little CZ. I actually bought it for me, to burn the barrel out of as a practice rifle. It has probably 4500 rounds through it in 10 years or so and the throat is starting to go. Probably shot too hot and fast on a fairly regular basis. It has always been a good shooter. 40 VMAX shoots good, and the favorite bullet I shot was the Midway 50 grain Dogtown spitzer. I got a couple thousand of those one time for a little over $50/500, and it really liked them. Shot them 1/2 MOA +/-, and they killed coyotes real well. 55's it doesn't really care for, some of the stumpy 60-65 grain bullets it will shoot OK for deer at 100-150.

Once my daughter got old enough to start shooting it I cut the stock down and adapted an adjustable buttplate system onto it. Then when the can went on the barrel got cut down to 18" She loves the rifle, it has just pretty much become hers now. It has a SWFA fixed 6x42 on it so she can dial it. The 6x is just fine for the hunting she does. I am using Warne 30 mm rings.

Once you have the AI chamber, yes you can just fireform regular 223 brass. As long as the GS did the chamber right. Technically the AI chamber is like .004 shorter or something. The right way is to set the barrel back a thread and re-chamber. If done that way it is pretty much guaranteed you won't have issues. Some do it without setting it back, sometimes that works, sometimes you end up having problems.

[meltingfeather]

I was thinking the AI conversion would help to make up for the shorter barrel.

Cool little project.
Learning opportunity for me... doesn't the AI conversion go against a shorter barrel?
Pressure rating for the chamber is staying the same... AI would allow more, slower burning powder, which will be wasted if you get to the point of muzzle flash. Isn't this the same reason you don't see mags with 18" barrels?
If you use a fast burner to get velocity up with a heavier bullet you're probably going to run into pressure issues is my thinking.
Interested in your thoughts.

[Jethro]

The conversion might go against it if we were talking a larger case that was overbore pretty badly to begin with. Like 243 or 22-250. To my way of thinking though the 223 is a small enough case capacity it shouldn't matter too much. 22-250 or 243 I wouldn't even shoot the std cartridge in an 18" barrel, whereas with the 223 with a 18" or even 16" is fine.

[Jethro]

So as an update, McClain sent me a few 223 AI cases for me to test feeding with in my CZ-527. I loaded up a couple dummy rounds using the 53 VMAX last night and they fed just fine in that single stack magazine. No problems at all. I have a friend bringing in a couple 65 SGK's for me to try over Thanksgiving but I expect no problems with them either.

Looks like it will come down to me just deciding if I want to do the conversion or stick with the std cartridge. I am sure leaning towards the AI at this point though.