223AI question....using with Hornady Headspace gauge

[Deleted old_dood]

what headspace gauge bushing should I use for 223AI. I already have the bushing for 223. Would I also have to have a fireformed case sent to them to use the OAL tool or would I be able to use my original 223 modeified case?

 

[bheadboy]

I have had and do have a number of AI calibers, I first sent a fired case to them, then tried the following

fire a round with a new case with a near max load, then remove the primer, and drill the primer pocket out and tap with a tap to match the Hornaday threads, the next thing is to carefully open the neck swith the expander button and clean thoroughly so the bullet will slide as needed. I can get the bump measurements, oal base to lands length and then load as I want for jump.

works fine.

Bob

 

[Deleted old_dood]

I was mainly concerned about which headspace bushing to use.

 

['Freak]

Buy Sinclair’s insert cut with a matching 40° shoulder instead of an orifice same as diameter at the datum line. They’ll fit and work in your old Hornady body or in Sinclair’s.

 

[Deleted old_dood]

would that be item 749-011-482WS ?

http://www.sinclairintl.com/reloading-equipment/measuring-tools/case-gauges-headspace-tools/sinclair-bump-gage-insert-ackley-improved-to-6mm-40--sku749011482-35265-74250.aspx?sku=749-011-482

 

['Freak]

Yes, Sinclair’s #749-011-482 is the one for your .223AI w/40° shoulder.

 

[Brians356]

I use the same Hornady comparator for 250 AI as specified for 250-3000. All you can really do with the gauge is monitor relative changes in the shoulder position, using a once-fired case as a baseline for comparison. As long as the bushing contacts the shoulder somewhere near the middle of the shoulder, you can really use a small range of hole sizes, but I just use the bushing specified for the parent cartridge. For 223 Rem that's the "330" comparator.

For OAL, either modify one yourself (drill and tap) or send it into Hornady. There's also a chap on this forum (I think) who offers to modify them.

But note that you should sand down and polish the body slightly to make sure it will slip into the chamber all the way to the shoulder with no resistance. Even a once-fire case, not even a hot load, will expand enough at the pressure ring to not want to slide home freely with light finger pressure. What you're really trying to create is a case with the shoulder pushed forward to you chamber's dimension, but the body still "as unfired". If, after you insert the gauge until it stops, you find you need to tug on it to pull it out of the chamber, it's too tight in the body!