223 AI throat length?

[LB243]

I am sending a rifle in to pacnor to have a new 223AI barrel put on. It is going to be a 1-12T barrel as I want to shoot light bullets 40-55 gr bullets with the possibility of a borderline 60 gr. My problem with my current 223 AI barrel is it was throated wrong, 1-12t with a throat for seating 80 or so grain bullets. Its currently a .158 jump for a 55 gr vmax bullet! I am trying to figure out if I want a sammi throat length(I think is 1.88) or a shorter length. The dummy rounds I have worked up place my 40 gr vmax at a COAL of 2.235 and base to ogive 1.840. This also works for the 55 gr vmax and 53 gr vmax but the latter two would be seated a bit deep into the case. Would this deep seating cause any problems? or could someone recommend a good seating depth? I hope this rambling mess makes sense! Thanks.

 

[expiper]

LB,,,.050" FB will work fine with 60 gr and smaller bullets,,,Roger

 

[Phil]

I did mine @ zero freebore, for whatever that`s worth...... ???

 

[Dvldawg]

I also built mine with 0 FB and I had no intentions of shooting anything other than 40 gr. bullets, I talked to Dave when I ordered the reamer and that was a suggestion that was made and as the throat erodes you can chase the lands..

 

[boltman223]

With my experience I would go no less than .040 and would probably do .050 like expiper said. I have a zero freebore 222 and a .025 freebore 223. with the zero freebore and a shorter neck like the 223 50 grain and up bullets would take up to much powder capacity even so with my .025 freebore 223 and that's just with the 50's.This is just my experience with my reamer.


Like others have said you can chase the lands but, it will take a lot of rounds to go even 040. I think that's a lot of rounds to give powder capacity and in turn velocity for. Think about if you want to take advantage of the 60 grain bullets, you will be sacrificing a lot of the advantage by not being able to use the whole boiler room. You can chase the lands for a long time with .040 or .050 freebore.

This is just my opinion based from my experience. I hope I helped.

 

[Fivebulletsonehole]

SAMMI freebore is .062". I know I literally just ordered my reamer.

I find that the SAMMI chamber works very well for all weights. It is very, very good for 52-55 grain bullets.

This is only .008" shorter than the Army 223 Match reamer (.070" freebore) that is used for 80 grain bullets. I guess more freebore could increase case capacity even more, but I would guess the Army did pretty well with their 223s.. haha

 

[ReedG]

I like .000" but never shoot anything but 40-52-53 gr. bullets and 1,000s of them with the case full of Varget.