size then cut, or cut then size

[T/C Guy]

Size then rough cut slightly long with a small tubing cutter and finish with your case trimmer.

 

[dhamby]

Never heard of using a tubing cutter but size then trim, cases get longer after they are sized.

 

[CathyInBlue]

Adjust for diameter, then adjust for length.

Necking a case changes its length.

Cutting a case does not change its diameter.

 

[sgtonory]

Get a rt 1500 and do all in one stroke.

 

[sgtonory]

Or close to noblesville can use my setup.

 

[T/C Guy]

Never heard of using a tubing cutter but size then trim, cases get longer after they are sized.

5.56/.223 brass is approximately 1.76" long and 300 blk / 300 W is approximately 1.36" long so there is about .4" of brass to remove from each case. It can be done entirely with a case trimmer but I've found it's quicker and easier to cut off most of the excess brass and then finish with the case trimmer.

 

[Broom_jm]

T/C Guy nailed it. I've converted quite a few 30/30 cases to 30 Herrett, which requires a similar process, and after trying different options I started to size and then trim with a tubing cutter. Later on a friend helped me set up a jig and high-speed cutoff wheel. That really sped up the process.

 

[jwh20]

I had the best results with cutting off the 5.56 cases right at the start of the taper to the neck with a cutoff wheel. Then sizing with the die which leaves a long 300 BLK case, then trimming the remaining excess length with a case trimmer. After you do a few you'll get a feel for where to cut initially for minimum trimming.

You can size first and then trim but that's a lot of trimming on the case trimmer. Mine is hand-cranked and my arm got tired really quickly!

If you haven't see this, you might have a look:

https://www.indianagunowners.com/fo...ng-300-aac-blackout-using-223-5-56-cases.html

 

[bstewrat3]

jwh20 has it. You run more of a risk spliting cases trying to neck the original neck and shoulder up to 30 caliber from 22. Just cut the case at the shoulder/body junction with a cut off saw and size it. Trim to length after sizing.

 

[Broom_jm]

Have any of the guys making 300 BLK cases from 223/5.56 found it necessary or advisable to ream or turn the necks, since the brass is a little heavier down the case?