I brought home four sets of .223 dies - 3 full-length, 1 small-base; 2 rolled crimp (which I cannot use), 1 tapered crimp, 1 with no crimp; all have some issue. To many options. Think I let this one set a day.

A small based die resizes the case back to minimum sammi specs for the cartridge. The idea behind the small based die is to resize the case back to minimum sammi specs so it will work on all platforms like semi-auto, bolt action, lever action. Be aware that the small based die does work the case harder and you will not get as many reloads out of the case compared to a normal FLD or neck die.

If you're sizing brass fired in your own rifle, you probably don't need a small base die if you have the standard chamber.

However if you've just picked up a big batch of machine gun fired brass as surplus from the military or other surplus house, you probably need a small base die.

Small based dies also sets the shoulder back a few thousands to minimum sammi specs.

That said, would it be beneficial to have both the small base die for the initial resizing of unknown origin brass and then use a full length or neck resizing die for subsequent reloads on the brass from YOUR rifle

Tapered crimp is a good idea for the ar platform!!

Sounds like someone at RCBS needs to be taught on how to pack items properly in a box before shipping.

Based on your comments, OV1, it sounds like I should load up some dummy rounds and run them through my chamber to make sure the full-length resizing does the trick. Turns out the RCBS Comp Die with the micrometer seating depth adjustment needs an adaptor to load .223 bullets. To many parts for me. I'm just going to go with the Redding Dies and keep it simple.

When I have filled seaters I have always used the hard hot-melt glue. I have also drilled a hole to relieve any pressure on the point.

Thanks, PaulS. I'm going to have to do something. The dies load 77gr SMKs and 75gr A-max just fine, but pull the Barnes bullets right out of their cases and I have to take the dies apart to get the bullet out.

Slim - I use the Forster micrometer seater with 75-77 BTHPs and A maxes and get no ringing. I used a Lee seater for a while and got some severe marks on the A max. The VLD type profile needs a modified seater as they will hit on the top of the taper ring that is profiled for a fatter 55-62 style bullet , which most stock seater dies are set up for. Forster seems to be a compromise taper ange on the seater ring that hits the bearing srface of the seater on a broad variety of bullet profiles.

FWIW - I have used a small base RCBS -X die and at 8 loads on a lot of Winchester brass and 6 on some LC brass and while getting a few neck splits since I never annealed them I am getting no signs of case separation. I set the should back .003 from fired dimension which in my WOA Wylde chamber... is Saami spec.

Thanks, Dawgdad. Does the full-length sizer set the shoulder back at all? I ran three cases through the Redding FL resizer. If I close the AR bolt slowly, it won't completely chamber the round and close the bolt. If I drop the bolt it does fine and cycles all the round through the magazine. Its the same for both my ARs. I had a friend full-length resized some brass for me and the bolts will close on the shell if I close it slowly. Is this an indication that I need to use a small-base die?

I would say hold off on buying the small base die for now. Since it seems like you will only be using new brass or brass that was fired in your gun, the cases will form to your guns chamber and will only need neck or FLD sizing.

Adjust the FL sizer die so it just barely, or even not at all, sizes the brass. Then chamber the brass and close the bolt, with no powder, primer or bullet, and see if it will close. It should not yet. Then keep adjusting the sizer down a bit at a time until it will. That is the best for your chamber. You will be sizing the brass enough to chamber, but not any more than needed. It will extend brass life, and can be more accurate.

FLD will set the shoulder if you set it to do that. Set it too low and you will make the neck squat like a 6mm Hagar case..

You may have a compatibility issue with the shell holder if you cannot get the set back or sizing you need. If the sizer die bottoms out on the shell holder . I have heard of guys facing off a few .001's on the bottom of their dies or top of the shellholder to get the setback they needed.

How are you measuring shoulder setback? Do you have a micrometer die or the Hornday tool for that?
I use a cheaters way. I use the Hornady OAL gauge for a 30 cal and use that as my datum reference for fired versus sized shoulder dimensions.

If you can find one, an a Mo's gauge by Mo Defina is the cats backside for .223 sizing control. Micrometer set to Saami with index values off of that datum point.

I would bet my left jewel that your WOA chamber is dead on Saami dimension and sizing to -.003" from that will not over work your brass and insure positive feeding.

Dawgdad wrote:

How are you measuring shoulder setback?

I have been using a Dillion case gauge. When I drop the fired brass in, its right at max length, maybe just a tad proud. After I run the case through the Redding FL die its slightly below the max level. I haven't found a good way to measure the difference. It might be a 0.001.

I have a wilson gauge with the cuts for min and max headspace but i cant usually get the case all the way into the gauge before sizing it some.

I like being able to measure my starting point with the OAL tool for 30 cal on the shoulder and set the bump back from that. Damn brass is springy stuff though.

I ran a couple of cases through the RCBS Small Base Die and compared to the RCBS Full-Length. There was no decernable difference in the shoulder position but the base dimension was 0.0008 smaller. Not as much difference as I would have expected.

How much did they shrink at the body/shoulder junction ???

I think that is about what you would expect with a small base. Shoulder definitely should not be different unless you set it to something longer.

the base diameter went from
0.3746 fired
0.3739 Full-Length
0.3731 Small Base

(this was the harder measurement to take but was the biggest change)
the shoulder diameter went from
0.357 fired
0.351 +- 0.001 Full-Length and Small Base were the same