Issues re-sizing 223 brass for 20 Practical.

[AlNyhus]

In my 20 Practical, a shortened 204R full length die worked better than a bushing die since it sized all the way to the neck/shoulder junction.

Good shootin'. -Al

 

[Bachekermooni]

I use Sinclair mandrels and die. I believe they have an expander(E) and a neck turning(T) for each caliber. The T is 0.201. The E expander is 1 thou under bullet diameter(my caliper measurements). You could all so use a pin gage in a collet bullet puller die, and have much more latitude for inside neck diameter and various brass thicknesses. The T mandrel works good for me, my 20p is an AR.

Thanks. Where do I get pin gauge(s)?

 

[Bachekermooni]

For my BHW barrel, my 20p brass, I can check brass in the Lyman small rifle ammo checker block(223R). If it drops in flush to the second step it will go into battery AND extract. Then it's only a matter of getting neck diameter correct.

I understand. I have a JP 223 Wilde chamber gauge. Anything that is to go thru that rifle gets checked. Hence, I am using it to check the re-sized cases. It is measures the entire case and not just the length like LE Wilson.

 

[searcher]

The fired brass is from my Kimber, so no AR dents and they never hit the ground. Interestingly, the brass gets approx 0.010" longer after resizing.

My final question: what case OAL do you use? 1.750"?

That is normal

 

[B23]

Interestingly, the brass gets approx 0.010" longer after resizing.

That's because you don't have your FL die screwed down far enough. If a FL die isn't screwed down far enough as the brass goes up inside the FL sizing die it's squeezing down on the case body which causes the base to shoulder length to actually grow or get longer until the shoulder comes in contact with the top of the die and is pushed back.

It's very common to hear of people having brass that would chamber in their gun fine until they FL sized it then they have a hard bolt close or it won't close at all. It's because the die isn't screwed down far enough. This is why it's best to have a set of calipers and a shoulder bump gauge set. They aren't all that expensive and something every reloader should have.

A lot of people freak out about cam over on their press but generally a FL die needs to be screwed down far enough to where you have a certain amount of cam over on your press. Now I'm not talking gorilla strength cam over but a certain amount is usually required or you'll end up with brass coming out longer, after FL sizing, than it was before you FL sized it.

 

[Bachekermooni]

Thanks B23.

I should have been more specific. I have the die turned down just right. The case fits perfectly in the JP Wilde chamber gauge, as before (and in the L.E. Wilcson gauge). The extra length, I believe, is the neck lengthening due to it getting squeezed. I think I have to re-size the case back down to 1.750"(?) again.

 

[B23]

Thanks B23.

I should have been more specific. I have the die turned down just right. The case fits perfectly in the JP Wilde chamber gauge, as before (and in the L.E. Wilcson gauge). The extra length, I believe, is the neck lengthening due to it getting squeezed. I think I have to re-size the case back down to 1.750"(?) again.

Just keep in mind those chamber gauges you're using are usually cut to SAAMI spec not to your actual chamber and chambers vary in size.

 

[457ciSBC]

Thanks B23.

I should have been more specific. I have the die turned down just right. The case fits perfectly in the JP Wilde chamber gauge, as before (and in the L.E. Wilcson gauge). The extra length, I believe, is the neck lengthening due to it getting squeezed. I think I have to re-size the case back down to 1.750"(?) again.

Yes, necking the case down displaces brass and it has to go somewhere,so the case gets longer. I just took 3 pieces of previously once fired, FL sized 223 brass ran it into my .226 case forming bushing and the case length grew .005-.007. These cases were already excessive in length when at 223 so they definitely need to be trimmed down now that they have been necked down to 20 caliber. By the same token, I have formed 20P cases from donor brass that was shorter and did not have to final form trim. I would say that 1.750 is a good trim length for an unknown case chamber length.

 

[Bachekermooni]

Just keep in mind those chamber gauges you're using are usually cut to SAAMI spec not to your actual chamber and chambers vary in size.

Actually the JP gauge is cut with the same reamer as the chamber, according to JP.

 

[Oso]

Actually the JP gauge is cut with the same reamer as the chamber, according to JP.

Yes...but... No.

They may be using reamers ground to the same initial dimensions, but as soon as a reamer starts cutting metal it starts changing dimensions as its cutting edge gets worn down. JP Enterprises is a quality operation for the AR platform with quality manufacturing and tighter tolerances then mil spec. However, there will be some variance/discrepancies in dimensions unless the exact same reamer was used to cut your chamber and then immediately used to cut your gauge Not likely from a large manufacturer... I am sure it is close enough for most guys, but some of the die-hard F-Class and Benchrest guys are getting heart palpitations just reading this

I have JP in my AR10 and AR9, and couldn't be happier. I have one of their case gauges for my AR10 308.