20 Practical brass life

[IA_shooter]

I'm starting to have issues with my 500+ pieces of 20 Practical brass I have that are on their 4th or 5th firings. It all started as once fired LC a few years ago. About 25-30% of them are starting to show signs of separating (the tell tale shiny ring verified by a paperclip run along the inside of the case to feel the bad spot) or are separating about 1/3rd of the way from the bottom of the case.

I have been sizing the brass to where the shoulders are about 6-8 thousandths set back from fired dimensions and I'm guessing that is my problem or my headspacing could be a touch long but I don't think so as my 223 go/no-go gauges tell me it should be fine. My fired brass measures 1.456" from the base to the shoulder (using the Hornady Cratridge Headspace Gauge Kit) and wonder if any very experienced reloaders and or gunsmiths can tell me if this seems to be an acceptable fired length. My next batch of LC once fired brass I'll be converting to 20 Practical I'll make sure I only bump back the shoulders around 2-3 thousandths to see if I can get better life out of the brass.

On a side note, if I go with a 20-223AI instead of the 20 Practical, how much better brass life can I expect with the Ackley Improved version? I think I have enough barrel to play with I may just have my GS ream it out to 20-223AI after I get back from my upcoming Prairie Dog trip I'm going on in a few weeks. Thoughts?

 

[Terry]

6-8 set back is far too much. The case should be sized so the bolt just drops freely on varmint rounds. If you can put a piece of scotch tape on the back of the case and it closes you went too far.

 

[Ledd Slinger]

Yeah thats too much sizng on the shoulder and sounds like either your die is built a little tight at the base or your chamber is a bit oversized. FL sizing shouldn't work the base so hard it creates a weak spot that ends up in head separation.

But theres really no reason to care about brass life with the 20 Practical because once fired 223 brass is very abundant and ridiculously cheap. I think I paid $40 shipped for my last lot of 500 LC brass to form 20 Tactical. I would still be happy if I only got one firing from them.

 

[nmkid]

I'm on 4 firings on my converted LC brass and the primer pockets are still fine. I bump back about 2-3 K's. I was planning on firing them once and then chuck them but, they are still fine, so, I continue using them.

 

[mensajd]

Get the redding competition shell holder set and bump shoulders back 0.003 for an AR and 0.001 for a bolt gun.

 

[jepp2]

I have been sizing the brass to where the shoulders are about 6-8 thousandths set back from fired dimensions

As mentioned, 0.002-0.003" shoulder setback from the length where you can feel the bolt close on the brass (not the fired dimension). It usually takes several firings before the case is long enough to feel the bolt close on the brass (depending on your load).

I haven't run a case life test on my 20P's. I did run a case life test on 223 brass fired in an AR. Never had ANY show any signs of incipient case head separations and got to 35 loadings. I would expect the way I load my 20P's to be at least as much.

I personally couldn't see much advantage to going with the 20-223AI, but could see several disadvantages. But I'm not you.

223 Go Gage length is 1.464" Unless you measure an actual Go Gage with your Hornady comparator, it might not be exactly the same. Pretty soft aluminum on the gage that can develop a slight bevel and change the reading. It is pretty close however.

 

[IA_shooter]

I personally couldn't see much advantage to going with the 20-223AI, but could see several disadvantages. But I'm not you.

The reason I'm considering going to the ackley improved version is to possibly make the brass more stable and less prone to "stretch" with the improved shoulder as well as a slight increase in case capacity.

Also curious to what disadvantages I may encounter doing this other than possible feeding issues?

Thoughts from others encouraged as well!

 

[jepp2]

I'm not trying to convince you not to, but these are the ways I see it.

Pro:
1. Greater case capacity and higher velocity
2. Less case stretch
3. Uniqueness factor

Con:
1. I can already get 4000 fps out of the standard case, so even higher velocity is going to reduce barrel life
2. I would expect I could get 35+ loadings from an AR and over 50 in a bolt gun, so how much improvement is really necessary?
3. Can't match the uniqueness
4. Have to fireform
5. Dies are going to cost more and be more limited in availability
6. Potential feeding issues, dependent on the rifle you shoot
7. Harder to find a barrel chambered for the 20-223AI, or a smith with the reamer
8. Resale value is going to be lower

But hey, I shoot a 20 Bobcat, so I already have experience with all the cons. And I like it.