Small base die for semi-autos?

[cfullgraf]

Don't have any 40 cal cases. Hopefully the Sheridan Case Gauge will come this week.

You could use any case that fits over the neck of the 308 Win case and rests somewhere on the shoulder. 3809 ACP maybe, 38 Special, or 357 magnum. If you can cut the body or\ a 223 Rem case square, that would work as well. Or another bottle neck case with smaller body that the 308 Win case.

Your measurement will be a comparison with a case that works, your measurement will not match any standard for the case.

A 40 S&W case just puts the case near the center of the shoulder and does not require any trimming.

 

[AJC1]

You could use any case that fits over the neck of the 308 Win case and rests somewhere on the shoulder. 3809 ACP maybe, 38 Special, or 357 magnum. If you can cut the body or\ a 223 Rem case square, that would work as well. Or another bottle neck case with smaller body that the 308 Win case.

Your measurement will be a comparison with a case that works, your measurement will not match any standard for the case.

A 40 S&W case just puts the case near the center of the shoulder and does not require any trimming.

One can try and drag a horse to water....

 

[redcon1]

As I said earlier I have an inordinate amount of Dies ,mainly because of experimental coatings and Many can't be undone yet function better than New ,so they get USED . ALL I'm saying is in MY particular experience once I realized the actual PROBLEM with MY 7.62x51mm LC machine gun cases ; I was able to rectify it without a SB Die . I had one Hell of a Time Resizing them and SB dies would have just compounded the problem ,as in Stuck Cases . I DIDN'T have to grind a shell holder ,as I DON'T use them but getting " ALL " the Play out of the press was CRITICAL . Bingo Die screwed in bottomed out ,sized the .200" line within spec and set shoulder back Nicely . MY problem solved ,as I also was having NO GO loads . M14's 99.9% fed NO problem but MY AR-10 in .308 I assembled was much tighter tolerance .

Lake City once fired through a machine gun brass is tough stuff to work with. Between the extra thickness and the stretching, there seems to be a lot of brass that needs to be moved around. This is evidenced by the difficulty of trimming this brass after resizing. There's quite a lot of brass getting trimmed off in that first trim. Some tools I found to be useful for reloading moderate to large volumes of it are:

• A Redding SB Body Die,
• a Forster SB Full length resizing die,
• Imperial sizing wax,
• a JP Enterprises min spec case gauge,
• a case prep center
• and a Giraud Tri way cutter.

There are probably other ways to skin this cat but simply passing the crappy once fired through a machine gun brass through the Redding body die before full length resizing them is the best way that I've found so far to get the cases to pass the min spec gauge consistently.
Do they need to pass a min spec gauge? I think so, because it guarantees that the final loaded cartridge will fit in any of the several .308 rifles I own (including my old B series Armalite AR10T) as well as any that I might acquire in the future. But like I say, I'm sure there's more than one way to skin this cat. This is just my way.

 

[Blue68f100]

When I'm working with once fired LC brass I anneal it before I start working with it. Makes sizing a little easier. A 3 way cutter is a must for doing large batches.

 

[cfullgraf]

Lake City once fired through a machine gun brass is tough stuff to work with.

I agree.

Shortly after I got my Springfield M1A, I bought a batch of "once fired" military cases. They sized and reloaded fine and chambered fine in my rifle.

But I had a high percentage of case head failures when they were fired. I suspect they were fired in a machine gun.

As a result, I've become more picky about sources of cases for my semi-auto rifles that use military cases.

For my M1 Garands, I got cases from the range that I shoot at that were fired in Garands. Also, I have cases I've generated from surplus ammunition that I purchased. So, no issues with machine gun cases there.

For 223 Rem/5.56 NATO, I buy new cases or surplus ammunition to generally generate cases for reloading.

 

[redcon1]

But I had a high percentage of case head failures when they were fired. I suspect they were fired in a machine gun.

I had that happen once with my FN FAL on a case that had been reloaded 3 times after it was initially cycled through a machine gun. This brass seems like it has been put through hell between the initial cycling through a machine gun and subsequent cyclings through various semi-auto rifles. I don't think the FN FAL is particularly gentle when it extracts and ejects a case and I think the rifle's violent extraction contributed to the case head separation. I may not have had the gas adjusted properly either. Regardless, I became more cognizant of the case head separation issue after that. Most sources say that rounds resized for a semi-auto should have .003" of headspace clearance so I shoot for that but with this particular brass, I find it to be challenging to get there consistently. That challenge is what led me to the Redding body die.

When I'm working with once fired LC brass I anneal it before I start working with it

Are you getting more reloads out of it by annealing it? I am hesitant to reload this brass more than once out of fear of case head separations. The only case head separation I ever had was with this brass and that was on the third reloading with the FN FAL that I mentioned above in this post. But I have come close to causing a case head separation just resizing the case on more than one occasion. I hypothesized that those particular cases were blown/stretched out in the machine gun more than normal such that I couldn't get them into the FL resizer die all the way and therefore had to pull them out before fully completing the stroke. Here again, the Redding body die seemed to stop that. I again have to hypothesize that it solved this problem by removing the neck sizing operation from the equation. Once it goes through the body die, it's a breeze to size the neck in a regular full length resizing die and the cases seem to give me the .003" of headspace clearance much more consistently. They definitely pass the plunk test in a min spec gauge more consistently. I have held off annealing because A) it's a PIA and B) I'm not sure it will extend the useable life of this brass. But if you're getting 10 or more reloads out of a case by annealing, I'd definitely have to incorporate that into my process.

 

[Blue68f100]

Some of my LC brass has over 10 firings through them. Annealing will not stop case head separation because that is below the area being annealed. Does make the initial sizing goes much easier. Case head separation is caused by pulling the brass out under high pressure stretching it. All my AR guns have adj gas blocks and some have gas to piston conversion with adj buffers. I can tune these to throw the brass in a small controlled pile 3-4' from me so I don't have to chase it. Delaying the extraction till the press drops will help greatly in eliminating case head separation.