Sizing cases and Properly seating over sized Boolits

[Smokepole50]

I have been reloading for a long time but this is my first real serious adventure into cast boolit reloading. I have loaded some 8mm Mauser boolits that I bought and used a 8mm expanding die to open up the case mouths after standard case sizing. Reading here I see that method basically causes the back of the boolit to be sized down by the brass that is sized to small. If not, then the standard seating die would achieve the same undesirable results of reducing the boolit driving bands size. So I have a few questions.....

What methods/tools do you use to properly size your case necks for the over sized cast boolits? Do you buy a custom (larger than standard) Lee collet die so the brass does not get over worked?

[pdawg_shooter]

Lyman "M" die works for me.

[robroy]

You can adjust the lee collet die to size just enough to hold a boolit. The collet won't be forcing the brass onto the mandrill at that point. It takes some tinkering but you can get the case neck to grip any boolit that fits into the unsized neck. Be careful if the size is too close to the ID of the chamber's neck the brass will not have enough room to release the boolit. I'm trying this with my Ruger 7722 Hornet. As cast 225462 from my mold just fits into the unsized necks. A dummy fits the chamber a bit tight so I need to size the boolits, I'm guessing, .001 and then size necks to grip the boolit. A set of pin gages would help to keep things consistant in sizing the cases and so would an impact slug of the chamber. If you don't have the gages and haven't slugged your chamber go by feel.

[462]

As mentioned, if you ignore the directions that come with Lee's collet neck sizing die, you can size the case to create your desired neck tension.

Then, a Lyman M-die can be use to open the mouth just enough to squarely hold the boolit.

Depending upon how fat your boolits are, you may need a custom M-die expander plug.

[DLCTEX]

Using the Lee collet die will require you to sort cases by at least headstamp when using the above method due to varying thickness of brass.

[Smokepole50]

If need be I guess I could always turn the case necks down a bit if I run into a chamber that is a little tight for the boolit I need to use. I think I have a 7mm mandrel.

After a long phone conversation with a fellow forum member here in VA, I believe I am relieved of my concerns about the ID of the case neck being to small after sizing with a standard 7mm neck die. His explanation was, that after the case mouth was belled out large enough with a M die for the CG to fit inside the mouth of the case, that the GC hardness would prevent the base of the boolit from being resized down below the desired dia. by excessive neck tension caused by a standard neck sizing die. I guess a 16-18 BHN lead alloy boolit with a copper GC properly applied would present enough strength to swell the remainder of the case neck below the M die bell and not sucum to any swaging during the seating process. I know this is probably splitting frog hairs here but I want to do things right the first time and know that my reloading process is not faulty if my groups are not as tight as I like. This 1912 Chilean Mauser is in NRA fine condition and should shoot very well if I do my part in the loading process.

[Von Gruff]

I use a VLD case mouth tool to chamfer the mouth almost to the outside of the mouth making sure to leave a rim of square on the edge. I have my dies stoned so they do not over size the neck down and then the expander mandrel of my neck trunong set is enough to allow the GC entry without the risk of sizing or shaving lead from the drive bands.

[243winxb]

Define oversize? Lyman "M" die & gas checked base is fine for a .310" boolit in a 308 -3006 or 30-30

[gunoil]

Lil' off subject:For pistol i use rcbs expander step dies instead of bell die's from other companies. Brass looks better at top and if ya use a boolit dropper they fall rite in. They seat and crimp better IMO. Its like a ring around the base of boolit to "set" in instead of a waller'ed out tipping bell brass top. Even if i did rifle i would do step expansions. I like lite dillon crimp dies.

[popper]

Use the 31 M plug for 310-311 sized cast.

[pdawg_shooter]

Use the 31 M plug for 310-311 sized cast.

That is what I do. I paper patch all my rifle bullets so the #31 is just about perfect.