9mm cast sizing question

[milprileb]

Gents, my sizing die is making my cast bullets come out .356 and a few .3565.

I have no issues with my loads or bullets sized this way but my question is this:

?? Is 356 the optimum sizing die for 9mm Luger ?? I seem to recall some of you
use .357 or .358 and get better accuracy.

I am getting no leading (WW water quenched bullets, 124 RN Lee mold) and would like to try sizing a different size to see if it would improve accuracy but I also do not want to go too large and end up with leading issues.

Some help and thoughts from your experience would be greatly appreciated.

[Cherokee]

Lots of people use 357, some 358 because their gun tells them they need the larger size. I always use .356 because it works in my guns. Make a dummy round of each size and see if they will "plunk" test in your gun barrel. If so, try a few, might be better, might not. Leading should not be a problem.

[milprileb]

Should I slug bore of my 9mm pistol with a unsized booolit and then go a size higher than it measures out to be?

thanks

[MtGun44]

Slug the bore and shoot .001 or .002 larger diameter is the usual route to success.

The 9mm is somewhat of a problem child. I recommend avoiding the Lee tumble lubed
designs, we have fielded questions from many folks trying TL in 9mm with poor results.

I have had excellent results with Lee 356 120TC conventional lube groove design with
NRA 50-50 lube sized to .357 diameter. Others find .358 works for them.

Bill

[milprileb]

Thank you MtGun44

[MtGun44]

You're welcome, sir. 9mm has been a challenge, with some finding that their carefully
size boolits were being resized by the brass case, or in some situations, a Lee FCD
was sizing down the case and the boolit inside. The end result was leading and
tumbling because the boolit turned out smaller than intended. Too small is THE
major issue with cast boolits, and esp 9mm since there is a very wide variation in
groove diameter seen in the field.

Bill

[Gunsmoke4570]

If you are not having problems, I'd stick with what you're doing. I load for a few 9mm and a couple want the .358", so I run mine through a .358 sizer so they work in all of them.

[evan price]

I use a 357 Lee push through sizer for my 9mms and it works better than 356 did. The Sigs seem to like fatter boolits.

[bobthenailer]

i size all of my 9mm & 38 super bullets to 0.357 dia all though they slug to 0.355 .
i have factory barrels in some and match Nowlin and Kart barrel in 2 others.
The Nowlin although EDM rifled and the Kart slugs 0.355 dia both shoot better groups at 25 yards with the 0.357 dia bullet over the 0.356 . testing was done from a ransom rest .
you mat also want to try 0.358 dia let your gun tell you what it wants !

[Hardcast416taylor]

I size .357" for my M92 Beretta.Robert

[leftylaroo]

i bought berrys plated bullits last time, this time i bought rogers better bullets. rogers are longer than berrys, what or how do i seat them so that the pressures are not dangerous?

[MtGun44]

You want to use less powder if you shrink the combustion chamber volume. If your boolit is
longer, you either seat it with the base in the same place as the previous one and deal with
the longer cartridge length. If the LOA is unacceptable, you need to go back to the starting
charge and work back up. A chronograph is a useful device for this, you would load until you
got the same velocity as the load book says, and with a smaller combustion chamber you will
probably get it with less powder - but roughly the same pressure.

Bill

[JRHYS]

I have been given advice by mould makers to slug barrel and size to .001 over slug diameter measurement. In my experience, hard cast bullets will come out of the mold into cold water .001 diameter larger. Jerry

[casterofboolits]

Your pistol will tell you what it likes. My HiPower sure did. It would tumble at five feet an lead the bore big time with .356 boolits. With a boolit sized .357 it was a one holer at 15 yards and it cleaned the lead out!

.357 works quite well in my Witness pistols too.

[Ugluk]

My taurus needs .358, but then I ran into difficulties chambering.
Using thinner walled FC, WIN or WCC brass fixed this.

The Lee 120TC I don't like so much as I feel the grease groove is too far from the base.

[milprileb]

Its worth 15 bucks to get the Lee .357 size die and see results.

I do get good accuracy at .356 but .357 might be the ticket. When
I went from .451 to .452 for 45 acp cast bullets, the difference n
accuracy was significant.

Considering time and effort and gear to produce the volume of cast bullets
I need to feed my pistol shooting addiction, a 15 buck sizer die is money
well invested.

[lead-1]

I am loading the LEE 356-120 TC boolit for my Kel Tec and it works great after some tinkering with a load. I am glad that boolit was suggested by another member.

If your load works as is then I would leave it but as stated slugging your barrel and going up .001-.002 is the answer. I started this learning curve with a .44 mag revolver and +1 on the pistol telling you what it likes.