9mm sizing diameter

[SoonerEd]

Got my first Star on the way and am going to use it mainly for sizing 9mm Luger and 45 ACP. I'm trying to figure out which diameter sizing die to order for the 9mm. Given the cost, I just want to order one 9mm for now. For the 45, I know that I need a .452.

I slugged 4 9's and got

.355
.355
.356
And one got an inconsistent reading and is somewhere between .355 and .356.

If I get a .357 die do I have a good chance of covering all four. Is there a down side to using a .357 bullet for the .355 barrels instead of a .356. The .355s are what I shoot the most.

The inconsistent barrel .355-.356 is a factory glock barrel so likely will not shoot much lead through it.

[Conditor22]

I know you don't want to hear this but: it depends on the gun, the hardness of the alloy, and if you PC or not, what type of lube and how fast you're going to push the boolit.

.357 shouldn't be too big, IF the accuracy isn't there for the .356 barrels maybe try .358

[SoonerEd]

I'm loading 9mm Luger so 1,000 - 1,050 fps range. The 45 ACP is a 155 SWC that runs around 1,200. I'll be using white label lube red carnuba.

So, while every gun is different, no reason reason to not buy the .357 first and see how it does in all for guns?

[243winxb]

A .357" diameter bullet may require a short COL if the throat of a chamber is smaller in diameter.

My 9mm Taurus requires smaller then .3568" to chamber correctly.

Been loading for 50 years, but just started 9mm for the grandson. https://www.thehighroad.org/index.php?media/users/243winxb.11944/albums

https://www.thehighroad.org/index.php?media/free-bore-throat-diameters-in-9mm-luger.3612/full

[Larry Gibson]

I'm loading 9mm Luger so 1,000 - 1,050 fps range. The 45 ACP is a 155 SWC that runs around 1,200. I'll be using white label lube red carnuba.

So, while every gun is different, no reason reason to not buy the .357 first and see how it does in all for guns?

The .357 sizing will probably do fine. For many years I shot many COWW cast bullets lubed with javelina (50/50) sized .356 through all sorts of 9mm including subguns w/o any problems at all. Then I read on the internet and in some gun rags that I should have gotten all sorts of leading any keyholing because i wasn't sizing the cast bullets larger. What I was doing wasn't broke but I went through a lot of gyrations trying to fix it. To the point; my cast bullets (of numerous designs from 100 to 125 gr) when sized larger than .357 began giving chambering problems in some pistols as 243winxb mentions. I never did have any leading or keyholing when a proper alloy was used. These days I've gone back to sizing .356 but bullets sized .357 were fine.....most of the time.

[SoonerEd]

I friend of mine said I can borrow his .356 die if I want to order a .357. Then I can test both through all the pistols and a PCC i haven't slugged. But Ive shot .356 125 commercial cast through the PCC with no issues.

[Bigslug]

Ed,

My slugging of seven 9mm's has shown mostly .356" barrels and one .355". Am running the NOE/Ranch Dog 135 grain tumble luber of WW + 2% straight out of the mold at .357" dunked in 45/45/10 and couldn't be happier with the results - even in the .355" gun.

Doing my initial sizing of Winchester brass with a Lee .38 S&W/.38 Auto to avoid brass swaging of the bullet and finishing in a Dillon 9mm taper crimp die to set the case mouth O.D. at the correct spec of .380"

[GBertolet]

I have found that cast bullets on the big side, shoot best in the 9mm. .357 is usually fine, but .358 is better if they chamber in your gun. 9mm barrels can run from .354 all the way up to .358. I have two BHP barrels that run .358. If you are going to load big bullets in the 9, you will need a custom, or at least a 38 special expander plug, as the standard 9mm expander is too small, and will swage down the bullets, as you seat them. This defeats the whole purpose of using big bullets. Many 9mm molds, don't want to cast that large, so you may have to settle on a .357 diameter 9mm bullet, or get a 38 special mold. The Lee 38 cal 125 gr mold is doable, and inexpensive to try.

I modified a 38 special expander for my single stage press, and made an oversided expander for my Dillon SDB. They work fine.

[Mal Paso]

I went .3565" which produces .357" with water dropped. Still experimenting with air cooled and water dropped.

I was thinking a light polish would make it a hair bigger if needed.

[hoodat]

Just remember, "If it won't plunk -- it's junk". jd

[gwpercle]

I have found .357" works fine for 9mm Luger . Have worked up loads in 5 different pistols .
It might be on the large size according to the "Book" specifications .

For 38 special / 357 magnum .358" works fine ... Truth be known , .357" would probably work just as well . I sized my revolver boolits .357" for 30+ years because the Lyman Cast Bullet Handbook 3rd edition specified it . Now the new 4th edition specifies .358" sizing dia. , so I bought a .358" die .
Honestly can't really tell a big difference . If you can only afford one size ... get .357"
and size them all .357" . I don't powder coat , soft lube only , Lithi-Bee is my favored lube .
All my handgun boolits are air cooled , 50-50 mix COWW & soft lead ( BHN 8 ) it is a rather soft mix but works , no leading with any handguns .

Note : Newer 9mm Luger's don't have much throat ... so .358" size may not chamber unless deep seated . I found Truncated Cone designs to work best and I prefer the 120 t0 124 grain weights best/most accurate ...there are exceptions of course !
Gary

[Old Caster]

What GBertolet said about having a large enough expander to keep from swaging the bullets down if they are a bit soft is very important. A bullet of a BHN around 8 (which I mostly use) can be swaged down to to as small as .351 by some brass and bullets will tumble when shot. Some brass does it worse as some is tapered quickly where it gets smaller not as deep as others. You may not be able to expand the cases as much as you want because the chamber may not be tolerant enough but I would expect you certainly should be able to go to .356. Check the expander you are about to use because generally they are way smaller than one would expect. Even a 38 may be smaller than .356. If you are shooting commercial bullets, usually brass is not strong enough to swage the bullet down too much.

[dale2242]

I size all bullets for 9MM to .357.
I haven`t had a problem in any 9MM with that diameter yet.

[ABJ]

My general rule for 9's is feed it the largest boolit that will chamber after the chamber is dirty. In my guns that is .357 in all of them except one. The PT92 will take a .358 but the difference in accuracy is nill, so everything gets .357 with a 125 truncated cone.
Side note, after slugging several Colt barrels in 38 and 357 the groove measurements are closer to .355/.356 range than .357. They always get .358 boolits. Just an FYI, I don't get excited about barrel groove measurements, I do about chamber and revolver cylinder measurements. I always check the barrel specs but if they are in spec, I don't worry about it.
Tony

[SoonerEd]

Thanks everyone. Got to get my dies ordered from lathsmith as my Star came in today.