What diameter do you size your 9mm Luger?

[Blkpwdrbuff]

First off thanks for the replies on the loads for a 9mm Luger.
I have decided on the Lee 120 gr TC bullet to load for my son-in-law.
Now my next question.
Do you guys size them .356 or .357?
I'm just trying to get a feel for this as I have never done a 9mm Luger before.
This will be shot in an HK P30 9mm.
Thanks for helping out:)
Blkpwdrbuff:castmine:

[Nora]

That depends on what size the bore is. Slug it first, then size to .002 over that is the base rule of thumb.

[JIMinPHX]

.359"

But then, I was loading for a sloppy old ex-military gun.

9-irons vary quite a bit. You really need to slug them.

[bohokii]

i thought i was sizing mine to .356 cause that is what the die said

but i calipered them and they are all .354 i guess my lee size die is shrinkin them a bit more than as advertized

unsized my drops are .357 but are abit oblong sometimes

funny my 452 sizer shrinks my boolits spot on at .452

cant really slug since i am loading for 4 different 9s

so far so good

[geargnasher]

First off thanks for the replies on the loads for a 9mm Luger.
I have decided on the Lee 120 gr TC bullet to load for my son-in-law.
Now my next question.
Do you guys size them .356 or .357?
I'm just trying to get a feel for this as I have never done a 9mm Luger before.
This will be shot in an HK P30 9mm.
Thanks for helping out:)
Blkpwdrbuff:castmine:

Try .342" and a 1" square of pillow ticking:kidding:

But seriously, no one can offer valid suggestions until you and we both know what your slugged groove diameter is, so please find out and we'll be glad to help.

Gear

[jimkim]

My Guru, has three different 9mm's and all three prefer a different size.

[NuJudge]

You have to worry about not just a bullet large enough to fill the grooves, you also have to worry about the bullet in the case being small enough to fit in the chamber. I have had guns with a groove diameter so huge that I could not chamber a cartridge with a bullet that big. If it happens to you, stick to jacketed.

CDD

[9.3X62AL]

2 SIGs and one Ruger all prefer .357" sizing.

[geargnasher]

You have to worry about not just a bullet large enough to fill the grooves, you also have to worry about the bullet in the case being small enough to fit in the chamber. I have had guns with a groove diameter so huge that I could not chamber a cartridge with a bullet that big. If it happens to you, stick to jacketed.

CDD

When that happens to me I rebarrel or sell the gun.

edit: sorry for the hijack.

Gear

[MakeMineA10mm]

I size all of my 9mm to .357", but I have all modern 9mms, except for a WWII P-38. It shoots the .357" boolits just fine (good accuracy, no leading), so I'm not complaining.... :Fire:

[snaggdit]

i thought i was sizing mine to .356 cause that is what the die said

but i calipered them and they are all .354 i guess my lee size die is shrinkin them a bit more than as advertized

unsized my drops are .357 but are abit oblong sometimes

funny my 452 sizer shrinks my boolits spot on at .452

cant really slug since i am loading for 4 different 9s

so far so good

I would slug your barrels and see what the grooves are. You might just want to load as cast. The oblong should fix when loaded/fired. The other option is enlarging your sizer. There is a thread a few weeks ago discussing this technique. It's not hard. Who knows? You might find all 4 have .356 grooves!

As for the poster, +1 on slugging YOUR barrel. That is the only size that matters! And as others have said, .001 to .002 over is where you need to start. I laughed out loud when I saw the .342... Since you are obviously casting these, cast a few in pure lead and slug the barrel. Best time you will ever spend. Trial and error will take wayyyy longer.

[Echo]

I have loaded for my Walther P-1, and it seems to sneer at all rounds I have loaded. But. I use .357 -402 Lymans and .358 105 Lee's, and blame the gun.

In any case see what is the largest size your gun will chamber, and try that...

[dromia]

To reinforce what has already been said.

The only thing that can answer your question is the barrel/chamber of the gun you are going to shoot a particular boolit in.

Make a slug/cast of your chamber, throat and bore and then you will know exactly what sizing your boolit needs.

[SCIBUL]

I had a SPHINX until last year and my boolits were .358 (as cast) but results were just OK. I'm sure it would have prefer .359...

[Will]

Isn't a 9mm supposed to have a grove of .354? I don't have a 9mm but load for my son and his slugged at .354 so that's what I sized for. I have since bought a .356 sizer to see if it would improve groups which are not real good at .354.

[Hardcast416taylor]

I have to pistols in 9mm Luger. They were made about 70 odd years apart. I solved my bore size problem by sizing all my boolits .357" and have nary a problem from either.Robert

[JIMinPHX]

i thought i was sizing mine to .356 cause that is what the die said

but i calipered them and they are all .354 i guess my lee size die is shrinkin them a bit more than as advertized

unsized my drops are .357 but are abit oblong sometimes

funny my 452 sizer shrinks my boolits spot on at .452

cant really slug since i am loading for 4 different 9s

so far so good

What are you measuring with? Dial calipers sometimes have a bad spot in the rack & give off readings in certain ranges.

[finishman2000]

all my 9mm's like 356 except my browning. 358 for that

[Rockchucker]

My Ruger likes .356 and seems to like em. I did change from alox to a stick lube to get the results I wanted. Slugging a barrel is kind of a pain, but worth while.

[Le Loup Solitaire]

Hi, The math in converting 9mm to inches says .354+something small; I originally tried using bullets cast to .354 and then .3555 and couldn't hit the side of a barn standing in it. As many folks can say .356 as others can say .357, and there are 2-3 ways to approach the problem. You can lay out the money for each size sizing die and size them yourself or else have someone lend you/make you bullets sized to each diameter and try them, or as many others have already said...slug your bore and either measure the slug or have someone with a good micrometer measure the slug for you. A local machinist may do you a favor as it only takes a couple of seconds in time. .358 and anything bigger may be a little on the big side and you might have a loaded round with a neck to big to chamber. At the same time bullets that are too small in diameter may cause two distinct problems; first they may not fill the bore and they will not seal gas and/or will tilt in the barrel which gives poor to terrible accuracy plus the probability of leading. Secondly and this is mega-important....in the 9mm you've got to have adequate case grip or neck tension on the bullet. If you don't have that then the bullet may move backward even a slight amount when it hits a/the feed ramp. Any decrease in the air/powder space in the 9mm round changes the pressure upwards by a lot more than anyone thinks and especially if one is using a warmer loading to start with...it can become excessive and if things get too hot then the gun gets battered, slides can crack and the whole deal can go bad. It is probably easier and best to slug the bore and find out exactly what sizer you will need. Going .001over that is ok if there is no bulging and use a mild taper crimp. Good luck. LLS

[Lloyd Smale]

Have had my best luck in the 9s with 357

[Salmon-boy]

I'm with everyone else for slugging your bore. It's really not that hard - use a soft lead round ball or similar implement.

My wife's got a bunch'o'nines and every one is different from the Sig at .356 to my BHP, which likes .358.

[Freischütz]

.357 has worked well for me. Most 9mm Par bores I've seen are oversized.

My Steyr M1912s need .359 (and I'd like to try .360).

[EMC45]

I'm with Salmon-Boy on this one. I have a MK3 HP and it loves a .358 boolit. That's all I load for it. IT feeds and shoots them very accurately. 120gr. Lee TC boolit over 3.5gr. Bullseye.