[karnaaj]

I'm loading 9mm for the first time (actually first pistol caliber I ever loaded) and I have been using the Lee manual that says a OAL of 1.169 yet when I was measuring a factory round it was quite a bit shorter. Around 1.100. The rounds I loaded will chamber fine but i have not had a chance to get to the range yet. Why the difference?

[RustyFN]

The max is 1.169. You didn't mention what style of bullet you are going to reload. I load RN bullets at 1.135. My manual calls for HP ot FP to be loaded at 1.120 but they wouldn't chamber in my CZ. I loaded them at 1.035 to get them to chamber, started at the start load and worked up.
Rusty

[karnaaj]

These are 115g RN FMJ.

[Jim Watson]

The maximum is 1.169" OAL but I have lately been loading 124 and 147 RN to 1.152", and might should go a little shorter still for use in the new Metalform 10 round magazine.

A hollowpoint or flatpoint will be a lot shorter.

[Galil5.56]

1.169" is the max dimension allowed for 9mm Luger. You will see a lot of factory ammo shorter than this (esp jacketed HP's with a flat meplet 'nose'), and for handloading 9mm a shorter OAL will be needed many times because of bullet weight, type, and shape.

For example, I load many cast bullets with a swc profile that have to be loaded just over an inch (1.075") in order to clear the rifling and function safely. Many times there is no hard and fast rule about OAL, but going too deep will develop higher pressures (almost catastrophic if too deep), and it is best to at first use a makers seating depth reccomendation first, and perhaps play a bit with it. IMO, it is best to start with a nice 115/124 round nose FMJ, where usually loading to 1.15" is a nice happy medium.

Good luck!

[Urbana John]

The OAL of 9mm or any cartridge for a semi auto weapon is not as important as the case length as long as the weapon will "cycle" the round.

The case length is important because that's the "chamber" depth/length. If the case is too long,the slide/bolt won't close.

If you try to get "right at" factory specs for OAL, some bullets won't set properly in the case, and may not fit the mag.

The OAL of a straight wall rimmed cartridge isn't that important either because the rim stops against the chamber like in a revolver cylinder.

Unless you load "hot" rounds, and use carbide dies, most "auto" type cases never need trimmed, but still good to check them once in a while.

UJ

[JDGray]

Factory WWB ammo using your bullets, oal runs 1.160. My reloads usually stay pretty close to 1.155(using win bullets), but every bullet profile is different between manufacturers.

[shu]

Just a thought, particularly if you are new to pistol ctg reloading.

The 9mm is a small case and typically runs at high pressure. As mentioned above, shortening the o.a.l. beyond some point will cause a large pressure spike. Where that point is, I don't know. But I do think about bullet weight and profile as well as powder load when I am tinkering in 9mm, and favor long o.a.l. rather than short.

Stay safe - shu

[Walkalong]

I load

Ranier 115 Gr RN at 1.135
Ranier 124 Gr TrFP at 1.060
Rem 124 Gr GS at 1.065
Berry's 124 Gr HP at 1.030
Zero 125 Gr HP at 1.080

Start low and work up.

[karnaaj]

Thanks for all the replies, guys. Its good to know that there is a little playing room in regards to OAL. Being new to this and also being kind of anal about things I tend to follow directions to the letter.

I have another related question. After resizing the cases I find that I don't need to use the die that flares the mouth in order to seat the bullet. They seat fine without that step. Is this an indication that I might be doing something wrong?

[goon]

It depends on bullet weight and shape but 1.169 is the max. You don't have to load them that long and if you're loading 115 grain FMJ's that long it might be a little more space than you need inside the cartridge. But it also shouldn't hurt anything as long as they fit in the mag and function OK. I always load just a little longer than the manual calls for and never load completely to the max. It just adds a little extra safety IMO.
Try chambering a loaded round, then extract it and look to see if there are any marks on the bullet from contacting the riflings. If there are it could cause a spike in pressure.

It would depend on what type of bullet you are using as to how hard it would be to seat without flaring. I have seen some LRN bullets that have a bevel at the rear so they'd probably seat without much flaring.
Try this - load and crimp a dummy round (you don't need much crimp on a 9mm) and measure the OAL. Then place the bullet against your bench and put a little pressure on the rear of the round with your thumb. Measure it again. It should be the same length you started with. You have now passed test 1.
Take the loaded dummy round to your 9mm firearm and chamber it from the magazine several times. Return to your bench and measure it again. OAL should still be the same. You have passed test 2.
If you don't have problems with your bullet slipping into the case with these "tests" I wouldn't worry much about it.

Also, keep the dummy round with your 9mm dies and load a dummy round for every bullet type you try. Then to reset your dies to a different bullet type all you have to do is loosen the seating stem, run the appropriate dummy round into the die, and tighten the seating stem down on it. It can save a lot of time with adjusting dies.

[murph50]

Quote
I have another related question. After resizing the cases I find that I don't need to use the die that flares the mouth in order to seat the bullet. They seat fine without that step. Is this an indication that I might be doing something wrong?

It sounds to me like your resizing die is not resizing properly. I would recheck the instructions that came with the dies that you are using and be sure you have it set up correctly

[RustyFN]

What press and dies are you using? How are you charging the case with powder? If you are using a powder through die and have it set close to the shell plate then it is expanding the case.
Rusty