Short 9 mm brass?

[Sophiedoc]

Although I have reloaded multiple other calibers I have not reloaded 9mm Luger.I acquired some 9mm used brass in good condition stamped 9mm Luger but all measures.741 to .744 in length.Several books including Lyman,Dunlap etc use the figure of .752 to .754 and trim to.751(Lyman).Dunlap lists max chamber as .758.This brass would seem to create too much headspace unless the extractor holds the round securely when fired?I'm confused.

[JCHannum]

A quick check of a couple of reloading manuals agrees with the 0.754" dimension.

It sounds like someone slipped a digit with the case trimmer. I don't think excess headspace will create a danger as much as it could result in reliability problems, causing a weak primer strike and potential extraction problems.

If you purchased the brass, I would recommend returning it as it is not in spec.

[Bguns]

I don't know where SAAMI came up with that long .754 figure..


Have to check the Euro version of SAAMI, CIP I think..

Most European 9mm Ammo is well under .750 Brand new....
S&B is ~.746
PMP ~.744
Canadian MKI Ball ~ .747

Have a box of US Made UMC, it is around .752

Have had no Problems with light primer strikes in Glocks, C96, Luger,
Open Bolt Stens, UZIs, Macs.... MP5s etc...

[Sophiedoc]

Will load some and try in P38 wearing eye protection etc.Thanks.

[deltaenterprizes]

Will load some and try in P38 wearing eye protection etc.Thanks.
You should ALWAYS WEAR EYE PROTECTION when shooting!!!!!!!!!!!
Do you thing anybody plans for a gun to malfunction or explode?

[huntinguy]

9mm is very susceptible to pressure. If the cases are short, it will drive pressure way up.

If it were I, I would keep OAL to published data and load at minimum. But that is just me. :)

[JCHannum]

A short case can result in a compressed load and higher pressures, so care should be taken.

If I remember correctly, European 9mm's are loaded at higher pressures, and the case length could contribute to that. The Luger requires quite a bit of pressure to operate and I seem to recall that some US ammo is too wimpy to for some to function reliably.

[Bguns]

Seating bullets too deep in any 9mm/or other Brass can/will drive up pressure.

Case length has nothing to do with Pressure. A slightly short case holds just as much with Bullet seated at same overall length as a longer case.

Bullet seating depth can be critical on small capacity cases like the 9mm..

Seating to recommended overall length will help minimise any chance of seating bullet too deep.

As I stated before, the 9mm was an Import in the US and the US standards do not match Euro standards..

Some of my older reloading manuals, skip the 9mm Para, even though guns were available ...

[JCHannum]

True, if you seat to the proper overall length, but it could be problematical if seating to the cannelure in the bullet. As with reloading any cartridge, all aspects should be checked & double checked, especially when working with maximum or near maximum loads.

[Bguns]

Roll Crimping into Cannelure will make things worse headspace/pressure wise.

Taper crimp does not depend on Cannelure to secure Bullet. If Bullet has a Cannelure and is being used for a Taper crimp Cartridge ignore it...

I really have loaded thousands of 9 mm..

http://www.redding-reloading.com/pages/crimpdies.html

Roll Crimping is NOT RECOMMENDED for 9mm, .45 Auto, .380 etc, Or any Cartridge that headspaces on mouth of case.......

edit:
There are always exceptions, and in this case, if loading for a Moon Clip type Revolver, a roll crimp into cannelure may be used.... Provided Overall length for that bullet/load is appropriate...

[Sophiedoc]

Good advice on the bullet type and crimp on the rimless 9mm, etc.My main reloading has been rifle ,belted and rimmed rounds.The headspacing on the 9mm is what worried me with the short cases.Thanks.

[deth502]

well, i know im digging up an old thread, but....

i dont have any manuals on hand right now to check, but it may be that some had cut down some 9mm luger cases to reload some 9x18 mak rounds.

ive done it myself, but i always first quickly chuck them in the lathe and cut a slight grove in the rim, just as deep as, and mostly obliterating the origional head stamping, to keep from mixing them up with the 9x19 reloads.

[mcskipper]

My copy of a NRA book (1981)
SAMMI For the cartridge is .754" -.010"
Chamber .754" MIN .776" MAX.
.003" short brass with that much tolerance in the chamber will be O.K. unless you like to load HOT.

NEVER roll crimp on any case that headspaces off the case mouth.
Taper crimp is correct if you like to crimp.