Short Brass

[jrplourde]

I want to evaluate some new cast bullets and would like to load as accurately as I can. These are 9mm and the manuals (Lyman, Lee and Hodgdon)indicate a trim-to-length of .751. With any auto shell length is important.

I have measured my random supply of shells and they ALL measure between .740 and .745.

What can I expect from these?

Bob

 

[jrplourde]

I want to evaluate some new cast bullets and would like to load as accurately as I can. These are 9mm and the manuals (Lyman, Lee and Hodgdon)indicate a trim-to-length of .751. With any auto shell length is important.

I have measured my random supply of shells and they ALL measure between .740 and .745.

What can I expect from these?

Bob

 

[OKFC05]

You didn't mention what kind of gun.
If you are using moon clips in a revolver, no problem.
If your semi-auto actually headspaces off the extractor as many do, you'll never know the difference. My Paraord Tac Five actually loaded and fired a .380 (case 2mm too short)I accidentally put the in magazine, no problem.
There are some pistols that short 9mm cartridges can possibly cause misfires.

 

[jrplourde]

OKF I'll be shooting with a S@W 39-2

bob

 

[OKFC05]

Can't see why you would have any problems with length.
Be sure and clean all the copper out of the barrel before shooting lead for best accuracy and to keep from scraping lead out of the barrel later.

 

[john traveler]

Whether your 9m pistol "headspaces off the extractor" or not is immaterial. Firing pin protrusion is almost unlimited in most auto pistol designs. You could reliably fire those cartridges even if the case was 0.100" too short.

 

[jrplourde]

Thank you very much gentlemen. This forum is certainly a learning experience.

Bob

 

[FrankD45]

Originally posted by jrplourde:


I have measured my random supply of shells and they ALL measure between .740 and .745.

What can I expect from these?

Bob

Were the cases fired and not yet sized? If so, it is normal for fired cases to grow a bit as a result of sizing. I have found that to be true with 9mm as well as .45 ACP.

I hope that helps,

Frank

 

[john traveler]

For top-notch accuracy in an autoloader, your brass has to match the chamber length. Usually, that means case length closer to maximum than minimum. Shooting a batch of loads with mixed-length brass will nothing except give you larger-than-satisfactory group sizes. Bullseye and accuracy shooters have known this for a long time.