Case length.

DGY

DGY

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Good evening all,

Regarding case length, if the book said the case is max length is 2.441(9.3x62) what would be too short? What is the ideal(if there is such a thing) trimmed length?
I’m setting up my case trimmer and want to make sure I don’t trim too short!
Thanks
 
Not sure there is a "too short" as long as the neck holds the bullet. Probably for accuracy/consistency there is a too short, but no idea what that would be. Too long is very bad. The danger is that if the case hits the end of the chamber/start of throat during firing it can crimp down on the bullet and make very dangerous pressures. Normally a chamber has some extra space even for a max length case but need to measure everything out to make sure.

I typically trim to 0.005" under max for my cases. Be aware that case length will change after sizing- so it is better to trim sized brass IMHO. No reason for 0.005", that's just what I do.
 
Yeah that is what I thought but just wanted to make sure! I always mesure the total case length before reloading and never use one that is longer than max length!
I’ll keep them under by a little!!
Thanks
 
During the Boer War, DWM supplied 7x57 ammo that was actually made by using 7.65x53 cases necked down, so 4mm short, or 5/32". The Boers soon experienced a rash of blow-ups, and the cause was put down to the short necked ammo ( and it was referred to as "kortneck"). The theory was that the short neck was causing excess throat erosion, and the increase in friction was raising pressures and causing the bullets to break up in the barrel. I'm not sure how definitive the proof was, they were in a shooting war after all, with little time or facilities for testing. At any rate, the ammo got a bad reputation.

7x57 Kort neck.jpg

The standard trim-to length in most reloading manuals is 1/10" below max case length. With the experience of the Boers in mind, I prefer to err on the side of caution and not trim below that.
 

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Thank you all this is good info! So .0005( more like .005 hahaha) it will be!
 
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DGY said:
Good evening all,

Regarding case length, if the book said the case is max length is 2.441(9.3x62) what would be too short? What is the ideal(if there is such a thing) trimmed length?
I’m setting up my case trimmer and want to make sure I don’t trim too short!
Thanks
Click to expand...

The ‘trim to’ length for the 9.3x62 is 2.431”.
 
9.3mauser said:
During the Boer War, DWM supplied 7x57 ammo that was actually made by using 7.65x53 cases necked down, so 4mm short, or 5/32". The Boers soon experienced a rash of blow-ups, and the cause was put down to the short necked ammo ( and it was referred to as "kortneck"). The theory was that the short neck was causing excess throat erosion, and the increase in friction was raising pressures and causing the bullets to break up in the barrel. I'm not sure how definitive the proof was, they were in a shooting war after all, with little time or facilities for testing. At any rate, the ammo got a bad reputation.

View attachment 563153

The standard trim-to length in most reloading manuals is 1/10" below max case length. With the experience of the Boers in mind, I prefer to err on the side of caution and not trim below that.
Click to expand...

Interesting facts! Another potential cause could be build up in the throat area from shooting the short necked brass and not getting this build up removed before using long necks again. Switching to the long neck brass could have resulted in not having room for the neck to expand because of the carbon/crap in the neck area ahead of the short necked brass. Anyway- thanks for the story, gotta learn from our history!
 
Mauser98 said:
The ‘trim to’ length for the 9.3x62 is 2.431”.
Click to expand...

Well my Lyman book, my Lee book and Nosler website all day 2.441… the only place I find 2.431 is on the barns website…
Chuck Hawk and Ron Spomer are also saying 2.441, so I don’t know what is right or wrong, but that is what I will go with!
 
My Frankfort Arsenal universal precision trimmer is everything but precise… really finicky to adjust! I need something else!
 
I get anything from 2.425 to 2.435… I would be happy with the latest. Is it safe to use the shorter ones?
 
DGY said:
Well my Lyman book, my Lee book and Nosler website all day 2.441… the only place I find 2.431 is on the barns website…
Click to expand...

Hornady 9th Edition reloading manual - page 588 - "Max. Case Length: 2.441" "Case Trim Length: 2.431". Same thing on page 650 of Speer #14 Reloading manual. Nosler 9 Reloading Manual - p. 66 - " ... measure the cases' overall length to be sure they do not exceed SAAMI maximum length". SAAMI 2015 calls out length for 9.3x62 case at 2.441"-.020", so SAAMI Max is 2.441" and SAAMI Minimum for case is 2.421". Be aware that the Otto Bock guy who invented the 9.3x62 in Germany, was perhaps 20 years before SAAMI existed, so there might be other numbers out there.

I do not compete, so others may know different - I want less than Maximum, and then all the same - maybe just being "fussy" when I do not have to be - I do not like mixed lengths - I want mine all the same as I can make them. Maybe from the times when I used to crimp into cannelure groove on bullets - I no longer do that any more, but old "habits" die hard ...

I happen to use the Lee Case gauge trim system - have not really fussed a lot about exact length - it makes each case the same as the other - when I measured, is shorter than Maximum length and often longer that "Trim" length, for any particular cartridge - must be more than a dozen of them here, for various cartridges. As above, your chamber is cut with a recess (space) for the case neck - so do not want to run into end of that - keeping your brass at or below Max length ensures that there is clearance there.
 
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Potashminer said:
Hornady 9th Edition reloading manual - page 588 - "Max. Case Length: 2.441" "Case Trim Length: 2.431" Nosler 9 Reloading Manual - p. 66 - " ... measure the cases' overall length to be sure they do not exceed SAAMI maximum length". SAAMI 2015 calls out length for 9.3x62 at 2.441"-.020" , so SAAMI Max is 2.441" and SAAMI minimum for case is 2.421". Be aware that the Otto guy invented the 9.3x62 in Germany perhaps 20 years before SAAMI existed, so there might be other numbers out there.

I do not compete, so others may know different - I want less than Maximum, and then all the same - maybe just being "fussy" when I do not have to be - I do not like mixed lengths - I want mine all the same as I can make them.

I happen to use the Lee Case gauge trim system - have not really fussed a lot about exact length - it makes each case the same as the other - when I measured, is shorter than Maximum length and often longer that "Trim" length, for any particular cartridge - must be more than a dozen of them here, for various cartridges. As above, your chamber is cut with a recess (space) for the case neck - so do not want to run into end of that - keeping your brass at or below Max length ensures that there is clearance there.
Click to expand...
Thanks!!
 
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