How critical is case length?

Prof Young · March 29, 2009, 11:24 PM

Loaders:
The saga of my first attempt to reload my 223 goes on. My Lee instruction say my case length should be no more thatn 1.760 inches. Most of my cases were coming in at exactly that. However I had a few that were measuring between 1.762 and 1.764. I put those aside and will get some trim equitment, but am wondering if that small difference truly matters. I am shooting these out of a bolt action (Remington model seven).
Thanks for you thoughts.

Prof Young

bullspotter · March 29, 2009, 11:38 PM

If they are over.... TRIM THEM. If they are to long they may jam slightly in the camber, smashing the case into the bullet posibly causing higher pressure when fired, If your reloading books say dont load a case over xxxxx.xx inches. Dont do it!!!

Mr Odd Six · March 29, 2009, 11:41 PM

Even one gives you 50-70/1000ths slack.

The only way you can know for sure is to make a chamber size gauge, and
see what yours is.

To long isnt bad, to short can lead to cartridge damage.

To give you an idea of how far they can be off.

The SAAMI standard for 30-06 is 2.494
One measures at 2.522, and the other at 2.510

.280 slop.

I can trim my cases anywhere between 2.517 and 2.494

I like a little wiggle room, so I use 2.500 (got this thing for even numbers)

which is 4x what I need, but I had a few buckled shoulders closer, so I gave them a tad more room to expand.

azsixshooter · March 29, 2009, 11:43 PM

I have reloaded some cases that were a couple thou. too short, but if they are too long I always trim them back. Lately I've just been setting the shorties aside and I'll figure out what to do with them later. I was told that reloading a slightly short case might just not be very accurate. I figured a couple of firings would stretch them back to an acceptable length. Keep in mind, I'm only talking about cases just slightly under, if I were to somehow screw up and trim them way too short then I'd probably just use them for making snapcaps with or something.

L'derry · March 30, 2009, 05:52 PM

azsixshooter,

Not to hijack the thread, but I only find MAX case lengths. I'm loading .380s and usually these come new around .673 - .674 and don't change more than 1/2 to 1 thou after full sizing. Max case size is .680.

So how much shorter than MAX should a re-loader consider a case to be "undersized"?

vranasaurus · March 30, 2009, 06:34 PM

Quote:

So how much shorter than MAX should a re-loader consider a case to be "undersized"?

The reason you only see max is because cases grow and not shrink. Your cases appear to be under the trim to length of .677", as listed in Lyman 47, but your talking about .002" to .004" which isn't going to make any difference.

I don't trim straight wall pistol cases and I know that a lot of other people don't either.

Shoney · March 30, 2009, 06:51 PM

L'derry
cases should be trimmed 0.010" shorter than max case length
i.e. case max is x.x35 you would trim to x.x25

Mr Odd Six
Are you saying that you trim cases 0.021" longer than the SAAMI recommended maximum???????????????????????????????????????????

**Shane Tuttle** · March 30, 2009, 08:18 PM

Quote:

The reason you only see max is because cases grow and not shrink.

This may be for bottleneck pistol and rifle cases, but I've seen .40SW, .45ACP, and 9mm shrink on a regular basis...

bullspotter · March 30, 2009, 08:52 PM

length is less critical for straight wall auto pistol casses, they will get shorter with more firings and reloadings, as you size a straight wall case, the die makes it smaller in dia, pushing the wall of the case in, but it also pushes down making it shorter. My glocked brass will shorten up a bunch after resizing in a carbide die, Now ive taken some microlon gun juice and lubed several 40S&W cases before sizing, and they are not as short (on average)as the non lubed casses, the reason is less friction on the die to brass surface forcing the brass in more insted of in and down. a auto pistol case head spaces on the case rim, if its shorter, the case will go in the chamber deeper, and if its to long, it will not go in as far, but in both casses the rim of the case is resting on the chamber edge, unless your brass is WAY to long or short, then you may not get good primmer hits, or the gun wont go into battery.

A rifle case headspaces on the shoulder of the case. When you size it, you often push the shoulder of the case back, working the brass makes the neck longer. If the neck is to long, it will hit the bore of the rifle before the shoulder of the case touches in the chamber, when you close the bolt, it forces the neck harder into the bore area, this may cause a tight crimp on the bullet as it will smash the case into the bullet. This will increase the starting pressure when fired, and some times alot!!! You may or may not be ok with a few thou longer, But if you ask me, if the reloading book says it shouldnt be over xxx.xxxx.....then it pry shouldnt....... they are giving that info for a reason!!!

vranasaurus · March 30, 2009, 10:53 PM

I stand corrected.

I will say that if a minimum length were important I would think it would be listed in reloading manuals. Especially considering how detailed they are.

Mr Odd Six · April 1, 2009, 12:51 PM

Quote:

Mr Odd Six
Are you saying that you trim cases 0.021" longer than the SAAMI recommended maximum???????????????????????????????????????????

Why yes I am.

Im not using a factory firearm. I had the chamber cut long, so the neck holds more of the projectile.

With factory built firearms you ALWAYS stay within the specs.

Mr Young,

You are correct in setting them aside. With out measuring your chamber depth and knowing how long or short from spec you are.

Shoney · April 1, 2009, 05:14 PM

Quote:

Mr Odd Six wrote:
With factory built firearms you ALWAYS stay within the specs.

Thank you for the clarification by adding that statement.

March 29, 2009, 11:24 PM	#1
Prof Young Senior Member Join Date: August 21, 2007 Location: Illinois - down state Posts: 2,404	How critical is case length? Loaders: The saga of my first attempt to reload my 223 goes on. My Lee instruction say my case length should be no more thatn 1.760 inches. Most of my cases were coming in at exactly that. However I had a few that were measuring between 1.762 and 1.764. I put those aside and will get some trim equitment, but am wondering if that small difference truly matters. I am shooting these out of a bolt action (Remington model seven). Thanks for you thoughts. Prof Young

March 29, 2009, 11:43 PM	#4
azsixshooter Senior Member Join Date: April 22, 2007 Location: Pinckney, MI Posts: 657	I have reloaded some cases that were a couple thou. too short, but if they are too long I always trim them back. Lately I've just been setting the shorties aside and I'll figure out what to do with them later. I was told that reloading a slightly short case might just not be very accurate. I figured a couple of firings would stretch them back to an acceptable length. Keep in mind, I'm only talking about cases just slightly under, if I were to somehow screw up and trim them way too short then I'd probably just use them for making snapcaps with or something. __________________ "Which side are we on? We're on the side of the demons, Chief. We're evil men in the gardens of paradise, sent by the forces of death to spread devastation and destruction wherever we go. I'm surprised you didn't know that." --Saul Tigh http://sargesrollcall.blogspot.com/2...s-no-more.html

March 30, 2009, 06:51 PM	#7
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	L'derry cases should be trimmed 0.010" shorter than max case length i.e. case max is x.x35 you would trim to x.x25 Mr Odd Six Are you saying that you trim cases 0.021" longer than the SAAMI recommended maximum??????????????????????????????????????????? __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

March 29, 2009, 11:38 PM	#2
bullspotter Senior Member Join Date: November 2, 2008 Location: Montana Posts: 308	If they are over.... TRIM THEM. If they are to long they may jam slightly in the camber, smashing the case into the bullet posibly causing higher pressure when fired, If your reloading books say dont load a case over xxxxx.xx inches. Dont do it!!!

March 29, 2009, 11:41 PM	#3
Mr Odd Six Junior member Join Date: March 17, 2009 Location: Washingrad not DC Posts: 133	Even one gives you 50-70/1000ths slack. The only way you can know for sure is to make a chamber size gauge, and see what yours is. To long isnt bad, to short can lead to cartridge damage. To give you an idea of how far they can be off. The SAAMI standard for 30-06 is 2.494 One measures at 2.522, and the other at 2.510 .280 slop. I can trim my cases anywhere between 2.517 and 2.494 I like a little wiggle room, so I use 2.500 (got this thing for even numbers) which is 4x what I need, but I had a few buckled shoulders closer, so I gave them a tad more room to expand.

March 30, 2009, 05:52 PM	#5
L'derry Member Join Date: November 6, 2008 Location: NH Posts: 63	azsixshooter, Not to hijack the thread, but I only find MAX case lengths. I'm loading .380s and usually these come new around .673 - .674 and don't change more than 1/2 to 1 thou after full sizing. Max case size is .680. So how much shorter than MAX should a re-loader consider a case to be "undersized"?

March 30, 2009, 08:52 PM	#9
bullspotter Senior Member Join Date: November 2, 2008 Location: Montana Posts: 308	length is less critical for straight wall auto pistol casses, they will get shorter with more firings and reloadings, as you size a straight wall case, the die makes it smaller in dia, pushing the wall of the case in, but it also pushes down making it shorter. My glocked brass will shorten up a bunch after resizing in a carbide die, Now ive taken some microlon gun juice and lubed several 40S&W cases before sizing, and they are not as short (on average)as the non lubed casses, the reason is less friction on the die to brass surface forcing the brass in more insted of in and down. a auto pistol case head spaces on the case rim, if its shorter, the case will go in the chamber deeper, and if its to long, it will not go in as far, but in both casses the rim of the case is resting on the chamber edge, unless your brass is WAY to long or short, then you may not get good primmer hits, or the gun wont go into battery. A rifle case headspaces on the shoulder of the case. When you size it, you often push the shoulder of the case back, working the brass makes the neck longer. If the neck is to long, it will hit the bore of the rifle before the shoulder of the case touches in the chamber, when you close the bolt, it forces the neck harder into the bore area, this may cause a tight crimp on the bullet as it will smash the case into the bullet. This will increase the starting pressure when fired, and some times alot!!! You may or may not be ok with a few thou longer, But if you ask me, if the reloading book says it shouldnt be over xxx.xxxx.....then it pry shouldnt....... they are giving that info for a reason!!!

March 30, 2009, 10:53 PM	#10
vranasaurus Senior Member Join Date: November 16, 2008 Posts: 1,184	I stand corrected. I will say that if a minimum length were important I would think it would be listed in reloading manuals. Especially considering how detailed they are.