determining max overall length - The Firearms Forum

virginiatech · 12-03-2003, 08:02 PM

I have heard that you can determine the maximum overall length for cartridges when handloading by setting the bullet to a depth where it just reaches the rifling. How do you do this? Is it a good technique? Should bullets still be crimped (does crimping do any good anyway?)

armedandsafe · 12-03-2003, 08:58 PM

That is one way to derive MOAL. Keep in mind that there will be variations in the length as you load, so back off about a thou.

Some guns shoot well with the bullet set out to the rifling, others need some freebore. Experiment. Make sure you have enough bullet in the case to get a good grip on the shank. If your gun normally calls for crimp, you should crimp.

Use a once-fired case and set the bullet into the neck. Push it in far enough that it won't fall out when you put it into the chamber. Put it into the chamber and gently close the action, making sure the action goes fully into battery. Gently remove the cartridge and start measuring. Mark that one with fingernail polish or some-such as a "standard." Mark it so you will know it is to be used only for determining MOAL

Pops

virginiatech · 12-04-2003, 07:27 AM

Thanks Pops. How do I know if my gun usually calls for crimp? As you can probably tell I only recently sarted reloading. I load for the .270 and the 7.7 JAP primarily. I got the cheepo LEE relaoding kit with a factory crimp die. Should I crimp for these cartridges?

Xracer · 12-04-2003, 07:35 AM

A & Ss way works well with rimmed or bottlenecked cartridges.

Be aware though, that on cartridges for auto pistols, they must be crimped, since they headspace on the crimp. Also, even though a particular pistol may have a longer chamber than the maximum published OAL, a cartridge made up to that length may not feed from the magazine properly.

armedandsafe · 12-05-2003, 02:50 PM

Rifle cartridges, particularily bottle-necked ones are not normally crimped. Any cartridge used in a tube magazine should be crimped (and flat-nosed.) The reloading manuals should tell you whether to crimp. The manual which comes with the dies will mention crimp, if it is normal practice to crimp that cartridge.

A light crimp or "factory" crimp on any cartridge is not usually a problem, unless you are loading to extreme pressures. As you might have noticed in my various posts, I am a great believer in having several reloading manuals and reading all of them.

Pops

12-03-2003, 08:02 PM	#1
virginiatech Member Join Date: May 2003 Posts: 5	determining max overall length I have heard that you can determine the maximum overall length for cartridges when handloading by setting the bullet to a depth where it just reaches the rifling. How do you do this? Is it a good technique? Should bullets still be crimped (does crimping do any good anyway?) -->

12-04-2003, 07:27 AM	#3
virginiatech Member Join Date: May 2003 Posts: 5	crimp Thanks Pops. How do I know if my gun usually calls for crimp? As you can probably tell I only recently sarted reloading. I load for the .270 and the 7.7 JAP primarily. I got the cheepo LEE relaoding kit with a factory crimp die. Should I crimp for these cartridges?

12-03-2003, 08:58 PM	#2
armedandsafe Former Guest Join Date: Dec 2002 Location: Moses Lake, WA Posts: 10,344	That is one way to derive MOAL. Keep in mind that there will be variations in the length as you load, so back off about a thou. Some guns shoot well with the bullet set out to the rifling, others need some freebore. Experiment. Make sure you have enough bullet in the case to get a good grip on the shank. If your gun normally calls for crimp, you should crimp. Use a once-fired case and set the bullet into the neck. Push it in far enough that it won't fall out when you put it into the chamber. Put it into the chamber and gently close the action, making sure the action goes fully into battery. Gently remove the cartridge and start measuring. Mark that one with fingernail polish or some-such as a "standard." Mark it so you will know it is to be used only for determining MOAL Pops

12-04-2003, 07:35 AM	#4
Xracer TFF Admin Staff Mediator Join Date: Feb 2001 Location: Minn-eeee-sota, ya, sure, you bet! Posts: 9,144	A & Ss way works well with rimmed or bottlenecked cartridges. Be aware though, that on cartridges for auto pistols, they must be crimped, since they headspace on the crimp. Also, even though a particular pistol may have a longer chamber than the maximum published OAL, a cartridge made up to that length may not feed from the magazine properly.

12-05-2003, 02:50 PM	#5
armedandsafe Former Guest Join Date: Dec 2002 Location: Moses Lake, WA Posts: 10,344	Rifle cartridges, particularily bottle-necked ones are not normally crimped. Any cartridge used in a tube magazine should be crimped (and flat-nosed.) The reloading manuals should tell you whether to crimp. The manual which comes with the dies will mention crimp, if it is normal practice to crimp that cartridge. A light crimp or "factory" crimp on any cartridge is not usually a problem, unless you are loading to extreme pressures. As you might have noticed in my various posts, I am a great believer in having several reloading manuals and reading all of them. Pops