Cannelure and Cartridge Overall Length

[Xeon64]

According to my reloading manual this is the Minimum COL. You can see next to loaded round the bullet and how little is seated. I am wondering if this is ok or if it would be ok to drive it into the Cannelure. This is a 30-40 Krag with a 150gr FMJ Hornady bullet loaded to starting load.

 

[Sig220]

In years past, projectiles were made for a cartridge and if they had a cannelure/crimp ring, the case mouth is where it was made to go. Most military cartridges are crimped to prevent the projectile being accidently pushed back in the case where it could cause problems for the user in times of need.

These days, they make the projectiles to load and fit a range of cartridges of the same caliber/diameter and the cannelure is not always correct. (For civilian/reloading uses) You should use the COL that is listed from the reloading data source you are using. This COL will get you to the correct chamber pressure. Shorten COL and increase pressure, lengthen COL and reduce pressure.

An example of is taking a 150gn fmj that was loaded in a WWII era .30 caliber (30-06) and loading the projectile in a .308, the cannelure will NOT be where it should be seated to.

So to the point and simply.... use the manual's minimum/maximum COL and you will be good. If you seat any deeper, you increase the case pressure as well.

 

[Xeon64]

Thanks. That is what I was thinking.

In years past, projectiles were made for a cartridge and if they had a cannelure/crimp ring, the case mouth is where it was made to go. Most military cartridges are crimped to prevent the projectile being accidently pushed back in the case where it could cause problems for the user in times of need.

These days, they make the projectiles to load and fit a range of cartridges of the same caliber/diameter and the cannelure is not always correct. (For civilian/reloading uses) You should use the COL that is listed from the reloading data source you are using. This COL will get you to the correct chamber pressure. Shorten COL and increase pressure, lengthen COL and reduce pressure.

An example of is taking a 150gn fmj that was loaded in a WWII era .30 caliber (30-06) and loading the projectile in a .308, the cannelure will NOT be where it should be seated to.

So to the point and simply.... use the manual's minimum/maximum COL and you will be good. If you seat any deeper, you increase the case pressure as well.