oldRoger
US Veteran
Actually your cases should be all about the same length after firing a few times. Straight-walled cases tend to shrink slightly after firing and in my experience stabilize after a while. I have some old military 45acp brass which has been fired countless times and is about the same length as newer cases fired 8-10 times.
The cartridge over all length is going to be dependent to a degree upon bullet shape. Lighter bullets usually end up not as deep in the case as the heavier bullet, this is a factor in the initial development of the load. So what you see published takes the bullet depth in the case into consideration and is why you see COL included in the data. It is an important figure because it affects pressure.
The listed dimensions for the .40 S&W Cartridge Overall Length (COL) is as follows:
Minimum=1.085”
Maximum = 1.135”
I strongly suspect that most pistols will not feed reliably at the minimum dimension. You will also find that your factory ammunition is probably under the max by a bit.
I think for your bullet, the 1.125” COL from Accurate Data is probably a good figure. If you plan to have all of them fall between 1.120/1.125’ you should be good.
I would make up enough dummy rounds to fill your highest count magazine, no primer or powder. at the correct COL and check for feeding in your pistol.
I use Sharpie permanent markers, they work and you can remove the marks if you want with thinner.
The cartridge over all length is going to be dependent to a degree upon bullet shape. Lighter bullets usually end up not as deep in the case as the heavier bullet, this is a factor in the initial development of the load. So what you see published takes the bullet depth in the case into consideration and is why you see COL included in the data. It is an important figure because it affects pressure.
The listed dimensions for the .40 S&W Cartridge Overall Length (COL) is as follows:
Minimum=1.085”
Maximum = 1.135”
I strongly suspect that most pistols will not feed reliably at the minimum dimension. You will also find that your factory ammunition is probably under the max by a bit.
I think for your bullet, the 1.125” COL from Accurate Data is probably a good figure. If you plan to have all of them fall between 1.120/1.125’ you should be good.
I would make up enough dummy rounds to fill your highest count magazine, no primer or powder. at the correct COL and check for feeding in your pistol.
I use Sharpie permanent markers, they work and you can remove the marks if you want with thinner.