COL Length?

[jaybrown]

Hey guys. I was loading some rounds the other day and was not having any luck hitting my COL that I was looking for. My spec was 1.125 and as I adjusted my die I kept hitting 1.1240,1.1260,1.1245 and so on. I kept bouncing around the number which was fustrating. Previous times I hit it on the nose. How precise does the COL need to be? The rounds seem to chamber fine. I'm loading for my 40S&W and I know case pressure could go up alot if the COL was too small. But does 0.001" really matter. I'm new and do things to the book. Am I being to picky? Thanks

 

[Sharps Shooter]

"But does 0.001" really matter." No.

"Am I being to picky?" Yes.

The bullet noses are not exactly the same. You're right to be careful though - seating a bullet way deeper than recommended can raise pressures. But by worrying about .001" you're only frustrating yourself.
Without changing the setting of the stem in your seating die, take a close look at a few of your completed cartridges. I'll bet with your naked eye, you can see minor differences in the noses, or tips of your bullets, which will account for minor differences in COL.

 

[jaybrown]

Thanks for the input Sharps Shooter

Its hard to defeat the perfectionist in me

Would you say 0.01" would be something to be concerned about?

 

[Sharps Shooter]

Yeah, I'm a bit of a perfectionist myself - my wife occasionally lets me know about it.
However, yes I do think .01" might be something to be concerned about. In your original post you mentioned you were loading for the .40 S&W. That's a relatively short cartridge. I mean, .01" is a greater percent of COL of the .40 S&W than it is of say the .44 Special COL. And it seems to me the .40 S&W operates at relatively high pressure for a handgun cartridge anyway.
But I'm kinda blowing smoke here. I've never loaded for the .40 S&W so I'm not sure if .01" differences in COLs, with the same bullets, would be that bad. I only suspect it would. It can make a difference in big game rifle cartridges. If I seated the bullets just .01" farther out in my, or my wife's rifles, the bullets would be tight up against the rifling lands.

 

[JDGray]

I like to load out as far as possible. I usually duplicate factory cartridges, which load on the safe side. The longer oal also helps with mag rattles. My Lee manual also gives the min oal, which is a very usefull spec. Load safe!

 

[Doug b]

Jaybrown try measureing a few of your bullets and I'll bet you get more than .001" difference.For auto's I seat out as far as the magazine will allow and still feed 100%.

 

[Run&Shoot]

Make sure your variation is all on the long side of the load data OAL. If the load data stated the pressures were with a OAL of 1.125, then make sure your variation is 1.125, 1.126, 1.127...

If this is for a .40 S&W with a 180 gr bullet then absolutely do not go shorter than the stated OAL. If you are loading lead bullets then keep checking every fifth loaded round or so to make sure lube isn;t biulding up insude the seating die and causing the bullet to be seated deeper the more you load.

It is always safer to load a little long. A little short may be OK, but with some powders and some cartridges adn bullet weights evena .01 difference can raise pressures significantly.

If for some reason you get a lot of variation in OAL then you should not try to load to max powder amounts.

 

[jaybrown]

Cleaning Tips?

Run&Shoot, thanks for your response. You were talking about the lube building up on my dies. After loading some of my lasercast I pulled the seating plug and didn't see much residue. My question is how should I clean my dies. Whats the best method to get the lube out. I have some good degreaser that I use to clean my guns. I just don't want to damage my dies. Same with the sizing die. People talk about keeping them clean.

 

[Run&Shoot]

I use Breakfree or anything similar that is handy. Once cleaned then be sure to wipe the Breakfree completely off. You don't need anything harsh. Q-tips, a nylon brush (the manly gun cleaning kind that only *looks* like a toothbrush), and a clean shop towel usually does the trick for me.

Just be sure to disassemble the seating die so you can get all the crud wiped off good.