projectile seating depth

[E Rock]

Oops double post

 

[Huckelberry75]

This is it exactly. The only way you would get perfect OALs is if your seating punch was totally flat and only had a point of contact at the furthest forward point of the bullet, which would be the same point you are measuring from with your calipers. As it is, the seating punch touches the bullet somewhere on the ogive, or a corner of the hollow point for instance. If your calipers measured from that same point of contact you would see almost no variance, unless it's a compressed load you are loading. There will be variances among the bullets even from the same box.[/QUOTE]

Exactly!! Just for giggles, take a box of any of your rifle bullets and put them all through the caliper. You will find a variation in bullet OAL from projo to projo. If you want to really get anal, when I am working up a load, I will weigh my cases and weigh and check length on each projo for my test rounds so things are as consistent as possible. Once I have the load built, then I don't worry about each projectile, and simple check every 10 or 20 rnds to make sure that things are still within +/- 0.003". But that is only on precision rifles, with pistols, +/- 0.003 is just fine. But like the others said, make sure that your neck tension is adequate, unless you just like excessive pressures....

Good luck.

 

[alank2]

Hi,

Crimping depends on the cartridge.

Bullets that have a cannelure like many revolver and rifle cartridges will have their case bullet tension increased by roll crimping the case into the cannelure.

Many automatic cartridges however do not have a cannelure to crimp into and these cartridges use a taper crimp which doesn't roll the brass into a cannelure. Their entire case bullet tension is based on how tight the brass was sized in the first place. For these you only want to crimp enough to remove the belling you added to the case to easily seat the bullet.

For 40s&w if you are using a good sizing die, you should be able to seat a bullet in an empty case, taper crimp to the remove the bell, and the bullet should want to stay put pretty well if you put pressure on it to force it into the case. It isn't to say that you can't push it in with enough force, but it should be easy...

Good luck,

Alan

 

[gl89aw]

Unless I missed it you didn't mention bullet type, I load a lot of cast bullets and I have found that I have to clean the bullet seater die occasionally or I will get variations in OAL. The lube tends to build up over time in the die.

 

[E Rock]

The projectile i'm using is a cast lead with one lube groove. I have not been lubing the cases, Lee says no need to? They seem to size very smoothly, but they are extremely clean so I'm sure that helps. The only lube is from the projectile itself, the waxy **** in the groove. I can see how over time that could work its way into the die, but my dies are new and clean.

NikatKimber scared me on my .223 stuff but i came home and measured a few out of a 2k bag. seem to be good there... whew!!

Still learning

 

[NikatKimber]

Yeah, those projos were out of a bulk bin from a gun show. I had no idea what brand, make, or anything.