Bullet Length and COL

[44 AMP]

I didn't...heh heh

Check your brass for uniform length. Adjust your dies so you seat the bullets with the case mouth in the middle of the crimp groove, seat and crimp. Your COAL will be within spec and appropriate.

Its not rocket surgery and its very little brain science, you don't need to overthink it, and you certainly don't need to worry about what match rifle shooters do with their precision ammo.

"racewinning" tips about adjusting your formula 1 Indy care aren't much use when you drive a pickup truck.

[hounddawg]

If you are talking about going from one similar weight roundnose to another then no it will not change much.

Just speaking for my pistol seating dies but all have a stem ending in a very slight concave surface. It's not quite flat. When you raise that ram as high as it will go the distance from the shell holder to the seating stem will always be the same. It really does not care whose brand bullet is being seated or whose brand bullet is being seated. The COL might change slightly when going from a round nose to a wad cutter becasue of the concave shape of the seating stem but that's about it. There may be a tad more bullet in the case depending on the difference in the ogives shape . But I don't think the radius will differ that much from one round nose to another.

[Unclenick]

Bob,

You can almost always assume the cannelure is in the right place if the bullet is designed for the cartridge you are reloading. With revolver cartridges, this is easy to check: You put a fired case into your cylinder and measure the length of the cylinder from the cylinder face to the bottom of the case. If your COL is shorter than that, assuming you've provided enough crimp for the case to hang onto the bullet during recoil and not let that experience start inertially pulling it out, then the cartridge won't jam the revolver.

Where peak pressure is concerned, bullet jump to the lands is a non-issue in revolvers. Unlike a rifle cartridge, which has much of the bullet ogive already past the throat of the rifling when it fires, leaving the shoulder of the bullet very little distance to travel to arrive at the throat, a revolver bullet always has the whole length of the bullet ogive to travel plus the barrel/cylinder gap plus the length of most of the forcing cone to travel before meeting the throat. That's lots of jump and won't raise pressure in any way.

As to how seating the bullet does affect pressure, that depends on how much space there is in the case and under the bullet for the powder to start burning in. If you have two bullets of similar similar shape and similar hardness (usually identified by them having similar construction method), then you can get pressure to match well by giving both bullets the same seating depth, even if they aren't exactly the same length.

Originally Posted by SAAMI Glossary

SEATING DEPTH

The longitudinal position of a bullet, primer or wad in a cartridge case.

As a practical matter, seating depth is measured as the length of the portion of a bullet that is seated below the case mouth.

Seating Depth = Case Length + Bullet Length - COL

Case Length, as used in that calculation may be either the maximum case length or the nominal trim-to case length, whichever you prefer as long as you use it consistently.

Once you have the seating depth of the original load using the original bullet's length, you can find the COL for a bullet of different length by rearranging the same formula to:

COL = Case Length + Bullet Length - Seating Depth (found for original bullet)

COL: stands for Cartridge Overall Length. Before the 1950s there were two spellings of overall. One is the compound word, first used by Chaucer, which means "taken altogether". The second spelling was hyphenated over-all, and was used for the total physical length of a boat or arrow or whatever. Since the 1950s, the hyphen form has been dropped. COL stands for the modern spelling, Cartridge Overall Length, while COAL stands for the obsolete spelling, Cartridge Over-All Length.

[Dufus]

Aguila Blanca Wrote: I must have eight different brands/calibers/weights of handgun bullets on my shelves (maybe even a couple more than that), and not one of them has a cannelure.

Well, do you load 38 Spec/357 Mag with them? If so, then you must be using something that I am not familiar with as far as jacketed handgun bullets.

As to the OP's question, he was asking specifically about those two using jacketed and lead bullets. I don't think I have ever noticed a bullet designed for the 38 Spec/357 Mag that doesn't have a cannelure.