C.O.L variation depending ''reloading chart''

[Varmintprecision]

There is an old saying... it prevents posts by folks like me from writing a huge tutorial here... it goes something like don't try to boil the ocean.... There isn't a short list of important things in reloading as a beginner, there is a lot to manage and it isn't for folks with a short attention span. Taken in with the right attitude and in an organized manner from a text book, it can still be learned safely.

Skip the crimp worries for now. Unless you are belling the case mouth open, your neck tension as a beginner should have plenty of margin for keeping the bullet in place for everything from a break action to a machine gun. In other words, don't ask for trouble with over crimping cause it will ruin accuracy when taken too far. Your neck tension should be roughly 0.002" - 0.003" in terms of diameter interference. Wait till you learn the ropes before experimenting with very light or very heavy neck tension.

The Hornady 40 VMax you are asking about is easy to live with cause it has a small boat tail. Chamfer your necks and you should not have to struggle to seat them. Not belling the mouth means you won't need to un-do the belling. This isn't the same as pistol loading.

Like anything else here, as a beginner you should stick to the middle ground and not explore very deep or very long seating depths. That old saying over the face of The Parthenon about The Golden Mean has been around for thousands of years and is good advice to beginning reloaders. Stay on the well traveled roads till you learn to explore safely.

Don't rush to the maximums or minimums till you learn what you are doing, that applies to charges, bullet weights, seating depths, etc.

Get a local mentor, you will learn far faster and with less waste.

Ok Ty,
I live in a place where i do not really have a chance to have a mentor close to me. For this reason i read a lot an follow a lot of reloader on Youtube. For crimping, i already did some try to see what a low to really heavy crimp does. And i pushed one that went to more than heavy neck tension(pried the bullet) and i tried with hammer puller to remove the bullet. It just did not move i used a pry plier to remove it and i saw the result on the bullet. And i understand that giving advice in this modern world is not always a good idea to anyone because that some clowns could sue othes. And i am not this kind of person hehe. I am always carefull even when i receive advice cause i don't want to injure me or others person. I will go to check how to measure properly the neck tension prior to test my first loads.
But as a base, i read the book,I deprime my brass on first step, i trim my brass(chanfrain and deburing),i remove primer crimp, i wash my brass and let them dry, i use the depriming/resizing die from lee) then,i measure my powder many times with my autodrum untill i know that the load is good,I use the lee die for seating bullet using the COL indiquated of my load, i use lee factory crimp die(gently ultil i see the 4 little dash, i take the weight of all my component and once 1 ammo is done i take the global weight again to be sure that all my ammunition have the same weight. I take weight of my bullet and brass. I know that most of the time i can have a 0-2 grains differences on my brass, so if one goes over or well under the normal weight i remove it. And i know that over crimp and seating a bullet too deep is no good for pressure. I don't own a chronograph for the moment so i will not have idea of real velocity i will get. But i will look at the ''overpressure'' sing once i fire a load. All my load are identified with type of bullet/powder(number of grains and powder type)/brass/primer/COL. I wish this is enough to start hehe
Thanks
Mat

 

[Varmintprecision]

Just because the overall length is shorter, does not mean that there is more bullet inside the case.

The two bullets you mention, 40 and 60 grain VMax have a difference in length of .187”. The 40 grain is .686”, the 60 grain is .873”.

The COL of the 40 grain is 2.200”, the 60 grain is 2.225”

For the 60 grain to have the same amount of bullet in the case as the 40 grain it would need to be loaded to a length of 2.387”

For the 40 grain bullet to have the same amount of bullet in the case as the 60 grain, it would need to be loaded to a length of 2.038”

If you want to compare seated depth in the case. Bullet length + case length - COL = seated depth.

.686 + 1.750 - 2.200 = .236”

.873 + 1.750 - 2.225 = .373”

Often the COL listed by the manufacturer is determined by bullet shape. Example the 40 grain bullet may not be able to be set to the depth as the 60 grain because the ogive will be below the neck. Or if set to the same length there is not enough bearing surface of the bullet contacting the neck to safely hold it in.

Here you can find many bullet lengths to compare

JBM - Bullet Length List

www.jbmballistics.com

Ok i get it why some other bullet from other manufacturer with different bullet show different COL. The 40 gr bullet lenght may vary according to manufacture. TY

 

[cem]

Hi again!
As new reloader there is still some things that i do not understant for Cartridge overal legth.
.... I know that deeper in brass can be dangerous...Could someone ecplain me?
Thank you.
Mat

It's not the things we don't know it's the things we know that aren't so. The rules for seating depth in a typical pistol cartridge such as a .40 S&W are that deeper in brass can kaboom (don't feed a cartridge repeatedly as by loading to start a shift, unloading and reloading the same cartridge to start the next shift).

The rule for most bottleneck rifle cartridges is that any reasonable neck tension - enough bullet in the neck to hold the bullet securely - loading deeper in the case reduces pressure by giving the bullet a running start -Weatherby freebore style - at the rifling and seating closer to the lands all the way up to jammed increases pressure - jammed with maximum case room increases pressure the most and can be a big deal. See e.g. Brownell's pressure factors from Wolfe or various writing by John Barsness or try it yourself with a strain gage. It is true that changing the seating depth changes the effective case capacity and varies pressure with capacity. As it happens the freebore effect is much much more significant so seating depth alone doesn't change the pressure enough to matter and is noisy enough to be hardly noticeable.

 

[Firearmsunlimited]

Forget COL unless it is restricted by a magazine. The bullet ogive to lands plus or minus setting is the only thing that matters.

 

[rijndael]

Excluding trying to fit a round in a magazine I don't worry about COAL. It's base to ogive for me.

The exception is: If you lose or damage your comparator insert, or change it, you may wish you also had a COAL measurement.