COL vs COAL??

[Nomo4me]

Definition for these please?

Thanks

[Hog Buster]

COL=Cartridge Overall Length

COAL= Cartridge Over All Length

[Nomo4me]

Oh
What is the acronym used to refer to case head to bullet ogive (where the lands will hit the bullet) length? I thought one of them referred to that measurement.

[Randy 1911]

It can be the same. Case Overall Length or Cartridge Overall Length. It depends on what you are talking about.

[wncchester]

The term "case over all length" does get used (misused) but it's virtually meaningless that way; case length is case length, it's "over all" by definition.

Thus, any "OAL/COAL" figure should only refer to the cartridge, meaning the case plus the seated bullet, ie, over-all!

There is no standard term for "OgL", yet (?). Measuring to the ogive is still a faily new thing for most reloaders and it really has no meaning except to the individual rifle and load, it isn't transferable as OAL is.

[SL1]

The point (on the bullet) where the bullet's ogive actually touches the rifling varies a lot from gun to gun, due to variations in the angle cut into the rifling in front of the throat and how much that has eroded with firing the gun many times before.

It would actually be a lot more useful if the manuals would provide "bullet jump distance" for their data along with COL, so that we could see how it corresponds to our own rifles.

And, while I'm wishing for things that I don't expect to get, it would REALLY help if the manuals provided the lenght and water capacity of the (fired) cases that they used in their tests. That more than anything else could go a long way towards answering the often-seen question about "Why does manual 'X' have a starting load that is higher than the max load for the same bullet and powder in manual 'Y'?"

SL1

[Hog Buster]

wncchester

OgL.....Pretty neat description.... I'm sure that you’ve just coined a term that will appear many times on this forum, like “ What the hell is OgL?”

[Nomo4me]

OgL works for me.
I annotate all of my load data by referencing OgL. Thus my assumption that either COL or COAL referred to OgL.

[Hog Buster]

Don't let your OgL cause your COL,COAL, or OAL to much exceed SAAMI specs because of BJ (bullet jump) or it may cause FP (feed problems). Excessive OgL, because of FTD (firearm throat depth), may also cause a lack of BNT (bullet/neck tension) creating other problems, PDQ................. Say what?.........So much for technical BS my head is swimming

[Nomo4me]

Good advice HB
I have only one gun where the magazine will allow me to seat a bullet to jam the lands and I am experimenting with optimal seating depth for that one.
On my other bolt guns if the magazine precludes seating within .030" or so of the lands I have found best results with just seating in the neck to the depth of the caliber at hand. This has worked with .222, 6.5x55, 7mm-08 for sub-.75 moa results for me.

[Hog Buster]

I'm way past the tinkering with ammo phase. Over the years I've found good loads for my rifles and pistols and have stuck with them. I did learn that in most cases a little space between bullet and lands makes for better groups. A few thousandths one way or the other had little effect as long as bullets didn't touch them.
While it's something to do, average shooters waste their time spent loading on making super duper cartridges, these rounds often exceed their abilities.

[RidgwayCO]

Nomo4me, I've always recorded your "case head to bullet ogive" measurement as the SPBCL (Stoney Point Bullet Comparator Length) in my logs.

But since Stoney Point is now owned by Hornady, I might have to reconsider that acronym...

[Nomo4me]

I don't hunt presently, so tinkering for best MOA out of a sporting or varmint gun is the goal in and of itself.
I do fall far short of the anal retentiveness required for BR grade loading however.

[Hog Buster]

Oh, I remember that stage also. Gets addictive, doesn't it?

[IllinoisCoyoteHunter]

COL: cartridge overall length

COAL: readily combustible black or brownish-black sedimentary rock normally occurring in rock strata in layers or veins called coal beds.

[wncchester]

"wncchester ... OgL.....Pretty neat description.... I'm sure that you’ve just coined a term that will appear many times on this forum, like “ What the hell is OgL?”

Oh well, ain't the first time I've caused confusion with my home-made terms..

[Unclenick]

IlliinoisCoyoteHunter has it right. I looked "overall" up one time, and it turns out to have been a compound word since Chaucer's time. I figure that's long enough that it no longer needs to be broken into two words or hyphenated. I blame the NRA, which used to speak of Cartridge O.A.L. in some of their older books, and it just stuck. I don't know any earlier references, but perhaps someone else will? I will stick with C.O.L.