Newbie Question About gr. ?

Z

z28pwr

New member
What does GR. stand for on a box is it grain ?
And what's better more or less, from what I've read it seems that less is faster but I'm not sure.
 
Yes, "gr." is generally an abbreviation for grains on an ammo box. While not always true due to different powder charges, a lighter bullet will usually have a higher velocity than a heavier bullet in the same caliber.
 
Hi,

Good Question.

And you will see why reloaders mark their boxes 'grains'.

Be certain when you read the box that someone hasn't abbreviated GRAMS as GR, because if you accidentally use grams where the recipe should read grains... KABOOM!
 
As a matter of reference, I use 7 grains of Accurate Arms #5 powder in my 9mm reloads with a 115 grain bullet.

If I switch to a 124 grain bullet the velocity will be less since the bullet weighs more and the amount of powder has been unchanged. The pressure will increase as well, since I am now pushing a heavier bullet with the same charge. BTW, 7.0 grains of this powder with a 124 grain bullet would be a +P type load.

If I lower the charge weight of powder with either bullet, their velocity (nad the pressure) will decrease as a result.

Clear as mud? :D
 
In the U.S., both bullet weight and powder charge are stated in grains. Most ammunition boxes will not list the powder charge (it varies with different powders) but do list the bullet weight. In general, the lighter the bullet, the higher its velocity at the muzzle.

On ammunition boxes printed for those who "speak metric" (which is most of the rest of the world), bullet weight and powder weight will be given in grams. Most ammo sold here, regardless of origin, will have boxes marked with the grain weight of the bullet or, sometimes, both grain and gram weights.

The abbreviation "Gr" is usually used for "grain". The abbreviation "G" or "g" is used for "gram".

Jim
 
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