.32 & .36 cal Aimpoints

[Zonie]

Playing with my roundball Ballistics program I was wondering: If you had your .32 or .36 cal rifles sighted in at 25 yards, at what distance would the maximum impact error not be greater than .200 (about 3/16) inch high or low?
I picked .200 because if your hitting within 3/16 of the center of a rabbit or squirrels brain, you can consider it "in the frying pan".

This also is based on the tip of the front sight being .530 above the centerline of the barrel.

Using Lyman's BlackPowder data for velocitys and Goex FFFg powder data, here's what I found.

.32 caliber with .310 roundball:
Load = Velocity = effective range
30 grains =1940 = 10-32 yards
40 grains =2072 = 10-42 yards
50 grains =2203 = 10-50 yards

.36 caliber with .350 roundball:
Load = Velocity = effective range
30 grains =1684 = 10-35 yards
40 grains =1894 = 10-45 yards
50 grains =2104 = 10-50 yards

I almost forgot the wind!
A 5 mile per hour crosswind blowing directly across your line of the shot will deflect your ball .5 inches at 25 yards range for the .32 caliber and .4 inches at 25 yards for the .36.

That makes that little crosswind a much bigger factor than the range is.

Now that I posted this and looked at the name I realize some of you may feel you were missled.
Not a single word (until now) was said about the "AimPoint". You didn't really think I was going to talk about electronic sights on your gun did you? :rotf: :grin: :rotf:

 

[arcticap]

I noticed the .530 sight height qualification.
Do you think that the length of the barrel could affect the sighting point too?
Does the program use a standard barrel length for calculating velocity?
Do you think that usually both the sighting (margin of error) and velocity could be affected by barrel length, only one of these or usually neither? :hmm:

 

[Zonie]

Lots of questions and I may not have all the correct answers but I'll give my opinion. :grin:

The sight height in the program determines how far the ball rises above (or falls below) the visual line of aim.
The velocity, Ballistic Coefficient of the projectile and the distance to the Aim Point in yards determines the angle of the center of the barrel relative to the visual line of aim thru the sights. Except for very close aim points (like 5-10 yards)this sight height should not have much effect on the angle.

The velocity is not calculated by the program. It is one of the variables you have to enter.
The value you enter of course depends on the powder load , the caliber and the barrel length.

For a given powder charge, the velocity in long barrels may be slower or faster than short barrels. Long barrels actually slowing a ball down, happens most notably with light powder loads in the larger bore guns.
The best way to know what a barrel length does with a given powder charge is to use a chronometer (or chronograph). Lacking one of these, I use the Lyman "Black Powder Handbook".
It's not perfect, but it is better than just guessing.