tell me about trajectory

[c1skout]

I haven't had time to make a proper range trip with my new Traditions 32 percussion gun (when I have time I've been squirrel hunting with it), so I have a question. I've shot it out to about 45 steps using 15ish grains of 3F goex powder and it hits "to the sights" at those ranges. I'm wondering at about what range the ball is hitting the top of its arch. I don't have a small powder measure so Ive been using pistol brass to measure my charge. My first shots were from a 38spl brass full of 3F, but that hit way high at 35yds, so I went to a 9mm case and it hit pretty much dead on at 35yds, center of a 3-shot group was 1/2" high. The same 9mm casefull hits about an inch high at 40 steps and 45 steps. On my woods-walks when I've tried to hit stumps, knotholes, or snowballs at ranges from 50 to around 70yds it seems I'm missing high.

Has anyone charted the flight path of a lightly loaded 32cal roundball? I know my 22lr sighted with sv ammo to hit on at 20yds will be high till about 50yds, then hit low again, and around 8" low at 100. Will I have to build a higher front sight to use a hotter charge? I'm happy with how mine shoots with this light charge for hunting squirrels, but I hope to find a faster load that will shoot well so I have more power if I chance on a coyote, and to use it for fall turkey season.

[mooman76]

Someone might be able to give an estimate but the trajectory really depends on how your sites are set up in relationship to your barrel. Something you more than likely will have to figure out through some range time.

[johnson1942]

i think you figured it out already. plenty enough powder to get you small game. most likely your bore is not fouled very much also. again, you got it down right.

[Cowboy_Dan]

Jbm ballistics can give you trajectory details. You will need to know, among other things, the ballistic coefficient of a .32 round ball and your muzzle velocity. As far as the velocity, though, you can start with it close and adjust it until the calculations match the data you have.

http://jbmballistics.com/

[Omnivore]

You have an interesting way of looking at the problem. I would find a load of decent power for the intended purpose that shoots small groups at the maximum intended distance, then adjust the sights accordingly. The trajectory will of course be different with different loads, so as I see it the first step is to find the most accurate load and proceed from there.

As you're finding, there will always be an "initial zero", which is the first point at which the ball crosses the line if sight as it rises. Then there's the "midrange point", the distance where the ball reaches it's maximum height above line of sight, followed by the "zero range", which is where the ball falls back into line of sight. The sight height over the bore, the launch velocity, the projectile's ballistic coefficient, and your zero range (and air density) will all change the three numbers.

The next numbers of interest are your "point blank range" which is that distance where the ball drops below line of sight by as much as it rose above line of sight at the midrange point, and your "point blank target size" is double the midrange height.

All those numbers change along with your load and your sight adjustments. You don't really need a chronograph though. Just find a good, accurate load, adjust your sights to the distance you want, and then experiment to find the other numbers. Point blank range and target size are of interest because they tell you what size targets you can aim dead on at, and still hit within your point blank range.

Your method of altering the load to hit point of aim without adjusting the sights is reminiscent of how one might regulate a double rifle, or determine the load for which a rifle was regulated by a previous owner.

[LAGS]

I would side with Omnivore, but I am no expert.
I like to find the load I like, then adjust the sights to get that load to hit where I am aiming.
Even if that means changing the front sight to one of a different elevation if you do not have an adjustable rear sight.

[45 Dragoon]

Omni has a good approach but just to be clear, bullets don't rise. The sight plane and bbl axis aren't the same. The "sight line" is straight but the bbl is canted up so the bullet travels in an arc (like throwing a football, baseball, rock . . .). It's a gravity thing. The bullet is falling as soon as it leaves the bbl.

Mike

[45workhorse]

Sighted mine in at 25 yards, filed front sight one or two strokes with a file then shoot, repeat till it hits POI. 30 grain charge FFFg at 25 yards, 40 grains at 50 yards. YMMV.

[fouronesix]

The trajectory is the trajectory… of any projectile. Use the JBM simplified calculator as has been suggested. The BC of a 32 caliber round ball is about .043. That calculator will show the predictive model of trajectory for any particular velocity. If you don't have a chronograph, then estimate it by using a reference like the Lyman BP Handbook and Loading Manual.

For proving the calculator, simply shoot at a sighting bull on a big piece of paper, without changing any other variable, at range increments out to whatever distance you think you need to.