The club I belong to is going through a re-certification of individual prophecy in order to shoot beyond 200 yards.  I have been shooting BPCR for about 12 years now and have my sight settings, for the guns and load I use.  (I have one load that I developed early on and have not varied from that)

In the process of re-certifying that an individual is qualified to shoot at the longer ranges a number of questions are asked regarding the individual’s equipment and how to get an “on target” shot the first time at any given distance.

For smokeless cartridges I have charts that diagram the trajectory and flight paths but for my BPCR loads I do not.

My sight settings were originally gotten from other shooters with similar equipment, to get in the ball park, and I then adjusted from there to suit my specific load and rifle.

I looked at trajectory calculations, on the inter-net and although I would love to be able to scrawl something like that on the back of a target for someone; I don’t usually carry a Trigonometry book around with me.

My cartridge data is as follows:

550 grain 20/1 bullet
63 grains 2FF (Dupont)
.063 Walters Wad.
Compressed 3/16
Bullet is seated to just kiss the rifling when chambered.

Velocity (as taken at Raton by NRA officials:  1067 (Average of 10 shots)

30” barrels on both guns


My questions then are: Is there a relatively easy way to calculate what the sight settings will be for any given range? Or, in other words, what the drop/trajectory of this load would be, from 100 - 600 yards?

By the way I am all for this certification.  I have seen too many idots that are dangerous not only to themsleves but also our sport.  I don't want to be considered one of them.

Any assistance is greatly apprecisated.


Thanks,

Robert

You can calculate it but about any single shot cartridge at black powder velocity will be roughly

100 Zero
200 add 9 moa
300 add 12 moa
385 add 15 moa
500 add 20 moa

About 60 moa from 100 yard  zero to 500  yard rams.  Expect this is about what your actual sight settings are for BPCS. Gets them near the swinger impact on the berm.  Actual depends on variables and could be 2 or 3 moa off rule of thumb more or less. This works at our range sighting in new shooters. Anybody or program that thinks they can make more accurate predictions considering all the potential variables  is kidding themselves.

We have "all shots must impact the berm' rule and it's a good one. Best way to make sure they do is start short then work out one berm at a time adjusting as you go.

Boats