It is relatively easy to carry out a shot pattern test which consists in calculating the percentage of pellets that come out of the barrel and are directed towards the target, radiating as a swarm longitudinally and transversely. The dispersion, however, is never casual but depends on the quality of construction of the barrel, its length and choke but also on the lead charge, the type and quality of shot and finally on the amount of powder that drives them. In tests at different distances, however, it is always necessary to use the same cartridges.
Place a sheet of metal (plate in jargon) with at least one meter on its side, on a stand. Smear it with mortar or lime, a shot is fired aiming at the center: the bullets will each leave an imprint. The point that is most affected by the bullets is considered and a circle with a diameter of 75 cm is created around it and the traces that correspond each to a pellet are counted. You will then get the percentage of bullets that will have reached the target based on the following formula.
n X 100 |
N |
n. shot that hit the circle
No. of shot contained in the cartridge.
There are tables that indicate the number of pellets based on weight and characteristics. 35 grams of bullets constructed by molding and with 11,14 specific gravity lead will be in the following quantity.
Numbering |
Quality |
9 |
770 |
9 |
662 |
81/2 |
576 |
8 |
504 |
71/2 |
350 |
7 |
392 |
6 |
354 |
6 |
311 |
Here is an example based on the table: at a distance of 35 meters with a 36 g lead n. 7 80% of the pellets entered a circle with a diameter of 75 cm.
canna |
mm |
m. 25 |
m.30 |
m 35 |
m40 |
m. 45 |
m. 50 |
Cylinder |
0 |
69 |
54 |
43 |
35 |
28 |
23 |
Cylinder |
0,25 |
81 |
66 |
53 |
42 |
33 |
26 |
Modified |
0,50 |
92 |
75 |
63 |
48 |
38 |
29 |
Improved |
0,75 |
100 |
86 |
76 |
56 |
42 |
32 |
Full |
1 |
100 |
96 |
80 |
63 |
48 |
35 |