PDA

View Full Version : Air Gun Ballistics



PakistanFirst
05-09-2011, 12:02 AM
I have not fired an air gun since the early 1950’s. At that time I had a.177 pistol and a rifle. Very recently I had an opportunity that I could not pass up. I made a trade and through that trade I acquired a RWS 34P in .177 caliber with a scope. The scope is mounted 1.5” above the bore of the rifle.

I collected and computed ballistics data for the pellets of interested to me for use in the RWS 34P. I have compiled that in a table. The data is “dense” meaning lot of information is packed in the table. Other member may be interested in this tabulation.

Here is how to read the table. Let us take the second pellet listed in the table - the Crosman Premier Lite. The weight is listed as “8.0t” - meaning the actual weight was tested and found to be 8.0 grains. The nominal weight of this pellet is 7.9 grains.

This pellet delivers 889 feet per second velocity at the muzzle. The ballistic coefficient (BC) of this pellet is .015. BC is a measure of overcoming air resistance. The higher the BC, the more aerodynamic the pellet shape.

There are five columns for distance, namely 30, 35, 40, 45 and 50 yards. In the distance columns is: [-.0.5”]. I will shortly explain what this number means. For illustration purposes, we will look at the column for the distance of 40 yards.

First line: [13/44/.6/27”] In this instance the rifle is zero set for 40 yards (the column heading). The pellet crosses the line of sight first at 13 yards an then again at 40 yards. At 44 yards it is 0.5” low. With the rifle sighted for 40 yards, the pellet attains maximum height of 0.6” above the line of line of sight at 27 yards.

Second line: [48/50.5] With the rifle sighted for 40 yards, at distance of 48 yards the pellet drops 1” below the line of sight. At 50.5 yards the pellet drops 1.5” below the line sight.

Third line: [637/7.21] At distance of 40 yards the pellet velocity is 637 feet per second. At this distance the computed energy of the pellet is 7.21 foot-pounds.

Some data in the table is highlighted in bold. These bold numbers represent ballistics that are superior compared to other pellets for the distances selected.