The FBI's fib about the Mannlicher Carcano

[Bob Prudhomme]

Bob:

So you are saying that the misalignment would have resulted in even more of a miss?

Like three feet?

Absolutely. There are many online ballistics calculators and it is a simple matter of plugging in such information as bullet weight, muzzle velocity, ballistic coefficient, etc. In this case, which I worked out a few years ago, it was necessary to work things out in reverse and find a situation where the scope would be zeroed on a target at 15 yards and the bullet would be impacting 2.5 to 4 inches high at 15 yards.

In this case, the scope would be looking severely downwards in relation to the plane of the barrel (or the barrel would be tilted severely upwards in relation to the scope - all a matter of perspective). With the bullet impacting WAY high of the target, I don't believe this cheap pellet gun scope had enough adjustment to bring it down in order to be 2.5 to 5 inches high at 100 yards.

Which brings me to the next point. It was shown to me, on which forum I do not recall, that the set of tests at 15 and 25 yards were not conducted at the same date and locale as the 100 yard tests, and that adjustments were made to the scope between the 15-25 yard tests and the 100 yard tests. Ms. Cranor was quite right on one point, that being a rifle shooting 2.5 to 4 inches high could not be shooting 2.5 to 5 inches high at 100 yards. By my calculations, if it was that high at 15 yards, the bullet would be travelling on a very high parabola, and would not come back down to the line of sight for at least 600 yards.

The question is, with limited internal adjustment, how did they adjust the scope vertically so that instead of shooting 36 inches high at 100 yards, it was only shooting 2.5 inches high? Do you understand, after looking at the photo of the scope mount on C2766, why it was impossible to "shim" the front end of the scope mount, in order to raise the front of the scope, which was necessary to allow this rifle to shoot 2.5 inches high at 100 yards?

I'll give you the answer. This scope mount was not forgiving at all of mounting mistakes by a gunsmith. With the two mounting holes drilled horizontally into the side of the rifle's receiver, it would be possible to use shims under the mount, on front or back end, if you only wanted to make adjustments laterally to the line of sight (side to side). BUT, to adjust the scope mount vertically, it was necessary to re-drill at least one of the two mounting holes, in order to raise either end of the scope. Obviously, this was never done, or we would see a screw hole above the forward screw hole currently used to attach the front end of the scope mount. Unless no one has bothered to remove the scope mount in the last 53 years, and it is hiding another screw hole?