60's - 70's BSA airgun sights

[evert]

Looking over some BSA mk3/4 Meteors and a mk1 Scorpion, I noticed that there are different heights in both front sight posts and the rear blade.
Does anyone know why they came with differing heights? Guessing it might be to compensate for productions errors in barrel boring?
Or was there any other reason?

[Leonardj]

I have always suspected that the reason for the varying height sighting elements was to compensate for barrel "droop" or "rise" resulting from the barrel to breech lock-up.

The early front sights had four different height elements that could be fitted to the front sight base by simply removing a small roll-pin, and reinserting it with the new sight element in place.
The later front sights had the adjustable sight elements.

TMK, all the rear sight blades had slotted mounting holes, thus allowing the sight blade to be raised or lowered as required, independent of the elevation screw.

[evert]

I have always suspected that the reason for the varying height sighting elements was to compensate for barrel "droop" or "rise" resulting from the barrel to breech lock-up.

The early front sights had four different height elements that could be fitted to the front sight base by simply removing a small roll-pin, and reinserting it with the new sight element in place.
The later front sights had the adjustable sight elements.

TMK, all the rear sight blades had slotted mounting holes, thus allowing the sight blade to be raised or lowered as required, independent of the elevation screw.

But when the rear and front sights are mounted on the barrel, why would you need to compensate for droop?
Maybe with use of the Cadet peep sight, but wasn't that sight introduced first on the Mk5?

The adjustable rear sight blades are on the Meteor Mk5 and Mk2 Scorpion, the rear sight height difference I've noticed is in the rear part of the mk3/4 sight.

[pajj]

Obviously to make up for fairly large performance differences in the finished mass produced rifles. The theory of both sights on the barrel negating these problems is clearly false.

[Geezer]

Just a thought.

If you are going to use the same sights across the 7” barrel Scorpion pistol, the 18” barrel Meteor youth springer, the 18” barrel Mercury, the 19” barrel Airsporter, and offer the option on the cadet Mercury and the Buccaneer of using the same rear sight with an aperture close to the eye, then different height front blades would be a good way of ensuring that all of those sights on all of those guns could be set up properly to hit point of aim at a typical 10-25m distance without having to crank the rear elevation all the way up or down for some of them.

[evert]

Just a thought.

If you are going to use the same sights across the 7” barrel Scorpion pistol, the 18” barrel Meteor youth springer, the 18” barrel Mercury, the 19” barrel Airsporter, and offer the option on the cadet Mercury and the Buccaneer of using the same rear sight with an aperture close to the eye, then different height front blades would be a good way of ensuring that all of those sights on all of those guns could be set up properly to hit point of aim at a typical 10-25m distance without having to crank the rear elevation all the way up or down for some of them.

That sounds logical, the ability to adjust to various models.

I agree about the fact that these guns all have large variations as a result of production, but cant believe that they actually sighted in and chose the correct sight blade height for every Meteor at the factory.

Do we have any available statistics on which models came with which front and rear sight heights?

[WebleyWombler]

Just a thought.

If you are going to use the same sights across the 7” barrel Scorpion pistol, the 18” barrel Meteor youth springer, the 18” barrel Mercury, the 19” barrel Airsporter, and offer the option on the cadet Mercury and the Buccaneer of using the same rear sight with an aperture close to the eye, then different height front blades would be a good way of ensuring that all of those sights on all of those guns could be set up properly to hit point of aim at a typical 10-25m distance without having to crank the rear elevation all the way up or down for some of them.

That is the probable reason but nobody has mentioned the different ballistics between the calibres?