I have one of these pistols. Bought new 1976/77 ish.
At that time the barrel sleeve/weight was available as an optional extra. I bought one and fitted it.
It was necessary of course to remove the foresight block by drifting out the large pin and as I recall it was tight!!
The instructions were to use an adhesive to bond the sleeve in place!
Ok if there is no intention to remove it. Mine is still in place and will remain so.
At this stage given the age of the pistols and no longer the pistol of choice for serious competition my advice would be to
leave it alone and in situ.
The flat is indeed to facilitate the fitting of the recoil plate.
The idea was to use it to lock the sledge system in place to give a degree of recoil in order to use the pistol as a trainer for
centre fire pistols. to tbis end it is possible to change the trigger weight by rotating the device in front of the trigger. set at 500 grams
for 10 metre air pistol and rotating gave a 1360 gram weight. The minimum allowed then for centre fire pistol competition, under the then international rules.
As an aside to anyone wanting to remove a barrel weight. I would see it as something to do because it can be, but a bit of a challenge maybe?
Bit like the "Do not remove" on the rear of Webley pistols in a way. Tell someone they can't do something and there's those that will see it as a challenge rather than
an instruction....but that is another story!!
I fancied trying one without the sleeve to see how different the balance is. However if it’s glued on and not straightforward to remove I might just have to get a second one instead...
Odd, isn’t it?
Like Mike, I think short spurs look better and that sport grips are cool.
If I’d have been a 10M pistol shooter in the 70s or 80s, I’d have thought exactly the opposite.
Anyway, I only have an 80. Must resist the 65 bug. (Though they are a much more handsome pistol.)