When did BSA change to 5.5mm barrels

[Dornfelderliebe]

A short while ago somebody asked this and nobody knows.
I checked my small Meteor collection plus my Mercury S and got this very limited result. Just by loading superdomes into the breech.
All Meteor Mk 1-4 allow the pellet to drop in 3-4 mm without resistance, ditto the Merc.S.
My Mk6 needs the pellet to be pushed firmly into the breech just as my Hw99 does suggesting it is meant that way and I suspect it to be a genuine 5.5.
Sadly my Mk5 is .177 so can any one else do the same test then assuming we can date the various Mks, we might be able to infer a rough date.
The Mk6 barrel also differs in that it has only one hole for the front sight, matching the modern front sights.

[andrewM]

It is a very good question and one that I think I asked before too. I don't recall that there was a definitive answer. Perhaps someone will know and respond.

Rgds
Andrew.

[Tinram]

I have Meteors, Airsporters etc in my collection….up to Mk4 Meteors (in my lot) Superdomes “drop” in a few mm into the barrel…in my Mk5 they don’t but “seat” normally. So as far as my guns are concerned, 5.5mm barrels start from Mk5 onwards !

[look no hands]

I shall check on Sunday (if I remember) as I have several .22 beezas now, I have mk1 and 2 Mercury S and an early Supersport and Lightning, I shall try a Superdome in each and see what happens.

[gunshop]

We generally say around 1986 was the change, when they went to European sizes (something to do with EU)

[evert]

We generally say around 1986 was the change, when they went to European sizes (something to do with EU)

1986 was when GAMO bought BSA....