Is there a way to tell

[SilentSniper]

The difference between a weihrauch, CZ, Bsa barrel?
If the barrel has been worked on to fit another rifle?
No manufacturer markings obviously.

Any help?

[averageplinker]

There may be a different number of rifling grooves and twist rates.

[MartynB]

There may be a different number of rifling grooves and twist rates.

Good point, also possibly diameter assuming not been turned along full length

[Benelli B76]

There are a lot of variables depending on the age and calibre of the BSA barrels. Sometimes you can see chatter marks from the cutting tool which made single passes for each rifling groove. Manufacturers use a number of methods for rifling that give different finishes on the metal, including broaching and button rifling.

Baz

[RobF]

The difference between a weihrauch, CZ, Bsa barrel?
If the barrel has been worked on to fit another rifle?
No manufacturer markings obviously.

Any help?

The shape of the lands is normally the indicator.