In the 1970's I bought a Brno ZH shotgun from the Australian distributor. Latter on I purchased the 7x57r and 22HP barrels. I was advised that CAREFUL fitting of the would be required. With a bit of care using jewellers files problem solved.
It may be of interest that at one time set triggers were available as a separate item. They work a treat in overcoming the horrible factory fitted triggers.
All rifle barrels are extremely accurate and fitted with scopes. They are ugly as hell but practical and hard wearing