The ubiquitous 40 mm/56 (1.5in) Bofors AA gun was used by almost every major player of WW II. Found in single, twin and quadruple mounts, this gun could be found on the smallest of PT combatants, and the largest of battleships and aircraft carriers.  Newcomer Master Model from Poland has released a set of turned brass 40mm barrels. This set of 20 barrels has grooves cut in to simulate the famous recoil spring of the 40, as well as the flared muzzle- and all this in 1/350! The barrels come well packaged with card stiffener in the main bag and a page of printed instructions.
L-R DML, Master, Trumpeter
INSTRUCTIONS

These barrels are so tiny, I really had a hard time taking useful images. In comparison, the barrels are a bit shorter than the ones from the Cyber-Hobby/DML 1945 USS Buchanan, but longer than 40's in the 1944 USS San Francisco from Trumpeter.

These amazing little barrels from Master Model #MAS350014  1/350 Bofors 40 mm/56 AA Barrels (20pcs)  are available for around  $16.95 US.

Master Products are distributed in the US by Georgetown Hobbies and are available at the following stores.

Spruebrothers.com