There are a few variations on 20mm Oerlikon barrels with at least three different types most commonly seen in period photos, ones with longer perforated jackets and no barrel grooves, with shorter jacket and no grooves as well as those with shorter jackets and barrel grooves.

This new replacement barrel set from RB Model provides a single barrel with the shorter perforated jacket, the smooth barrel and comes in a small zip lock plastic bag without any instructions or fancy packaging, just a simple B&W label.

Three barrel parts with close up of muzzle bore

The set consists of just three parts, the turned aluminium barrel, machined brass perforated jacket with the holes cleanly rendered and a small recoil spring. The only cleanup needed on any of the parts in my set was a small bur on the base of the barrel which is easily filed off.

The barrel as mentioned is smooth with a slight flare at the tip which is correct for the Oerlikon barrel and the muzzle is also hollowed out for a good appearance. There is one issue in that the barrel is about 2mm longer than available information would indicate and other than cutting the barrel to shorten most would live with this if using the barrel on its own or paired for the Crusader AA for example.

Assembly is quite straightforward with the spring fitting over the barrel base and the perforated jacket slipped over the spring to form the distictive appearance of the 20mm Oerlikon recoil spring jacket. You have to take care when fitting the spring and jacket as the spring is slightly compressed with the jacket in place so ensure you hold this firmly in place till the cyanoacrylate (super glue) or epoxy has cured completely as releasing your grip too soon could see you chasing the jacket across the room or the universe.

The fit at the front of the jacket around the barrel is a little loose but filling any gaps with thicker cyanoacrylate will take care of this as well as help ensure the jacket isn't going anywhere.

Assembled barrel showing muzzle flare and spring inside perforated jacket


A brief comparison with the brass 20mm Oerlikon barrel from Lion Roar (Set #LB3530) shows the length discrepancy as mentioned with the Lion Roar barrel also representing the grooved barrel type for good variety. Some photos of Crusader AA's show a mix of the smooth and grooved barrel types but unfortunately the additional length of the RB Model barrel doesn't make for a good mix with the Lion Roar barrel for this configuration without shortening the RB Model barrel.

Comparison with Lion Roar 20mm Oerlikon barrel from set #LB3530
The RB Model barrel is 2mm too long in barrel length


Fitting the assembled barrel to any available kit, plastic or resin is quite straightforward, simply cut off the original barrel if need be, drill a 1mm hole for the barrel pin and attach the metal barrel, very easy.

RB Model barrel fitted to the Italeri 20mm Oerlikon from their Elco 80' Torpedo Boat PT-596
Kit #5602 with additional etched parts from the Lion Roar U.S.Navy PT Boat set #LAS35003

RB Model barrel fitted to the gun mounting from the Italeri Crusader Mk.III AA Mk.III Kit #6444
with the Lion Roar 20mm Oerlikon barrel for comparison
This is a very well done 20mm Oerlikon barrel with the separate spring inside the cleanly machined jacket portraying this feature of the Oerlikon very well indeed and the barrel muzzle flare also adds the good appearance with easy fitting to any available cannon.

The only issue of concern is the additional 2mm barrel length, but other than this the overall appearance is very good. Mixing this barrel with the grooved Lion Roar barrel is compromised due to the length issue and the only solution is to shorten the barrel to the correct length if you want this combination.

Highly recommended

Thanks to Leo at LionMarc Model Designs who now carry the full range of RB Models barrels for the review set.