Historical Background

Beginning in June 1942, the main gun used in Stug IIIs was upgraded from the 7.5cm StuK 40 L/43 to the L/48. The switch began in only some of the Stug III F/8s and continued into the Stug III G , as well as the Stug IV. The 7.5cm StuK 40 was developed by Rheinmetall-Borsig and was mainly produced by Wittenauer Maschinenfabrik, Berlin-Wittenau, and Skoda. While changes were made throughout the production of the L/48, the only noticeable difference was the muzzle brake. When production began , production of the double chambered muzzle brake was in short supply, and some of the F/8s had received the ball-shaped single chamber muzzle brake. Once a steady supply of the double chamber began from the Stug III G onward, further changes had been made to the muzzle brake to improve sighting visibility during firing. In May 1943 the muzzle brake was changed to one with side flanges, which helped reduce the dust and smoke when fired. After May 1944 a further change was made which added full disc flanges to the forward part of the muzzle brake. That being said, references show a combination of all types being used throughout the Stug III G production.

• Standard double chamber muzzle break without flanges
• Double chamber with rear side flanges
• Double chamber with front and rear side flanges
• Double chamber with rear full disc and front side flanges
• Double chamber with front and rear full disc flanges

The Set

This isn’t just the barrel alone. You also get the muzzle brake assembly. There are eleven metal parts, which include 1 aluminum turned barrel, 5 brass metal parts and 4 brass photo-etch parts which make up the muzzle brake assembly. There are no instructions provided. You will need some knowledge of how the muzzle brake assembles. There are photos of the assembled brake on the RB Models website which will help. You may also be able to refer to kit instructions if you are building one of Dragon's latest releases. That will at least give you some idea of where the parts go.
The parts measure up correct with 1/35th scale drawings and are accurate and complete for the muzzle brake assembly. The barrel is not hollow throughout , but is drilled at the business end and includes the rifling detail. There are also threads for screwing on the muzzle break, though on my copy some of the threads on the end are almost missing. This will be fine if attaching the muzzle break, but not suitable if your planning on a model with it removed.

which version?

RB Models 7.5cm StuK 40 L/48
When I received this set from RB, the first thing I noticed on the label was the intended model, Stug III Ausf C. Surely a mistake I thought. However, after researching this barrel, I did find there were some Ausf Cs that were upgunned with the 7.5cm Stuk 40 L/48. Generally speaking, this set was mislabeled, since the RB website has been updated to correct this to be used on the Ausf. G. But I wanted to note, it can be used to ‘up-gun’ and Ausf. C if that’s what you want to do. You will still need to modify more than just changing the gun barrel. It can also be used on the Stug IV as well. Another note about the label, which states this is a “middle model”. This refers to the muzzle brake, the mid model muzzle provided in this set. This is slightly incorrect. The front chamber provided has the side flanges, introduced in May 1943, which would be the middle model. However, you get the rear brake chamber with the full disc flange, introduced in May 1944, making it a late model, or rather a mix of mid and late model. There are photographs which support this combination, so its not incorrect all together.

Conclusion

In the end, this set is top notch for aftermarket barrels. The details rendered are quite accurate once assembled. It would certainly be beneficial to the modeler if instructions had been provided, either with the set, or downloaded from their site. But without them, one may have to guess or do some extra research just to assemble it. There is no recommendation for which kit this is intended for. It does not fit the Dragon Stug III/IV Smart Kits without alteration to either the gun barrel sleeve on the Stug III or mantle on the Stug IV. This is not a ‘one barrel fits all Stugs’ set. You will need to compare the specific Stug you are modeling to decide if this is the barrel you need, due to the variations with the muzzle brakes.