122mm D-25T Barrel for IS-2, IS-3
RB Model Set 35B32
1:35th Scale

Review by Terry Ashley

The set:

This replacement barrel from RB Model is designed for either the Tamiya Russian Heavy Tank JS3 Stalin (kit#35211) or Russian Heavy Tank JS-2 Model 1944 ChKZ (Kit #35289) although it could also be used on the applicable Dragon IS-2 kit with some minor modifications if desired.

As with all RB Model sets there are no instructions or fancy packaging, just the parts in a zip lock plastic bag and a simple B&W label and as this set has a number of etched and metal parts you may want to refer to the RB Model website which has colour assembly photos of the barrels if need be.

The set consists of the aluminium barrel with the muzzle drilled out and includes inner rifling and outer threading for fitting the muzzle brake. Plus a three part brass muzzle brake which is threaded on the inside and two small etched frets with the raised ridges for around the muzzle brake cut-outs and the small attachment bolts. RB include additional spares for these parts in case of mishap as there is quite a bit of assembly required with the muzzle brake.

The parts are very cleanly machined resulting in no cleanup at all required before assembly and the etched parts are also cleanly etched but require the usual care removing from the frets.

Barrel parts
RB Model
Thread in muzzle brake and barrel
RB ModelRB Model

The metal barrel has the correct taper along the length and also features threads for the muzzle brake and rifling as mentioned with the length matching the 1:35 plans in IS Vol.1/II Wydawnictwo Militaria No.273/294 but is 1.5mm shorter than the 1:35 plans in Ground Power Magazine #165. Additional data in the Russian magazines listed below suggest the 1:35 plans in the Ground Power Magazine are correct while those in the Militaria IS books not so meaning the metal barrel is also 1.5mm too short.

The muzzle brake on the other hand is oversized and the incorrect shape as well as lacking any of the cast texturing which is a feature of the large muzzle brake on the D-25T gun.

The 1:35 plans in both the Militaria IS books and the Ground Power Magazine agree on the muzzle brake size but the brass muzzle brake is a little over 1mm longer than indicated.

Both sides of the forward section of the muzzle brake should be parallel when viewed from above but on the RB muzzle brake the edges are not parallel but angle in towards the back which gives an “odd” appearance” when seen from that angle.

Muzzle brake sizes compared to actual Muzzle Brake.
This is too long and too angled from above, the forward sections of the muzzle brake
should have parallel edges, not angled as with the RB muzzle brake.

RB Model
RB ModelRB Model

Muzzle Brake Assembly:

The muzzle brake has the large housing in one piece with separate brass parts for the inner flange and the end cap as well as separate etched brass parts for the raised ridges around the muzzle brake gas cut-outs and the small securing bolts.

This results in quite a bit of assemble and soldering the etched ridge parts to the muzzle brake is really the only option due to the contours of the muzzle brake and edge joins that have to be blended in with the muzzle brake and not pronounced as they would be if the brass ridges were just attached with cyanoacrylate.

Firstly the etched ridges have to be conformed to the contours of the muzzle brake and this is best done by squeezing these hard against the muzzle brake using you fingers and thumb, there may be some final adjustments required as the etched parts have to conform as closely as possible to muzzle brake contours before soldering.

Muzzle brake assembly.
Bend the etched ridge part by pressing firmly (with fingers/thumb) around the brass muzzle brake
to get the correct contours on the etched part.

RB Model

It’s not possible to solder the complete etched ridge in one go due to the size and contours involved and also due to the fact that contrary to the usual practice you should apply quite a bit of solder to fill/build up the join which will be blended in later with filing/sanding.

I soldered the ridge in four quarters as well as both ends (six soldering steps) and this raises another issue when you have soldered one section and you then have to solder the next close by with the heat dislodging the previous soldered join.

This is one reason to ensure the etched ridge parts conforms tightly to the muzzle brake contours before soldering to lessen any problems, if one join is loosened while soldering another it will stay in position when the solder re-hardens.

A further precaution is the take a tissue and fold this several times into a small square which you then dampen slightly and use to hold the muzzle brake and already soldered parts as this will reduce the heat reaching the already soldered joins and more importantly your fingers. This also helps keep the ridge in place should a previous join be loosened while soldering the next as it is held firmly in place. Of course due care is needed when doing this but applying the soldering iron only for short periods (a second or so) at a time will also reduce the chances of problems with the previous joins and with your fingers.

You should also note the rear join of the ridge isn’t really a ridge but blends in smoothly with the muzzle brake (see images of the real muzzle brake above); this requires the application of more solder to be blended (filed) to shape afterwards.

After the two etched ridges have been soldered into place you can attach the inner flange and the end cap which is also soldering place, this is best done incorporating the soldering of the end section of the ridges as this will solder both the ridge join and the cap in the one operation. The end cap join is very good leaving only a very small join line to be eliminated but the raised lip around the bore hole is too pronounced, this can be fixed by filing down the lip by about half for a better appearance.

To finish off you have to file the solder to shape and finish off by sanding/polishing with fine steel wool to fully blend in the joins, I also had to re-apply some solder as there were still gaps in the joins which further added to the assembly time.

From here there is still the cast texturing to be applied but I’m not sure if Mr Surfacer or the like will adhere to the metal surface of the muzzle brake? Also there is a weld bead along the sides of the muzzle brake and the lip of the end cap which could be applied using the Archers Fine Transfers weld beads (set #AR88066) to make life a little easier, which you probably need after getting this far.

Finally there are the two small retaining bolts and you can attach these using cyanoacrylate and they are also offset on the muzzle brake neck correctly as most kit and other metal barrels (other than the ABER and armorscale sets) have these located centrally which they are not.

Assembled Muzzle brake.
Note heavy application of solder to "blend in" the etched ridges.
This is then 'sanded' with fine steel wool to smooth out and 'round' the edges of the etched ridges.
Also note the lack of cast texture and weld seams on the final muzzle brake which will have to be added.

RB Model

The muzzle brake then simply screws onto the barrel without any more fuss ready to add to the kit and doesn’t need to be glued if you don't want to, just screw nice and tight and it will stay in place without any problems.

The barrel is optimised to fit the Tamiya IS-2/3 kits and all that is needed is to cut away the two inner locating ridges inside the kit gun mantlet/collar (part C45) with the barrel then fitting perfectly through the mantlet and into the inner gun mounting (part C35) for a perfect fit.


Previous replacement barrels from RB Models have offered good value with accurate details but unfortunately someone was out to lunch with this barrel set as it’s simply a World of hurt.

We have the short barrel along with the oversized and incorrectly proportion muzzle brake that requires considerable assembly effort, not to mention the soldering skills required. You are then left with a smooth finish without any texturing or weld beads and the best way to overcome these issues is simply to buy the excellent ABER IS-2 barrel (set #35 L69) in the first place.

Not recommended

Heavy Tank IS 2/2M
Model Detail Photo Monograph No.6
ISBN 88-916229-6-7
Heavy Tank IS-2
Ground Power Magazine
#165 - 2/2008
GALILEO Publishing Co.,Ltd.
IS-2 Heavy Tank 1944-1973
Osprey New Vanguard 7
by Steve Zaloga, Peter Sarson
ISBN 1 8552 3986 6
IS Vol.I
Tank Power Vol.XLVII
Wydawnictwo Militaria No.273
ISBN/EAN: 9788372192738
Tank Power Vol.LXIV
Wydawnictwo Militaria No.294
ISBN/EAN: 9788372192943
Tank Power Vol.LXXII
Wydawnictwo Militaria No.306
ISBN/EAN: 9788372193063
Heavy Tank IS-2
Modelist Konstruktor
publications 3'98
Soviet Tanks

Russian text

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

Page created August 10, 2009