17pdr anti-tank gun
for Sherman Firefly

RB Model Set 35B07
1:35th Scale

Review by Terry Ashley

The set:
This replacement barrel from RB Model privided parts for the 76.2mm QF 17pdr barrel for the is Sherman Firefly and is designed for any of the available Dragon Sherman Firefly kits.

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 which may require a bit of thought to get the parts in the right place but shouldn't be a problem for those with experience assembling metal barrel sets.

The set has the aluminium barrel tube, a two part brass flash suppressor, two brass collars and four parts for the gun mounting that includes a washer and nut to secure the cross T mounting.

Brass and aluminium barrel parts
RB Model

The barrel tube is hollowed out slightly and there is thread on the muzzle for fitting the muzzle brake which has corresponding threading inside the rear section.

The Ordnance drawing dimensions of the actual 17pdr barrel indicate the tapered section as it comes out of the mantlet is 11 inches (27.94cm) along the tapered edge and the barrel from the front of the tapered section to the back of the muzzle brake is 110.625 inches (280.1cm). This equals in 1:35 scale 7.98mm and 80.02mm respectively with this barrel measuring 8.5mm and 83.0mm accordingly give a take a fraction of a millimetre which means the barrel is all but 3mm too long. These Ordnance dimensions also match the 1:48 plans in the Hunnicut Sherman book to confirm the measurements further.

The muzzle brake being in two sections has to be joined leaving a seam to be eliminated and soldering the halves together will make eliminating the seam easier but ensure the side openings in the two muzzle brake halves line up correctly as you join these together.

You then fit the two brass collars over the barrel and screw the muzzle brake into position, this also secures the collars so there is no need to glue these parts but don't over tighten the muzzle brake.

Muzzle brake, gun collar and barrel rifling/threading
RB ModelRB Model
Assembled muzzle brake
RB Model

Assembling the T mounting bracket is quite straightforward, you firstly slip the brass collar into place and fit the T section over the threaded pin. The washer is added and the nut screwed into place to secure the bracket but you must ensure the T bracket is aligned correctly with the side gas holes in the muzzle brake but this comes later.

Gun mounting parts to fit the Dragon Firefly kits
RB Model

Fitting the barrel to the Dragon Firefly kits will require a bit of work unfortunately and remember not to attach the muzzle brake until the barrel in fitted through the kit gun shield. You firstly need to widen the opening in the gun shield for the barrel to fit through and sit in the rear locating lugs, this is easily done with a sharp #11 blade.

Next the rear mounting plate will not fit due to the large securing nut and you have to cut the plate into two sections to fit over the mounting pins, but not you have to cut these level with the small square holes due to the step on the metal T section (see images).

Once these modifications have been made the barrel can be fitted but when attaching the mantlet there is a large gap around the barrel which will need attention and due to this poor fit the only option for securing the mantlet is to glue it to the gun shield negating any gun elevation after assembly.

To fit the barrel to the Tasca Firelfy kits will need additional work as the neck on the barrel is a different diameter to that of the Tasca barrel meaning it isn't a straight replacement, but why would you want too when this barrel is 3mm too long? If you want a metal Firefly barrel you are far better off off getting either the ABER or Lionmarc/Passion Models barrels instead which are the correct length.

Opening in the kit gun shield has to be widened to allow the barrel to fit through
RB Model
Opening widened, then the mounting plate doesn't fit due to large securing nut
and you have to cut the plate into sections (right).

RB Model
Fit of gun shield leaves large gap around the barrel (left), modified mounting plate to fit (right)
RB Model
Comparison of available metal Firefly 17pdr barrels
with only the ABER and Lionmarc/Passion Models barrels being the correct length.

This barrel set from RB Model is nicley machined but is almost 3mm too long and there is quite a bit of work to fit to the Dragon Firefly kits and even more if you wanted to use it on the Tasca kits, but why would you?

Note recommended, better off getting either the ABER or Lionmarc/Passion Models barrel instead.

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

Page created March 15, 2009