Roco 4.5 Inch Gun Conversion

In 1906 the US Army designed a 4.7 inch field artillery gun.  It was put into production and used during World War One.  At least 48 saw combat use with the US Army.  After the war the US worked to build an improved model and despite some prototypes no new guns were put into production.  By 1939 work was picked up again and the newest version used the same carriage as the M1 155mm howitzer, as made by Roco Minitanks.

By April 1941 the US Army had changed their minds on the caliber and went with a British caliber and the 4.5-inch Gun M1 on Carriage M1 was standardized.  It also had the same carriage as the M1 155mm howitzer, the only significant difference between the two pieces was the barrel on the 4.5 inch gun was longer by three feet, 9 inches.

Between 1942 and 1944, 426 of these guns were manufactured.  The US Army fielded 15 field artillery battalions with this gun in Europe during World War Two.  They were declared obsolete at the end of the war.  The 4.5 inch gun had a longer range than the 155mm gun but a smaller bursting radius.  The tan 4.5 inch compared to the OD 155mm.

I had a number of rather ratty Roco howitzers in my collection.  So I gathered all my howitzer parts and did an inventory.  I needed a few base plates and some of the Y supports that hold the gun in traveling mode.   These replacement parts were made out of white plastic.  Note the tan gun above; it has a white plastic base plate between the trails.  It also has a white plastic rod holding the barrel onto the trunnion.  The first photo on this page shows one of the guns with the scratch built Y piece.  The photo below is two painted 4.5 inch guns.

Then I got surplus barrels from my spares box and used them to extend the length to the proper distance.  I added about 22 millimeters or just shy of an inch to the barrel.  The barrels were from Roco Z-135 US self-propelled howitzer.  These old kits often came with three different barrels.  The last inch of the 175mm gun barrel looked right to me and since I had built most of mine as 155mm and 203mm versions I had plenty in the spares box.   The M1 155mm howitzer had a barrel length of 12 feet, 5 inches.  The M1 4.5 inch gun had a barrel length of 16 feet, 2 inches.  Photo below shows the before in OD green and after in tan.

Using a sanding stick, I smoothed down both the old barrel and the new barrel.  Then I used regular liquid model glue to attach the new barrel.  This is a very quick and easy conversion.  I suspect there were at least 24 of these in a battalion and with fifteen battalions in US Army corps artillery that’s 360 of these guns in service in Europe between D-Day and V-E day.

Four guns in action with towing tractors.  Hat WWI British Artillery figures as early WWII US Army troops.  Tractor is a small model train accessory.

Mike Bunkermeister Creek


Bunkermeiser Blog