RC Tank Warfare community hobby forum

Hello there folks,
Bit of a query I hope someone can help me with. I heard on quite a few tanks that the barrel is often the wrong size. Anyhow, unusally on the Heng Long Panzer IV with L48 the metal replacement barrel is reputedly incorrect. Whilst I've noted many people have lengthened it to be correct not many people are actually revealing how long it should.
As I'm new to RC tanking and not fully up on the terms when it comes to barrels except the Mantlet and Muzzle brake I decided to draw a sketch. What I'd like to know is either the "real" measurements or 1/16 scale measurements, particularly A-C as I intended to split the barrel and put an "insert" piece to correct it's length.

I have the following in 1:35 scale

A - 13 mm
B - 49 mm
C - 15 mm
D - 12 mm

Note that this is for the square muzzle brake and not the round one.

Thanks for that

i think its this
a/c about 158mm a/b 136mm aprox dave