The Topic is a bit confusing I know, but at the moment I'm working on the idea of using turned-metal gun barrels to replace the barrels on some of my Warhammer 40K models.

Yeah, I know, the scale differences. I've seen two good ones though - one of them used 1/35 Tiger barrels for his heavy AT tanks, and they came out quite well. The other I've seen was an ML-20S barrel on the Basilisk, turned out nicely as well, I plan to use that for one project.

The part I come to is what I'm considering - I'm looking at replacing barrels on smaller weapons, and as such I'm at an impasse. I can't find dimensions for the barrels I'm considering, so I come here to the Armor Modeller's forum, looking for help. These are barrels I'm considering using for my projects. I would love a measure of the diameter at the breech end of the barrels, so here's the ones I'm looking at, all of them in 1/35

Master Model 1/35 M61 Vulcan 6x20mm
7.5cm PAK-40
5cm KW.K39/1 L/60 Puma mount
5cm PAK-38
M-134 Minigun set
5.5cm Flak for E-50 Flakpanzer
7.5cm KWK-40
3.7cm Flak-36/37

Those are the guns I'm considering for a few different applications. Conversely, I would love other alternatives for a gun with a decent muzzle brake, with a breech-side diameter somewhere around 4mm, though that's a flexible number for a good looking gun barrel.

I figured there has to be somebody in the forum who's used these barrels, so hopefully I can get the numbers to crunch the ideas for my projects. Thanks in advance, guys.

I find myself confused... nobody can provide the answers I seek? I don't need caliper-micrometer measure, I'm just trying to get a rough estimate for the concepts I'm working off.

Actually, it's a good question Simon. If you're not deep into the armament world, the actual size of the barrel is largely a matter of magic. Is the barrel of a .50 cal machine gun an inch in diameter (~.25" either side of the barrel or bigger?) would a .014" tube look OK in 1/72, .029 in 1/35. Curious modelers need to know.

I'll check my bombs and bullets issue.

I'm actually at this point looking, as you can see, at swapping in some of the 1/35 metal barrels to give some of my guns a slightly different appearance... so that's why I'm looking for the diameters at the mantlet/breechblock, so I can avoid having gun barrels that are too narrow, by comparison, or other situations. I'm almost sure I'm going to likely pick up the M61 for one of my tank upgrades, and I know I'll be using the ISU-152's ML-20 for my Basilisk SPG, it's just a question for the smaller guns, since I've seen 1/35 Tiger guns fitted onto Leman Russ turrets with a suitable visual effect, but not many look at the idea of replacing the smaller gun barrels, and thus my dilemma - I'd like to avoid spending coin on a barrel that won't work, as cash is extremely tight right now for me.

You can fit barrels that are too narrow by adding a shim to them. If they are too wide, simply drill the mantlet to match. I've done this a few times.

That's not really the situational problem - I'm not replacing barrels on typical armor models, so I have to figure out what caliber of guns will fit the weapon mountings I'm out to replace.

I'm working on Warhammer 40K models, I want to replace some of the heavy weapon barrels with some metal ones to give them a bit more of a different visual, so I'm looking for the diameter on the listed barrels, at the mantlet mounting, so I can compare to what I'm replacing, and get an idea for which ones I want to purchase for the purpose intended. Thus lies my problem - I can't find the diameters on the typical metal barrels in the listed calibers, since they're simply earmarked for the designated model. From there, once I have those numbers, I can compare and find what I'm looking for.

Over in the Main Armor thread, somebody suggested I contact the manufacturers... so far I've only heard from Master Model, who were very prompt, with the M61's base diameter. Puts it in a usable realm, for another project I have in mind.

Still would love the help of anybody who has the possibility to just quickly measure the diameter of the guns in question at their mounting point...