We had a Howitzer at the old American Legion hall back in the early 70s when I was a kid and I remember that it was sun faded olive drag green with rust beginning to show here and there. The old tires had gone flat years earlier and were what you might say were flat black. That's about all I can remember. It was stollen about twenty five years ago by persons unknown...
There are some very interesting photos if you do an image search for "us artillery museum".
Ed
American Legion Hall in Highland California has one out front. It is green. I usually paint tires a medium gray because tires fade some and black is too dark. Look here. https://www.google.com/maps/@34.1354095,-117.1864536,3a,60y,237.57h,86.67t/data=!3m6!1e1!3m4!1sM29s8oUuAZ35s-xuldRE_w!2e0!7i13312!8i6656?hl=en
I'm seeing some Vietnam pics where the barrel looks like it was left unpainted or maybe in a light gray. Not sure why you would do that for a field piece. But it's your VFW and it's been used since WW2, there are a lot of options that are correct.
Henry
COB Potomac & Northern
Shenandoah Valley
Military equipment on public display rarely is painted anything like what the equipment looked like when it was in service. This is good for us, because all those stencilled markings do not need to be researched.
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When on display, these are usually given a quick coat of whatever "military" color is available. I have seen helicopters and armored fighting vehicles painted some of the most hideous shades of green in public parks/memorials.
I have seen some equipment where the operating handles are painted red or yellow, but this is not very common, and looks silly to me.
The common thing is that they all fade.
A light beige or light green would look best to me. Tires look great painted dark brown with a wash of thinned black. Some rusting with pastel powders and you should be good to do.
-Kevin
Living the dream.
https://www.flickr.com/photos/lunken_spotter/12387785763/in/photolist-37Hufd-8M4ku5-fCk6W5-99mnxn-ZQdtib-965Wtm-Yo1aNw-97L9bW-97H1Vp-an3bzi-97H2ec-97H2rK-ZkZBU3-UHbroC-W3BXFS-VvWU4d-BVkkdc-oYB9dC-W3BXsW-965Ws3-pnNYHV-my5DRB-6qnXYq-965Wos-bd7b2e-esrrp9-8bSzuz-8bSzyT-pnN25n-oHqKQE-8bVSZh-an62Tw-B7Ni8c-8bVSWy-wtDsvA-6ycidd-ozKK5w-8bVTk7-an62DA-22WHnLG-8bSzoD-962VBx-qJWxwF-YHWnoQ-VigdjM-ti76Y8-tfLvgU-oiRVog-wwr3xB-jSED8a
In that picture you can see Big Howie and his family, right to left is, Little Howie, Mrs. Howie, Big Howie himself, Big Howies father Old Man Howie, and oh and Shorty Howie (Big Howies cousin)!
Far as the model, perhaps do olive drab with a light overspray of desert sand and moss green to imitate weathering, maybe do some oxide brown too as rust.
Steve
If everything seems under control, you're not going fast enough!
Maybe folks over at the sister publication's forum would be better suited to help?
http://cs.finescale.com/fsm/general_discussion/f/9.aspx
Just like lots of steam locomotives left to the elements on "display" they sometimes had a silgle coat of cheap black paint, which quickly turned to rust.
Lots of the artillery on display in township parks and VFW halls are similarly covered top-to-bottom in faded OD.
https://www.flickr.com/search/?text=M114%20155MM%20howitzer
Good Luck, Ed
I am planning on having a VFW hall on my HO scale model railroad. I will have a herpa M114 155MM howitzer out front. What colors should it be? I know most of it would be olive drab, but what about things like the tires and recoil springs?