Great stuff!
Saw your query on another forum I was browsing about who makes 28mm US Army with M14 in OG-107 uniforms. Only one manufacturer that I can think of and that’s Killer B games, they do a small range of US Army and it includes an M60, a radio operator and an officer as well as various GIs with M14.
I can’t say the sculpting appeals to me and the M14s look way too short but that’s all that’s out there that I know of and YMMV.
https://killerbgames.co.uk/shop/ols/categories/invasion-xActually for 1958 you are better off going with M1 Garands and BARs. Roll out of the M14 was incredibly slow and a lot of units had only just received them by the time they made the switch over to the M16. If you look at photos and footage of the Berlin Wall crisis in 1961 you’ll see that at the time the wall went up in August the troops on the front line were all armed as per 1945. This caused something of a scandal and M14s were rushed to Berlin, so that by October the Berlin Brigade and the reinforcements sent were mostly M14 armed.
Brigade Games do a range wearing OG-107 and M1 and of course for cooler weather you can always use WW2 troops in M43 coats. Artizan do suitable figures. The only required change might be to file back the buckles on the boots and paint’ em black. Empress’ WW2 range is another alternative.
I will eventually be doing parallel forces for 1961 with my Berlin project and the Artizan/ Empress route is how I plan to tackle the Yanks. If you are creative with plastic card for magazines and brass wire for a barrel it should be possible to convert most model Garands into M14 proxies. You would have to sculpt new webbing though.
Hope you don’t mind answering your query in another thread on a different forum.