(Found) 1970s fantasy book

[hobbesbooks44]

I read this book in the late seventies and remember very little. I have been looking for a while and I hope someone might help.
The story starts in Vietnam when an armoured american vehicle is transported to another world. I don't remember why.
The vehicle is transported back to Earth. Later the hero is asked to go back. He collects some weapons including a M1 carbine and goes back.
I don't remember the plot but he makes friends with a King who fights without weapons and a beserker.
There is a sinister figure also from Earth who has a gun.
I remember little but it is bugging me.
Any help with author or title would be helpful.
Regards
Martin

 

[Danny McG]

I think this probably The Doomfarers of Coramonde by Brian Daley

The Doomfarers of Coramonde by Brian Daley

MISSION TO HELL<br /> <br /> Gil MacDonald cursed in disgust.<br /> <br /> Twenty-four hours ago, he and his men had been fighting off an ambush in a Viet Nam jungle. Now, thanks to some kind of m

www.fictiondb.com

 

[hobbesbooks44]

Thank you. That's the one or should have said two. Ordered them already. Thanks again
Regards
Martin

 

[Happy Joe]

just info;
B. Daley also wrote a sequel to Doomfarers titled;
The Starfollowers of Coramonde (1979)
both are pretty good books.

Enjoy!