I had the double eagle M3 version of the tri-shot and it only worked on .12s, with virtually no accuracy. I'd much rather have the ACM M3 and use it in some sort of special forces/law enforcement setup, I'm not very interested in having a totally realistic setup gear wise.
edit: Ed, CAW make stupidly expensive clones of weapons, they have an ICS MGL clone for £300. Mosquito, better known as mosquito moulds, make tiny RIS mounted GLs (http://www.fire-support.co.uk/product/mosquito-molds-m203-mini-launcher). The shotgun you linked is just an expensive version of the double eagle weapon. The double eagle version has the exact same metal:plastic ratio and it's about £90 cheaper .