Internally? They're all pretty much the same with the TR15/GR15 offering 'blowback' as an added bonus.
The TR15 is an all metal upper/lower.
The GR15 and CM16 are both polymer.
A lot of the more expensive brands like VFC and Krytac - what you are paying for is additional features like integrated mosfets, higher quality internal parts, and licensed trademarks (like actual Colt branding for example), using varied RIS like Keymod or M-Lok instead of the NAR you normally see.
Someone may be able to provide more detail, but that's what I found out when I was looking at the various M4 versions. If you're planning on having them as 'loaner' stock - then I see no reason not to go with the CM16. Any issues that come out of them will be easily fixable and they're by and large good value for the dollar spent.
|