First off, don't use the default checker that comes with max. Realistically, it doesn't provide enough information on your uv scale and more importantly, facing direction. Try using the one I've attached. Also make sure you've scaled the texture down enough so that you can actually tell how even your unwrapping is.
B.) Before unwrapping, it's always a good idea to clear the history of a model by apply a reset XForms modifier found in the utilities panel. For whatever reason, max will hold on to the creation history of a model and when you don't erase it, it'll lead to a bunch of silly problems, such as crashing. Collapse the stack and resume unwrapping.
iii.) Try pelt mapping the trigger guard if you haven't already. It'll automatically bring the UV section to the center of the grid. If that doesn't work, click the top left button in arrange elements to bring all your uv pieces into the 1,0 space.