Going power armor for a little bit and I need a big gun that doesn't need missiles, 50 pounds of 5mm, or balls of flame.

What's your take on these two fine support rifles?

Edit: to clarify, -the- automatic rifle from DM and not just -an- automatic rifle.

I usually decide ahead of time which ammo is going to be "normal" and which is going to be AP (5mm vs 5.56), then use both accordingly. 200 round of anything is always fun though.

Tactically I'd say a semi-automatic rifle would be best... Of the 2, LMG I guess, the automatic rifles are innacurate

Both 5.56 and .308 have AP variants so that's a plus.

I'm going to be pretty close to medium range with these weapons and out of vats, I'll likely tap the trigger to burst so inaccuracy won't be too problematic.

Good points though, you two.

Well one of my tactics is to shoot them while they're far enough away for spread to work in my advantage..

If you're trying to get them legitimately and quickly, I'd say automatic rifle would be way easier to get and the ammo is plentiful.

I'm missing something here. How does one use spread advantageously?

Let's say I'm going to a fiends camp, I'll have weapons that are more accurate (Modded, or something like a sniper rifle or with a scope, maybe even good ironsights like on the .357) and squat down, get the first kill with a sneak attack critical, and then try to snipe the rest down quickly, then their weapons like varmint rifles and semi-automatics, 10mms etc are all spreading around me and none hit me.

I'm not sure which DLC makes the changes to the ammo (probably Gun Runners?) because I recently got the Ultimate Edition, but the normal 5mm now has an automatic -10DT and the 5mm AP has -25DT. Great against BoS and other heavily armored baddies.

You'll probably burn through just as much ammo with the Light Machine Gun as you would with a 5mm, at least that was my experience. If your aim is to go easy on your ammo consumption, why not try a Marksman Carbine? They can be almost as fast as a fully automatic like the LMG, but are way more accurate. They're very good rifles for mid-range shots. It also uses 5.56 ammo so it will be easy to keep yourself supplied.

Depends, what difficulty are you playing through? Anything on Hard and above makes any leadspitter nearly useless.

P.S. stop trying to shove other weapons in this guys lap, if he only wants the comparison of these 2, than give it to him.