[Voice of Reason88]

Okay, since we’re on the subject, a couple of ‘uninformed’ (as opposed to stupid..) questions:

1). Besides dimensionality changes, are there any real differences between the M4 and the venerable M16?

2). For a time it seemed like many had a front handle/grip on their rifles – but that ‘fashion’ seems to have gone away, why is that?

(Those folks not using a front grip are simply grasping the rifle around the front rails)

Is there a compelling reason for this? or is it just personal preference?

[grobdriver]

Avoids the heat build up from the barrel.
"Stock" ARs have heat shields built into the hand guards - the minimalist rail forends can get hot when shot a lot or, I would imagine, on full auto.

[dangerdoc]

I shoot better without the forward grip. I haven’t quite figured out what to do with my elbow when using one.

[Yo-Yo]

Okay, since we’re on the subject, a couple of ‘uninformed’ (as opposed to stupid..) questions:

1). Besides dimensionality changes, are there any real differences between the M4 and the venerable M16?

M4 has a shorter barrel, and a shorter, adjustable stock. The M16 has a longer barrel and a fixed stock.

2). For a time it seemed like many had a front handle/grip on their rifles – but that ‘fashion’ seems to have gone away, why is that?

(Those folks not using a front grip are simply grasping the rifle around the front rails)

Is there a compelling reason for this? or is it just personal preference?

The vertical foregrip is perhaps most useful on a full automatic weapon. Some even have bipods hidden inside of them. But they are heavy and can snag on gear when carrying. ARs are Men's Barbies, and are easy to accessorize with foregrips, flashlights, lasers, optics, buttstocks, railed forearms, etc. So you'll see a lot of stuff on an AR that isn't necessarily as useful as it is fun.

[jstaff]

The M16 has full-auto capabilities, the M4 can only fire 3 round burst on auto. The fore grip is mostly personal preference, useful on shotguns or some rifles with heavier recoil. The light recoil of the AR15 design, in 5.56, makes them just a pretty decoration, tho this is just my opinion.

[smokingfrog]

The M4 is a short barrel carbine.

The main difference is the length of the barrel and the gas tube. The Marines still use the M16A4, which has the longer, heavier barrel, and fires 3-round burst instead of full auto. The longer barrel also has the advantage of giving you a better sight radius. Rifles with the longer gas system are considered to be more reliable as well.