Is the m4a1 tag really necessary, or can we just alias it to m4_(carbine)?

There are different variants of certain guns, but I wouldn't know for sure if the A1 has enough visual distinctions to warrant it.

The m4a1 tag should be unnecessary. An alias to m4_carbine would be useful.

m4a1 -> m4_carbine

From wikipedia -

The M4A1 has a "S-1-F" (safe/semi-automatic/fully automatic) trigger group, while the M4 has a "S-1-3" (safe/semi-automatic/3-round burst) trigger group.

Done