THE SECOND WAY OF THE WARRIOR:
remember the pistol duplicate that we got? so let me use it to show you another way to do a barrel.
first, select the face in the front and extrude it, making it smaller.
(actually, make it smaller than the barrel we did before. it was too large...
Extrude it inwards.(that word exists?)
change to Ortog. view, top view, and IN EDIT MODE create a cylinder. this way the cylinder is in the object.
Enter in Wayreframi mode.move it to the center of the gun.
Centralize the cylinder.
hmmm why I did take this screenshot?
so, rotate it 90° in X axis.
get it into the hole. make sure it is in the center.
change to side view. oh, no! our first pistol is still there! so...
select the other pistol and press H(or see the picture above to see the button in the menus)
Ta-daaa now it got abducted.
so go back to edit mode and side view, and put in Wireframe mode(Z)
OH NO! our cylinder got deselected?
press B and use that select-multi tool
or press B again to a circle tool, to select thing in that area.
if you select something other than the cylinder, just deselect it.
when pressing B you'll notice that it will appear a cross. just drag it to select things.
so you select it again!
so make it larger in Y axis, so that it fills that hole.
you can always select that front faces and drag them to where we want.
make sure it's aligned. and....
SELECT THESE FRONT FACES...
AND KILL THEM. SHOW NO MERCY!!!
(hmm L4D...)
(completely unrelated, but I made those words with grease pencil, which comes in my version of blender. cool no?)
MAUAHHAHAHAHHA I KILLED THEMMM!!!!
ahmm ok, back to the business...
select the outer edges of the square hole.
Subdivide Multi. value: 3.
this will create 4 edges at each 1 edge. so you'll fill these holes.
so... fill them by selecting one edge at one side, another on another side and bang! press F and it will create a face.
so let's call the aliens to bring back our booleaned pistol.
press ALT-H, or see the picture above to see where it is located in the menus.
notice how beautiful, organized our manually made barrels is! it's so clean!
and the booleaned is so irregular and messy...
but feel free to use any method. no one might notice this ingame
THE THIRD WAY OF THE WARRIOR
Using my superpowers, I got back in time while the pistol don't had any barrel.
(i.e, I've loaded a previous save)
so, select the front face, and extrude it, making it smaller.
select that mini-face and W->subdivide Multi-> value 3.
it'll create lots of mini faces.
make sure it is in a square form.
select the outer vertices(the corner vertices, that is) and activate the proportional fallout, that button with a torus. scale
these vertices to make it all look like a circle.
and extrude.
so I'll use that pistol with that last barrel.
by that, I'll ASSASSINATE the previous pistol. I'm much evil. muahhaaha.
*Continued in Part 3*