OK so hopefully this will show you how to convert some scouts. The text was written after i took the pictures but before i looked at them so the pics and the descriptions dont quite match up, but i am sure you guys will get the idea.
Stuff Used
Bits of plastic stock (sprue, banner pole off an old style base, two old SM devastators), brass rod approximately 0.25mm and 0.5mm in diameter, bit of green stuff (or in my case brown stuff).
Sniper Rifle
Muzzle
Cut a lump of sprue and drill a hole in the middle, then cut the sprue down so that it is the right length for your muzzle piece (flash suppressor??) I drill before I cut because it is easier to hold a big piece of plastic.
Glue a length of the thin brass rod into the hole (stage 1).
Start to cut the plastic down around the rod. I cut to within 1 or 2mm of the rod all the way round, then I scrap the blade along the plastic to shave it closer still. Finally I use a file to smooth off the plastic and get it as close as possible (stage 2).
Rifle Body
Cut another lump of plastic, this time a fairly long bit. Drill into the length of the plastic. Glue the barrel of the rifle into the hole. Trim the plastic down on either side of the barrel so that its about 3mm across (still stage 2). Draw the shape of the rifle body on the side. Draw it slightly larger than you actually want (stage 3). Cut the plastic to the shape you have just drawn. File both sides of the gun, so that it is about 1mm across with the barrel in the centre.
Play around with the shape of the rifle by shaving and filing (stage 4). Example I round off the forward upper and lower sections in front of the magazine, I try and make the butt as thin as possible. Mess around until your happy with the proportions.
Cut a short length of the 0.5mm dia brass rod to use as the telescopic sights, and glue it on top of the rifle (stage 5).
Arming the Scout
Take the arms off the scout model and do not loose them! (still stage 5) Decide how you want to pose the scout, if having the rifle go across the chest then you need to shave the chest plate and the inside of the rifle so that they fit together and look marginally like the scout can hold it.
Glue the rifle into position. (erm i am missing a pic there so use your imagination
)The arms you didn't loose now need some attention. You need to chop the arms down to fit (stage 6). Depending whether you make your scouts left or right handed. In most cases I trim the inside of the arm down. If its going over the top of the rifle then it gets trimmed significantly as well as a little bit of the gun (stage 7). But as all I really want from the arm is the elbow pad, as long as you get that in a realistic looking position then the rest of the arm can be green stuffed.
Follow a similar method for the other arm, but trying to get the hand into a holding the rifle position. I cut the hands off the arms before I do any of this. the right hand needs to be green stuff any way as getting the scouts hand into the right position will be hard. I cut the left hand off because I am hoping to have to green stuff that too and make it look like the hand is holding the rifle. if the rifle ends up too far away I glue the original scout fists back on. (i lost one of the arms so it looks like one of my scouts now has a bionic arm lol)
Fill in the gaps with green stuff and you have a scout with a sniper rifle (stage
.Heavy Bolter
Ok cut a block of plastic down to size. Cut a short cylinder of plastic for the barrel (an old banner pole in my case) and glue it on the front. The magazine is the magazine from the SM devastators missile launcher. Cut 2 small sections of plastic, one for the fore sight and the other for the ejection port. Glue them on, and there is your heavy bolter (HB1).
Again shave the chest down on the scout so the heavy bolter can be glued across his body. The right arm ?is trimmed as above and the wrist rotated abit, to look like the bolter is held at the rear with a handlebar grip. The left arm is trimmed and glued into position with out trying anything fancy with how he is holding the heavy bolter (HB2).
And the gaps are filled with green stuff.
I know my descriptions aren't very good, but hopefully the pictures speak a thousand words.
The finished converted Scouts
details...