Sling Mounting Points
As we all know the Colossus doesn't come with any sling mounting points, even though it's size and weight would make having such points useful. A sling also allows you to carry additional blasters easily.
What you need:
2x Philips screwdrivers (size 0 or 1 and size 3 or 4 [These sizes are guidelines only. A screwdriver at the correct size for the screw head, may not fit into the screw well.])
1x Packaging wire (from the Colossus box)
1x Thin flat plastic (from supermarket food boxes, broken plastic ring-binder files etc. Be inventive!)
1x Scissors or knife (strong enough to cut plastic)
1x Drill bit (whatever size you want to make the sling mount hole)
Optional:
1x Additonal drill bit (5 or 5.5mm)
Although it doesn't actually have any sling mounting points the Colossus is a very simple blaster to add loops to. If you look towards the front of the blaster, between the top of the PC and the casing, there is a small gap, just behind the PC mounting point. This load bearing mounting point is where we are going to attach the front sling loop.
Front Sling Loop
Open the blaster by removing all of the screws. Remove the small screws first. This is because some of the larger screw's heads may dig into the walls of the screw wells, forcing the blaster casing apart as you unscrew them. If you remove the small screws first there is no chance of you damaging the casing, and it reduces chance of stripping threads.
Below are the locations of the screws. The RED arrows point to the larger (size 3 or 4) screws. The BLUE arrows point to the smaller (size 0 or 1) screws. The PURPLE arrow points to the long size 0 or 1 screw (same size head as the other size 0 or 1 screws, but double the length):
If any of the larger (3 or 4) size screw heads did bind in their screw well, you may want to carefully drill out the well to 5mm, or 5.5mm if it's still a bit too tight (remove the screw first).
WARNING! Be careful not to drill through the piece of plastic (with a small hole) at the bottom of the screw well, otherwise the screw won't do anything to hold the blaster together and you may ruin your blaster.
You can continue with these mods WITHOUT removing the pump cap. The pump cap is glued on and will need to be re-glued if you remove it completely. It is easier to perform these mods if you do remove the pump cap, but try to break the connection between the pump cap and ONE of the casing halves, leaving the pump cap connected to the other the casing half. I managed to remove one half of the casing by gently tilting one half of the casing, breaking the glue and pulling it away from the pump cap cleanly. If you aren't careful YOU WILL either snap the casing or remove the pump cap completely.
Gently lift the PC out of it's forward mounting peg.
Take the packaging wire, cut it to length (~3" long [you might want it longer or shorter depending on how big your sling clip is]) and loop it through the front mounting hole in the PC, as close to the PC as possible. Twist the two ends of the wire together and manoeuvre the wire so that the twisted section is hidden in one of the recesses around the mounting peg.
Re-mount the PC and check the wire doesn't foul anything, check that the casing closes properly, check that all of the connections and linkages (specifically the trigger wire and valve lever arm), before inserting the screws.
If you want to perform the anti-lag pump intake mod, don't close up the blaster yet!
Rear Sling Mount
This mod can be performed on a blaster in any state of assembly. This part of the mod isn't completely necessary. If you wanted to, you could skip this step and use the loop on the reservoir cap retainer. This would definitely work on smaller blasters, but considering the size and weight of the colossus, I thought it best not to use this cap retainer as a sling loop. If it breaks, you loose the sling and potentially the reservoir cap as well.
Take the piece of plastic and cut it into a rectangle large enough to fit around the filler neck of the reservoir (you can use the cap retainer on the Colossus' cap as a guide). If you are using a very thin piece of plastic (especially if it's less than 0.5mm in thickness, like the plastic from a food package) make the strip long enough to fold over and double up.
Mark out a hole at one end of the plastic (at the opposite end to the fold if you've doubled it up) large enough to fit over the filler neck of the reservoir (again use the Colossus' cap retainer ring as a guide). Use the drill bit to make a small hole in the centre of the marked circle, to give you somewhere to insert the scissors/knife. Cut out the circle, but try to leave some material to fit between the threads (similar to the three bumps on the inside of the cap retainer ring) to stop the sling pulling the cap off when refilling.
Drill a hole in the opposite end of the plastic (the side closest to the fold if you've doubled it up) large enough for your sling clip.
Cut the corners off the plastic to make it less sharp and to look nice!

The finished product should look something like this:
Or this if you doubled it up:
Fit it to the blaster beneath the cap retainer ring:
Add a strap, and voila! A working sling

Anti-lag Pump Intake
The pump of the Colossus does lag a bit when you really start pumping it quickly. This mod doesn't completely remove the problem (the internal tubing and check valves are a bit restrictive), and does involve removing the small plastic filter on the intake tube. This does mean you have to be more careful about the water you put into the reservoir. Nevertheless it did make a big difference on my Colossus.
The other issue with the intake tube in the Colossus is that it is far too long and lies in the wrong place in the reservoir to make use of all of the water. This mod also shortens the tube to make it lie in the lowest point in the reservoir. The blaster now uses, as near as makes no difference, all of the water in the reservoir, whereas there used to be a sizeable volume left which I couldn't seem to use no matter how I positioned the blaster.
What you need:
2x Philips screwdrivers (size 0 or 1 and size 3 or 4 [These sizes are guidelines only. A screwdriver at the correct size for the screw head, may not fit into the screw well.])
1x Scissors or knife (strong enough to cut thick plastic/rubber tubing)
Open up the blaster (see sling mod above)
Remove the reservoir completely from the blaster casing. It is held in position by pegs built into the casing, and is connected, via an o-ring, to the rest of the internals without glue. Hold onto the white plastic connector as you pull the reservoir out of the connector (prevents anything getting broken). It will take a fair amount of force to pull the reservoir off the connector the first time. The intake tube will easily slide out of the reservoir.
At the end of the intake tube is a white plastic filter thing. The bars are very thick and restrict the flow of water through the tube by quite a bit:
(This pic shows the bars removed. I first tried to enlarge the holes, but then wanted to make use of more of the water in the reservoir by shortening the tube)
Cut the tube shorter. Cut it at such an angle (~45°) that the opening in the tube points DOWNWARDS when placed back into the reservoir:
(yeah, I cut it the wrong way in this pic

Cut a small bit off at a time until the tubing just fits in the lowest point of the reservoir:
Re-assemble the blaster! If you HAVEN'T drilled out the screw wells, tighten the large (size 3 or 4) screws before fitting the small (size 0 or 1) screws for the same reasons as when you took the blaster apart.
You now have a Colossus which doesn't have pump lag as badly as it did before, and that can make use of all of it's reservoir's water!

Sling Mounts on Other Blasters
The style of rear sling mount in this guide can be used on virtually any blaster, but is especially effective on blasters where the reservoir cap is the highest point on the blaster:
You can quite easily adapt these guides to suit other blasters.
For example, to make a front sling loop for a blaster with a clip on (not glued in any way) nozzle cover, use the same principal as the rear sling mount and fit it behind the nozzle cover:
(These XP70 sling mounts were my first attempt at sling mounts and were made very quickly a few years ago. Hence the really rough look.
