All you need is:-
Some strong glue I use some Cyanoacrylate based glue that bonds in seconds, longer drying glues may be more fiddly!
Some Caps, these are sold in most toy shops and are also available online...if you live in the UK they are now classed as "fireworks" and cannot be sold to anyone under that age of 18 (i know its pathetic...) they are available in many types 8 and 12 shot rings for revolvers, strips of 10 and the reels of 100 paper caps for the relay old style guns...these are individual caps and have to be separated from the mesh, but work well for this purpose.
Long or needle nose pliers I'll show you what they are useful later.
A knife to help separate the caps from the mesh.
And of course your projectiles. This method workd for both .22 and.177 pellet types.
Step 1: Glue time!
What i have done here is to cut the mesh into managble sections, lines of 2 each holding 16 caps.
Simply apply a small amount of glue into each cap, make sure this entirely fills the cap, the amount of glue depends on what pellets you want to use.
Pointed pellets protrude into the cap which means more contact with the glue, domed do the same but need extra filling, flat headed pellets as i said have less contact and need an almost overflowing cap.
Once the caps have been filled place a pellet in the dricetion of travel onto the cap making sure their is not too much run-off from the glue.
Step 2: Cut the little buggers out!
obviously if you are using tackier glue then the drying times may be much longer.
Once dry (you will know when the cap cannot be easily separated from the pellet) it is safe to remove them from the mesh. i found the best way is to cut round them with a knife, pulling them out can damage them and break the glue bond.
You may find some of the bonds less that desirable and the pellet and cap will separate so leave them on the mesh and use the needle/long nose pliers to return the pellet to the cap and apply extra glue.
What are they like to shoot you say?
Well depending on how well you have managed to seat the pellet on the cap they fly pretty true, would not be suited for hunting purposes, nor would i want to use these in anything more than a cheap air rifle or pistol as i have no idea how these would affect your barrel/auto loading for CO2 systems.
They have about a 95% explosion rate on hard targets and most detonate on softer targets too.
They make quite a loud bang and produce smoke, also have been seen catching fire due to the nature of the glue used.
Happy plinking and remember don't use these against anything living, make sure you have a safe area to shoot in and NEVER point a loaded gun at anyone (even if it is just an air rifle)