I have a friend back in Edmonton that has tried many thing with these things and this is now what he always does with them.:
He paints all of his shells white with a bright pink stripe around them in the middle that way they are easy to spot, even in dense dark bush.
He always puts those shitty Walmart brand .12g BB's in them. He's never had any issues with people saying they are too dangerous to use or that people got injured by them. He never stuffed them with BB's as it tends to waste them and as stated previously decreases the expansive space when they are filled, but throwing 100 or less BB's in at a time has never had any effect that him or I can see on the pop time.
As well, because they only tend to burst in one area of the shell, he did a nifty little trick that actually works very well, most of the time. He takes an Exacto knife and makes shallow cuts vertically on the shell with about an inch spacing between each cut. This means that it now has areas in which it will more likely burst, and usually bursts in more than two. We even had several that burst in all six spots. The only downside to this is the shells burst about one to two seconds faster than normal. He avoids hand burst by simply holding the spoon down as he throws the grenade that way the pin will not hammer the CO2 cartridge until the whole piece is already in flight. He himself has never had any problems with this and several of his friends all use this technique. I personally don't use Thunder B's, but after seeing and trying this technique many times in his backyard (acreage, so quite large) and in little skirmishes, I would say that from personal experience it works well and is safe so long as full seal eye protection is being worn.
Try it out for yourself.
Note: make very shallow cuts on the shell and really try to make them all similar depth or else if one is much deeper than the others it will simply burst at that one spot.
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Last edited by Zack The Ripper; December 6th, 2012 at 13:03..