Manufacturer: Hakkotsu
Package: 1x Firing Core, 2x Cotter Pins, 1x Flashbang shell, 2x MK2 “Pineapple” shells.
Type: Grenade
Rating: 4/5

My lust for a functional airsoft grenade goes back to my very early days of airsoft. Way back then, we used tennis balls with a streamer attached. Ghetto-milsim, but it was better than nothing. Gradually, we moved up to cast-rubber grenades with streamers attached. Not too shabby, low tech and cheap, but calling hits was always and issue. Then came my beloved Escort M26 gas grenades which had a finicky and difficult timer system and only blew gas out of the bottom . At this point, I swore off grenades forever, convinced I would never find a truly functional milsim airsoft grenade. Then came the Hakkotsu Thunder B. I first experienced the Thunder B at a now-closed CQB field in SoCal when one rolled in the room I was bunker’d in. When it went off, my ears rang and I leaped out of my skin… I must have it.

I received the Thunder B Beginners Package from Airsoft Extreme in the mail a few months later and ripped into the package accordingly. The operation of the Thunder B is amazingly simple in it’s complexity. A 12g CO2 cartridge is fed into an aluminum tube where once the spoon is released, a sharp plunger is thrust into the narrow end of the CO2 cartridge. The gas expands and bursts the plastic shell, letting out a horrific 130db boom. Very satisfying to say the least and the loudest non-pyro grenade I have heard.

The Thunder B amp’s up MilSim events like I always dreamed they could be. Loud booms all over the field really sets the immersion level bar higher than your average airsoft game. I do find that when fields allow these sound grenades in as area weapons, we ran into the same problem of folks not calling hits simply because they can’t identify if they are in range. No fault to those players, 130db is disorientating and quite frankly hard to range in the open field. I see the Thunder B much more of an asset to the CQB arena but still has it’s place in the large overall field games.

While I do love the Thunder B, it’s not without it’s draw backs. For example, firing core head is made of plastic and gives it a very “toy” feel. I have heard reports of this plastic breaking for some users on the first throw and while this is not the case with my unit, it is something to be wary about when lobbing this towards your foe. Another negative is the arming procedure. I found it a little cumbersome and difficult to cock the firing hammer, set the spoon, set the pin, put in the CO2 cartridge, screw on the cap and screw on the shell. Seems a bit much in my opinion, but for a functional airsoft grenade, I can cope. Lastly, I don’t care for hauling out the spent grenade shells. I wouldn’t dream of littering, dropping them in the field, but hauling garbage out is not fun and with the Thunder B, it’s a must.

In conclusion, the Thunder B adds a rich dynamic to airsoft events that you need to experience to believe. I love the Thunder B so much that I have 20+ extra shells on hand and keep them permanently in my airsoft go-bag “just in case”. The immersion factor alone makes these grenades a must for any serious MilSim player and all negatives stated above are out-weighed by the bowel-shaking 130db assault your opponents feel when one lands at their feet. You can pick a beginner pack up from Airsoft Extreme for $22.99 USD.