Hello Dave,
The HW 100 is an excellent pice of kit with many features but the thing I like most about it is that you can't load two pellets into it by accident.
There is a clever lockout in the mechanisim that stops the magazine from indexing until its been fired, that is once you load it you can work the lever again but you wont load another pellet until you've pulled the trigger.
Also this means that if your hunting and its been a while between shots if your in doubt as to whether the rifle is loaded you can just work the cocking lever again to check, or check whether the safety catch will operate, as this will not move until the rifle is loaded.
It all adds up to a very safe rifle thats also realy accurate, has a good silencer and an optional single shot magazine [ideal for HFT]
Its true that its a bit heavy but not so much you cant live with it and the spec far outweighs this small niggle, compared to other brands in this class its excellent.
If it was my money i'd buy it without question.
I bought one when they first came out and were only available in .22 and had a poor silencer but now they have adressed these issues and i can see me buying one in .177 in the next few months.
Regards RH.