I got that AB Biller on suggestion of my neighbor as good a beginner spear gun. My girlfriend refers to the AB biller style spear gun as the AK-47 of spearguns, cheap , reliable, plentiful, powerful but not that accurate (at long ranges). I would agree to some degree with her. The Biller style guns are popular with scuba divers, because they are hip loaders, and are excellent for free shafting and they are “old school”. A lot of scuba divers are “old school’ too, and have probably been using these style guns for years with great success, so for them I think “if it aint broke, don’t fix it” would apply. This gun and trigger style has been around for many years, and its is rare to hear of them breaking or not functioning properly. Another good thing about these guns is they are cheap and it’s easy to change the size. All you need is a shaft and piece of wood to replace the stock, both of which are sold relatively inexpensively by Ray Odor.
For free diving though I don’t think these guns are ideal, for one the out of the box rigging for line shafting these guns involves a slide ring on the shaft. So essentially as the spear is fired it must slide through this ring which eats up its forward motion. This slide ring coupled with the heavy shaft billers shoot and the wood track the spear slides on make for not a lot of range. You can use a lot of rubber to offset this but its still inefficient. Try shooting a biller with one 5/8 band compared to a rail gun with one 5/8 band and there is world of difference. Of course on the upside with the heavy shaft if something is in range, it demolishes it.
It’s also not really cheap, I mean it is cheap compared to riffe or a custom wood gun, but you can actually get a euro or railgun for the same or less then a biller gun.