Some comments on the photos:
Photo 1) the embrasure is protected by reactive armour while the gun mounting is protected by composite armour. Chains should give additional protection against hollow charges. The perforated tube holds a water spraying system, I suppose to reduce the infrared signature and deflect laser beams for laser guided weapons.
Photo 2): this is the Bison battery covering Sargans. This photo was taken shortly after the completion of the two casemates. Nowadays the trees are much higher. In normal circumstances the chains hang down. All Bison casemates can only fire indirectly
Photo 3): this is the prototype. You will note that the chains are much shorter and also the niche on the right for the barrel seems to be more shallow than the final casemates.
Photos 4) and 5): the rate of fire is often given as 5 rounds per 25 seconds. It seems that the gun has a 5-round magasin. The rate of 15 rounds/min stated on
http://www.militaryphotos.net/forums/sh ... 601&page=9 is unlikely to me as I have not found any evidence for water cooling for the barrel. Lets not forget that the Bison technology is dating from the early nineties, in fact the barrel (Long 47 caliber) is identical to the Panzerhaubitze 88/95, an upgraded M109. According to info from 2001 this provides a maximum range of 36.400 m. with a base bleed cargo round.
Impressive as it might sound, in my humble opinion the Bison batteries are already outdated. Besides the fact that they are sitting ducks, despite their protections, their guns are outperformed by the current generation of 52 caliber long 155 mm guns
Best regards,
Caspar