Bolt-actions technically were around at the very tail end of the 19th century (Lee-Metford & Lee-Enfield), so they're not wholly out of place. But all the massive, cannon-laden behemoth airships and tanks in the NS depot don't seem to hold fast to a very Victorian setting, which is what I think Rare intended by limiting tech to the late 1800's, as on the first page.

For example, if we were to stick to a more Victorian setting, we'd be seeing artillery like this:
[hider=Links][url=http://en.wikipedia.org/wiki/RBL_12_pounder_8_cwt_Armstrong_gun]
[url=http://en.wikipedia.org/wiki/RML_9_pounder_8_and_6_cwt_guns]
[url=http://en.wikipedia.org/wiki/Ordnance_BL_12_pounder_7_cwt]
[url=http://en.wikipedia.org/wiki/Mountain_gun][/hider]
Not the WWI & II-esque siege engines in the NS sheets.

-Agrees with Tatsua-