Ox also do a 'rodless' caulk gun:
https://www.protoolreviews.com/ox-pro-rodless-caulk-gun-review/
Whilst it's not as compact as the Siligun (it uses a metal clock-spring wound up into the handle as the rod, so still pushes from the rear) it's certainly an improvement on the normal style. And based on that review, it seems to manage this without any drawbacks over a traditional style gun.
https://www.protoolreviews.com/ox-pro-rodless-caulk-gun-review/
Whilst it's not as compact as the Siligun (it uses a metal clock-spring wound up into the handle as the rod, so still pushes from the rear) it's certainly an improvement on the normal style. And based on that review, it seems to manage this without any drawbacks over a traditional style gun.
