Good choice of subject - there isn't (afaik) a large scale 25PDR around.
If you need images - just ask - there's a 25PDR outside an RSL (Returned Services League) club a few km from my place. I think it's an Australian made one with a muzzle break.
1/16 seems to be a good scale for guns - the Drafmodel guns and Patero's ZIS-3 are al 1/16.
Regards,
Charlie