Unfortunately, we do not currently carry replacement caps for this riflescope. I would recommend contacting Vortex directly for assistance in sourcing a replacement set.
The Vortex Diamondback 4-12x40mm Riflescope does not include any scope rings. You will need to use a 1-piece base or a picatinny rail base with a set of picatinny rings to mount this scope. Email us at Techsales@opticsplanet.com for assistance.
The Vortex Diamondback 4-12x40mm Rifle Scope can be used on a 50 caliber muzzleloader.
The Vortex Diamondback 4-12x40mm Rifle Scope is made in China.
The Vortex Diamondback 4-12x40mm Rifle Scope would work fine with an AR platform rifle. However, depending on your specific rifle and the application you intend to use it for, there may be better options more suited to your build. Email us at Techsales@opticsplanet.com and let us know what rifle you have, and what you intend to use it for. That way we can recommend an optic that will work best for your setup.
This link is the closest scope Vortex makes to the specs that you asked about. https://www.opticsplanet.com/vortex-crossfire-ii-6-18x44-ao-rifle-scope.html
This scope has parallax fixed at 100 yards so it will not focus down to 25 yards. That said, shift should be negligible at 25 yards so it should still work for you.
Please contact us at techsales@opticsplanet.com with the make, model, and caliber of your rifle and we will be happy to assist further.
This scope is 12" long.
Neither are correct, the 30270 cap should be the ideal one. This scope has a 1.89" outer diameter on the objective end. Those scope caps stretch a bit, so you don't want one the same size (30280), let alone bigger (30290). Since the 30270 cap is the next size down from the scope's diameter, that is the ideal option.