Choke construction question on why SBE2 vs SBE or Stoeger

[reynolds243]

just looking at some of the chokes out there for the mobil choke system and the crio plus system and wondered why the same choke (ill use the Hevi Shot Choke) for the SBE2 is a 667 vs the mobil choke as a 656? from what i understand the bore is the same on both guns so why would they not shoot more the same ideal choke sizes. From shooting stoegers for a few years i know the 650-660 range is awesome in those guns and would assume that is the same case for the SBE2 using the same barrel diameter.

just a thought i noticed today and I'm sure there is a pretty obvious reason....just didn't make a ton of since to me at the moment.

[gobblingghost]

I have an SBE and shoot a Sumtoy 650

[the Ward]

I was wondering the  same thing myself the other day while browsing some internet stores .Maybe due to the 3.5 chamber more common in crio plus barrels vs 3" chambers more common in mobil choke guns?