Hi Gatsby

Thanks

Did cartridge length apply also???

Saw a 12b double rifle of 14 lbs 6 ounces, one im looking at is 11 lbs. The heavy one is a 3" and this is a 2.5"

I still find it difficult to work out, as unless im mistaken the gun firing a 3" cartridge would be under more pressure in the chamber etc, meaning the gun had to be not just heavier but stronger too, or???

For example the 577 bp versus the 577 nitro, the latter is heavier AND stronger to allow for the higher pressure/equivalent of more powder.(nitro being worth x amount more than bp)

Many thanks

Ben