A modern 10 3.5 will deliver an equal load a lil faster than the big 12. Think about it, a 2 or 2.5 oz load will have more room for powder in a 10 than the 12. But the difference is miniscule. I personally wouldnt have a 10 simply because of the larger and heavier gun they entail carrying around. The modern 3.5" 12 is carrying a larger payload than a 10ga did 50 years ago. It likewise is 95%+ too the 10ga of today.

Maytom the reason a #6 HeviShot hits as hard or harder than a #5 lead is because HeviShot is 8% heavier than lead. If you drive anything equally fast yet it is heavier than something else, the heaviest projectile will yield the most energy. BUT also remember that HeviShot isnt shaped equally or as cleanly as lead. A #6 HeviShot "pellet" is usually larger than its lead equal. Plus it typically is any shape but round!

I have shot HeviShot for several years and swore by them until this past season when we started shooting Nitro's. They still utilize HeviShot but with much better technology like shotcups and buffer, Ray loads them too MUCH heavier and more devastating rounds than Remington could. I shoot his triplex load of 4,5 &7.5 in a 2.25oz variant in my 870 SuperMag with an old TruGlo tube. I killed two toms in MO last spring at 50 and 64 laser ranged yards! One of our guys killed two over 70 (one at 77) with the same load in a 3.5" Gold. We also have one of our guys getting a 10 ga built especially to shoot one of Ray's 3oz #7.5 Nitro loads. The pellet count is nearly 2000!!! With these loads being honest "70+ yd turkey loads" the need for a red dot or optic sight setup is MANDATORY. A common bead simply blocks out too much surface area at such ranges.

LMAO, those old days of "hung up just 10-20yds to far out there" are GONE!!!
RA