Wink, the difference is the amount of energy the two rounds produce and can transfer. It has nothing to do with the actual diameter of the bullet.

A typical standard 7mm uses a 145 grn controlled expansion bullet and can deliver near 2000 ft/lbs of energy at 100 yards.

Where as a standard 3 inch mag .410 uses a simple non expanding chunk of lead that weighs around 90 grns (sometimes less) and delivers around 400 ft/lbs of energy at 50 yards.

So even though the .410 slug is larger in diameter than the 7mm the 7mm rifle would make a larger wound channel and transfer more energy to the target than the lighter, less powered larger slug.

There really isn't much comparison between a high powered rifle and a .410 slug. Even a .223 would create a larger wound channel and deliver more energy than a .410 slug will.

In an earlier post I said the 410 was closer to a 32 handgun in ballistics, after looking at more data I will amend that and say depending on what load you pick in each it is closer to falling in between a 38 and a .357. However the pistol rounds would be using a better bullet. When I was looking earlier I was only comparing 2.5 inch loads because that is all I can use in my winchester lever gun. Some of the 3 inch loads are a bit more impressive, if you want to call those numbers impressive.

I still feel that if you keep the range limitations in mind and pick the right shot it can get the job done. If you can put something through the lungs the deer will die, really doesn't matter what you use to make the hole.

Paul