"more powerful" is kind of a realative term when it comes to firearms. I don't want to get all technical so i will keep it simple.
The 30.06 is normally considered more powerful. It has a much longer effective and accurate range. In excess of 500yards in the hands of a skilled marksman. The 30.06 has taken more north American big game than all other calibers combined.
Almost every hunters safe will contain at least one 30.06.
The 30.30 is normally a short range "brush gun" because of the style of weapon it is used in. A short barreled, quick pointing, lever action carbine. The most effective range for a 30.30 is less than 150 yards.
It uses a 30 caliber or .308 inch diamiter projectile. .308
Yes.
In it's military service it was called "Ball, caliber .30". In the metric system it is 7.62x63.
case length
All rifles or reasonable caliber are going to have recoil, I would look at your mounts or scope. tighten up your scope rail
No
An "Eddystone" is properly a US Rifle, Caliber 30 of 1917. Value will depend heavily on condition, and whether it has been modified in any way. I paid $800 last year for one in very good original condition.
Section 3006.
The short answer is no. The longer answer is, you might be able to get a .40 caliber cartridge to fire from a .45 caliber gun, but it may damage the gun, and even if it doesn't damage the gun, it will cause other problems. In general (with only a few exceptions) you should never try to fire any cartridge in any gun other than a gun designed for that caliber.
No You could build a rifle in .306" or any other caliber but you are likely referring to 30.06. A 30.06 rifle is referred to as "30 Caliber" but to be accurate it is nominally .308"
You did not give any numbers
Maxicam-3006-Dumbbell-Rack is dumbbell rack for keeping dumbbells and it does not come with any weights.
Pretty much the same as any other revolver or semi-auto.
I would say either the 5.56mm or the 7.62mm.
Can't be answered unless you tell us who made it.
Any caliber can do the job. Most states regulate what can be used.