12ga chamber theory and trivia- 3 1/2" Magnum or not ?

[preventec47]

I found today that a penney that is exactly .75 inches in diameter will fit into the
chamber of a 12 ga but will not fit into the barrel.  further the chamber of an
H&R single shot with 3" chamber markings will hold exactly 63 pennies.
These sixty-three pennies measure 3 9/16" when stacked. 

I attribute the overall length of the chamber as being designed to also
accomodate the crimp when the cartridge is fired.  Thusly it would seem
that a 3 1/2 inch magnum might conceivably work in a 3 inch chamber
"IF"  that cartridge did not have any crimp material.

This is probably all common knowledge but I wanted to mention the
sixty-three penneys trivia.  CAUTION !    one penney will be wedged
into the barrel slightly where the chamber tapers into the barrel.
I used a small screw by dropping in from the muzzle end to knock
the last wedged penney out of the barrel.  You must look through
the barrel to make sure it is clear after this activity.

This info could prove useful in the future if any gun is encountered
and you need to know whether it can handle 3 1/2" magnums or not.

[plumberroy]

  I fired a partner shotgun chambered for 3 1/2 12 ga shells with  a 3 1/2 shell  I don't need to know if it has a 3 1/2 chamber cause  I ain't shooting any more 3 1/2 shells out of a 5 1/2 lbs gun   jsut for the record I fired 27 10 gauge slugs from the bench in one setting  so I'm not recoil sensitive

[Foggy]

Plumberroy
You will go far pilgrim you are not a foolish man.
Foggy

[deernhog]

One round of 12 ga 3 1/2 #4 fired sitting and I thought that someone had took the shotgun and hit me with it like a ball bat. The bones in my head hurt and after two more rounds I figured the pattern was worse than the 2 3/4 "and the 3" shells. This was from a Mossberg 835 and made me cringe to think of shooting a single shot H & R. I have never shot a 10 ga that kicked like that.
On the other hand I worked with a firearms instructor that fired 3" rounds in his 2 3/4" chambered 870 for turkey, he said the pattern was tight and had killed several toms with it out to 40 yards.