I am some what confused as to what is considered a light load.  Are birdshot light loads?  Is 6 considered a light load?  

Basically, it has to do with the amount of powder and the weight of the shot...not so much the size of the shot. More powder = more velocity = heavier load; and/or more shot = more weight, which... with a given amount of powder = heavier load.

mike103 or some of the other guys can enlighten you further, but with shotshells, powder is measured in "drams"...as in 3 1/4...shot measured in ounces...as in 1 1/4...and shot size is given last...as in 8. So my old favorite dove load is expressed as "3 1/4 - 1 1/4 - 8"...a "medium" load if you will...but pure poison for flying dove even if it was a little more expensive!

Ikor is right. Two things make a shotshell a heavy load, the amount of powder and the amount of shot, not the size of shot. Powder is measured in "dram equivalent" and shot is measured in ounces. I went to the Remington catalog for this comparison of field or game loads.

Field Load - catalog #GL12 - 12 Gauge, 2 3/4", 3 1/4 dram, 1290 FPS vel, 1 oz shot, #6, 7 1/2, 8 shot. This is a classic light field load. Small amount of powder and only 1 oz of shot. This load would most likely not work in a 11-87 police model.

Heavy Game Load - Catalog #RP12H - 12 gauge, 2 3/4", 3 1/4 dram, 1220 FPS vel, 1 1/4 oz of shot, #6, 7 1/2, 8 shot. This is called a heavy game or field load. Same amount of powder, lower velocity, but heavier shot charge. Even though this round has the same amount of powder, it is pushing a heavier amount of lead and it will have more recoil. This will help with recoil operated shotguns and might work in a 11-87 police.

Express Long Range - Catalog #SP12 - 12 gauge, 2 3/4", 3 3/4 dram, 1330 FPS vel, 1 1/4 oz of shot, comes in everything from BB's down to #9 shot. This is a extra heavy long range game load. More powder, more shot, higher velocity. If this does not work in your gun than get your gun fixed.

MIKE.

then you have target loads which are so light they are used to break skeet targets and won't reliably kill a game bird.

16 drams is one ounce.

The dram unit of weight is an old unit of weight and is part of the avoirdupois measurement system, which we use in the US today.

It includes the ounce, pound, and ton.

As far as I'm concerned this measurement system is bizarre....16 ounces to a pound?
5280 feet to a mile?

I LOVE METRIC....everyting is 10 of something else.

Quoted: I LOVE METRIC....everyting is 10 of something else.

I'll second to that.

The "dram equivalent" is a measurement that matches an amount of smokeless powder with an amount of black powder that will produce the same velocity if using the same shot charge.

Like ECS said this makes no sense at all. Match this with the number of lead ball of the same size that equal a pound, the formula for the gauge of a shotgun and you just have to wonder if the guys who started all of this were smoking crack!

I resisted the change to metric only because that imbecile of a president, Jimmy Carter who couldn't rescue his wife from the bathroom was the one who was pushing it. MIKE.

mike103;

Was Carter unable to rescue Roslyn before or after the rabid squirrel incident?