Knight......
The ONLY way to really tell how the gun is choked is to pattern the gun and count the holes.
To pattern a shotgun, use a piece of plain paper (like the back of a large paper target) and put an aiming point (like a bright orange self-sticking sticker in the center of the paper).
Put the paper on a target board 40 yards away and fire at the center of the paper. Then put a 30-inch circle around the most dense part of your gun's pattern on the paper and count the number of shot inside the 30-inch circle.
Then divide the number of shot inside the 30-inch circle by the total number of shot in your shotshell. The decimal answer is your percentage of shot inside the pattern and the indicator of how much choke that barrel has.
I will list the total number of shot in some normal 12 gauge loads according to shot size so you can do the work and figure out the chokes.
Normally, a cylinder bore (no choke) will put 40% of the shot inside that 30-inch circle.
Improved cylinder choke = 50%
Modified choke = 60%
Full choke = 70%
Since the standard 12 gauge load is 1¼ ounces of shot, here's the shot-count of the various sizes of shot in 1¼ ounce load:
#6 shot = 281
#7½ " = 437
#8 " = 513
Divide the number of shot-holes you count in the densest part of the pattern around which you've drawn that 30-inch circle and then divide that number by the above number that is appropriate for the size of shot you're using in your gun for patterning. The answer will yield a decimal number like .61 (or "61%") which is the percentage actual percentage of the shot in the pattern within a 30-inch circle at 40 yards. This percentage will determine your choke(s). Therefore, a .61 or 61% pattern would be a slightly tighter pattern than a "modified" choke, but close enough to call it a "modified choke".
As an example, let's say you're using #6 shot and shooting a 12 gauge shotshell that has 1¼ ounces of shot indicated on the outside of the shell box. And let's also say that you pattern the left barrel with #6 shot and you count 217 shot-holes inside that 30-inch circle. If you divide 217 by 281 (the number of #6 shot in a 1¼ ounce load), the answer is ".61" or "61%. That would indicate the choke was very slightly greater than a "modified" choke.
For all intents and purposes, you would call that a "modified choke".
Also note WHERE your gun barrels pattern. If they shoot in the center, you'll be indeed fortunate. If they shoot high... or high to the left or right, you should take note of that and remember it on longer shots so that you can center your shot pattern on the game at any range.
Often... inexpensive (and even some "expensive") double-barreled shotgun's barrels are not too well "regulated" and will not center their patterns in the center of a piece of patterning paper at 40 yards.
However, perfectly "regulating" shotgun barrels on double guns can be a very expensive undertaking and not worth the cost or effort unless you are a rich perfectionest with lots of patience.
Strength & Honor...
Ron T.
