Shotgun PC Comparisons
What is often lost in comparing chokes and gauges is that the definition of pattern efficiency does not change just because you change shells, payloads, or gauge. For starters, let's look at the basic pattern percentages used by Trulock chokes, at 40 yards. PC means the Payload / Choke Relationship.
A “Full” choke is going to put about 65% of your payload into a 30 inch circle at 40 yards. It doesn't matter if you are using a 28 gauge or a 10 gauge, it doesn't matter if you are using a 3/4 oz. payload or a 2 oz. payload, it doesn't matter if you are using #9 shot or BB shot, regardless: a 65% pattern percentage is roughly “Full” choke performance.
This is why making any all-encompassing recommendation for choke isn't possible. The question quickly changes into “65% of what?” Percentages of course don't drop doves or smash targets, pellets do. Suggesting that someone should just use a modified choke doesn't make any sense at all, unless you also consider shooting ranges, target size, payload, pellet size and so forth.
Recently, we have been dove hunting. The most appropropriate choke, under our conditions, which is using #7-1/2 shot, is “Full” choke. It may not be the case for others, and likely is not. The kill zone of a dove is very, very small as is the bird itself. More often than not, I'm using 1 oz. of #7-1/2 shot out of a 20 gauge. Yesterday, it was Winchester AA 1 oz. shells, 1165 fps stated velocity, a Browning B-80 20 gauge, and a “Full” pattern percentage Trulock Precision Hunter choke.
Pellets bag birds, not percentages, so consider what a “Full” choke actually means. American #7-1/2 shot is about .095 in. in diameter, with about 338 pellets to the ounce. Most everything in shotguns is “approximately” or “about.”
Full choke as it relates to pellet count means this, based on #7-1/2 shot, in the 30 inch circle at 40 yards.
3/4 oz. (219.7 pellets): 40 yard pellet count: about 143 pellets
7/8 oz. (295.75 pellets) 40 yard pellet count about 192 pellets
1 oz. (338 pellets) 40 yard pellet count about 220 pellets
1-1/8 oz. (380.25 pellets) 40 yard pellet count about 247 pellets
1-1/4 oz. (422.5 pellets) 40 yard pellet count about 275 pellets
“Modified” choke performance with an 1-1/8 oz payload is 60%,
or about 228 pellets. The notion of suggesting a choke, to be helpful
must include pellet count. An improved cylinder pattern with an 1-1/8
oz payload (190 pellets) puts about as many pellets into a 30 inch circle
at 40 yards as a “Full” 7/8 oz. payload.
That means that the 3/4 oz. 28 gauge shooter shooting a Full choke vs. a 1-1/8 oz. 12 gauge shooter using an Improved Cylinder choke is doing very close to the same thing as far as pellets in 30 inch circle, with the same pellet diameter, at 40 yards. A one oz. load out of a 28, 16, or 20 gauge that produces "Full Choke Performance" is no different than a one oz. load out of a 12 gauge that produces "Full Choke Peformance."
With
one oz. AA #7-1/2 20 gauge loads, for dove, I'm throwing 65 - 70% patterns
at 40 yards out of B-80s, A-5 20 Mags, 303s, and an M2. It puts 143 -
154 pellets into that 30 inch circle. It is virtually indistinguishable
from any other 65-70% 1 oz. load. Sure, a 1-1/8 oz. 12 gauge load that
throws 65-70% means more pellets, 160 - 172 in that 30 inch circle. An
extra 14-18 pellets in a 30 inch circle (706.85 square inches!)
doesn't mean much to the tiny kill zone of a dove. Well-centered patterns
bag birds, the ones that are not do not do nearly as well.
Copyright 2012 by Randy Wakeman. All Rights Reserved.
