Originally Posted by
smokepole70
I really appreciate the formula info, that is really impressive to discuss the choke constriction in that much depth. The one load that amazes me the most is 3 inch remington 000 buck. It usually patterns better in a I/C choke with most of my 12 gauges. But, I got one old passed down Remington Wingmaster pump 12 gauge with a 30 inch fixed full choke that patterns 3 inch 000 buck better than the rest. It really dont make alot of sence.
Ultimately, the formula is a guidepost. Like I said, it doesn't mean jack when it comes to tiny shot, it only really works for buckshot that the d/D (diameter of the shot over diameter of the choke) is fairly large.
The easy answer, rather than using the formula, is that d/D should be less than 0.46. For example: 00buck = 0.33" divided by 0.46 => minimum choke diameter of 0.717". OR, say for a 0.660" choke, the largest shot you can expect uniform patterns from would be 0.304" diameter (0.660" x 0.46 = 0.304"), so #1 MAYBE or #2 buck.
And again, none of that is accounting for the shotcup thickness.
The packing pattern is really important as well. Buffered 9pellet or 12pellet 00buck in 3.5" 12ga will generally have a more uniform and controlled packing pattern, so they may group better in a tighter choke than a 15pellet 00buck would. What this is talking about is how the pellets are stacked in the cup. That "cos(30)" term above is referencing 3 pellets arranged in a flat triangle leaving at the same time. If you can stack the pellets so they don't leave 3 at a time, and would only leave 1 or two at a time, basically you can shoot balls up to 50% of your choke diameter (rather than 46%), or even larger if they're leaving one at a time.
What I'd GUESS is happening out of your 30" full choke is that you're shot is rattling around down the tube and finding a "happy place" before it exits, so the 000 pellets aren't leaving 3 at a time.
The only real BAD effect of shooting oversized shot is that you'll generally get planing of a few pellets. At short ranges, this isn't usually noticeable, but down range, you'll start getting bigger and bigger holes in your patterns, rather than having uniformly distributed patterns. Does that mean the difference between a hit a miss on a coyote at 50yrds, not usually. Does it mean the coyote might run a little farther than it should have, yeah, maybe. Then again, sometimes even well hit dogs will make it a long dang ways before dropping.
The good news is, each pellet in a 00buck shell has about the same energy as a 22mag, so if you slap an 8-10" pattern on the ribs of a coyote at 50yrds, it's like you hit him with 12-15 22mag shots all at once... Pretty dang devastating...