Dave McCracken
Moderator In Memoriam
Like groups shot with rifles and handguns, slug groups are best measured center to center. To do this, measure the longest distance from edge to edge, then subtract the nominal diameter of the slug.
In 12 gauge, that's about .729". No one here will cast stones at you if you round off to .75".
20 gauge, .62" will get you in the ball park.
Doing it this way gives apples to apples results.
My best slug shooter does about 3.9" groups edge to edge at 100 yards with the best slug, so center to center is about 3.15 or so. Of course, that's with bore diameter slugs. Sabots differ.
A question I get frequently runs something like.....
" What level of accuracy is acceptable with slugs on deer and similar game?".
The answer, at least in my opinion, is.....
I'd not take a shot I had serious doubts about. If you think you may miss or worse cripple, you probably will.
If it's at a distance and angle where I can keep them inside 6" from field positions or if hunting from a stand where I have a fixed rest, I'm ready to take that shot. IF.....
I look at the deer and think,"This animal is dead if I choose to make it thus"....
Lost, wounded critters bother me way more than unfilled tags.
As for pattern spread for sporting purposes......
Spread is a result of choke, load and distance.Ideally we want as much spread as we can get to ensure hitting the target. However, it's not that simple.
The pellets must pack enough energy to break the clay or inflict enough shock and damage to a live target like a bird to drop it. Of course, on live game, we also want enough moxie to kill quickly, without pain.
Those who know more than me say on smaller game birds we want a retained energy of 1 foot lb and a pellet density of 1 pellet every two square inches of target.
Load and choke are the conjoined twins of Shotgunning. We want a load and choke combination that will give us that energy and density at a given distance.
Shotgun gurus commonly recite stuff about a 30" spread. In the real world, it's few loads and chokes that will give that density and still have a 30" spread of real utility.
More common is a real effective spread of 26-28". There will be some pellets out there further, but these are invariably deformed, unround ones fast leaving the shot cloud.
Shot clouds have a core and a fringe. Cores contain round pellets that will keep speed as much as any sphere will. Fringes contain those that have been deformed. These bleed velocity and veer out of the pattern.
Of course, fringe pellets do sometimes hit targets, but the results are not dependable or repeatable.
Pattern your load and choke at a given distance. Eyeball the USABLE spread and mark it. Measure it and repeat for a couple more times.
If the usable spread is less than 24", try the next choke tube you have with less constriction.
If it's more than 28" but there are thin spots, tighten up the choke or use a better grade of shell.
Sometimes, even using the same brand, 7 1/2s will not pattern well in a given barrel and choke but 8s may. Or vice versa, there's few absolutes in Shotgunland.
In 12 gauge, that's about .729". No one here will cast stones at you if you round off to .75".
20 gauge, .62" will get you in the ball park.
Doing it this way gives apples to apples results.
My best slug shooter does about 3.9" groups edge to edge at 100 yards with the best slug, so center to center is about 3.15 or so. Of course, that's with bore diameter slugs. Sabots differ.
A question I get frequently runs something like.....
" What level of accuracy is acceptable with slugs on deer and similar game?".
The answer, at least in my opinion, is.....
I'd not take a shot I had serious doubts about. If you think you may miss or worse cripple, you probably will.
If it's at a distance and angle where I can keep them inside 6" from field positions or if hunting from a stand where I have a fixed rest, I'm ready to take that shot. IF.....
I look at the deer and think,"This animal is dead if I choose to make it thus"....
Lost, wounded critters bother me way more than unfilled tags.
As for pattern spread for sporting purposes......
Spread is a result of choke, load and distance.Ideally we want as much spread as we can get to ensure hitting the target. However, it's not that simple.
The pellets must pack enough energy to break the clay or inflict enough shock and damage to a live target like a bird to drop it. Of course, on live game, we also want enough moxie to kill quickly, without pain.
Those who know more than me say on smaller game birds we want a retained energy of 1 foot lb and a pellet density of 1 pellet every two square inches of target.
Load and choke are the conjoined twins of Shotgunning. We want a load and choke combination that will give us that energy and density at a given distance.
Shotgun gurus commonly recite stuff about a 30" spread. In the real world, it's few loads and chokes that will give that density and still have a 30" spread of real utility.
More common is a real effective spread of 26-28". There will be some pellets out there further, but these are invariably deformed, unround ones fast leaving the shot cloud.
Shot clouds have a core and a fringe. Cores contain round pellets that will keep speed as much as any sphere will. Fringes contain those that have been deformed. These bleed velocity and veer out of the pattern.
Of course, fringe pellets do sometimes hit targets, but the results are not dependable or repeatable.
Pattern your load and choke at a given distance. Eyeball the USABLE spread and mark it. Measure it and repeat for a couple more times.
If the usable spread is less than 24", try the next choke tube you have with less constriction.
If it's more than 28" but there are thin spots, tighten up the choke or use a better grade of shell.
Sometimes, even using the same brand, 7 1/2s will not pattern well in a given barrel and choke but 8s may. Or vice versa, there's few absolutes in Shotgunland.
Thank you for taking the time to share your experience with others - it makes a big difference!
