Combo duck & goose 20ga

24 Oct 2020

Someone was looking to make a 20ga load that would be good for small ducks, the hardest duck load to make as it takes the most pellets, AND also for geese. The intent was that there would be enough larger pellets in the pattern at range to penetrate to kill a goose, even if the smaller steel pellets used for duck lethality bounced off.

At first I thought it was a waste, but decided to look at the numbers, and it turns out to be very do-able, and might be a great load.

For this analysis, I’m going to use KPY ballistics results at 32F, 1000’msl, and 1485fps muzzle velocity. I’ll use that speed because that is the speed that my 1oz 20ga handload goes. I will use 1.5″ for required gel penetration for large duck body penetration to estimate good lethality on body shots, 1.2″ gel for small ducks, and 2.25″ gel for geese. Of course head/neck shots take much less penetration than this, but we’ll do worst case body shots here. These are all just assumptions to allow comparisons between shot sizes, if you think more or less is needed that’s just fine and you can use whatever YOU think is needed for lethality. These are the numbers most folks use for shell comparisons.

Steel #3 is a good 1oz 20ga load. You can already get 152 pellets in a 1oz 20ga shell, so you’ve already got a shell that has enough pellets to be lethal to large and med ducks and penetrate out to 39 yds or so. For small ducks, you probably only need 1.2″ gel penetration, so that gets you out to 48 yds… now you just need enough pellets to get you 145 pellets in the pattern, and you’re good for small ducks. If you can get an 80% pattern, you’d need 181 pellets, that’s just 29 extra pellets, swapping in some #9.5 TSS will do it, but we want a goose pellet. #9.5 TSS is about the same as #B steel, and it gets 2.25″ gel penetration (goose) at 39.6 yds, the same as the #3 steel does for 1.5″ gel (large ducks). So, if you want a 40yd duck/goose combo load, this will do it. We just need to figure out how much steel to replace to get the correct amount of total pellets, which will kill the ducks, and TSS pellets, which will kill the goose.

#9.5 TSS
If you’re trying to make a shell that will kill ducks out to 40yds AND geese, and the goose kill is done purely by the TSS content, then you need 55 TSS pellets in the pattern at goose range, according to CONSEP chart summarizing lethality studies. At 40yds, you can get 100% of the TSS in the pattern, so that means 55 pellets or 55 gr of TSS in #9.5 (nice 1gr/pellet!), which is 1/8oz. If we replace 1/8oz of the steel #3 with 1/8oz of #9.5 TSS, we get:
383gr #3 steel, 133 pellets, 1.5″ gel to 39yds (mallard), 1.2″ gel to 48 yds (teal)
54.5gr #9.5 TSS, 54 pellets, 2.25″ gel to 39.6 yds (goose)
Total pellets 187
, all usable for ducks and plenty for a 48yd pattern on small ducks. And you have the 54 pellets for geese out to 40 yds. Great combo shell.

#8.5 TSS
If you want to make it a bit beefier for geese, giving bigger pellets for longer ranges and able to break a wing maybe, we can use #8.5 TSS, which is the same as #BBB steel ballistically. Everyone likes #BBB steel on geese, so this should be plenty. An 80% pattern for TSS should be easy even at 50 yds, so that means 69 TSS pellets. #8.5 TSS at 1485 fps (the speed of my 1oz 20ga steel loads) will get you 57 yds of 2.25″ gel penetration, that seems plenty for a goose shot. So:
336 gr #3 steel gives 117 pellets. 101.5 gr #8.5TSS gives 69 pellets. Total weight 1oz (437.5gr), total pellets 186.
SO– 80% pattern gives you plenty of pellets even for small ducks out to 45 yds or so, and plenty of TSS to kill a goose at 57 yds if you can keep 80% of the tss in pattern there, which you probably can. This would be a good longer range goose load, and more lethal at 40 yds too.

#7 TSS
I will do #7 TSS, because Ballistics Products Inc is now selling TSS (18.0 g/cc shot) in sizes #7 and #9. They always have to rename a product to give the impression they aren’t just purchasing something and reselling it to you, so they call this “Sphero Tungsten Super Max-18”. The numbers are good at 18.06 g/cc nominal, 0.0772″ diameter for the 9s and 0.0996″ diameter for the 7s, again nominal sizes. I haven’t done actual pellet counts per ounce, but KPY calculates pellet counts for that pellet size and density. For #9 TSS just interpolate between my #9.5 and #8.5 results.

Basically, #7 TSS isn’t as good a choice for a combo load from a pattern density view, because there are only 185 pellets in an ounce… and if you recall from up top, to achieve the 145 pellets in a 30″ pattern we want for small duck lethality, assuming an 80% pattern we need to start with 181 pellets. So basically a pure load of #7 TSS, so that’s not economical at all! Also, it will penetrate the 2.25″ gel (we are using as a notional goose-body lethality metric), all the way out to 85 yards! You may want that #7 TSS “knockdown” power, which may break wings better and cause better instant kills versus 100 yard gliders. While I don’t need to kill a goose at 85 yards, and the smaller pellets are getting good reports for goose lethality while still giving plenty of range, the larger pellets are getting better reports for instant kills. Since I’m going to be peppering the goose with a hundred small steel pellets jacking up the meat maybe, I don’t really care about the TSS getting pass-thru with the 7s, which I otherwise might. We need a smaller TSS pellet so that as we replace #3 steel with TSS, the total pellet count goes up more. You could stop demanding the 145 pattern pellets for small ducks, instead asking for 120 pellets for medium duck lethality, and then the TSS #7 would work– it’s still a decent duck/goose combo with bigger goose pellets, but you’d have to limit your small duck ranges to closer in where you’ll have the pattern density to kill small ducks, wherever you’re getting 90% patterns. Here are the numbers for that load:
305gr #3 steel gives 106 pellets; 132.5gr #7 TSS gives 56 pellets; total weight 1oz (437.5gr) and 162 pellets.

Which TSS size?
I would go with the #7, or #7.5 thru #8.5, instead of the #9.5s if you expect geese.
There aren’t many reports from folks comparing lethality of #9.5 vs. #7 TSS, or any sizes– just not enough folks are shooting both with enough birds to comment. However, I search for and save every such report I find on forums. There have been enough reports of ducks gliding 100 yds then dropping dead, with small TSS, and pinholes in wings vs. broken bones, that I now believe the larger TSS sizes give more instant lethality. It appears the smaller wound channels don’t cause as fast bleeding or vitals failure, and birds can glide 50-100 yards then drop out of sky. Also you may not get broken wing bones which can drop a bird and give you one in the bag. The alternate view, for those espousing small steel and head-shots, is that the increased pellet counts with #9.5s results in more chances for head/neck hits and instant kills from that mechanism. I’d expect this to be true in closer where pattern density for that still exists, and body hits to take over as the kill mech on further out shots, 40-50 yds, but who knows how all these things and bird angles will combine in the field. I’m hedging my bets and loading up #8.5 TSS for this season, but I don’t see many/any geese usually.

COSTS: Here is a rough cost breakdown:
I used $64.50/lb for TSS 9.5, $45/lb for TSS 8.5, $55 for SpheroTungsten Super Max-18 #7 (TSS#7 from BPI), $2.29/lb for steel shot, $15/500 20ga 3″ hulls, $22/lb for LilGun powder, $25/1000 ch209 primers, $10/100 SAM1 20ga 3″ wads. Your costs will vary, but these are what I was able to get.

$0.24 per shell for hull/primer/powder/wad for all versions
#9.5 TSS—-$0.63 per shell for TSS and steel shot, or
—–TOTAL $0.87 per shell, or $21.75 for a box of 25 for comparisons.
#8.5 TSS—-$0.76 per shell for shot,
—–TOTAL $1.00 per shell total or $25 per box.
#7 TSS—-$1.14 per shell for TSS and steel shot,
—–TOTAL $1.38 per shell total or $34.50 per box.

Of course, you could package these two loads up in a 16ga hull or a 12ga 2.75″ hull also. You could even make a more TSS heavy similar load that would work in a 28ga– I’ll do that next time 😉