TSS + Steel Duplexing: when is steel enough?

Open discussion on Steel Shot loads and results.

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Dave in AZ
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TSS + Steel Duplexing: when is steel enough?

Postby Dave in AZ » Fri Apr 22, 2016 4:18 pm

I wrote this for my reloading blog; but I haven't really advertised that place yet while I try to figure out the menus and look, and wanted to post it somewhere. Decided this would be a good spot

TSS + Steel Duplexing: when is steel enough?

Let’s start with this: Why even load TSS in the first place, let alone duplex it? Answer: TSS gives great pellet counts for very small charges, so you can shoot light loads– low recoil. TSS has 18 g/cc density vs. 7.8 g/cc for steel, giving it massively better ballistics: the pellets go further and hit with more energy and penetrate further than steel, orders of magnitude better. Speed: TSS will retain it’s velocity much better than steel, so you can launch it at 1200fps and still get awesome penetration and range– you don’t have to shoot 1550 fps loads. This give two distinct advantages, better patterns and much lower recoil.

BUT… do we even NEED that improved pellet count, range, penetration, and low recoil? If we can achieve our needs for killing waterfowl with straight steel shot, why use TSS? My quick answer is that we don’t NEED it once you get above a certain payload size. You don’t have to do any calculations really, just take a look at Tom Roster’s “CONSEP” chart and read it, it will tell you how many pellets you need, size and range… IF you’re smart enough to see you have to interpolate from smallest to largest pellet offered, as you go from shortest to furthest range listed. A lot of guys aren’t it turns out, and there are endless posts online such as “it says you can use #6 from 20-45 yards!” when it actually says #6 at 20 and #3 at 45.

Let’s do some calculations ourselves though, and follow the logic to see what steel payload will be sufficient for ducks. First, I want enough pellets in my load to achieve CONSEP kills on small ducks, so that’s 135-145 in a 30″ pattern. For medium ducks I need 115-120, and for large ducks 85-90. Not all the pellets shot stay in the 30″ pattern, we have to account for that. I also don’t necessarily want the super tight 85% pattern– it sounds good on paper, but 85% at 40 yards usually means a 15″ pattern at 25 yards that will be hard to hit with AND turn your target into useless hamburger–and more ducks are shot at 25 yards than 40 yards, so we want to plan for that. A standard American “modified” choke gives 65% pellets in the pattern. However, a large benefit of TSS is it’s range, so let’s concentrate on the longer range shots, and say we are using an 80% pattern.


As you can see from the CONSEP table above where I calculated pellets needed with various choke percentages, an 80% “Extra Full” choke performance that delivers 145 pellets in a 30″ pattern must start with 181 pellets. Medium ducks I could start with 150 pellets, and large with 113 pellets. Unfortunately I never know what size duck is coming, and I’d like to be able to reliably hit them all with one shell– that may not be possible without TSS, 181 is a lot of pellets. With a very evenly distributed pattern Tom Roster says 135 pellets would work for small ducks giving 168 total needed–but you’ve got to have a good pattern for that; we’ll keep it in mind but use 181 pellets for now.

So now we know how many pellets we need, what about the ranges? All my ballistics calculations are from KPY Ballistics software, at 32F, and 1000’msl because 80% of the country is roughly that altitude. I used 1485 fps MV for the below, because it’s approximately what I get when testing “1550fps” ammo over the chronograph and it’s a “good” handload speed that you can achieve. And the best 20ga reload possible I know of is 1 oz at 1485, so I’ve done a lot of calculations using that load. Here’s the ranges steel shot and TSS #9.5 will penetrate 1.5″ of ballistic gel, which simulates the results found needed for consistent kills on a large mallard duck (Patuxent, Nilo, CONSEP studies).


You can see under the yellow “Tgt Ran” column the ranges at which the pellets will penetrate 1.5″ gel, and the crux of the matter for most folks is probably there between #2 at 47.1 yards and #3 at 39.4 yards. If you can set up your hunt so that your max range is inside 40 yards, then #3 steel will reliably and consistently kill all the duck sizes– you have enough penetration. And you can see in the column under “#” the number of pellets in 1 oz, so 152 for #3 steel. If that’s not enough range for you, and to be honest I usually feel that it isn’t for me in my hunting situations, then you have to move up to #2 steel with 47.1 yards range and 124 pellets per oz. I think most folks will agree that 47 yards is usually enough range for ducks, and probably past what most of us can reliably hit or should be shooting at. Since I don’t want to be “ammo limited” but rather “skill limited”, I’d like to use #2 if I can get the pellet counts. I’ll concentrate on #2 and #3 pellets, since we’ll see they bracket the 40 yard range a lot of folks might end up using for decisions, and they bracket the pellet counts we saw we needed above.

In order to get the 181 pellets we calculated were needed for small ducks, it takes 1-1/2 oz of #2 (185 pellets), or 1-1/4 oz of #3 (190 pellets). That’s a lot of weight to be shooting at 1485fps, with 58 ft-lbs of recoil in my Maxus for the big load–too much for ME to shoot more than a few of! However, both these loads ARE available in the 12ga, 3.5″ shells are needed for the 1-1/2 oz load, but the 1.25oz load can be had in 3″ shells. So there’s your answer on what it takes to reliably kill all ducks to 47 yards: 3.5″ 12ga shooting the biggest load made… Really? “I kill ducks just fine out to 47 yards with smaller loads!” you may be saying…

This is a common logical fallacy that catches folks up– WE calculated what it took to kill SMALL ducks at 47 yards consistently… who of you have ever shot 20 Green Wing Teal in a row right between 45 and 47 yards, and actually measured it each time in the field? No one, that’s who. What we HAVE done is shoot a mallard at 30, 3 teal at 25 to 45, a wigeon at 40, wound one at 45 that took a 2nd shot to kill, and a pintail at 50 or so… and in our MIND, that all equates to the same as 7 teal at exactly 47 yards. It’s not remotely the same, but it’s hard for our brains to remember the differences and accept that the two data sets aren’t even comparable. Still, since that’s how my hunts go actually, maybe I’m being too conservative in what pellets I need for a day’s hunting?

Let’s try looking at the lower CONSEP number for “medium ducks”, 115. We’ll assume that we can get good even patterns so the smaller number is workable; and we’ll assume that we shoot mostly at medium or large ducks: wigeon, shovelor, mallard, pintail, gadwall. Maybe a teal once in a while, and we’ll hope he’s in close where the pellet density is good for him still. What kind of load do we need for THAT? Take 115 pellets / 80%, gives 144 pellets needed. We can get 139 #2 pellets in 1-1/8oz, that’s pretty darn close, and 152 #3 pellets in 1oz. Ahh, NOW that is starting to sound familiar to me, that’s what I use! So for a mix of Med-Large ducks inside of 47 yards, the standard 3″ 12ga duck load of 1-1/8oz at 1500 is just fine.

I want to also give some range calculations for medium and small ducks using reduced gel penetration numbers– if we happen to be shooting at smaller targets, we don’t need as much penetration for reliable kills, and can see increased range effectiveness against these smaller targets. Doesn’t mean it will consistently work against a mallard, but if you get a mix of ducks with medium and small mostly, it may be valid to look at these longer range numbers for smaller shot. Dove are often simulated with 0.5″ gel; I think 1.3″ for medium ducks like wigeon and 1.2″ for small ducks like teal is appropriate. The table below gives steel #1 through #4 launched at 1485fps with 1.5″ gel (“Tgt Ran” column), 1.3″, and 1.2″. You can see that each 0.1″ gel gets you 4 yds with #2 and 3 yds with #4. Of interest will be the 46 yards for #3 against my estimation for medium ducks, and 38 yards for #4:


I think these results help explain why so many folks online swear they “kill ducks to 40 yds” with #4 steel, while others report poor performance past 32 yards– virtually NONE of these anecdotal reports contain tabulated data by species and range, and we can be pretty darn sure various mallards at 30 yards and wigeon at 39 yards, some incoming easy exposed targets and others outgoing penetration-intensive presentations, are blending together into one memory, depending on what that hunter saw that day.

This variable-penetration required idea has interesting utility when loading MULTI-SIZE duplex loads of one density, particularly where the CONSEP-required 90 large-duck pellets are present in the load (prima facie evidence the shell should already result in consistent large duck kills) and smaller pellets are then added to “flesh out” the pattern density just for small ducks. In this case, the smaller pellets only need to penetrate the smaller ducks they were added to densify the pattern for, resulting in longer range utility similar to what the larger pellets in the shell are delivering against large duck targets. See my blog post analyzing B&Ps Copper duplex loads for more thoughts on that.

But now we know the edges of the envelope! If I demand enough pellets to shoot small ducks at beyond 47 yards, I’ll need something more extra to steel. If I want to shoot a 20 or 28ga and want to reach beyond the 31 yards #4 shot gives me with enough pellets for small ducks, I’ll need more pellets, thus another potential use for some TSS. If I want to manipulate the pattern and maybe get a core of pellets that will maintain density to 60 yards, maybe I can achieve that with some TSS.

For some analysis of duplexing TSS and Steel, what sizes to use, what the benefits are, areas it might help you, see my blog post on TSS + Steel: What sizes

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Re: TSS + Steel Duplexing: when is steel enough?

Postby Fishh2o » Fri Apr 22, 2016 5:12 pm

Made this one a sticky.

Thanks Dave

Roll with it. If you stay above 55 the wheel wont fall off.

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