#7 HW x #9 TSS Duplex ?

Talk about 10 12 & 16 gauge shotguns here.
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Yule
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#7 HW x #9 TSS Duplex ?

Post by Yule »

I would like to know if anyone has tested a duplex load using #7 Heavyweight shot and #9 TSS? If so, results? I was thinking about it for a 12 gauge - 2 oz load.
Thanks
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GLS
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Re: #7 HW x #9 TSS Duplex ?

Post by GLS »

If you are planning to use  #7 HW 13 , you'd get the same shot count using 1.7 oz. of straight #9 TSS.
At 1100 fps, #7 HW 13 has  a limit of 1.5" of penetration at 40 yards.  TSS 9, 58 yards.  Straight TSS 9 with the proposed duplex count of shot would  weigh 1.7 oz.  Straight TSS 9 at 1.7 oz. is a better load unhindered by the inferior penetration of HW 13 compared with TSS 9s.   By limit of penetration at a particular yardage, I mean the penetration begins to decline beyond that  yardage, but that doesn't mean it is no longer lethal beyond the '1.5" limit' as a penetration of 1.25" is more than enough at head and neck.

If you plan on duplexing  HW 15, at 1100 fps, HW 15 has a penetration of 1.5" in ballistic gel at 64 yards.   TSS 9 has  1.5"  penetration at 58 yards.  1.6 oz. of straight TSS9's equals the shot count of a duplex load with HW 15 and TSS 9s.

The proposed duplex load of HW 13 and TSS 9's is inferior to a straight load of TSS 9s in the same shot count.  It also has more recoil.  Arguably, the HW 15 and TSS 9 duplex load has better penetration considering the 6 extra  yards of the HW 15, but the recoil is far heavier comparing 2 oz. in the duplex load to 1.6 oz. of straight 9's, but the straight 9's have been demonstrated to have  killing penetration beyond the limit of 1.5".  Unless you already have the HW 15, there's not much point in duplexing it with TSS 9's, all things considered.  These limits of penetration far exceed the distances many of us would deliberately shoot at a turkey, but are generous enough for distance miscalculations.  My calculations above were made using Shotshell Ballistic Calculator version 2.0.  Gil
Yule
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Re: #7 HW x #9 TSS Duplex ?

Post by Yule »

Thanks Gil. That is what I was looking for.
I have some HW15 and was looking for a way to conserve my TSS.
I assume you would put the larger shot in first?
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GLS
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Re: #7 HW x #9 TSS Duplex ?

Post by GLS »

According to this thread, smaller shot on the bottom. However, I don't know one way or the other about shot of unequal size AND density. Probably doesn't make a lot of difference. Gil
https://www.gobblernation.com/phpBB3/vi ... ss#p168715
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el diablo
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Re: #7 HW x #9 TSS Duplex ?

Post by el diablo »

HW 7's on the top. It is heavier than the TSS 9, not more dense. I used a 1 7/8oz load of duplexed HW and TSS when I first started loading my own. It was a recipe Hal cooked up.
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RapscallionVermilion
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Re: #7 HW x #9 TSS Duplex ?

Post by RapscallionVermilion »

Just a caution that if you replace TSS with HWT shot, by weight, in a given load recipe, the pressure will go up.
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GLS
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Re: #7 HW x #9 TSS Duplex ?

Post by GLS »

Good point about pressure variance. I am a stickler for pressure limits. However, for how much pressure it took for Tom Roster to blow up an 870 3" 12 ga., this was surprising:
https://www.shotgunlife.com/shotguns/to ... sures.html
sasquatch
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Re: #7 HW x #9 TSS Duplex ?

Post by sasquatch »

RapscallionVermilion wrote: March 29th, 2020, 10:32 am Just a caution that if you replace TSS with HWT shot, by weight, in a given load recipe, the pressure will go up.
why is this? if tis the same weight its hard for me to grasp. Just trying to learn
jsh909
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Re: #7 HW x #9 TSS Duplex ?

Post by jsh909 »

Volume. Weight and volume are 2 entirely different beasts when relating to pressure.
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RapscallionVermilion
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Re: #7 HW x #9 TSS Duplex ?

Post by RapscallionVermilion »

sasquatch wrote: March 29th, 2020, 10:47 am
RapscallionVermilion wrote: March 29th, 2020, 10:32 am Just a caution that if you replace TSS with HWT shot, by weight, in a given load recipe, the pressure will go up.
why is this? if tis the same weight its hard for me to grasp. Just trying to learn
My understanding is that the longer shot column, for the same weight of shot, generates more radial pressure under compression.
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Re: #7 HW x #9 TSS Duplex ?

Post by 870 Shooter »

I cooked up a 1-1/2oz 20ga load and sent it into the lab. I took a 1-5/8oz tss recipe that came back around 12k-ish and the hw7xtss came back at 13,4 if I remember correctly. I'd have to dig the sheet out to get a exact. It's not apples to apples.
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Spuriosity
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Re: #7 HW x #9 TSS Duplex ?

Post by Spuriosity »

RapscallionVermilion wrote: March 29th, 2020, 10:57 am
sasquatch wrote: March 29th, 2020, 10:47 am
RapscallionVermilion wrote: March 29th, 2020, 10:32 am Just a caution that if you replace TSS with HWT shot, by weight, in a given load recipe, the pressure will go up.
why is this? if tis the same weight its hard for me to grasp. Just trying to learn
My understanding is that the longer shot column, for the same weight of shot, generates more radial pressure under compression.
This is exactly correct. Given equal cushioning, a 2 oz load of HS (12 g/cc density) will yield greater pressure than a 2 oz load of HW (15 g/cc) which will yield more pressure than 2 oz of TSS (18 g/cc). The TSS load is the shortest and will have the least bearing surface against the chamber and bore upon ignition. And cushioning won't be equal. There is no room in a 3" 12 ga shell with 2 oz of HS for cushioning since the shot column is so long. But there is room for cushioning with a HW load and even more room for the TSS load. More cushion also helps keep down pressure with the denser shot materials.
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Re: #7 HW x #9 TSS Duplex ?

Post by bcturkeynut »

Also trying to learn,,,so would "cushion" be like felt or cork in the bottom of the wad?
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Spuriosity
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Re: #7 HW x #9 TSS Duplex ?

Post by Spuriosity »

bcturkeynut wrote: March 30th, 2020, 9:26 am Also trying to learn,,,so would "cushion" be like felt or cork in the bottom of the wad?
Yes, or a cushioned wad like the CLBC. It looks like a regular lead wad with a cushioning (collapsible) section under the shotcup, but it is made from thick, dense plastic like any other wad designed for steel, HS, TSS, etc.
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