choosing shot size - optimal balance between pattern density and pellet penetration

Open discussion on Tungsten Super Shot "TSS" Handloading.

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hawglips
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choosing shot size - optimal balance between pattern density and pellet penetration

Postby hawglips » Fri Feb 03, 2017 2:08 pm

A question that always comes up with TSS, is what shot size to use.

Given that the whole reason TSS is so much better is due to the high density of the pellet material - which enables one to go down in shot size in order to increase pellet count and pattern density, without losing any individual pellet penetration energy or to actually increase that penetration energy - the question of optimal pellet size of how far down in size to go, is a good one to consider.

The good news is, with the available ballistics software, it's easy to come up with what the optimum pellet size for a given situation is. Here's how I look at it - using turkeys as the game for illustration purposes.

You have basically two things to think about - pellet penetration and pattern density. You need both to kill turkeys consistently and cleanly. And there is a trade-off of those two things with each shot size and payload. For pattern density, I have a minimum standard of 100 in a 10" circle. For pellet penetration - 1.25" in ballistics gelatin. (These standards will be obviously different for other game birds and waterfowl.) Both these minimum standards must be met in order to know you will have a dead turkey 100% of the time you put the core of the pattern on him, at whatever range within those limits. The ideal shot size is the one where you max out on both those minimums at about the same time. Then you aren't dealing in overkill on one, at the expense of the other - since a shortage of either will hurt you. That's why I generally prefer smaller shot sizes in the smaller bores, and larger in the larger bores - to match up the pattern density and pellet penetration - thereby maximizing the efficiency of your rig and ammo.

For illustration, let's say I have a 1-5/8 oz 20 ga load that goes 1150 fps MV. What's the optimum pellet size?

With number 8s, I know I can get 220 in a 10" circle at 40 yds. Using the .7 rule, that means I can get 100 in a 10" circle out to a little over 60 yds. And the 8s give 1.25" penetration out to 92 yds. So, I have a gap between the pellet penetration and the pattern viability of about 30 yds.

With number 8-1/2s, I know I can get 270 in a 10" circle at 40 yds. Using the .7 rule, that means I can get 100 in a 10" circle out to almost 70 yds. And the 8-1/2s give 1.25" penetration out to 82 yds. So, I have a gap between the pellet penetration and the pattern viability of about 15 yds. We're getting closer to the optimal size for the 20 ga.

With number 9s, I can get 310 in a 10" at 40 yds, so the numbers are 70+ for the pattern viability, and 72 yds for the pellet penetration energy. Those match up almost perfectly, with no gap between the pattern viability and pellet penetration. So, that's why I choose #9s for the 20 ga, for turkeys.

You can do that same exercise with any pellet size, payload, and game, to figure out the optimal pellet size for what you're trying to do.



hawglips
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Re: choosing shot size - optimal balance between pattern density and pellet penetration

Postby hawglips » Wed Feb 08, 2017 9:42 am

Let's use that same method to illustrate what I'd choose for shot size with a 2-1/2 oz 12 ga turkey load, with 1182 fps MV.

With 9s, let's say I can get 475 in a 10" circle at 40 yds. Using the .7 rule, I should have 100 pellets in a 10" circle out to almost 90 yds. But the 1.25" penetration limit of 9s at that MV is 73 yds. So, I have a sizable gap between the pattern viability and pellet penetration capacity of that load, with 9s.

With 7-1/2s, 189 in a 10" circle at 60 yds is an actual pattern a buddy averages with them. So, that gives him 100 in the 10" out to almost 80 yds. The 7-1/2s give 104 yds of pellet penetration - so, once again, a sizable gap between the pellet penetration energy and the pattern viability.

With 8s, I get 93 yds of 1.25" pellet penetration. With 390 in a 10" at 40 yds, the .7 rule shows almost 80 yds of pattern viability. Got a gap of 10 or 15 yds still.

With 8-1/2s, you get 83 yds of 1.25" penetration, and with 420 in a 10" at 40 yds, the .7 rule shows you have right at 80 yds of pattern viability. So, that's a very good match.

And that's why 8-1/2s are a very good choice for the heavy 12 gauge turkey loads.



Dave in AZ
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Re: choosing shot size - optimal balance between pattern density and pellet penetration

Postby Dave in AZ » Tue Feb 14, 2017 12:54 pm

Good analysis. I do the same with CONSEP numbers and 1.5" ballistic gel for ducks. For geese, I'm using 2.25" per toasty, but not totally sure that's the best ROT for gel penetration.

Wish I could hunt turkey, but in AZ you have to get drawn and the limit is 2. Never got drawn here.



hawglips
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Re: choosing shot size - optimal balance between pattern density and pellet penetration

Postby hawglips » Fri Feb 17, 2017 6:04 am

I've always used those same numbers for big ducks and geese.

I use 1.25" for small ducks.

Randy Wakeman says 1.75" for pheasants.

Then you have these numbers that are often used for pattern viability:

Geese - 60 in a 30" circle
big ducks - 90 in a 30" circle
small ducks - 120 in a 30" circle
pheasants - 110 in a 30" circle
grouse and chukars - 130 in a 30" circle
doves and woodcocks - 230 in a 30" circle



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Fishh2o
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Re: choosing shot size - optimal balance between pattern density and pellet penetration

Postby Fishh2o » Thu Mar 02, 2017 3:51 pm

Dave in AZ wrote:Wish I could hunt turkey, but in AZ you have to get drawn and the limit is 2. Never got drawn here.



Sounds like we need to get you to NM in the next couple years. We will be headed up in a couple weeks to do a little work and relax. The girl and I are bringing the tent and going to camp for a week. I want "HER" to pick the view she wants and im going to start clearing junipers and cedars where she wants the house. Im going to leave all the pinons I can and keep the junipers just not around the house.


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

jimg
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Re: choosing shot size - optimal balance between pattern density and pellet penetration

Postby jimg » Mon May 22, 2017 11:55 am

Do you have any experience or thoughts on mixing shot sizes in a load. I currently shoot 10 ga Hevi-Shot loads from Nitro Company that are #4,5,7 mix 2 1/4oz. I have had great results with these loads but am interested in loading TSS and trying to pick the best shot size for the ultimate turkey load.



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james.moffat
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Re: choosing shot size - optimal balance between pattern density and pellet penetration

Postby james.moffat » Mon May 22, 2017 10:00 pm

Hello JimG,
I have duplexes 8.5X9 TSS with decent patterns. Out of a 2.5 oz load, I got 346 pellets in a 10 inch circle and 632 pellets in a 20 inch circle, at 40 yards. Just be sure to load your heavier shot on top. In my case, 8.5's over 9's.



Fabalis
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Location: France

Re: choosing shot size - optimal balance between pattern density and pellet penetration

Postby Fabalis » Thu Jun 22, 2017 3:40 pm

Just to sleep quiet tonight... the .7 rule ? Does it mean that when you increase 10 yards, the density is multiplied by 0.7 ?



hawglips
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Re: choosing shot size - optimal balance between pattern density and pellet penetration

Postby hawglips » Wed Jun 28, 2017 4:47 am

Fabalis wrote:Just to sleep quiet tonight... the .7 rule ? Does it mean that when you increase 10 yards, the density is multiplied by 0.7 ?


Take the number of pellets in a 10" circle at 40 yds, multiply by .7, and that will give you approx what to expect at 50 yds. Etc...



Fabalis
Posts: 27
Joined: Sun Apr 03, 2016 11:29 am
Location: France

Re: choosing shot size - optimal balance between pattern density and pellet penetration

Postby Fabalis » Tue Jul 18, 2017 4:32 am

Thank you Hal, that's what I have understood and check with the data I have for lead and It's correct.




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