switching to TSS - 3 questions from a neophyte

[duckrogers]

Duplex pattern #4 (full choke):

Refer to my post #228 for details of the load, the patterning procedure and pattern analysis.

Pattern statistics:

Steel pellets on the board = 98 (88% of total steel)

Tungsten pellets on the board = 177 (93% of total tungsten)

Steel pellets in 30” circle = 62 (55% of total steel)

Tungsten pellets in 30” circle = 168 (88% of total tungsten)

Total pellets in 30” circle = 230 (76% of total pellets)

Total pellets in 20”-30” annulus = 57 (16% of total pellets)


Comments on duplex pattern #4:

This pattern has a very dense core of tungsten shot combined with a modified steel shot pattern. It has an adequate total pellet count inside the 30” circle, but lacks pattern density in the outer 20"-30” annulus.

 

[Dr Swane]

Duplex pattern #4 (full choke):

Refer to my post #228 for details of the load, the patterning procedure and pattern analysis.

View attachment 382289

View attachment 382290

Pattern statistics:

Steel pellets on the board = 98 (88% of total steel)

Tungsten pellets on the board = 177 (93% of total tungsten)

Steel pellets in 30” circle = 62 (55% of total steel)

Tungsten pellets in 30” circle = 168 (88% of total tungsten)

Total pellets in 30” circle = 230 (76% of total pellets)

Total pellets in 20”-30” annulus = 57 (16% of total pellets)


Comments on duplex pattern #4:

This pattern has a very dense core of tungsten shot combined with a modified steel shot pattern. It has an adequate total pellet count inside the 30” circle, but lacks pattern density in the outer 20"-30” annulus.

Better pattern, can an Improved modified be used? I’ve liked the consistency in Briley x2 chokes, and Carlson (delta, sporting clays, or Cremator chokes). I also like the Briley Light Full for smaller shot sizes

 

[duckrogers]

Better pattern, can an Improved modified be used? I’ve liked the consistency in Briley x2 chokes, and Carlson (delta, sporting clays, or Cremator chokes). I also like the Briley Light Full for smaller shot sizes

I did not end up shooting the improved modified. I chose to shoot another 4 patterns with modified choke to get a 5 shot average for that choke which I thought was closest to my goal. I have processed the data from the other 4 modified choke patterns. They are all qualitatively similar to and somewhere in-between pattern #2 and pattern #4 posted earlier. The pattern statistics for the 5 shot modified choke group were:

Shot #	30” %	% of steel in 30”	% of tungsten in 30”	Pellets in 30” circle	pellets in 20”-30” annulus
2	63	30	81	188	56
5	59	37	71	178	54
6	65	34	83	198	59
7	68	46	80	205	75
8	64	23	87	193	65
Ave	64	34	81	192	62

Pattern #7 did meet my success criteria (the only one of the eight).

I have a line on some Alliant steel powder so I'm going to move on from this load and try the load CD2 designed.

 

[duckrogers]

Ditch the longshot, ditch the roll crimps, ditch the 2-3/4 hulls with that load

I finished testing a 3/9 duplex load similar to yours:

Load recipe:

• 12 ga Cheddite 3” new, primed, skived
• 35 grains Alliant Steel
• TPS 12ga 35mm wad
• X12X Symmetrical Gas Seal
• 5/8 oz Zinc-Plated Steel Shot #3
• 5/8 oz TSS #9 (under the steel)
• 12 ga overshot card
• roll crimp

I had to use a roll crimp since I don't have a reloader yet.

The loading and patterning procedure were the same as in my previous post #228.

Here are the results:

Weather was 72 F, 5 mph breeze against the shot.

Pellet count is: 239 TSS#9, 93 Steel #3, 332 total

Cylinder choke:

shot#		40 yd % <30"	POI distance from POA (inches)	# pellets analyzed	% of total pellets	30" count	20"-30" count
1​	all pellets	58.1​	7.25​	281​	85%​	193​	60​
8​	all pellets	69.6​	8.30​	292​	88%​	231​	73​
9​	all pellets	31.3​	7.70​	244​	73%​	99​	70​
10​	all pellets	71.7​	8.91​	294​	89%​	238​	68​
Ave		57.675​	8.04​

shot 1

shot 8

shot 9

shot 10

Recall that my success criteria are:

• Total pellets in 30” circle around POI > 170
• Total pellets in 20”-30” annulus around POI > 70

Only shot 8 meets the criteria. In addition the POI distance from POA is unacceptably large (7"-9") for all 4 shots with the cylinder choke. All shots were taken from a bench rest so human error is less than 3". This series of patterns is too erratic for my purpose.

Note: test results are continued in the next post due to the limit of 5 image attachments.

 

[duckrogers]

Here is a second series of shots with an improved cylinder choke:

shot#		40 yd % <30"	POI distance from POA (inches)	# pellets analyzed	% of pellet count	30" count	20"-30" count
2​	all pellets	42.8​	13.51​	217​	65%​	142​	64​
4​	all pellets	69.2​	4.96​	314​	95%​	230​	104​
5​	all pellets	67.7​	5.78​	284​	86%​	225​	85​
6​	all pellets	76​	5.66​	267​	80%​	252​	47​
7​	all pellets	69.2​	3.74​	299​	90%​	230​	84​
Ave		63.925​	7.48​

shot 2

shot 4

shot 5

shot 6

shot 7

Shots 4, 5 & 7 meet the success criteria. Shot 2 was wildly erratic. It does not have a gaussian (bell curve) pellet density and POI is very far from POA. Shot 6 is too centrally dense for my purpose. A 3 out of 5 success rate is not adequate. This load is not viable for my hunting application.

At this point I am left with lingering questions:

1. Has anyone shot a test series (5 shot or more) with a duplex load like this with the goal of getting a nominal 60%-70% pattern instead of an 80% or 90% pattern?
2. Is the 3/9 duplex shot load interacting with itself in an unstable manner as the TSS moves through the steel?
3. Is the overshot card on the roll crimp interacting with the shot in an unstable manner? I have done some research on the overshot card question. BPI recommends roll crimps and states that overshot cards do not negatively affect patterns. Prairie Wind Decoys states that overshot cards do not affect patterns. I've read various forum posts with opinions either way. Some posts say the overshot card moves off the shot before the shot exits the shot cup and they have no effect on the pattern. Some posts state that the overshot cards can negatively affect patterns.

 

[A5B]

Here is a second series of shots with an improved cylinder choke:

shot#		40 yd % <30"	POI distance from POA (inches)	# pellets analyzed	% of pellet count	30" count	20"-30" count
2​	all pellets	42.8​	13.51​	217​	65%​	142​	64​
4​	all pellets	69.2​	4.96​	314​	95%​	230​	104​
5​	all pellets	67.7​	5.78​	284​	86%​	225​	85​
6​	all pellets	76​	5.66​	267​	80%​	252​	47​
7​	all pellets	69.2​	3.74​	299​	90%​	230​	84​
Ave		63.925​	7.48​

shot 2
View attachment 387991

shot 4
View attachment 387990

shot 5
View attachment 387992

shot 6
View attachment 387993

shot 7
View attachment 387994

Shots 4, 5 & 7 meet the success criteria. Shot 2 was wildly erratic. It does not have a gaussian (bell curve) pellet density and POI is very far from POA. Shot 6 is too centrally dense for my purpose. A 3 out of 5 success rate is not adequate. This load is not viable for my hunting application.

At this point I am left with lingering questions:

1. Has anyone shot a test series (5 shot or more) with a duplex load like this with the goal of getting a nominal 60%-70% pattern instead of an 80% or 90% pattern?
2. Is the 3/9 duplex shot load interacting with itself in an unstable manner as the TSS moves through the steel?
3. Is the overshot card on the roll crimp interacting with the shot in an unstable manner? I have done some research on the overshot card question. BPI recommends roll crimps and states that overshot cards do not negatively affect patterns. Prairie Wind Decoys states that overshot cards do not affect patterns. I've read various forum posts with opinions either way. Some posts say the overshot card moves off the shot before the shot exits the shot cup and they have no effect on the pattern. Some posts state that the overshot cards can negatively affect patterns.

Some suggestions

Put the tss on top the steel shot.

Ditch the steelshot and go pure tss.

Maybe your being a bit too picky, some of those patterns are fine and will kill all day long.

 

[duckrogers]

Some suggestions

Put the tss on top the steel shot.

Ditch the steelshot and go pure tss.

Maybe your being a bit too picky, some of those patterns are fine and will kill all day long.

I have some 1 oz, TTS #9, 1600 fps shells loaded. I'm going to pattern them next. I have hope that if I can get a reproducible 70% pattern with my cylinder choke, they will meet my goal.

 

[cd2]

Duckrogers, respectfully, this is shotshell loading, not brain surgery. The patterns you have posted above with the IC choke look great. There are a multitude of factors that are leading to the variability that you see. The cleanliness of the barrel, the exact weight of powder, the tightness of each roll crimp etc etc. None of it is perfectly consistent. Send off 5 shells to be tested and you will see this. They do not all test the same. Everything with shotshell loading is based on averages due to the naturally erratic nature of this hobby that we all enjoy. There is nothing wrong with being inquisitive, but recognize the limitations of the subject that you are studying. Good luck!

 

[duckrogers]

Duckrogers, respectfully, this is shotshell loading, not brain surgery. The patterns you have posted above with the IC choke look great. There are a multitude of factors that are leading to the variability that you see. The cleanliness of the barrel, the exact weight of powder, the tightness of each roll crimp etc etc. None of it is perfectly consistent. Send off 5 shells to be tested and you will see this. They do not all test the same. Everything with shotshell loading is based on averages due to the naturally erratic nature of this hobby that we all enjoy. There is nothing wrong with being inquisitive, but recognize the limitations of the subject that you are studying. Good luck!

Thanks for weighing in on this. Have you observed shot-to-shot variability in your duplex patterns which is similar to my IC choke shots? Do you feel the consistency of my IC choke sequence is about as good as it can get and it is not worth the effort to pursue further design changes (e.g., switching to a fold crimp)?

 

[cd2]

I have, yes. Shot 2 might be an exaggerated example of that in your case, but yes I have experienced variability in patterns. The most accurate patterning method is to take 5 shots and average your percentages to get an overall idea of what the load is doing. You can go down an absolute rabbit hole with aftermarket choke selection to see what may provide more consistency. I'm not sure that going to a fold crimp would improve your patterns per se, but it may provide you more consistency in pressure and velocity based on your method of roll crimping. I have went down several rabbit holes chasing consistency in pressure and velocity testing. SAAMI specs allow a pretty large standard deviation in velocity and pressure, too large in my opinion. I have tried to fine tune every aspect of my loading process and have achieved an extreme variation in a 5 shot string as low as 7 FPS and 310 PSI. This equates to a standard deviation of 2 FPS and 131 PSI. For reference, a standard deviation of 10 FPS or less is the target for long range precision rifle shooting.

I prefer fold crimping for hunting loads just due to how weather proof and consistent they are with the right equipment. A lot of it comes down to personal preference. I say load up a box or two and go hunting. If you are impressed in the field then you have done your job!