Trapshooters Forum banner

1 - 19 of 19 Posts

·
Registered
Joined
·
235 Posts
Discussion Starter #1
Does anyone have resources for shot velocity? For example, if a particular shell has a 1200 ft/s muzzle velocity, what is the actual velocity of the shot at say 50 yards or the average velocity over that distance for a given muzzle velocity? I'm sure someone has done studies on this subject.
 

·
Registered
Joined
·
2,018 Posts
From KPY Shotshell Ballistics

1350 fps lead #8 shot is down to 527 fps at 50 yards, it has .66 lbs energy at 50 yards and gets .81" of gel penetration, time it takes to travel 50 yards is .192 seconds.
1200 fps lead #7-1/2 shot is down to 514 fps at 50 yards, it has .73 lbs energy at 50 yards and gets .85" of gel penetration, time it takes to travel 50 yards is .202 seconds.

So at 50 yards the #8 shot that started out 150 fps faster is only 13 fps faster at 50 yards and it doesn't hit as hard or penetrate as deep as the slower #7-1/2 shot.
 

·
Premium Member
Joined
·
8,305 Posts
From KPY Shotshell Ballistics

1350 fps lead #8 shot is down to 527 fps at 50 yards, it has .66 lbs energy at 50 yards and gets .81" of gel penetration, time it takes to travel 50 yards is .192 seconds.
1200 fps lead #7-1/2 shot is down to 514 fps at 50 yards, it has .73 lbs energy at 50 yards and gets .85" of gel penetration, time it takes to travel 50 yards is .202 seconds.

So at 50 yards the #8 shot that started out 150 fps faster is only 13 fps faster at 50 yards and it doesn't hit as hard or penetrate as deep as the slower #7-1/2 shot.
Why do they do this comparison not using the same shot size?
MG
 

·
Registered
Joined
·
2,018 Posts
Why do they do this comparison not using the same shot size?
MG
I showed that comparison just to show the difference between the two shot sizes.

With KPY you can select 16 shot types that are different densities, 25 sizes of shot and 16 different load weights and select the inches of gel penetration that you require. Kpy uses 20% gel so it is pretty tough to penetrate. You also select the shot speed at the muzzle and it gives you the pellet counts for the weight of the load and shot type uou enter.

All of the loads below are 1 oz loads and the gel penetration was set at 1.50". Look at the speeds the different shot types start out at, the yardage for the 1.50" of gel penetration, the amount of energy it took that shot type to get that penetration and the pellet count for 1 ounce.

Steel #7 shot at 1800 fps gets 1.50" of gel penetration at 16.7 yards, energy 2.23 lbs with about 417 pellets.
Bismuth #7 shot at 1300 fps gets 1.50" of gel penetration at 22.3 yards, energy 1.81 lbs with about 339 pellets.
Lead #7 shot at 1300 fps gets 1.50" of gel penetration at 35.8 yards, energy 1.57 lbs with about 294 pellets.
Hevi-Shot 12g/cc #7 shot at 1300 fps gets 1.50" of gel penetration at 43.4 yards, energy 1.46 lbs with about 244 pellets.
FHW 15g/cc #7 shot at 1250 fps gets 1.50" of gel penetration at 73.1 yards, energy 1.17 lbs with about 219 pellets.
TSS 18g/cc #7 shot at 1150 fps gets 1.50" of gel penetration at 102.9 yards, energy .98 lbs with about 182 pellets.
 

·
Registered
Joined
·
286 Posts
The data used two variables, which become complely irrelevant.
Only one variable should be used with a comparison. Either the velocity or payload weight, but never both.
MG
Lets see your numbers then hot rod.
 

·
Registered
Joined
·
2,018 Posts
The data used two variables, which become complely irrelevant.
Only one variable should be used with a comparison. Either the velocity or payload weight, but never both.
MG
The data used two variables, which become complely irrelevant.
Only one variable should be used with a comparison. Either the velocity or payload weight, but never both.
MG
About the only thing that payload weight shows you in KPY is the pellet count. It would have been nice if it showed a number for estimated recoil from the pay load weight and the speed.

With KPY you won't learn much very quickly if you only enter one variable at a time. Especially for hunting loads. Below is the equivalent of a 3" 12 ga 1-1/4 oz #2 steel shot duck load compared to a 2-3/4" 20 ga 1 oz duck load with 1 oz of 15g/cc #7 shot.

12 ga 3" 1-1/4 oz steel #2 shot at 1600 fps gets 1.50" of gel penetration at 50.1 yards, has 3.34 lbs energy and about 154 pellets.
20 ga 2-3/4" 1 oz 15g/cc #7 shot at 1250 fps gets 1.50" of gel penetration at 73.1 yards, has 1.17 lbs energy and about 219 pellets.
 

·
Premium Member
Joined
·
3,402 Posts
When analyzing an equation, best to change only a single variable (eg. x), so any change in the equation can be accurately attributed to the change in that single variable (x). When you change two variables (e.g. x, y) it would be difficult at best to attribute the change in the equation to just x, or just y, or even x+y, or xy, or how much of x and how much of y contributed to the change.
 

·
Registered
Joined
·
2,018 Posts
I didn't realize I was analyzing an equation. This whole time I have been using KPY Shotshell Ballistics I thought I was looking at the performance of different shot types and sizes at different speeds.

So how should I compare shot sizes, shot types and speeds between each other?
 

·
Registered
Joined
·
3,796 Posts
From KPY Shotshell Ballistics

1350 fps lead #8 shot is down to 527 fps at 50 yards, it has .66 lbs energy at 50 yards and gets .81" of gel penetration, time it takes to travel 50 yards is .192 seconds.
1200 fps lead #7-1/2 shot is down to 514 fps at 50 yards, it has .73 lbs energy at 50 yards and gets .85" of gel penetration, time it takes to travel 50 yards is .202 seconds.

So at 50 yards the #8 shot that started out 150 fps faster is only 13 fps faster at 50 yards and it doesn't hit as hard or penetrate as deep as the slower #7-1/2 shot.
Why do they do this comparison not using the same shot size?
MG
MG, I understand what you are saying about the comparison, but the number he posted, might help someone make the "7 1/2 vs. 8" argument, where the numbers show that even when 8's are fired with an additional 150 fps muzzle velocity, the 7 1/2's STILL carry more energy and clay-breaking energy down range.
 

·
Premium Member
Joined
·
8,305 Posts
MG, I understand what you are saying about the comparison, but the number he posted, might help someone make the "7 1/2 vs. 8" argument, where the numbers show that even when 8's are fired with an additional 150 fps muzzle velocity, the 7 1/2's STILL carry more energy and clay-breaking energy down range.
Sorry, I can not agree.
Unless you test 7 1/2's at both 1200 & 1150, and then test 8's at 1200 & 1150, your only waisting your time.
In order to see the difference, only one variable can be changed with each test.
JMHO,
MG
 

·
Premium Member
Joined
·
3,402 Posts
I didn't realize I was analyzing an equation. This whole time I have been using KPY Shotshell Ballistics I thought I was looking at the performance of different shot types and sizes at different speeds.

So how should I compare shot sizes, shot types and speeds between each other?
I am not familiar with KPY Shotshell Ballistics. How is 'performance' quantitified? Does it have a unit of measure? If it does, then you're dealing with an equation. So "how should I compare shot sizes, shot types and speeds between each other?" With multiple variables in your comparison, the short answer is you can't...at least not scientifically. In essence, you would be picking what appeals to you (with maybe a purpose for the pick in mind). And nobody can fault you for it.
 

·
Registered
Joined
·
2,018 Posts
Home - KPY Shotshell Ballistics


I copied and pasted the below information from the above link.

This Shotshell Ballistic Program was developed to compare lethality and penetration for factory and custom shotshell loads for all materials including steel, lead, and tungsten based pellets. The user inputs the factors of shot size, material, initial velocity, and temperature and elevation to calculate down range performance along with pellet count. User can select velocity, distance, time, energy, energy density, or gel penetration to find the effective energy of a pellet. This is excellent to compare factory loads of different materials to find the best load for your hunting trip or sporting event. It can also be used by reloaders to calculate the effect of higher and lower velocities, shot size, and load changes.

After calculation, the user can then name and save the load in a catalog. Several loads can be added for comparison and then saved to a local hard drive and recalled whenever you need to reference the data.
 
1 - 19 of 19 Posts
Top