# Penetration and Pattern Density tradeoff



## DEDGOOSE (Jan 19, 2007)

Seems there are alot of guys getting on board now getting ready to set up their gun.. So I figured I would jot down some boring reading LOL This is not to promote long range turkey gunning, I hate it.. It hopefully will get some folks minds churning about ideal patterns at the ranges they intend to shoot.. There are guys waaaay more intelligent on the science and physics of this stuff than I. 

The ethics of pulling the trigger on a longbeard comes down to two things, penetration of the pellet and the density of the pattern at the given range. 

I see alot of my gun patterns "good, great etc" at outlandish ranges and makes one wonder what their standards are and what is "good" or great". I tend to skip over these posts.. 

I see alot of folks that still shoot lead 4s, because of the extra "energy" that they carry at long range. And while yes, a lead 4 will out penetrate and equal pellet in size 6, the extra energy of the lead 4 will never be realized when pattern density comes into play. 

A common standard of pattern density has developed to ensure adequate pattern density at a given range. Whereas your gun can no longer place 100 evenly spaced pellets in a 10" circle you have over stepped the effective range of your given gun/choke/load combo.. This can be 30 yards or 50 yards.. The standard is based on the fact that a 10 inch circle has approximately 80 square inches. The 20 extra pellets ensure some wiggle room for consistency of shell to shell as well as evenness of the pattern. 

Looking at a #4 lead shotshell it contains 266 pellets whereas a equal loading of #6 contains 439 pellets. Obtaining 100 of the 266 pellets in a 10 inch circle at lets say 40 yards is obtainable, leaving 166 pellets to provide room for error outside the 10 inch circle. Another circle folks look at is a 20 inch circle for wiggle room.. 

20 inch circle contains 314 sq inches. 

314-80(10inch)=234 square inches to fill. It is impossible to fill in the remaining 234 square inches of wiggle room even with the most evenest of patterns with 166 pellets. 

Now with the #6 loading you have 339 pellets to fill the remaining 234 square inches of space outside the 10 inch circle to ensure wiggle room.. Additionally going by just the math 339-234= 105 extra pellets that you could tighten your 10 inch circle by, and still by the math have enough pellets to ensure wiggle room making a possible of 205 pellets in a 10 inch circle . ( I have never seen a lead shell break 200)

So what about penetration? Yes the #4 pellet is going to give you penetration to kill further, but with the meager number of pellets you will most likely not have the pattern density to couple with the penetration to ensure an ethical shot.. 

So I say go with the smallest pellet possible that still has ample penetration at the ranges you intend to shoot.. #6 will effectively kill to 40 yards so will #4 lead. Whereas #6 lead will start to run out of energy much beyond that, #4 lead will lose the needed pattern density to shoot much beyond that. A #6 loading gives you the additional pellets to work with to ensure pattern density at the ranges in which it has the energy. 

HTL 

The rise of heavier than lead ammo in a nutshell has allowed us to truly improve the Pattern Density/Penetration equation.. The increased density of the pellet has allowed us to decrease pellet size increasing our total number of pellets while maintaining or increasing penetration.. 

Various types of HTL shot are/were available: Win XTD, Rem HD, Hevishot =12 g/cc. Fed Heavyweight = 18 g/cc Tungsten Super Shot 18g/cc.. 

Additionally when you move to denser substances energy is no longer the answer but become part of the equation of figuring the energy over the frontal surface of the pellet.. Thus a #4 lead pellet may have more energy than a TSS #9, but the frontal surface of the #4 prohibits penetration and thus the TSS #9 will outpenetrate a lead 4. 

The rise of this shot has made small pellets popular on turkey. 7s-9s have become common to shoot turkeys with based on the density of the pellet.. I think the biggest prize of the HTL shotshell is the rise of the smaller gauges making them better than 12 gauges shooting lead.. 

Here is the difference between a #5 lead pellet and a #7 Fed HW pellet




















So not only do you get increased penetration but an increased number of pellets 326 for the Heavyweight in a 1.5oz loading vs 256 for the lead shotshell in 1.5oz 5s.. This is not taking into account, the fact that in a 20 gauge outside the Federal the largest payload of 5s found is 1 5/16 equating to only 222 pellets.. 

But Federal too has missed the boat on the Penetration/Pattern Density equation.. A Federal HW 15 g/cc pellet launched at 1100 FPS still has the standard regarded penetration of 1.25 inches of ballistic gelatin at 75 yards and upped to 83 yards with the 1300FPS loading in the 12 gauge.. Much like lead 4s it has the penetration but fails to have the pattern density at said range thus making the extra energy worthless. They would have been much better off increasing the pellet count with a true 7.5 or 8 shotshell which would have had a better mix of penetration and pattern density..

Blended Loads

A chain is only strong as its weakest link.. Hevi Shot introduced Mag Blend a few years back and it is a great shotshell. The problem lies in the fact that it is no more effective than a straight loading of Hevi 7s. Hevi 7s have the penetration to kill to 45 yards, thus the blend being a mix of 5,6,7s only should be deemed ethical to 45 yards.. You nor I or Environmetal despite their claims and ads can ensure that the 5s are holding the core downrange to their outlandish claim of 75 yards.. 

The same physics can be applied to the Rem Duplex 4x6, Hevi Metal and all other duplexed loads.


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