Do Overshot Card Effect Patterns?

 

When I started reloading, I heard a lot of people say overshot cards have a negative impact on patterns, so I took the stand of never using them. That habit stuck even when I heard folks say overshot cards have no impact on patterns. Afterall, if it has no effect, what's the point? And I've never heard anyone claim overshot cards have a positive impact on patterns.

Being bored, I decided to see for myself. Now, this wasn't a lab test or in any way intended to be conclusive. It's just a dude shooting stuff in the backyard waiting till the time when he can start on the beer without raising eyebrows.

12 ga 2.75” Rio
G-1000
30 g HS-6
CSD100 + stiff felt square
1 oz #4 steel
 
A.       16 ga .042” overshot card
B.       16 ga .0875” mini nitro card
C.      Soft felt square .375”
D.      12 ga Gualandi plastic overshot disc .073”
F.        Control load with 2 x stiff felts under shot
 

Pattern at 40 yards Remington 870 Express through a Rem flush IC choke

Load:	Shot in 30” circle	Total shot on paper
A: 16 ga OSC	129 / 192 = 67.2%	175
B:: 16 ga nitro card	117 / 192 = 60.9%	164
C: soft felt	71 / 192 = 37%	137
D: plastic disc	119 / 192 = 62%	175
F: control	136 / 192 = 70.8%	175

(BTW, the circle was smoother, but I had to go over it again with a thicker sharpie to make it show up in the photo.)

No overshot device. 136 / 192 = 70.8%

Overshot card. 129 / 192 = 67.2%

7 fewer pellets--meh. Maybe a bit less even? I call it a wash.

BPI/Gualandi plastic overshot card. 119 / 192 = 62%

This one surprised me since it's sold as not impacting patterns.

Nitro card. 117 / 192 = 60.9%

Pattern performance only matched by my ability to hit the paper...

~3/8" soft felt. 71 / 192 = 37%

This one also surprised me; I was expecting a poor pattern, but not this bad. It also makes me wonder about the older RSI loads that specify felts on top of the shot.

Conclusion? We don't need no stinkin' conclusions.

It appears the overshot devices do/don't hurt patterns binary is to simplistic, and that overshot device composition is more important than it's mere presence. Once again, like all things shotgunnish, it all depends.

And... another load might not work out the same way of course.