80-90% in the 10" @ 40yds. Really!!?? Even with 18 g/cc tungsten, which you said you shoot, I only average about 50% in the 10 with a .665". That's with #8s which tend to pattern a little tighter than the #9s from my experience. I consider a good, broadly effective pattern to yield to a 40yd pattern of 45% in the 10" and another 40% in the 20".

Personally, I like the #9s as either will kill as far as 99.9% would consider and it allows me to open the choke (.670") a bit and larger patterns yet still get 100 in the 10 to 70yds.

Using your 10ga, how much shot are you throwing? I assume you're going something like 2.25oz and shooting #8s or #9s. Otherwise, why not just shoot a 12ga. Yes?

So, you're getting something like 450 and 640 pellets with #8s and #9s, respectively, in the 10" at 40yd, assuming the low end (80%) of your estimate. I've never heard or seen anything like that before. I can't imagine getting to those percentages with lead, or 13g (Hevi-13) or 15g (Federal HW) shot. All I can say is you're consistently getting 80-90% @ 40yd is you're ready for the NWTF championships. You'd beat the best 2-3X over. Just sayin'...

...you may have an outlier there as I've never heard of any load that will consistently deliver 80-90% in the 10" at 40yd...

I had a 30" barrel honed by Denny Tubbs so there are no imperfections in the bore and the I.D. is consistent. I also had the barrel cryoed and then I coated the bore with UBC. Denny also machined a choke (also cryoed) for me that was made to go with the wad I use (TPS). In fact, I had everything metal in my SP-10 cryo-treated. I killed a Jake last year with it on the last day at 68 yards. I hit him once in the head and twice in the neck. I couldn't find any in the body.

It is true, the pellet count is awful low when you compare it to a lead payload, but the HTL shot patterns more consistently than lead with a higher % of the load staying in the center of the pattern.

This is why I found your choice of #4s curious. Frankly, you were very, very lucky to get that many pellets in him at 68yd with #4s given the likely pattern density. Yes, tungsten will pattern tighter, on average, compared to lead other HTL shot. However, it's not enough to overcome the fact that you're shooting #4s of 18g shot, which has far few pellets per ounce than lead.

Why not go with #8s or #9s? To me, and everyone else that I know who shoots tungsten, that's the whole point of going that direction -- dropping shot size to increase pattern density and still retain adequate penetration at extended range. Tungsten #8s offer adequate penetration to 90+yd and #9s to nearly 75yd. Why handcuff yourself with #4s?