I'm shooting Federal Premium 7 shot TSS 20ga. The box says 1100FPS. I shortened the Encore barrel from 24" to 20". What should I be expecting for a velocity drop?

Nothing significant. Mebbe 20 fps. Shotgun powders are fast burners.

And maybe not that much--depending on the interior dimensions of YOUR barrel.

I have chronographed a LOT of shotgun ammo, both factory and handloads, and have yet to find muzzle velocity varies enough from "advertised" to make any difference in the field. What does matter is how many shot hit the bird, which is why patterning shotshell loads is far more important than chronographing 'em.

Cracked me up!

Cracked me up too, when I read it in Travels with Charley!

I believe he camped in the Little Missouri badlands then travelled through Glendive on the way to points west. Need to reread that book.

Thanks, men. That's helpful. I shortened the barrel to 20" and when I patterned the new barrel length at 20 and 50 yards it appeared to be patterning the same as the 24" barrel had. I was anticipating both a velocity drop and a measurable drop on the pattern board. My first thought was reconfiguring the barrel had caused a rise in shot flight path ie. "she's shooting a little higher so landing where it did before." Your explanation is far more satisfying! Thanks
Terrific Turkey Taker!

I loved the book and that quote always stuck with me.

The other quote that cracked me up came from the older gray haired lady CEO of the investment group on Yellowstone, she said, “Montana is just poverty with a view”. Coming from a “New Yorker” 😀

That's a good one too!

One of my college professors once said that he moved to Montana because, "I always wanted to live in a third-world country, with decent sanitation and natives who spoke English."

Love it.

It sucks that it can’t remain that way.