Not sure of the original poster so I cant give props but here
Shotgun Primers
Winchester 209ML ........................221 f.p.s.
Winchester 209 Triple Seven ML......244 f.p.s.
Remington 209 Kleanbore ML .........318 f.p.s.
Std. Winchester No. W209A ...........336 f.p.s.
Remington STS.............................338 f.p.s.
Std. Remington No. 209 ................341 f.p.s.
Cheddite No. 209 .........................347 f.p.s.
CCI 209M.....................................379 f.p.s.
Federal No. 209A ..........................381 f.p.s.

at 50 yards there may not be a difference, try 100.

I went from a one hole group at 100 yards with cci 209mag primers to a 3 - 3 1/2" group just by switching to fiocchi primers.

How about the CCI 209 primer?

Hey Muley you need to find the original guy.

toby bridges

How did he measure fps for a primer? What did he shoot?

through a chronograph. I could do the same thing but i hate to waste sabots lol.

He shot just a sabot? I don't think a primer would hurt it.

Tried the Winchester Triple 7 primers. They made the 777 crud ring worse. With 2F Pinnacle they caused vertical stringing, a sign of inconsistent ignition.

back when I was shooting 777 I tried triple 7 primers. They were terrible in my guns, dirty dirty things that did in fact make a bad crud ring. I found that remington kleanbore primers work much much better.