velocity estimate??

[Hesp]

This is for my Lyman Great Plains 54 cal. 32"Bbl. , 1/60 twist. Shooting the Lee 300gr "REAL" bullet. Charge is 80 grs, Triple 7 FF. Just wondering if anyone might be able to venture a velocity. I'm dead on at 50 yds , & 5" low at 75yds. Also, this sounds stupid, but I did not think to shoot at 25yds. Was thinking, maybe 2" high??

 

[longcruise]

Ball Park 1200 fps +/-

 

[Hesp]

Kind of what I was thinking... 1200 ish.

 

[kelvinator]

Triple 7 is pretty hot stuff, I bet your closer to 1400fps.
This is a good calculator, it only has Swiss powders but is pretty accurate from my comparisons.
https://www.p-max.uk/cgi-bin/black_powder.cgi

 

[Hesp]

Wow.. That shows about 1450 fps. Very much in the relm of the 45-70.