Does an Oxyoke OP wad increase or decrease velocity?

[roundball]

Testing the effects that an Oxyoke OP wad had with a PRB load.
Oxyoke advertises that using their wad will improve accuracy by reducing group size due to lower standard deviation from shot to shot due to better, more consistent gas sealing.
I also expected that same improved gas sealing property to produce higher velocities from increased pressure being sealed behind the wad, but was surprised to find that was not the case...velocity was actually a little lower using a wad.

APPROACH
GM .62cal/.20ga Flint ”˜Rifled’ barrel
100grns Goex 2F
.020" Oxyoke prelubed pillow ticking
.600"/325grn cast lead balls (Eddie May/Georgia)
Wiped the bore after every shot
Pact Pro MK5 Chronograph at 15 feet

WITHOUT an Oxyoke wad over powder
Average velocity = 1270 fps
Standard Deviation = 25 fps

WITH an Oxyoke wad over powder
Average velocity = 1232 fps...velocity averaged 38 fps slower
Standard Deviation = 6 fps...did improve significantly

 

[Skychief]

Hmmmm.....

Does this lend authenticity to another posters results of slower velocities with tighter fitting loads (all else being equal)?

I think you will recall those posts RoundBall.

Sometimes, the results I read here makes me wonder if we need to re-write the book regarding a lot of long-held theories in muzzleloading.

Which way is up?

Best regards, Skychief.

 

[hanshi]

I chronographed loads with and without wads in (one) long gun years back. Though I can't recall specifics adding the wad did indeed reduce the sd but in my case it added a few fps to the velocity. But only a few.

 

[Skychief]

hanshi, I was referring to Herb's thread in January of this year. :thumbsup: