how much power for 10 metre paper targets?

[johnyjohnjonno]

how much power in fps do you think is needed for 10 metre shooting?
i've just got a tau brno b96 which works off the little co2 powerlets, it's nicely balanced, got a fantastic trigger and i'm well pleased with it .
but when i shoot it's jumping a bit and looking at the dents in the backstop it's shooting more powerfully than my old pistol , the pellets are more mashed up aswell.
i havn't chronographed it yet , but how much fps is needed , i don't intend to use it for anything but 10 metre paper targets?
if it's overpowered which is causing the flip could it be turned down easily?
your opinions will be appreciated
cheers
johno

[bullbarrel]

Power isnt fps, its ft/lbs.

10 metre rifles are usually 6 ft/lbs

You'll need to do the maths to work out the fps required for your chosen pellet weight.

[johnyjohnjonno]

hi mate i know what you mean but my chrono works in fps , it's an f1 chrony , then i work backwards with a chart i've got if you know what i mean
john

[bullbarrel]

but fps is meaningless without knowing your pellet weight

[Hsing-ee]

You could adjust the power down to about 400 fps (7.8 grain pellet) - 2.8 ft/lbs. Any less and you might lose accuracy because of the amount of time the pellet spends in the barrel.

[johnyjohnjonno]

the weights are 7.35 gns , you've hit the nail on the head , what's the speed i should be looking for to reduce the flip , yet not be in the barrel any longer than needed
john

[bullbarrel]

FPS Grains ft/lbs
300 7.35 1.47
350 7.35 2
400 7.35 2.61
450 7.35 3.31
500 7.35 4.08
550 7.35 4.94
600 7.35 5.88
650 7.35 6.9
700 7.35 8
750 7.35 9.18
800 7.35 10.45
850 7.35 11.79
900 7.35 13.22

[Hsing-ee]

I think it is still 400 feet per second, which with these pellets is about 2.6 ft/lbs. The pistol weighs 2 lbs so the flip should be minimal, otherwise consider adding weight under the fore-end. With a 6" barrel the pellet will spend 1/800th of a second travelling through it, so you need to hold the sight picture and pistol still for 0.00125 of a second.

[Harry's Lad]

Power isnt fps, its ft/lbs.

Power isn’t ‘ft/lbs’ either. You may be thinking of Kinetic Energy the units of which are FtLbf (Foot-Pound-Force), sometimes written as Ft-Lbf or Ft.Lbf or (particularly in the USA) as FPE (Foot-Pound-Energy)
i.e., a distance times a force.

Power, on the other hand, is the rate of change of energy with respect to time.

‘Ft/Lb’ makes no sense at all.

Clear as mud, eh?

HTH
Dave

[bullbarrel]

Power isn’t ‘ft/lbs’ either. You may be thinking of Kinetic Energy the units of which are FtLbf (Foot-Pound-Force), sometimes written as Ft-Lbf or Ft.Lbf or (particularly in the USA) as FPE (Foot-Pound-Energy)
i.e., a distance times a force.

Power, on the other hand, is the rate of change of energy with respect to time.

‘Ft/Lb’ makes no sense at all.

Clear as mud, eh?

HTH
Dave

But "Units of power: The foot-pound force per minute (ft·lbf/min), foot-pound force per second (ft·lbf/s), and horsepower are units of power derived from the foot-pound force"

And more importantly its taken as the defacto measurement on the BBS and gun manufacturer's literature

[Harry's Lad]

But "Units of power: The foot-pound force per minute (ft·lbf/min), foot-pound force per second (ft·lbf/s), and horsepower are units of power derived from the foot-pound force"

Yes, that’s correct. That’s what I said in the previous post – Power is the rate of change of energy with respect to time. You were referring to ‘Power’ when you meant ‘Energy’.

And more importantly its taken as the defacto measurement on the BBS and gun manufacturer's literature

Not by me it isn’t. Show me where it says that we have to use the wrong units. Please refer me to this manufacturer’s literature.