Velocity adjustment question for FWB P70 10Meter

gizmodave · Post by **gizmodave** » Sun Feb 19, 2012 12:41 pm

I found a very reasonable deal on a FWB P70 5 years old with no leaks or modifications, internally adjusted as it was from the factory, but the seller states the muzzle velocity is 400 FPS. Does this sound right for a 10 meter gun?
I have searched the web and it seems 570 FPS is the current norm except for the long range guns.

Any info will be appreciated.
Dave

justadude · Post by **justadude** » Sun Feb 19, 2012 3:14 pm

For the muzzle velocity 400 that is quite low. As you have gathered, mid to upper 500s is more the norm.

'Dude

headwizard · Post by **headwizard** » Fri Mar 30, 2012 9:41 am

Maybe that's why it's such a good deal? Needs to be mid-upper 500's to maintain best accuracy.

bpscCheney · Post by **bpscCheney** » Fri Mar 30, 2012 11:14 am

As previously stated this is rather low but it might have been adjusted and the seller doesn't know about it, there should be a screw that is near the air intake that adjusts the velocity. It almost sounds as if the rifle was adjusted for maximum air efficiency rather than accuracy.

Rover · Post by **Rover** » Fri Mar 30, 2012 12:13 pm

I'm not really up on that particular model, but most guns are the same.

You'll find a screw head on the back of the action that controls the force of the hammer spring. To increase power turn it clockwise (righty-tighty).

The hammer spring tends to get a little tired, so you increase the tension on it. After a while you'll want a new one (next rebuild).

I'd guess that half a turn should put you about where you want to be, but it's not at all critical.

Have fun!

GaryN · Post by **GaryN** » Fri Mar 30, 2012 1:18 pm

Just guessing but, it might also have a regulator or valve problem.

gizmodave · Post by **gizmodave** » Fri Mar 30, 2012 2:50 pm

Thank you all for the information.
We have fired the P70 from a gun vice and produced a 5 shot group that very nearly matches the original test target using standard Crossman pellets.
We will be sending it to Pelkington for seals, tune up, and pellet testing this summer after the last of the local matches are complete.

Rover · Post by **Rover** » Fri Mar 30, 2012 5:03 pm

Glad it's working for you. They'll put a new spring in for you on the rebuild, but mention it anyway.

Interested to hear about the Crosman pellets, since in my testing they didn't do well. The RWS Basic for about the same price did much better.