SSP shoots heavier pellets better...anolomy?

[218bee]

I have a FAS604 that I just resealed and its shooting 7 grainers at a healthy 375-385 fps. Tried about 8 or 9 light pellets , including R10's, Meisters, Finale's, JSB's, H&N's, Basics, etc...and couldn't get it to group as well as my $200 Air Venturi V10 SSP. Stringing, flyers, etc, and just couldn't shoot a group smaller than a golf ball @10m. (Don't shoot competitively)
On a whim I tried some JSB 8.4 grain Diabolo's I have laying around and the groups immediately shrank to a dime-sized ragged hole. The pistol seems to have found the pellet it likes ..big time. Haven't chronie'd it yet, but I would hazard a guess they are in the 330-340 fps range.

I know I loose velocity with these pellets, but gain ALL the accuracy back. So my question: is this an anomaly, or have others found this to be true? I mean its not even close, how much this pistol likes these pellets.

[Rover]

In three different PCPs, I found JSB light pellets beat every other pellet, and the groups were FAR smaller than your best.

I don't think pellet weight has ANY bearing on accuracy.

[william]

In three different PCPs, I found JSB light pellets beat every other pellet, and the groups were FAR smaller than your best.

I don't think pellet weight has ANY bearing on accuracy.

C'mon, Rog, pellet weight is everything - except for all the other fads-of-the-moment. Haven't you seen the equations that calculate accuracy based on pellet weight as a function of relative humidity, ambient temperature, barometric pressure, speed of the compression stroke, brand of coffee had for breakfast and shoe size?

Sorry, I forgot to mention latitude, moon phase and sunspot activity.

[Rover]

You forgot to mention lowered sperm count due to too-tight underwear.

Look for my important PM.

[william]

You forgot to mention lowered sperm count due to too-tight underwear.

Look for my important PM.

Thanks for the PM - got it.

Funny thing about getting old, you forget things like the importance of properly fitting knickers.

[JamesHH]

Are these groups off hand or from a rest?
In my limited experience heavy pellets group better from a rest but light ones are easier to shoot off-hand.

[218bee]

Off hand.

[kevinweiho]

I had a Gamo Compact (aka Air Venturi V10) that grouped very well with Crosman domed 7.9gr premier pellets. Some air pistols are more accurate with loose fitting pellets and some snug, go figure. If the FAS groups better on a rest, then it's you, could also be a dirty bore or damaged muzzle crown.

[Rover]

I don't own a FAS, but noticed that there were a lot of posts on FAS quality control and tweaks. Do a Search.