1701P query

[Blackrat]

Hi,
Has anyone put their 1701P across a chrony to try & find the optimum fill pressure?
As far as I'm aware these are not regulated, i know it makes a big difference to PCP rifles if the optimum pressure is used, keeps the ft/sec variation to a minimum.

Thanks for any tips/ comments regarding this.

[arkmaker †]

I found 2800 to 1800 was my sweet spot. Think I was getting about 60-70 good shots. I could run down to 1400 for plinking.
I'll try to find some graphs for you.
Rich


EDIT: Added graphs.
I never recorded my ending pressure, but I am pretty sure it was around 1400 psi.

[Blackrat]

  Thanks Arkmaker, appreciate the help.
I will give that a try.
I only have the Chrony 625 Mk 4 which won't fit on the pistol.
thank you.

[breakfastchef]

Chrony is helpful, but not necessarily needed to figure out the best fill pressures for the pistol. I read a post on another forum where a fellow shot a series of five shot groups at a series of bullseyes with the gun benchrested. After shooting a full fill, he cut and pasted the targets from #1 to the last target side-by-side. The resulting graphic showed a gradual rise of POI, and the fall off from the peak. Lots of work, but the test demonstrated it could be done. The problem comes when you want to tweak the pellet velocities. For that the chronograph is needed.

[arkmaker †]

Yes, a chrony is the only way to tune for fps. When I started shooting this string the gun was set at a starting point of 390 fps @ 2800 psi. That is just fine for 5M shooting, but I wanted a little more zip. When Crosman sent the test pistol around for testing, it was set at about 450 fps. I wanted to match that, so tweaking it up over the chrony was the only sure way. Best $80. outside of another gun purchase that I have spent since starting to mod these pistola's 


Rich

[Tater]

I just googled the 1701P and man, that's a cool shooter. What caught my eye on the Crosman sight, was that in the "primary use" section it said predators.
Is 450 fps with .177 acceptable for that?!?!? 
http://www.crosman.com/airguns/pistols/1701P

It doesn't seem to be made for predator hunting to me. Strange.

[Fronzdan]

Predator parakeets.

[Gippeto]

Predator parakeets.

I believe that under "primary use", the section that's dark red is the applicable use...in this case target shooting. My 1701P has taken a few ground squirrels (thirteen lined) and a couple starlings....IMO add pest control.

Al

[arkmaker †]

I just googled the 1701P and man, that's a cool shooter. What caught my eye on the Crosman sight, was that in the "primary use" section it said predators.
Is 450 fps with .177 acceptable for that?!?!? 
http://www.crosman.com/airguns/pistols/1701P

It doesn't seem to be made for predator hunting to me. Strange.

Target Shooting is what it is made for. But, being that it is extremely accurate, I figure short range tree rat hunting to be ok. Remember, 450 fps is what a stock 2240 shoots and lots of people use them. As for preditor size hunting? That's just going to annoy a coyote