Crosman 1720T + Huma Regulator Advice wanted

[d_ray50]

I just bought a 1720T and I want to add a regulator. I know very little about regulators so would appreciate your expertise. Also I ordered a Marauder/Challenger trigger with spacer and trigger guard from DiscosRus and a 2260 stock from Crosman . I plan on doing away with gauge completely. With a reg do I still need to do the BStaley tune ? also it looks like I should open the TP to .110 do you think that is correct ? I see AoA sells Huma for Prod is that the one I need ? any help will be appreciated Thanks Dan

[Frank in Fairfield]

Dan,
The two names I will give you will chime in soon but, you can PM them yourself.

motorhead
Kerndtc

Very knowledgeable.

For me..my 1720T has a four o-ring bStaley mod, a PRod TP (whatever that size is) and a .300 x .041 x 1.5” spring.

Good luck
With 7.33 JSB pellets I get 20 shots at 11.5 FPE.

[Motorhead]

Lol,
Thanks frank.

When you ask a PCP to make equal power at reduced ( regulated pressures ) it has too breath better & taking the VALVE to BARREL transfer size up to @ .110" is a great start !
Hammer weight and /or spring rate likely will take a bit of fiddling to get an efficient tune established.   IMO stock hammer is a bit heavy once regulated, but does work ok.

good luck and have fun !

[d_ray50]

Thanks for the reply gents. I have a lot to learn but that is a lot of the fun of the journey. I will read and absorb what I can and ask some questions. Will I still need to do the BStaley o-ring stack or will that not benefit me with a Reg?

[Motorhead]

Thanks for the reply gents. I have a lot to learn but that is a lot of the fun of the journey. I will read and absorb what I can and ask some questions. Will I still need to do the BStaley o-ring stack or will that not benefit me with a Reg?

Once regulated generally NO .... In the case of the P-rod, one could tune via Bstaley o-rings to limit valve lift & dwell, consistency will suffer with temp changes that change o-rings firmness being there absorbing hammer energy.

[Mont]

When you ask a PCP to make equal power at reduced ( regulated pressures ) it has too breath better & taking the VALVE to BARREL transfer size up to @ .110" is a great start !
Hammer weight and /or spring rate likely will take a bit of fiddling to get an efficient tune established.   IMO stock hammer is a bit heavy once regulated, but does work ok.

good luck and have fun !
[/quote]
With the tranfer port at .110 where should the regulator be set at?  What type of FPS would be expected? What pellet would recommend to try and start with for this tune? (I understand that every gun has a preferred pellet) What brand of regulator do you prefer for the prod?

[Motorhead]

HuMa with plenum, no gauge .... likely find @ 100-110 bar to be close.
The rest is fine tuning and speed dependent on pellet & weight.
Mid to upper 700's is realistic with the lighter, mid weight pellets ... more is there but valve work and a re-spring likely required tho.

[Pelletjunkie]

I don’t have a reg in my p-rod but I did put one in my BSA Ultra and it has a very small air tube also. Don’t swing for the fence looking for high velocity unless you want a one mag wonder. I would set the reg at 110 bar, back the hammer spring all the way off and have a couple progressively bigger transfer ports on hand. There is no shortcut to a good tune unless you are lucky enough to find someone who already did exactly what you are striving for. With enough Chrony time, your gun is going to tell you where it wants to be. I had my BSA shooting over 900fps for one magazine. But as the data piled up, I saw that it really liked shooting 4 magazines at 820fps. Do some research on rstern and reg tuning. That guys posts got me pointed in the right direction. Good luck.

[d_ray50]

Thanks sounds like a plan. First I will order a good Crony. I was thinking the reg might need to be set around 110 bar so I think I am on the right track. I would like to get around 11 or 12 fpe if I can have a decent shot count with that.

[ray1377]

Thanks for the reply gents. I have a lot to learn but that is a lot of the fun of the journey. I will read and absorb what I can and ask some questions. Will I still need to do the BStaley o-ring stack or will that not benefit me with a Reg?

Once regulated generally NO .... In the case of the P-rod, one could tune via Bstaley o-rings to limit valve lift & dwell, consistency will suffer with temp changes that change o-rings firmness being there absorbing hammer energy.

Motorhead, I've read tons of stuff on the Bstaley mod but never heard anyone mention consistency variances with temp change. That's good stuff to
know sir. That would mean a Prod set and adjusted now at 90+ degrees is gonna shoot alot different at say 40 degrees.  Something else to think about while tuning I guess.  Thanks for the info and for the original poster, sir I didn't mean to hijack your thread. And good luck with your 1720T
Thanks
Ray

[Motorhead]

Thanks for the reply gents. I have a lot to learn but that is a lot of the fun of the journey. I will read and absorb what I can and ask some questions. Will I still need to do the BStaley o-ring stack or will that not benefit me with a Reg?

Once regulated generally NO .... In the case of the P-rod, one could tune via Bstaley o-rings to limit valve lift & dwell, consistency will suffer with temp changes that change o-rings firmness being there absorbing hammer energy.

Motorhead, I've read tons of stuff on the Bstaley mod but never heard anyone mention consistency variances with temp change. That's good stuff to
know sir. That would mean a Prod set and adjusted now at 90+ degrees is gonna shoot alot different at say 40 degrees.  Something else to think about while tuning I guess.  Thanks for the info and for the original poster, sir I didn't mean to hijack your thread. And good luck with your 1720T
Thanks
Ray

 The bstally mod generally is used in NON REGULATED guns and the damping effect of the o-ring on hammer is more subtle.  In a regulated action the available pressure with in the valve is a constant, hammer energy opening poppet DIRECTLY effects the valves lift and dwell.  using the o-rings in a Bstaley type mod to control the poppets lifts will directly effects the dwell of poppet. Any changes in damping effect of o-ring firmness has a direct effect in changing valves open / dwell cycle.   AND THE WHY FOR we don't use such miens in regulated actions.  Hammer weight in concert with spring energy against the poppet is the better way to tune a regulated PCP.

[d_ray50]

What is some options to lighten the weight of the 1720T hammer ? And how about the adjustment of the hammer would you start by backing the striker all the way in ? Sorry if any of my questions are silly just trying to understand about this procedure. When it comes to hammer spring I plan on setting it to the lightest setting . I think I will like a reg setup I sure will like a light cocking effort . Could someone recommend a Chrony at one time I was looking at Caldwell Ballistic Precision Premium Chronograph Kit .

[Pelletjunkie]

I would start with the striker all the way in. Fire a couple shots, record fps. Turn it out 2 turns, fire and record. Now you know how it is going to effect things. You may need this tuning tool down the road now that you know what it does. A chronograph is just as important as your Allen wrenches. You can’t do this without one so get one ordered. You don’t need a Mega Chrony, you just need one with lights unless you plan on doing everything outside.