Prod tune thoughts?

[larspawn]

All,

My Prod is untuned.  The only thing I've done besides cosmetics is install a 3 o-ring buffer.  I've just been shooting it as is and now thinking I should get into tuning it.  I did the following shot string and was surprised at how bad it is.  lol

So my real question is to tune or to get a Huma reg?  Or just be lazy and stick with slightly less than 3 mags of good shots?  My only thought is that the air tube is so small that a reg may give more consistent shots but not really that many more?

Thoughts?

[EdinGa]

All,

My Prod is untuned.  The only thing I've done besides cosmetics is install a 3 o-ring buffer.  I've just been shooting it as is and now thinking I should get into tuning it.  I did the following shot string and was surprised at how bad it is.  lol

So my real question is to tune or to get a Huma reg?  Or just be lazy and stick with slightly less than 3 mags of good shots?  My only thought is that the air tube is so small that a reg may give more consistent shots but not really that many more?

Thoughts?

I'm wondering if the o-ring buffer is helping or hurting. My extreme spread is around 25 fps over 3 magazines from a 2500 fill.

[Tucobenedicto]

The o ring buffer works,tried it in the past,but you can't merely install the orings,it require tuning of preload and trow adjustement.

[Ribbonstone]

The list and the yellow shaded in box is probably the most useful for this.

Without doing major surgury/mods,can pretty much move that yellow box up or down a shot string. Crank the striker spring tension up, and the yellow box would start nearer to 3,000psi....be faster/more energy per shot....and likely about the same number of 4% shots.

I figure  the best balance is a short string that starts 4% under eventual max when at the top pressure ...rises to max speed...and falls to 4% under max (and you can change that to 3% or up to 5% depending on what you are wanting to do with the PCP).

You could crank on that striker spring harder and get it to shoot faster and faster,but each shot after the first declines in speed....basically you are cutting off the front half of the curve, getting more power, but less total energy out of the system

Fiddle around enough with all the little stuff, nothing that can't be un-done easily, and you can get something like 24 shots at about 15 foot pounds inside that same 4% range.


REGULATION:

Best comparsion out there would be to the PP700.  LOOKS nothing like a P-rod, works nothing like a P-rod, but it is the same basic 65cc volume and pretty close to the same barrel length...it just squirts the air behind the pellet differently.

So would be a pretty good analog to a regulated P-rod (although the P-rod would have to give up some volume for the plentium and the regulator space).

Have not found it hard to get 40 good shots (and of those, 35 of them were more like 2% varation) at the same 15 foot pound level.

Which brings me back to your "yellow box".

You managed 20-22 shots using basical 50 BAR of air (175bar to 125bar) with the P-rod at 4%

The PP700 (at least my old Gen.I version) can manage 44 shots from the same volume,but it takes  100BAr of air.

So yes you get a lot more shots with regulation....but it's proportional to air use.

Get a lot more uniform shots....maybe you're good enough to tell 30 yard groups at 2% vs 30 yard groups at 4%....I'm not good enough to proove it one way or the other.

[moorepower]

It does not look like your touching the buffers. I would use a .041 spring also. It's been a long time, but I am thinking I got 700-720-700 for almost 3 mags, with 14.66 pellets, without really trying. Some are getting 4 mags with a little tweaking, but I just fill after 2 mags and am very content with what I get.

[Ribbonstone]

Likely right...are more mods that can be done...I've just gotten complacent/use to it.  But likely more mods/and adjustments to the regulated 700 that could also be done to keep the  ratio of power/shot count between them about equal in air use.

Just comes a time when acutally using the PCP outweighs the experiments.

Which is likely which I ended up with two ultra-lite .22 carbines at about the same power level and efficiency.

One as a non-reged repeater (for when the "ship" is going down fast and fursious..like "burst mode") and one regulated as a single shot (for when the pacing between shots is more laid back):







QUESTION: Other than ethical and moral issues, in the stage of life, is there anything that can't be cured by either spending more $$ or spending more time?

[EdinGa]

Just comes a time when acutally using the PCP outweighs the experiments.

I'm really trying to resist the urge to mess with mine. It's a sweet shooter over 3 mags at 13 fpe.

[Ribbonstone]

Can't say that 13 foot pounds vs. 15 foot pounds really makes a ratt'sarse. Other than the difference on paper, it's a matter of getting 2-3 steps closer or holding a little bit higher.

[larspawn]

Ok.  Thanks for the thoughts.  Based on your thought of pushing fill to 3000 and getting starting velocity up more towards my peak in stock form, I got these results.  A huge improvement in my mind since my curve starts flatter and at higher velocity.  So less extreme spread, less SD and more power.  All around better.


I might be able to mess around and get 4 mags at lower velocity but I think I'm pretty happy with 3 mags at this curve.

 

[RDB]

It does not look like your touching the buffers. I would use a .041 spring also. It's been a long time, but I am thinking I got 700-720-700 for almost 3 mags, with 14.66 pellets, without really trying. Some are getting 4 mags with a little tweaking, but I just fill after 2 mags and am very content with what I get.

Agreed, I run 4 orings. Should be able to flatten that out and start out at a higher pressure.

[larspawn]

It does not look like your touching the buffers. I would use a .041 spring also. It's been a long time, but I am thinking I got 700-720-700 for almost 3 mags, with 14.66 pellets, without really trying. Some are getting 4 mags with a little tweaking, but I just fill after 2 mags and am very content with what I get.

Agreed, I run 4 orings. Should be able to flatten that out and start out at a higher pressure.

Hmm, I might try putting another o-ring in at same settings I have now since it looks good at a 2900 fill.  Perhaps it might flatten out the 3 mag curve.  Not sure it would get me to 4 usable mags?

[Ribbonstone]

Lock it down. Not that you can't do a little better, but figure the "nick-name-for-Richarding" around you'd need to do to gain another 4-5 shotsvs. just shooting it... it still won't be a full 4th mag. better.

[TF89]

It all depends on what you want in regards to shot count vs power.  I did this awhile back and the only thing I did other than adding the o-orings was drill up the TP to .109 and have not changed it since.

Stock P-rod
Stock TP .080 ID
Hammer at stock 1 5/8 CCW setting.
Spring stock setting (not sure how many turns factory does)
Fill 2650 shoot down to 1800 psi.
Crosman Premier 14.3
19 shots staying inside of 4%
Average 645fps

Add 3 x o-rings  (Bstaley tune with the o-rings sitting about 1/8” taller than valve stem)
Stock .080 TP
Hammer at stock 1 5/8 CCW setting
Turned spring tension adjuster in 4 turns from factory setting (added tension)
Fill 2650 shoot down to 1800psi
Crosman Premier 14.3
23 shots inside of 4%
Average 606fps

Here is in the eye opener for me and the effect of TP size.

Same 3 x o-rings  (Bstaley tune)
TP drilled up to .109 (7/64ths)
Only change made was swapping out the TP and fill pressure
Fill 2300 shoot down to 1600
Crosman Premier 14.3
19 shots inside of 4%
Average 699fps