2260 PCP

[bigtaviles1]

Hi fellas, I have a 2260 PCP that I am going to rebuild. My goal with this is to have a 20 plus shot string centered at 15 fpe. Right around 650 fps using CPHPs or 615 fps using JSB JEHs. I have the notion to use a .107 transfer port to achieve this. Is my head in the right place? Thanks!!

[rsterne]

Sounds about right, it will depend on the pressure....

Bob

[bigtaviles1]

Thanks Bob, your two cents was what I was shooting for.

[Ribbonstone]

Answer just two questions, and we can tell how easy that goal (+20 shots/ 15 foot pounds/ .22cal) would be.

Need to know the pressure your fill to (easy enough).

And the volume of the air tube. That's not so easy, as it's not just the length/diameter of the air tube, but the length of the air filled part of the tube.


But given the pressure and the volume of air, can make a pretty good stab at what you can expect.

[rsterne]

2260 tube with a gauge block is about 65 cc, without about 70 cc....

Bob

[Ribbonstone]

OK...so like a P-Rod's air volume.

Lets assume a 2K fill.

(Haven't you and I worked on a 20 shot / 20 foot pound shot count for a volume close to this, but at 1500psi fill pressure, in the past?)


Lets also assume unregulated.


Certainly 20 shots/ 15 foot pounds seems pretty do-able with no non-reverable mods would do it....actually think that something more like 24-28 "good" shots could be had.

[rsterne]

My Grouse gun uses a 2260 tube, with a 2000 psi fill, and gets 16 shots at 20 FPE (18 gr. @ 700).... so 20 shots at 15 FPE, being pretty much the reverse (and a fraction less total FPE) should be achieveable.... I use a 1/8" transfer port, so a bit smaller on a 15 FPE gun should be OK....

and yes, the PRod and 2260 tubes are the same length and volume....

Bob

[Gerard]

For another point of reference, my 2260 has been through a number of power levels from 10fpe up to around 18fpe, but I like it best where it sits now at 13.5fpe with .22" 18.13gr JSB Heavy from the 18" barrel. It's quiet this way, and gives me 30 decent shots from 1,200psi down to 400psi, a very safe max pressure so I never have to worry about fatiguing the tube nor the very beefed up trio of valve retention bolts. It uses a Disco valve modified for excellent flow, and 0.125" ports throughout. The last few shots in this string shot this evening are slowing a bit but still pretty close to the average of 583fps.

585
590
579
580
579
590
584
587
588
594
588
591
585
590
586
593
591
591
583
587
583
588
587
577
580
573
576
569
557
557

I've got a home made SSG in there, tuned to my liking with about a 10mm long hammer travel, about a 50% preloaded 1mm x 8mm spring, the hammer hollowed out a little and turned down to just 38 grams. Also a couple of 1mm O-rings stacked up behind the valve in the bstaley manner to shorten valve travel.

So as others are suggesting, you should have little trouble getting 20 shots at slightly higher power than I'm set up for at the moment. Back in 2015 I had this one set up for 16.1fpe over 20 shots, with the SSG and O-rings in place but adjusting differently, with a slightly heavier spring and harder strike. Still just 3mm of valve travel happening with that setup though. I was filling then to 1,500psi, but decided a bit later to back off a few hundred pounds.

[bigtaviles1]

Thank you all for the great feedback!!