Author Topic: XS60C PCP Repeater project (Read 455988 times))

lloyd-ss · « **Reply #1480 on:** May 14, 2016, 04:05:42 PM »

Quote from: rsterne on May 14, 2016, 12:44:22 PM

Lloyd, I think making them for the PRod Double is a no-brainer.... Is there any change required, or will they be a drop (screw) in?....

Bob

The disco double tubes are married together at the front end such that the reg can go easily between the upper and lower tubes, creating two separate chambers for high and low pressure. Conversely, the prod tubes are married together at the rear end, so re-engineering will be needed.
Lloyd

RMM · « **Reply #1481 on:** May 14, 2016, 04:17:45 PM »

Can't wait to get this airgun in my hands and start wringing it out.

Thanks gentleman and I am truly honored to be #1.

RMM · « **Reply #1482 on:** May 14, 2016, 04:26:31 PM »

Ok, I've lost my way but I'm hoping someone will push me in the right direction. With the new capabilities of stalwart's 3K and it's a double reservoir with regulator I want some heavy .22 bullets that will fit in the 3K magazine. Push me in the right direction gents or lead me to another path.

rsterne · « **Reply #1483 on:** May 14, 2016, 04:47:12 PM »

Lloyd, I didn't know the PRod tubes joined at the back....

RMM - JSB have a new 34 gr. Beast pellet, that is my plan.... Alternately, if you want to cast bullets, get in on this Group Buy at NOE....

http://noebulletmolds.com/smf/index.php/topic,1322.0.html

Bob

RMM · « **Reply #1484 on:** May 14, 2016, 06:38:27 PM »

Quote from: rsterne on May 14, 2016, 04:47:12 PM

RMM - JSB have a new 34 gr. Beast pellet, that is my plan.... Alternately, if you want to cast bullets, get in on this Group Buy at NOE....

http://noebulletmolds.com/smf/index.php/topic,1322.0.html

Bob

Thanks Bob, JSB's will get me started.

RMM · « **Reply #1485 on:** May 14, 2016, 07:03:34 PM »

Quote from: rsterne on May 14, 2016, 04:47:12 PM

RMM - JSB have a new 34 gr. Beast pellet, that is my plan.... Alternately, if you want to cast bullets, get in on this Group Buy at NOE....

Bob

This came up on AirgunDepot site. The heaviest .22 cal pellet yet! Note: Does not fit in rotary magazines http://tinyurl.com/jbuqhj9

I hate to ask but ask I must even though lot of research went into the use of the Prod magazine. Will these fit into the Prod magazine??

stalwart · « **Reply #1486 on:** May 14, 2016, 07:13:56 PM »

Would it kill manufacturers to include the OAL in their specs?

rsterne · « **Reply #1487 on:** May 14, 2016, 07:27:26 PM »

The 34 gr. is 0.42" LOA.... MRod .22 cal NO.... PRod .22 cal maybe if modified.... MRod .25 cal with a .22 cal wheel installed OK....

Bob

stalwart · « **Reply #1488 on:** May 14, 2016, 07:46:49 PM »

How much relief would a PRod mag need? I could cut one to see if it would work. The .25 mag, as you know, requires a lot more work to fit (elongated custom block).

RMM · « **Reply #1489 on:** May 14, 2016, 08:14:58 PM »

Quote from: stalwart on May 14, 2016, 07:13:56 PM

Would it kill manufacturers to include the OAL in their specs?

Another campaign for another day??

Quote from: rsterne on May 14, 2016, 07:27:26 PM

The 34 gr. is 0.42" LOA.... MRod .22 cal NO.... PRod .22 cal maybe if modified.... MRod .25 cal with a .22 cal wheel installed OK....

Bob

Thanks Bob, I'll have to measure the PRod mags and a pellet or bullet hunting I will go.

stalwart · « **Reply #1490 on:** May 14, 2016, 08:26:27 PM »

John Cripe made me a huge selection of bullet styles, that fit the PRod mag, and all are 30-31gr.

pelletgarden.com

rsterne · « **Reply #1491 on:** May 14, 2016, 10:30:29 PM »

IIRC, the PRod mag is 0.40" to the flat edges, and a bit deeper in the center, so the 34 gr. JSBs might be VERY close to working.... I'm sure you could tease another 0.020" out of them without too much problem.... In fact the .22 Predator Polymags measure 0.412", and they fit a PRod magazine, because the narrow point fits into the groove in the front of it.... so basically, if you used a 7/32" ball end mill and cut out the front of the mag until you just cut out the bottom of the existing groove, you should be good to go....

Hmmmmmmmmmm.... I'm guessing I just figured out what to do with my new Regulated Disco Double....

Bob

lloyd-ss · « **Reply #1492 on:** May 14, 2016, 11:13:47 PM »

Quote from: rsterne on May 14, 2016, 10:30:29 PM

.....................................
Hmmmmmmmmmm.... I'm guessing I just figured out what to do with my new Regulated Disco Double....

Bob

he he he he

Lloyd

Sfttailrdr46 · « **Reply #1493 on:** May 15, 2016, 09:08:10 AM »

I can't keep up with you guys now I will have to see if I can fit a M-rod regulated Double tube into my Purple Beauty

rsterne · « **Reply #1494 on:** May 15, 2016, 01:43:16 PM »

One of the most interesting parts about the new Disco Double (and it's XS-60c cousin) will be tuning it.... My thought is to come up with a tune that is half way between a regulated tune (flat velocity until setpoint, then dropping) and an unregulated tune (bell curve with 4% ES, low-high-low).... The plan is to use, as an example, a 2200 psi setpoint, and tune the gun for peak velocity at about 2000 psi, and then refill the bottom tube at about 1800, back up to 3000 psi.... This should give (ie can be tuned to give) about a 2% ES over the entire string, with the first part of the string at a constant velocity until the setpoint is reached, then a gradual increase (not more than 2%) and then tapering off back to the original velocity.... In other words, a plateau, followed by a shallow bell-curve.... This represents a slight "downslope" type of tune for a regulated PCP, which results in great efficiency and quiet operation while above the setpoint, which should be about 2/3 - 3/4 of the total shots.... and then a slight drop in efficiency, and corresponding increase in report, as the pressure drops below the setpoint towards the refill point.... I think this may be the best way to take full advantage of the large plenum volume represented by the upper tube....

Bob

stalwart · « **Reply #1495 on:** May 15, 2016, 03:45:58 PM »

Quote from: rsterne on May 15, 2016, 01:43:16 PM

One of the most interesting parts about the new Disco Double (and it's XS-60c cousin) will be tuning it.... My thought is to come up with a tune that is half way between a regulated tune (flat velocity until setpoint, then dropping) and an unregulated tune (bell curve with 4% ES, low-high-low).... The plan is to use, as an example, a 2200 psi setpoint, and tune the gun for peak velocity at about 2000 psi, and then refill the bottom tube at about 1800, back up to 3000 psi.... This should give (ie can be tuned to give) about a 2% ES over the entire string, with the first part of the string at a constant velocity until the setpoint is reached, then a gradual increase (not more than 2%) and then tapering off back to the original velocity.... In other words, a plateau, followed by a shallow bell-curve.... This represents a slight "downslope" type of tune for a regulated PCP, which results in great efficiency and quiet operation while above the setpoint, which should be about 2/3 - 3/4 of the total shots.... and then a slight drop in efficiency, and corresponding increase in report, as the pressure drops below the setpoint towards the refill point.... I think this may be the best way to take full advantage of the large plenum volume represented by the upper tube....

Bob

This is everything we hoped for... can't wait to get some 60s up and running with the big dogs! And, then...

RMM · « **Reply #1496 on:** May 15, 2016, 08:29:50 PM »

Quote from: rsterne on May 15, 2016, 01:43:16 PM

One of the most interesting parts about the new Disco Double (and it's XS-60c cousin) will be tuning it.... My thought is to come up with a tune that is half way between a regulated tune (flat velocity until setpoint, then dropping) and an unregulated tune (bell curve with 4% ES, low-high-low).... The plan is to use, as an example, a 2200 psi setpoint, and tune the gun for peak velocity at about 2000 psi, and then refill the bottom tube at about 1800, back up to 3000 psi.... This should give (ie can be tuned to give) about a 2% ES over the entire string, with the first part of the string at a constant velocity until the setpoint is reached, then a gradual increase (not more than 2%) and then tapering off back to the original velocity.... In other words, a plateau, followed by a shallow bell-curve.... This represents a slight "downslope" type of tune for a regulated PCP, which results in great efficiency and quiet operation while above the setpoint, which should be about 2/3 - 3/4 of the total shots.... and then a slight drop in efficiency, and corresponding increase in report, as the pressure drops below the setpoint towards the refill point.... I think this may be the best way to take full advantage of the large plenum volume represented by the upper tube....

Bob

I'm ever so glad you posted the above because I being a novice was going through the thought process of how to tune my pumped up 3K with my novice capabilities. Now I have a primer to start with, thanks.

lloyd-ss · « **Reply #1497 on:** May 16, 2016, 10:55:46 AM »

Quote from: rsterne on May 14, 2016, 10:30:29 PM

IIRC, the PRod mag is 0.40" to the flat edges, and a bit deeper in the center, so the 34 gr. JSBs might be VERY close to working.... I'm sure you could tease another 0.020" out of them without too much problem.... In fact the .22 Predator Polymags measure 0.412", and they fit a PRod magazine, because the narrow point fits into the groove in the front of it.... so basically, if you used a 7/32" ball end mill and cut out the front of the mag until you just cut out the bottom of the existing groove, you should be good to go....
....................
Bob

Bob,
I just did some measuring, trying a couple of different methods and it looks like the 34 gn beast, if no longer than .42", will just barely fit a .22 cal P-Rod mag. The depth to the flat edges of the bottom is .400/.405, and the depth to the extreme bottom of the groove is .429/.431. The .412 long .410/.412 polymags I tried rattle a little in length in the mag, and measurements indicate about .010 clearance, so the .42 long Beasts ought to just barely fit. I also tried some of the JSB jumbo monsters (25 gn) which are .343 long and the extra clearance measured to indicate that, again, the .42 long pellets will just barely fit.

If binding is experienced, there are a couple of solutions that are easier than a ball nosed endmill. If you disassemble the mag, you'll notice that there are some molding ejection pin witness marks in the bottom of the groove. Some of them have slight raised edges/burrs. A little bit of deburring, and slight deepening of the groove with some 400 grit paper will make the pellets index more reliably. Also, when reassembling, the spring could be set with a little more tension by moving it to the next of the 3 holes in the back. Of course, you'd have to note which was the original hole location before disassembly.
Lloyd

rsterne · « **Reply #1498 on:** May 16, 2016, 12:16:53 PM »

Yeah, I kind of thought they "might" fit in a PRod mag., my comments erred on the side of caution, so that guys know they might have to ease things a bit.... It will depend on how "blunt" the nose on the 34 gr. is, compared to the skinny point on the Polymags.... Thanks for the info, Lloyd, I know what mags I will be basing my breech on....

Bob

stalwart · « **Reply #1499 on:** May 16, 2016, 11:15:58 PM »

The potential just keeps growing.

Couldn't be happier, here, to see this.

Thank you to our advertisers!

XS60C PCP Repeater project

Author Topic: XS60C PCP Repeater project (Read 455988 times))