Author Topic: XS60C PCP Repeater project (Read 456169 times))

rsterne · « **Reply #1540 on:** May 26, 2016, 01:20:45 PM »

I'm looking forward to your results with the new MRod Powerhouse Valve, Lloyd.... I have no doubt that you will be able to coax some impressive FPE from it.... However, knowing the dimensions available inside a 3/4" tube, as used on the XS-60c (which will accept the Disco version only).... I still have my doubts about reaching 400 FPE using the Disco Powerhouse Valve.... However, I've been wrong before....

Bob

Sfttailrdr46 · « **Reply #1541 on:** May 26, 2016, 01:24:18 PM »

Quote from: rsterne on May 26, 2016, 01:20:45 PM

I'm looking forward to your results with the new MRod Powerhouse Valve, Lloyd.... I have no doubt that you will be able to coax some impressive FPE from it.... However, knowing the dimensions available inside a 3/4" tube, as used on the XS-60c (which will accept the Disco version only).... I still have my doubts about reaching 400 FPE using the Disco Powerhouse Valve.... However, I've been wrong before....

Bob

Lloyds efforts will be closely watched by me and once I start my project I will be sending him my Marauder bolt for upgrading to .30

Buldawg76 · « **Reply #1542 on:** May 27, 2016, 03:38:47 AM »

Quote from: stalwart on May 26, 2016, 04:41:06 AM

Quote from: buldawg76 on May 25, 2016, 07:26:03 AM
Quote from: stalwart on May 25, 2016, 04:14:36 AM
Gas Ram Striker... discussed a while back. An air spring, adjustable over a very wide range by changing the pressure in it.

Thanks and sounds very interesting and I can see how it would very adjustable for a wide range of levels. Is it small enough to fit in a normal spring pockets constraints and by chance do you have a page range where it was discussed to narrow it down in rereading the entire thread.

Mike
I don't have a range for you, when you find it please post the beginning post #?

I have been keeping a table of contents, but neglected to put that in it.

I no longer discuss prototypes here. The GRS concept was brought out in Russia, 2 months after it was posted here. The guy got it wrong, but the point remains... I have had people waste a bunch of my time (the list is growing, VRD LLC ring a bell?), trying to steal my ideas while pretending to want to help, invest or buy. I'm quite embarrassed at how much of my time I let these kind steal from me... I don't need to worry any more about being made a fool of.

Eric
I do understand your concern of pirating of ideas and designs and in today arena is all to real so I just want to assure you that it is in no way, shape or form any of my intent to even attempt to do so but rather to gain knowledge to be able to make informed decisions on what projects and parts I would need to source and where from to enjoy this hobby to it fullest.

I understand with the length of this thread it will be a time consuming task to proof read thru it to find the GRS posts but when I get time I will do so and let you know the first post about it so you can add it to your table of contents as that's the least I can do for all you provide for those of us with limited knowledge and means to build and enjoy some of the best innovations thought out and brought to life here in this forum.

Thanks Mike

stalwart · « **Reply #1543 on:** May 27, 2016, 07:05:36 AM »

Bob, Cothran got a max of 373fpe out of that valve. Frankly, I'd be happy to get close to that. Not to worry about me... many of the things I built (over 40 yrs) started out as "impossible", and I find some joy and satisfaction out of coming as close as possible to the impossible. If I don't get there, at least I'll know why.

Let's play with your "reality" thingy for a bit? LOL... an agile, durable, 7#(or so) 300fpe repeating gun would be a thing of beauty, no?

Mike, if I thought you were "that" guy, rest assured I would not be responding to you. Instead, you'd get a post like this: http://www.gatewaytoairguns.org/GTA/index.php?topic=49115.500 , #543 (last page)... take it upstairs... and poof, you'd be gone.

I frequently say "GTA rocks"...and, that I can prove it. Most guys never get a chance to find out just how securely GTA has our backs.... but, I did.

Buldawg76 · « **Reply #1544 on:** May 27, 2016, 08:15:39 AM »

Eric
I can see just what you mean and I would have to agree that they do have all our backs indeed and I had one incident that I let my judgment and thoughts get out of hand and it was tempered very swiftly and with no uncertain terms from the upstairs as well. I don't need to be told twice that's for sure.

This is the best place to learn and share for all of us in all ways.

Mike

rsterne · « **Reply #1545 on:** May 27, 2016, 03:17:28 PM »

First of all, I believe this is the first reference that Eric made to using a Gas Ram Striker.... http://www.gatewaytoairguns.org/GTA/index.php?topic=59114.1040 .... If you start reading at Post #1047, you can see how that idea developed, and ended up being the basis for my SSG (the idea is mentioned in Post #1074, first build in #1089).... Other posts about the GRS system continued for several months from that point onwards....

Eric, you are correct, I see that Don indeed got 374 FPE in .45 cal, although he does not mention barrel length or pressure.... He is at 250 FPE in .357 with a 26" barrel and 270 FPE with a 29.5", with a 232 gr. bullet at 700-725 fps (again, no pressure stated).... As you know, using extreme weight bullets (which a 232 gr. in .357 certainly is) at very low velocities sways the FPE heavily, compared to what might usually be used.... I do not know precisely the exhaust port diameter of the Disco Powerhouse valve, but from the photos it looks to be less than 1/4", which makes sense.... I find about 7/32" to be the maximum practical size in a 3/4" OD valve.... I have never tried building a .45 cal with such small ports (less than 50% of bore area), but it is possible that driving a very heavy, and therefore slow moving bullet, could produce significant power, given enough pressure and barrel length.... I personally think that for more practical use, a .357 cal would max out the capabilities of a 3/4" ID tube.... although using 4500 psi could push that up to .40 or even .45 cal, I suppose.... As you say, doing the "impossible" has a certain charm, and I wish you the best of luck....

Bob

Buldawg76 · « **Reply #1546 on:** May 27, 2016, 04:14:00 PM »

Bob
Thanks for finding it first about the GRS and it leading to the development of the SSG you came up with for all of us to experiment with and benefit from its simplicity yet superb results.

I have it bookmarked to read as time permits.

Mike

StevenG · « **Reply #1547 on:** May 27, 2016, 07:05:59 PM »

Bob,
Assuming one wanted to shoot your boat tails and was ok with a very long barrel, 30+ inches, would you go .357 or .308?

Pig would be the largest animal, but real every other weekend use would be to wow folks at the gun range. 3000 psi ideally.

rsterne · « **Reply #1548 on:** May 27, 2016, 11:08:06 PM »

I've never shot a pig (we don't have any here).... and in any case it would depend on the size (weight) of the pig, and whether you are talking head shots or heart/lung.... Manny shoots a lot of pigs with .22 and .25 cal pellets, at 30ish yards, but only in the fusebox.... IMO, for a heart/lung shot you would not want less than 1 FPE per pound of body weight, at the target, and 2 FPE would be preferable.... Ask yourself if (and where) you would shoot a large boar with a .22 LR rimfire at 50 yards, and you will get my point....

Our Mule Deer bucks here can run 200+ lbs.... Getting 200FPE to arrive downrange, even at 50 yards, would be a challenge for a .308 cal running on 3000 psi, so I would opt for a .357 for that job.... For the "WOW" factor at the range, for picking off small targets at 100-200 yards, my choice would be a .257 cal, shooting ~ 70ish gr. bullets at ~ 150 FPE.... IMO, the .308 is a great caliber for Predators (eg. Coyote), and smallish pigs, but a little small for deer, particularly big ones.... and a little large for target shooting and varmints.... although if you can only have one, I can see it being the best compromise....

Bob

rsterne · « **Reply #1549 on:** May 28, 2016, 02:47:42 PM »

Eric, I just had one of those DUH! moments.... Here is the way to restrict the velocity when moving down from a 400 FPE gun to one of 40 FPE or less....

The screw at the back pushes a rod forward which prevents the bolt handle from fully withdrawing into the J-slot.... You can drastically reduce the power, because the full diameter bolt nose progressively covers the barrel port....

I don't know if you can work a J-slot into the XS-60c, but if you can, this could solve the drastic detuning issue when you change calibers.... You could even do it with a conventional, non-adjustable, probed bolt, by having a threaded sleeve on the probe that could move forward and restrict the barrel port on the smaller caliber.... or just drill a tiny barrel port in the smaller caliber barrel....

Of course you still have to deal with the weight and travel of the hammer needed to open the valve at 400 FPE.... but a balanced valve would go a long ways towards fixing that....

Bob

StevenG · « **Reply #1550 on:** May 28, 2016, 03:20:11 PM »

Bob you literally just invented an actual on demand power adjuster.

You just did what airforce airguns has been pretending to do for years.

That is awesome in the original sense of the world.

rsterne · « **Reply #1551 on:** May 28, 2016, 06:14:19 PM »

Not "just invented", I've been using it for a couple of years.... particularly when I go from bullets down to pellets.... It just occurred to me that it might solve Eric's detuning problem between large changes in caliber....

Bob

StevenG · « **Reply #1552 on:** May 28, 2016, 07:09:49 PM »

Either way, something no commercial endeavor has yet made work.

rsterne · « **Reply #1553 on:** May 28, 2016, 07:21:16 PM »

The velocity adjuster in an MRod chokes up the transfer port.... I believe Air Arms have a similar device?.... They just don't restrict the bolt movement....

Bob

StevenG · « **Reply #1554 on:** May 28, 2016, 07:47:10 PM »

Both of which require pulling the gun out of the stock, I think. So not exactly on demand.

Either way it was just a compliment.

rsterne · « **Reply #1555 on:** May 28, 2016, 09:08:20 PM »

Much appreciated.... I just don't like to take more credit than due.... *grin*.... Yes, it is extremely easy, and repeatable, to adjust....

Bob

stalwart · « **Reply #1556 on:** May 29, 2016, 05:55:51 AM »

"...or just drill a tiny barrel port in the smaller caliber barrel.". I figure I could start with that, and my adjustable bolt idea in a custom bolt. Starts at post #273... Results in #317. It's quick and easy. As posted, it made a great dual use gun. It's a favorite here.

A couple passes on the receiver, and I may be able to increase the nose travel quite a bit, and nearly close off the port.

The .731 evanix mags will also allow just enough space behind them to reach the set screw easily. This means all the tuning tools can be accessed without any disassembly of the gun, (past pulling the stock to adjust the GRS, on the fusion/60s).

A dual cal kit would only need a barrel, and a bolt nose. I'm less worried about absolute numbers as being able to create a useful range. What is considered the best FPE range for tree squirrels (something to shoot for?)?

drewciferpike · « **Reply #1557 on:** May 29, 2016, 12:18:47 PM »

Go for 20. More than enough for clean hunting, even at range..., and someone can even try in FT!

Buldawg76 · « **Reply #1558 on:** May 29, 2016, 01:17:06 PM »

I cannot say on an Air Arms but I do know for a fact that on a Mrod it is just a matter of some light filing work to clearance the stock to access the air screw without removing the action from the stock and if done slowly and carefully can end up looking factory done. All three of my Mrods have it done including the one in the Boyds stock and they look factory done.

As far as the required FPE for killing wild pigs I would agree with Bob on at least 2 FPE per pound for best results. But back in the 70s when I lived in Florida and had a friend with a Hog claim on timber company land that meant he owned every wild " Boar " on 450 acres of land we could hunt them year round. The reason I state Boar and not pig is the Boar we hunted would get over 1000 pounds with 12 inch tusks that were razor sharp and if you did not have a BIG enough gun to make a one shot kill shot you would end up being the hunted not the hunter. The only guns we had were 30/30s and a 35 Remington magnum at the time and I can speak from experience that those were not BIG enough. We had more than a couple occasions of encountering a Boar of 800 pound plus and shooting it but not hitting lungs or heart cleanly or hitting the skull only to have the bullet ricochet off and left one angry boar that then proceeded to turn and charge us. The only escape since they can outrun a person two times over is to find the biggest tree and climb it in hopes that the boar can/will not uproot it with you in it.

We had spent several nights in the trees with the Boar trying to uproot the tree to get at us more than I care to remember. I am talking a 1 1/2 to 2 foot diameter tree that would be swaying all night with the Boar digging at the roots trying to knock it over only to come the next sunrise and a discouraged Boar that finally gives up to wander away.

We were in our 20s and met a older man in his mid 40s that lived and hunted those Boar all his life in that area and he did not carry a gun at all but instead hunted them with 8 to 10 Pit Bulls and two Airedales and a 12 inch bowie knife that he used to cut their throats as they would suffocate on their own blood in under 5 minutes. He had times when the Boar had killed all his Pits and was lying in wait for him to show up and would chase him up a tree as they did us.

Wild Russian Boar that had been brought into Florida years earlier are one of the few game that if made angry will hunt you just as fast as you hunt them and will do so with intent to kill.

Just for what's its worth.

Mike

StevenG · « **Reply #1559 on:** May 29, 2016, 04:00:33 PM »

This would be feral hog in Texas. We hunt from steel raised blinds, so unless they have power tools or learn to climb ladders we are pretty safe.

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XS60C PCP Repeater project

Author Topic: XS60C PCP Repeater project (Read 456169 times))