XS60C PCP Repeater project

[stalwart]

Thanks for understanding, guys.

I'm tickled pink here... Shooting from my desk, no chrony, at 5m, I just tuned the bolt back and forth from slow enough to watch the arc... to huge muzzle blast and ripped bean can. CO2, decent tolerances (but nothing extreme).

Chuckles tonight... numbers tomorrow.

[RMM]

Hear! Hear! 

But understand stalwart is correct in what he says in opening his heart.  There's a lot that goes into turning out a safe high quality product. Look at the collaborated openness in forum and think about the behind the scenes collaborations that go on to turn out a safe high quality product.  I have a lathe and mill but not the years of experience (tooling, metallurgy, setup experience, etc.) to turn out stalwart's more than reasonably priced product so I was more than willing to take the plunge for a Bobcat plus he has another of my 60's for another conversion when that comes, and it will come, stay tuned.  This man's genius is still not tapped and don't forget the genius of others whom are more than willing to share their years of experience for our passion, airgunning.   Stay tuned, there's more to come. 

Bill, I think Betty Lou should thank her lucky stars we don't live within a half hour of each other. I buy Midnight Oil by the drum here. 

Guys, I got the adjustable bolt function proto made. I just don't have the legs to test it today... soon, I hope. I went with 4mm port and passage, to match the stock barrel... to keep it simple. It's set up to go from open (shown) to closed within the space needed to reset the screw. Single shots can have a really cool click adjuster (by shortening the tray slightly to fit) and the repeaters, if stretched, can have it too. I used a repeater barrel in this one just to speed up getting into testing. I'll find out how many degrees it takes to get a good range of power, and build to that number. Stay tuned, this is gonna happen.

Mike, best I can do atm is the Bobcat @ $110. With 10% going to GTA, Paypal getting it's slice, and my time/costs to handle CS, receiving and shipping (not to mention the cost of production)... the only way I can make these any cheaper is to sub some of the operations out. I looked into that, and given the current economy, I can't afford to have 50 pieces made... freezing this project until most are sold... so I can sit and hope someone doesn't undercut me (easy, if you don't give a d**n about how stuff fits, prefer imitation to innovation, and incurred no R&D costs) and leave me beside the road choking on a bunch of quality work.

The daring ones who bought the first batch covered the tooling needed to get to this point. They made a reasonable turnaround time a reality. If someone wants to get real daring, and order 20... we can talk about knocking the price down. If I can't make my shop rate on these, I have a lifetime's worth of other (albeit less fun  ) work that will. This is my 30th year of self employment, and I have never had a sign, or even needed a business card. My work has always spoken for itself... and my customers have always, unbidden, taken care of advertising.

I have seen posts that say things like "If I had a mill, I'd do it myself". I want to know who makes a mill that can cut an ID ring groove... or cut a precision chamber. I gots to get me one! I can't even find a mass produced ID groove cutter small enough, or an OTS chamber reamer. I strongly suspect that anyone who can't even see the tooling and processes involved here, probably can't do a quality imitation of my work... so, they just give me a chuckle... no worries.

Sorry about the long answer to your question, Mike! It's been building up for a while, fueled by the comments I get stating that I'm charging too much for mods to a "$100" rifle (thereby demeaning not only my work, but the entire concept I have spent so much developing)... said by guys who have no problems applying hundreds to $40 pistols (using only a screwdriver). 

Short answer, more appropriate: $110 Bobcat, $160 drop in...smoothed (no exchange needed), $180 Teflon, slick kit, assemble and shoot.

[rsterne]

Guys just have no concept of the time it takes to do machine work by hand.... or the costs of CNC machines to automate the process.... If you asked them to work for a couple of dollars an hour they would look at you like you were a space cadet, but that's about what I make when I sell one of my prototypes, if I'm lucky.... and ALL of that money gets rolled back into tooling.... That is why I refuse to do work for others making parts or guns.... Even being retired there aren't enough hours in the day to do my own projects....

Sounds like the rotating bolt nose is working great.... Can you index it without removing it from the gun?....

Bob

[stalwart]

Guys, the temptation to express my gratitude with a hideously long (and , let's face it... mushy) post is great, but your obvious understanding of this situation makes me believe I can better do it in 1 sentence:

Gentlemen, it is an honor to be in present company... every one of you.

Now, let's have some fun! Bob, the stocker's got enough room to fully adjust, in seconds. At 0*, it runs 355fps, at 45* it hits 490, at WFO... 586.     The gun needs tuning and bigger ports, but worked perfectly to show a curve very much like your graph... maybe a bit gentler (the CO2?). I need to get some stock to make the clicker, but I highly recommend this arrangement, as shown, to anyone with a lathe. When time permits, I'm going to build a .177 and start counting shots. I couldn't be happier with this.

Guys, retirement never meant ceasing work, it is about being able to choose who I work for. So... No kidding here... if anyone refers to Mr. Melick's efforts as a "$100 rifle" within earshot of me, in a tone anything less than appreciative...

[au hunter]

  Stalwart I feel the same way about all the armchair machinists and know it alls out there. Can be darn frustrating, I just got done building a prototype for an inventor,so he can get his patent work completed.
like to drive me NUTS!! (not that it's a very long trip some days) I tackle some projects that by the time I'm done,I wish I'd never met the person.  BUT after reading this thread and other threads here and other sites I cannot get over some of the talent and skill involved.
   An old machinist friend and mentor of mine told me one time that he was willing to share his knowlage with anyone( but the quickest way to get thrown out of his shop was to say to him "all you gotta do is"  his reply  GET OUT!!!)   rant over!
 great thread and site!! keep up great work

[stalwart]

It's pretty clear I'm in good company...  I'm not suggesting we unionize and strike, but it might not be a bad idea to periodically point out the fact that, like figure skating, it's not quite as easy as it looks from the stands.

The stocker, turned all the way down, runs at exactly the speed of a 10" .22 P17. They make authoritative 20M gallery guns, spin the spoons like crazy. I'm getting chuckles out of it big time. I'm really glad I tried this, I now have a rifle that plinks with the best, but can be turned, in seconds, into something that can humanely guard a garden from the usual suspects.

[stalwart]

Well, I was wrong. There is room in a single shot for either a clicker, or a set screw arrangement... without modding the barrel.

[RMM]

Well, I was wrong. There is room in a single shot for either a clicker, or a set screw arrangement... without modding the barrel.

Nice job!!  And a very innovative way to control flow externally.   

[stalwart]

Thanks! The nose is cut to fit closely, and I'm thinking about slotting the ports. At 355fps, I don't need it to go slower... but I want to see how fast I can make it go without affecting the lowest setting.

I'll follow Bob's recommendations on tuning, get numbers, and we'll get a good look at how much difference adjustments can make. I'd be happy with 350-600 fps, but you know me... can't leave well enough alone.

[stalwart]

The chambers in 60s vary a lot in depth. I cut this nose to just gently nudge the pellets in this one just until they grab. 4mm passage, 4 x 5.5mm port.

With the 4mm round port, the gun adjusted from 4fpe to just under 11fpe with 14.3 gr CPUMs.

I have to dress and polish up the ports, cut the nose free and set up the mounting, then pull the gun down and match the ports. A 4 - 12 fpe rifle would be nice, but I'm hoping I get more on top... it's a lot of work for just a couple.

Any guesses what this could do on CO2? Anyone?

[rewinder]

Hi All

I was wondering if anyone had their "Bobcat" conversions up and running yet? Haven't seen any reports, but may have missed them.

I received mine a few weeks ago, but sadly have issues with the tube/receiver threads. Not anything to do with stalwarts fine machining job, that part is a thing obf beauty.

My problem is the threads on tube are undersized and receiver threads oversize, making for a loose thread in of the tube, and when trying to seal on the square o ring, tube just spins-- basically stripped.

I have a solution, my wizard buddy machinist is going to make a new oversize thread on tube, by about 1/2 mm and the same thread on a piece of steel rod the same bigger size---then use the rod as a tap to chase the receiver threads to fit the tube.

Unfortunately my buddy is in the midst of moving his shop to a larger space, and will be busy for a few more weeks.

So are are there any reports on the Bobcat users out there, love to hear how they are doing

[rsterne]

You don't want to fool around with poor quality threads where the tube and receiver meet.... The end force at 1500 psi is about 750 lb.f.... which means it should be engineered to stand 3 times that, or over a ton.... Make sure your machinist buddy is aware of that.... The threads need to be strong enough to lift a small car....

Bob

[rewinder]

Yes Bob , we've talked about just that problem
 I should have taken care to see that the threads were rugged and fit well when I received the gun, But I just stripped it down and sent the parts out for the mod.

If it doesn't workout to a good fit, I'll just scrap the project and learn that lesson. A couple hundred buck loss is nothing compared to an accident

[stalwart]

There is plenty of meat for him to work with... I'm betting he can give you a fit that will be quite reassuring.

All this extra work will give you good reason to finish it up nicely... it will be a great little gun. Worth the trouble... IMHO.

[stalwart]

Matched the ports and throated the valve and chamber. Took quite a while, but it's relaxing work.

[RMM]

Should I bow or genuflect, Sir Stalwart.   

Amazing work..

[silent_airman]

Should I bow or genuflect, Sir Stalwart.   

Amazing work..

Just kiss his ring.

[stalwart]

G, whatever gave you the impression I could afford jewelry??

I turned the single shot up to max, and got a high of 692fps, and a low of 427. I'll have to turn it down a bit, I like the 4fpe. And, although it looks odd, the cheap sight makes it easy to snap shoot with decent accuracy. As a gallery gun, it's a blast.

There's an adjustable repeater in the foreseeable future.

[silent_airman]

G, whatever gave you the impression I could afford jewelry??

I turned the single shot up to max, and got a high of 692fps, and a low of 427. I'll have to turn it down a bit, I like the 4fpe. And, although it looks odd, the cheap sight makes it easy to snap shoot with decent accuracy. As a gallery gun, it's a blast.

There's an adjustable repeater in the foreseeable future.

Was that with CO2?

[stalwart]

Yup. I'll try a stock bolt, to get an idea where this took me (then I'll tune it down a bit), but it's going to live as a plinker with the option of pest control if needed.

Nice thing about carts is that it can be activated after years, if needed, with the tightening of the cap. Have <$60 into it, could toss it behind a truck seat without a second thought. I grabbed it for testing cuz the stock was so so... good excuse to not worry about looks. It's a beater with very good manners... what's not to like about that?