My Field Target Project

[michaelthomas]

Douglas,

That's a good idea, but in this case it is probably not needed.

With the small amount of shooting that I have done so far, I have already become accustomed to just leaving the breach slightly open until ready to shoot.  It's in a very convenient location, and it's a good habit to get into.  With the breech open the transfer port hole no longer lines up, and pulling the trigger amounts to nothing but a light tapping on metal sound.  Rotating the breech to the firing position right after a misfire seems to result in nothing as well.

The cap in this setup holds it full charge for about 1/4 second after the battery power is removed.  After about 3 seconds, the remaining power is not enough to fire at all.  There won't be any surprises after extended storage.

I think you may be referring to the disposable camera flash units.  This is just a photo cap and a DC to DC boost converter. A regular cap would probably have worked fine in this setup, too.  I'm only using 60 volts.....those disposable units are closer to 300, with a much smaller photo cap.  (10uf)

Mike

[willbird]

Douglas,

That's a good idea, but in this case it is probably not needed.

With the small amount of shooting that I have done so far, I have already become accustomed to just leaving the breach slightly open until ready to shoot.  It's in a very convenient location, and it's a good habit to get into.  With the breech open the transfer port hole no longer lines up, and pulling the trigger amounts to nothing but a light tapping on metal sound.  Rotating the breech to the firing position right after a misfire seems to result in nothing as well.

The cap in this setup holds it full charge for about 1/4 second after the battery power is removed.  After about 3 seconds, the remaining power is not enough to fire at all.  There won't be any surprises after extended storage.

I think you may be referring to the disposable camera flash units.  This is just a photo cap and a DC to DC boost converter. A regular cap would probably have worked fine in this setup, too.  I'm only using 60 volts.....those disposable units are closer to 300, with a much smaller photo cap.  (10uf)

Mike

I read the whole thread :-), cool :-).

Two questions, do you get the cool "whine" when you charge the cap ??

Also I thought about using a solenoid to just cock a coil spring, and or work a bolt, with a little work it could make a Marauder into a sort of semi or even full auto :-).

I never really thought about how much "work" a single 9 volt battery will do, but it sounds like the answer is "quite a bit".

A friend shared some of the cap boosted solenoid stuff with me when I was looking at using a solenoid to open a damper on a meat smoker, it is a good way to get a low hold current (so the solenoid does not heat up) but still move some mass to position, effectively allowing you to use a lot smaller solenoid.

Curious about the LW barrels, I had talked to that guy via email and never knew that if/when I do order I will have no idea if I actually GET what I order :-).

Bill

[PakProtector]

It has been a while, but the disposable flash cameras I had ran 80-160 uF/330V caps. If you've got room I bet you can tune hammer energy with the cap size. Boost the voltage and you'll be able to run smaller caps...and I can't help wondering what metalized mylar in the 150 V range would do for you...
cheers,
Douglas

[michaelthomas]

Hi Bill,

There is no detectable noise on my gun.......bummer, eh? 

The gun is completely silent throughout the whole cycle except for the actual firing.  No cocking noises, etc.  If I was a hunter, I suppose that would be a cool side benefit of this solenoid and rotating breech.

You have to submit an order via email, and wait for them to respond with a PO.  It took roughly a week and a half to get a response from them with a PO.  It took several calls during that time as a reminder.

When I ordered my barrels from LW, I was assured that they would ship the same day that they received the funds, since they were in stock.
They do not take credit cards, so you must send a cashiers check or money order.  I paid extra to send my funds quickly.  I waited a week, then called to check on the shipping.  They said that they had not yet shipped, but were going out that day.  I waited another week, and made another phone call.  They, then,  told me that they didn't think they had shipped, but there was no real way they could be sure.  They told me to send them an email with the PO again, and they would get back to me.  They were not very nice, and they seemed to want me to feel bad for them because they were so busy.  I never received a response, but the barrels showed up a week and a half later.  When I order from them again, I will factor in 6 weeks for delivery....at least.

Things happen to people that disrupt their normal expected functioning.  Some folks are frank about circumstances and apologetic when things fall short on their end......others try to make the customer feel bad when they don't do what they said they were going to do.  My dealing with LW has been of the latter category.  Whether it's true or not......I feel that if I had not followed up with them repeatedly......I may not have any barrels today.  If they told me they were real busy and it would take 6 weeks.......and it did.......nobody would be upset.

That said, I'm pleased with the barrels.  I really don't know what other options are available, either. 

Mike

[willbird]

Hi Bill,

There is no detectable noise on my gun.......bummer, eh? 

The gun is completely silent throughout the whole cycle except for the actual firing.  No cocking noises, etc.  If I was a hunter, I suppose that would be a cool side benefit of this solenoid and rotating breech.

You have to submit an order via email, and wait for them to respond with a PO.  It took roughly a week and a half to get a response from them with a PO.  It took several calls during that time as a reminder.

When I ordered my barrels from LW, I was assured that they would ship the same day that they received the funds, since they were in stock.
They do not take credit cards, so you must send a cashiers check or money order.  I paid extra to send my funds quickly.  I waited a week, then called to check on the shipping.  They said that they had not yet shipped, but were going out that day.  I waited another week, and made another phone call.  They, then,  told me that they didn't think they had shipped, but there was no real way they could be sure.  They told me to send them an email with the PO again, and they would get back to me.  They were not very nice, and they seemed to want me to feel bad for them because they were so busy.  I never received a response, but the barrels showed up a week and a half later.  When I order from them again, I will factor in 6 weeks for delivery....at least.

Things happen to people that disrupt their normal expected functioning.  Some folks are frank about circumstances and apologetic when things fall short on their end......others try to make the customer feel bad when they don't do what they said they were going to do.  My dealing with LW has been of the latter category.  Whether it's true or not......I feel that if I had not followed up with them repeatedly......I may not have any barrels today.  If they told me they were real busy and it would take 6 weeks.......and it did.......nobody would be upset.

That said, I'm pleased with the barrels.  I really don't know what other options are available, either. 

Mike

The impression I got was that if I ordered anything BUT the in stock items they would me made overseas and shipped here, and then I would get tracking info on the shipment.

Bill

[michaelthomas]

It has been a while, but the disposable flash cameras I had ran 80-160 uF/330V caps. If you've got room I bet you can tune hammer energy with the cap size. Boost the voltage and you'll be able to run smaller caps...and I can't help wondering what metalized mylar in the 150 V range would do for you...
cheers,
Douglas

Some sort of voltage regulation for the charge would have to be put into place.  When I was initially messing with the camera circuits, the voltage was all over the place......which is why I abandoned it for the boost converter.  The boost converter maintains an exact output over a very broad range of input voltages.

I don't know anything about metalized mylar caps.  What is their claim to fame?

Bill.....I would prefer to have the barrels shipped from overseas with tracking than deal with the US distributor.

Mike

[lloyd-ss]

Mike,
I came in late on this project but have read thru all the posts.  Very impressive, and darn fast too. Type A personality? LOL. Honestly, first class all the way.

I'd like to bother you for so more information if I can, please.  Do you have a PN and source for the boost convertor and solenoid that you are using?  That will be a nice reference starting point to put in my hat for later, should the need to strike, strike.  Also, and this is second hand information, but I have heard that over voltaging a solenoid might eventually start to magnetize the armature. I don't know if that is fact, or if it is even a concern in your case.  That armature looked pretty stout.

And lastly, for now anyway    ,  a possibility of any detail photos of the swing breech?

Thanks for sharing this great project!
Lloyd

[michaelthomas]

Hi Lloyd,

This is the solenoid......http://www.onlinecomponents.com/guardian-electric-tp8x16i12d.html?p=11480738
I purchased the return spring kit from the same place, but am unable to find the number for that at the moment.

The boost convertor is an ebay item.....http://www.ebay.com/itm/LM2577-3-34V-to-4-60V-DC-Step-up-Convert-Power-Supply-Boost-Charge-Module-5-12V-/390642391009?pt=LH_DefaultDomain_0&hash=item5af419d7e1

I also bought another boost converter that was capable of 97v output, but it never showed up.  The 60v model seems adequate for my gun's power level, though.

There is a place on the web called solenoid city, and they have a much larger array of solenoids in this basic size (and many others). The solenoid that I used measured 9ohms, and using the same components with a solenoid of 4.5ohms would result in twice the power.  If the one I bought proved to be inadequate, I was going to do just that.  Because of the 3-5 millisecond duty cycle, I don't think the voltage rating really means much.  I have been unable to detect any heat buildup whatsoever after thousands of repetitive cycles.

I don't know anything about magnetizing armatures, as this is my first foray into capacitive discharged operation.

What exactly would you like to see about the breech?  It may be easier to see the cad drawings that I used to make the parts.....otherwise, there is not much to see on the outside.

Mike

[lloyd-ss]

Mike,
Thanks, just what I needed. Always good to find new sources for components. 
So if I have this right, the convertor is just to supply the higher charging voltage for the caps, the pot on the board controls the regulated output voltage, the resistor on the input to the caps controls the charge rate, and the resistance in the solenoid coil controls the discharge rate.  No need for a diode to protect the convertor from the solenoid, or is that built in?

Regarding the swing breech, does that swing out between the transfer port and the barrel? Just trying to visualize the layout and the sealing technique used used at the breech.
Thanks,
Lloyd

[michaelthomas]

Ya.....that's pretty much it.  The discharge rate and power  is more of a combination of voltage, capacitance, and resistance in the solenoid. 

I do have a diode to protect the booster......it's a separate part from the boost converter.  Its nothing special......just some 1000v diode  I had here.

I first bought some scr's to keep the current out of the switch, but have not actually found a reason to use them, yet.

Just a small microswitch.

This link is to a calculator that can be played with to get a feel for the relationships of the above variables.  http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capdis.html

The swing breech is the transfer port on my gun.......and the Mac1 USFT.  It was the motivation for my rendition.  If you look at my valve, you will see 2 Orings.  There is a crossdrilled .100" hole in the valve body between the orings......which lines up with the transfer port in the part that I have been calling the swing breech.  I didn't know what else to call it.  I guess it may be more of a rotating transfer port.  The rotating transfer port then has an oring that seals to the back of the barrel when turned into place.  There is about .001" clearance between the cylindrical valve body and rotating transfer port (RTP from now on).  The valve body bottoms into the plenum, creating a .500" space for the thickness of the RTP and a pair of Delrin washers.  It rotates as if was on very snug, but smooth, bearings.....due to the shock absorber like friction from the orings that it rides on.

I originally though I would have the cylindrical valve body turn with the RTP, but it seemed overly complicated since that would require the valve body to dynamically bear the air pressure load.

I have no idea how the USFT works......I just saw some pictures, and made it work for me.  It's the simplest way I could come up with.

Bob noted that I have roughly the volume of a hogged out .22 Marauder between the bottom of the valve and the pellet.  Surely more efficiency could be had if that was smaller, but there isn't any practical way that I can readily see to make it appreciably smaller with the design as it is.

It seems reasonably efficient as it is. 

My original goal was to get at least 50 consistent shots once regulated, but it appears as if I'll get at least double that. 

Mike

[michaelthomas]

These may be more helpful.

[QVTom]

I don't know for sure, I'm just guessing from the few pictures I've seen, the USFT breech seems to have an angled hinge which allows the breech swing arm to move back as it swings to the side.  Your system appears to be much easier to construct.  Great stuff!

Tom   

[lloyd-ss]

Michael,
The pictures and your explanation make the functionality pretty clear.  I see that you have used a fairly thick cross section o-ring which I guess aids in the smooth closing operation you describe.  Getting the correct compression on an o-ring for a special application can be a little tricky sometimes.  Looks like you got it figured out. Nice!
Lloyd

[michaelthomas]

Haven't had much to say lately.....I've been doing a lot of shooting, though.

Still have the muzzle weight, and some other pieces to finish......and then some anodizing.

The butt stock is stolen from my "modified" Avanti753.  I finished the knee rest, but don't have it painted, either.

Pics are of the intended look, and the gun in it's current condition.  I got the base coat on, and decided to put it back together and shoot for a while.  I'll have to wet sand, recoat, then do the charcoal......then clear.

Shooting from a vise at 40 yards yields a maximum 5 shot group of size of .335" c to c.  Smallest are just about a pellet width.  I shot 25 groups on individual index cards.  I think it can still improve some.

I'm gonna polish the bore and retry some more vise groups.  My typical 20 shot groups shooting from 30 yards off a front bag are about .280" or so with the occasional flyer messing things up.

I'm moving forward......but not nearly as fast now that I'm having fun shooting the thing.

I found out that the valve stem was galling the aluminum valve body.  It eventually stuck open and dumped the whole reservoir in one shot.

I took it apart, reamed, then polished it good with the stem.  The efficiency went way up, along with the power.  It's now doing a steady 1.45FPE/CI at 19.6FPE with JSB Exact Heavies around 925fps. 

The JSB Exact 8.44's were grouping the best, but I ran out of them, so I have been using the heavies.  I think it will probably be shooting the 8.44's a bit hot, now.  I will probably drop the capacitance and try to get them in the 930 range......when the order shows up.

Mike

[Bent]

Sweet.. and a big congrats on job well done...

[thercman]

Very nicely done!

[michaelthomas]

Thanks, guys......it feels like a mighty weight has been lifted from me.  I'm sleeping good, again.....lol.

Mike

[Bent]

I think I've been reading this thread about a dozen times.... I now know what my winter project will be.... 
I've ordered the bits and parts from DX, Ebay and a 12V 12 Ohm solenoid from a Danish dealer...http://www.conrad.de/ce/de/product/502261/Zylindermagnet-Intertec-ITS-LZ-2560-D-12VDC-12-VDC-Befestigung-Schraubgewinde-Ausfuehrung-drueckend-Anfangs-Endkraft-07

Thank you Michaelthomas 

[michaelthomas]

Yep.....no problem.

 It will keep you entertained for the cold season.

If I can be of any help,  just let me know.

Mike

[joel w]

Awesome project Michael, I might have to try this someday after seeing your 30yd FT scores.. 

Simply an amazing design, well done!!!