Sythetic Flashpup Adventure Started

[DLP]

That is one nice looking can! I have the Ronin. It’s still louder than I would like. Not bad. No problem shooting in the basement. I do need to get rid of the internal noise.

[Rallyshark]

20 shots at 50 FPE is incredible!

That wood flashpup is looking good with the carbon shroud and large LDC.

I just finish a 50mm LDC with baffles, nothing beats volume.

Nice!  LDCs are like (some)engines in some respects, there is no replacement for displacement   That looks real nice!

I know mine has a 20 shot 50 fpe tune it, because it is still shooting the 27 grain slugs at 930 fps on shot 18!  1/4-1/2 turn on the HS should put it in the sweet spot for 50 fpe pretty easily I think.  I imagine the ES will be right at 4% for those 20 shots, but still... I'll take that for hunting.  It is in these higher power tunes where that extra barrel length starts to shine!  It will still make 50 fpe at 135 bar after all,lol. 

I know I mentioned it before, but I want to mention it again, because I feel like many people are probably losing a lot of potential when they are opening up the porting/valve.  I know some of you are well aware, but others  are likely over looking it.  I over looked it myself at first, and just assumed things lined up.  When you are going to open up the single exit hole on the valve, pull the gauge and bleed screw, so you can spin the valve in the gun 180 degrees.  With the large grub screw removed(that gives access to the transfer), you can see where that valve hole is lining up with the transfer when you rotate the valve in the gun 180 degrees.  Every gun I've checked doesn't line up just right.  The air exit hole on the valve is a little too far towards the muzzle end, so the transfer hole is only seeing about 3/4 of that hole in the valve. 

In other words, don't just drill out that hole in the valve to a bigger size.  It still won't line up all the way.  Instead, use a carbide cutter bit in a dremel/rotary tool to open up that valve hole more towards the rear of the gun to get the alignment right.  You'll end up closer to the o-ring on the end of the valve, but it will be fine.  What I do is rotate the valve 180 degrees, then mark the part I need to open up with a pencil.  That way, I know exactly how much and where to open up that valve exit hole.  That can be a few fpe left on the table.  I hope that helps some of you guys  

[Rallyshark]

Thane, Darrell, I just thought of this, and maybe you guys already mentioned it and I forgot, but...  I wonder how your guns would do if you guys bonded that 14mm x 20mm CF to the barrels as opposed to tensioning it?  You'd certainly have a dang stiff barrel, and still get the truss effect with the 20mm OD tube.  I don't know if that would end up more rigid in the gun or about the same as the tensioned setup.  I would think the end result would work quite well.  What do you guys think?  I'm just thinking out loud is all. 

If I had the right combination of CF floating around I would give it a try myself, but I haven't even got to test my current setup on target yet.  Hopefully, I'll be able to this weekend.

[DLP]

It might help. My only concern on it is, would you be able to center the barrel in the block with out cutting the orings?  I mean, you really have to work getting the CF shroud on the barrel and then it just squeezes through the band. Not sure it will line up in the block straight. With out the shroud(s), the barrel has plenty of play to carefully slide into the block. Better yet, add a bull barrel turned to size to start with. If I only had the money and machines to do it!

[Rallyshark]

It might help. My only concern on it is, would you be able to center the barrel in the block with out cutting the orings?  I mean, you really have to work getting the CF shroud on the barrel and then it just squeezes through the band. Not sure it will line up in the block straight. With out the shroud(s), the barrel has plenty of play to carefully slide into the block. Better yet, add a bull barrel turned to size to start with. If I only had the money and machines to do it!

I wonder about the alignment as well, but I'd think it would probably be okay.  I mean, it doesn't exactly have a ton of wiggle room as is, but who knows.  I don't know if I'd want to do a regular bull barrel.  That sucker would add some serious weight! 

[Thane]

Did the SFP with a bonded 19 OD 15 ID carbon tube, very stiff and needed to be bonded because of air gap, but no tensioning effect due to the shroud being locked to the barrel. So the only tension developed is between the LDC shoulder to the end of barrel. So the carbon tube is in contact with breech, but provides little bearing pressure across diameter of tube.

The WFP has the 20 OD 14 ID while tight, still slides on barrel. This allows the LDC to be torqued against the carbon which slides until it comes under tension against breech. The bearing against the breech block is great, definitely limits motion at connection. The barrel is in contact with tube, no bonding needed to increase stiffness. The barrel has no where to flex in the tube, and that 3mm walled tube isn't going anywhere.

It is definitely worth it to open up the 20mm tube. It can be disassembled, no shim to barrel band, and can be tensioned.

[Rallyshark]

Did the SFP with a bonded 19 OD 15 ID carbon tube, very stiff and needed to be bonded because of air gap, but no tensioning effect due to the shroud being locked to the barrel. So the only tension developed is between the LDC shoulder to the end of barrel. So the carbon tube is in contact with breech, but provides little bearing pressure across diameter of tube.

The WFP has the 20 OD 14 ID while tight, still slides on barrel. This allows the LDC to be torqued against the carbon which slides until it comes under tension against breech. The bearing against the breech block is great, definitely limits motion at connection. The barrel is in contact with tube, no bonding needed to increase stiffness. The barrel has no where to flex in the tube, and that 3mm walled tube isn't going anywhere.

It is definitely worth it to open up the 20mm tube. It can be disassembled, no shim to barrel band, and can be tensioned.

I was just thinking about it, instead of tensioning the barrel, and wondering what if any difference there would be between the bonded or tensioned 20mm OD tube.  On one hand you loose the tensioning effect, but on the other you have an extremely stiff barrel that is fitting tightly in the band.  I'm sticking with the tensioned myself, simply due to convenience and not having to order more CF, haha. 

On another note, I did get a chance to re-test the 24" barrel with slugs.  The results are the same, and that barrel will not shoot slugs no matter what.  That was the first attempt I made at doing an FX liner barrel, and I'm sure I just got it wrong in the leed in somewhere.  On the plus side it is still a laser with the 34 grain beasts, and tensioning helped it with those pellets.  It is basically 1/4" groups with those pellets at 30 yards anywhere from 58-65 fpe.  I just hate that it doesn't like slugs  

What would really be nuts, would be to make a 700mm liner barrel at some point.  Who knows what kind of power it could make with that?!  In .25 I think the 75-80 fpe mark would certainly be a possibility.  If these guns could handle a 250 bar fill, it would be insane.  Thane, you've got the skills to bottle one of these guns, especially given what you were able to do with that Hatsan "pistol".  I don't have that kind of skill or equipment myself 

[DLP]

I got to test out the CF barrel mod yesterday. Went to our family’s farm and my cousin’s farm squirrel hunting. The gun shoots great! It was off and on mist/snow and 37* with no wind at all. Got my limit of squirrels with 1 Grey and 4 Fox. Also picked off a little Red at about 65 yards. Oh ya, and 2 coons. Man them critters raised *(&^ on the corn last fall.

[Rallyshark]

I got to test out the CF barrel mod yesterday. Went to our family’s farm and my cousin’s farm squirrel hunting. The gun shoots great! It was off and on mist/snow and 37* with no wind at all. Got my limit of squirrels with 1 Grey and 4 Fox. Also picked off a little Red at about 65 yards. Oh ya, and 2 coons. Man them critters raised *(&^ on the corn last fall.

Isn't great when all the tinkering comes together, and you get to put it to work?  Nice job!

[Thane]

I got to test out the CF barrel mod yesterday. Went to our family’s farm and my cousin’s farm squirrel hunting. The gun shoots great! It was off and on mist/snow and 37* with no wind at all. Got my limit of squirrels with 1 Grey and 4 Fox. Also picked off a little Red at about 65 yards. Oh ya, and 2 coons. Man them critters raised *(&^ on the corn last fall.

Wow, Great hunt! 65 yds off hand is incredible.

[Thane]

I was just thinking about it, instead of tensioning the barrel, and wondering what if any difference there would be between the bonded or tensioned 20mm OD tube.  On one hand you loose the tensioning effect, but on the other you have an extremely stiff barrel that is fitting tightly in the band.  I'm sticking with the tensioned myself, simply due to convenience and not having to order more CF, haha. 

On another note, I did get a chance to re-test the 24" barrel with slugs.  The results are the same, and that barrel will not shoot slugs no matter what.  That was the first attempt I made at doing an FX liner barrel, and I'm sure I just got it wrong in the leed in somewhere.  On the plus side it is still a laser with the 34 grain beasts, and tensioning helped it with those pellets.  It is basically 1/4" groups with those pellets at 30 yards anywhere from 58-65 fpe.  I just hate that it doesn't like slugs  

What would really be nuts, would be to make a 700mm liner barrel at some point.  Who knows what kind of power it could make with that?!  In .25 I think the 75-80 fpe mark would certainly be a possibility.  If these guns could handle a 250 bar fill, it would be insane.  Thane, you've got the skills to bottle one of these guns, especially given what you were able to do with that Hatsan "pistol".  I don't have that kind of skill or equipment myself 

The fact that your FX liner is precise with pellets is in itself an excellent result.

I have very little experience with slugs, but what I've seen is that slugs perform with a very high bias requiring a lot of trial sizes/weights/velocities.
It was dumb luck for me with the WFP, heavy choked barrel, shoots the FX slugs with great accuracy, sub 1/4" at 30 yds. The 33 FPE is not as great, but the accuracy is one of my best results to date.

An offset bottle block could be entirely made on the mini-lathe with a 4 jaw chuck, one of the best upgrades for lathe operations. I have all the parts and have been blocking out different configurations. SFP has little space for a bottle with the factory barrel length, forward trigger location and larger LDC. The AT-P2 bottling I started with a lower power and speed goal to reduce noise 30FPE 820FPS. The bottle is entirely in front of the trigger and under the QE shroud leaving room for the telescoping carbon fiber shroud extension.

So I'm still working out the goal for the SFP, high power with a short barrel is an air hog in need of a bottle with little room for the bottle.

[DLP]

I got to test out the CF barrel mod yesterday. Went to our family’s farm and my cousin’s farm squirrel hunting. The gun shoots great! It was off and on mist/snow and 37* with no wind at all. Got my limit of squirrels with 1 Grey and 4 Fox. Also picked off a little Red at about 65 yards. Oh ya, and 2 coons. Man them critters raised *(&^ on the corn last fall.

Thanks. I just left our woods and was heading across the field to my cousins. I seen him sitting on a broken limb when I was about 100 yards or so out. I tried sneaking closer. But at 65 he got squirrelly! Didn’t think I could get any closer out in the open field. Anyway, do you guys have a link for a stiffer, shorter spring for the .25 WFP?

Wow, Great hunt! 65 yds off hand is incredible.

[Rallyshark]

I got to test out the CF barrel mod yesterday. Went to our family’s farm and my cousin’s farm squirrel hunting. The gun shoots great! It was off and on mist/snow and 37* with no wind at all. Got my limit of squirrels with 1 Grey and 4 Fox. Also picked off a little Red at about 65 yards. Oh ya, and 2 coons. Man them critters raised *(&^ on the corn last fall.

Thanks. I just left our woods and was heading across the field to my cousins. I seen him sitting on a broken limb when I was about 100 yards or so out. I tried sneaking closer. But at 65 he got squirrelly! Didn’t think I could get any closer out in the open field. Anyway, do you guys have a link for a stiffer, shorter spring for the .25 WFP?

Wow, Great hunt! 65 yds off hand is incredible.

I got my spring(s) from Ace Hardware.  They usually have a pretty good selection of compression springs.  I think Thane got his from there too.  I did have to cut it to the proper length needed, since it was a bit longer than factory. 

I was just thinking about it, instead of tensioning the barrel, and wondering what if any difference there would be between the bonded or tensioned 20mm OD tube.  On one hand you loose the tensioning effect, but on the other you have an extremely stiff barrel that is fitting tightly in the band.  I'm sticking with the tensioned myself, simply due to convenience and not having to order more CF, haha. 

On another note, I did get a chance to re-test the 24" barrel with slugs.  The results are the same, and that barrel will not shoot slugs no matter what.  That was the first attempt I made at doing an FX liner barrel, and I'm sure I just got it wrong in the leed in somewhere.  On the plus side it is still a laser with the 34 grain beasts, and tensioning helped it with those pellets.  It is basically 1/4" groups with those pellets at 30 yards anywhere from 58-65 fpe.  I just hate that it doesn't like slugs  

What would really be nuts, would be to make a 700mm liner barrel at some point.  Who knows what kind of power it could make with that?!  In .25 I think the 75-80 fpe mark would certainly be a possibility.  If these guns could handle a 250 bar fill, it would be insane.  Thane, you've got the skills to bottle one of these guns, especially given what you were able to do with that Hatsan "pistol".  I don't have that kind of skill or equipment myself 

The fact that your FX liner is precise with pellets is in itself an excellent result.

I have very little experience with slugs, but what I've seen is that slugs perform with a very high bias requiring a lot of trial sizes/weights/velocities.
It was dumb luck for me with the WFP, heavy choked barrel, shoots the FX slugs with great accuracy, sub 1/4" at 30 yds. The 33 FPE is not as great, but the accuracy is one of my best results to date.

An offset bottle block could be entirely made on the mini-lathe with a 4 jaw chuck, one of the best upgrades for lathe operations. I have all the parts and have been blocking out different configurations. SFP has little space for a bottle with the factory barrel length, forward trigger location and larger LDC. The AT-P2 bottling I started with a lower power and speed goal to reduce noise 30FPE 820FPS. The bottle is entirely in front of the trigger and under the QE shroud leaving room for the telescoping carbon fiber shroud extension.

So I'm still working out the goal for the SFP, high power with a short barrel is an air hog in need of a bottle with little room for the bottle.

I've made two FX liner barrels at this point.  The second one was a 500mm liner and it does better with a few different slugs.  That's what makes me pretty sure I messed up the first one in some way that just won't work with slugs.  I think I opened up the leed in too much, so they aren't always hitting the barrel the same when fired.  I've literally tried every weight and size that NSA and H&N offer in the longer barrel, and it just ain't gonna happen,lol.  Thankfully, that barrel does just fine with the heavy pellets though.  I've toyed with the idea of doing a 700mm liner, but man, that is one long barrel!  Granted, the SFP(with LDC) would still be a good 5" shorter than my Flash rifle was with a 24" barrel and pickle.  Thane, I'd love to see what kind of power your gun would make with a longer barrel in .25!  By my estimates, my gun picked up around 10+ fps per inch fwiw. 

[GoneShootn]

Hi, Donny. I'm kind of lost on the Flash platform, but I know what the inside of an AT44 looks like. I'm sure I can find a video on disassembling the Flash, so without necessarily going into a great deal of detail, could you, and/or others, point out some differences in the mechanics and what you think about them? For example, how does the Flash address hammer bounce?

[Thane]

The Flash models uses a greatly simplified, single breach block design unlike the AT44 2 parts (breach bolted onto hammer+valve+airtube combo).

The valve and air-tube are similar to AT44, but the valve is held captive with set screws. Transfer port is just a hole in breach block with no additional parts.

Flashes stack the Pellet Probe over the Bolt/Lever, over the hammer with a single rod penetrating all three. Rod is fixed to the probe, travels loosely through the lever bolt and into a slot in the top of the hammer. This allows all three to be pulled back until the sear catches the hammer and then the pellet probe and lever bolt only go forward loading the pellet into the breach. The lever bolt has a sprung loaded catch to stop hammer rebound, hammer rides under the sloped portion of catch and rebounds against the 90° end. Spring length can also be adjusted to maintain a free flight space and keep pressure off valve stem.

[GoneShootn]

The Flash models uses a greatly simplified, single breach block design unlike the AT44 2 parts (breach bolted onto hammer+valve+airtube combo).

The valve and air-tube are similar to AT44, but the valve is held captive with set screws. Transfer port is just a hole in breach block with no additional parts.

Flashes stack the Pellet Probe over the Bolt/Lever, over the hammer with a single rod penetrating all three. Rod is fixed to the probe, travels loosely through the lever bolt and into a slot in the top of the hammer. This allows all three to be pulled back until the sear catches the hammer and then the pellet probe and lever bolt only go forward loading the pellet into the breach. The lever bolt has a sprung loaded catch to stop hammer rebound, hammer rides under the sloped portion of catch and rebounds against the 90° end. Spring length can also be adjusted to maintain a free flight space and keep pressure off valve stem.

So, hammer spring can be adjusted? Externally or only with the stock off?

[Thane]

So, hammer spring can be adjusted? Externally or only with the stock off?

Yes, stock off,  as it ships from the factory.

Drill one hole in the rear stock and enlarge bolt lever rear slot to uncover set screw that locks the grub screw in hammer... then you can adjust spring tension with stock on.

Donny tapped the rear spring retension bolt, added a set screw for some slick 1 wrench adjusting (still needs a hole added to rear of stock).

[GoneShootn]

So, hammer spring can be adjusted? Externally or only with the stock off?

Yes, stock off,  as it ships from the factory.

Drill one hole in the rear stock and enlarge bolt lever rear slot to uncover set screw that locks the grub screw in hammer... then you can adjust spring tension with stock on.

Donny tapped the rear spring retension bolt, added a set screw for some slick 1 wrench adjusting (still needs a hole added to rear of stock).

Neat! Good to know. Thanks. What is your opinion re this design over the AT44, especially regarding ease of maintenance/repair and potential for accuracy? I always felt that the removable cylinder, which turned out (for me, anyway) to be not much of an advantage, might be an impediment to accuracy or consistency due to the lack of rigidity. Goodness knows I had enough trouble in that regard. Maybe Donny will chime in, too, when he can.

[Thane]

I have 4 AT-44 variants which I have tooled on pretty hard. The huge advantage of the removable air tube for me was easy access to the valve over the extra tube capacities.
Fortunately the AT-44 valve tuning tricks work for the Flashes.

I do not miss the AT-44 wishbone bounce device, anti-double feed parts, extra magazine bolt, 2 part receiver, plastic spring retainer, transfer port tube, dumbell shaped hammer, flex in the receiver due to overcut at magazine.

Gripes on the flash; rough bolt operation, plastic rail risers, Plastic barrel band/trigger assembly, still has a non-standard rail, no lever option (available soon).

I find the flash to be a more elegant solution, fewer moving parts, lighter and more simple to modify. A couple of tear downs and you'll appreciate the turk's efforts.

I know Donny has his own list.

[GoneShootn]

Thanks, Thane!