Sythetic Flashpup Adventure Started

[Rallyshark]

I bet you guys thought I was done doing things to my SFP didn't you?  I've been sick, but finally felt well enough today to finish up my latest shenanigans.  Well, I decided to just go full nuts, and make a 700mm slug liner barrel for it,lol.  I've come up with a name for these FX slug liner barrels I've been making.  I'm gonna call them Thug liners,hahaha!  I came up with that name, because I'm basically totally misusing those FX liners   I haven't even put the gun back together or did any target testing.  I did shoot a few over the chrony for the fun of it.

I got few little bits I need to fix/change, and I may change out the hammer spring to a shorter stiffer one.  I ordered some springs to play with.  I made brass inserts/guide pieces to add a little weight to the hammer and keep the spring from bowing when under really heavy compression.  I slapped the thug liner in the gun and did a few power tests to see what that 27.5" barrel could do.  I'm getting a "pop" at full tilt, and I suspect it is the spring leaning on the valve so hard that the valve isn't fully closed when the pellet leaves the barrel.  It may be an o-ring somewhere too.  I know it shouldn't be an o-ring, because I checked and double checked them all, but still possible.  There could be a tolerance issue causing some blow by somewhere.  I should get the answer to that when I try some other springs though.  The pop goes away when I lower the power level.  I'm pushing the gun as hard as it can take right now, so anything is possible. I'll figure that out one way or the other when I have more time for troubleshooting. 

Anywho, you guys ready for some CRAZY numbers??  First, let me say these numbers are in no way a tune or level I intend to actually use.  They were only to see what the gun is capable of, and no the gun will not do a decent string at these velocities.  Peak power was reached with the 34 grain JSB Beasts.  The Beasts topped out at, drum roll..... 

1045 fps for 82 FPE  I will say, I backed out the HS after that and did 6 shots with all of them over 1000 fps and averaging 1015 fps.  That tells me a 10 shot 70 fpe tune is certainly feasible, and really makes me wonder what kind of 20 shot power tune I could get.  Next, I turned the HS back up and I stuck an H&N 30 grain slug in it, and it was 1081 fps!  These brief numbers will conclude my quest to see what the max power out of a Flashpup can be  

After I get my new springs in, I will try and give it a usable tune, and continue on to target testing in the 50-70 fpe ranges.  That will likely be in a week or so.  Everybody say a prayer for my thug liner, and that I did all the machining correctly, and that it will like some heavy slugs! 

[Thane]

82 FPE!

Incredible and without balanced valve assistance.

So where are you sourcing the FX slug liners?

[Rallyshark]

I've got them from a few different places.  Usually from whoever has them in stock. Palm Beach Air Guns, PA, and the last one came from Trenier.  Pam Beach is, by far, the fastest shipper, and easy to talk to. I've chatted with those guys on FB a few times.

[HunterWhite]

Donny, do you think that the pop that you are hearing could be the pellet breaking the sound barrier? The speed of sound is about 1100 FPS but can be faster in thick air, or slower in thin air. The 1045 FPS was after you backed off the hammer spring?

Hunter

[fgwhite]

i took off my cheak riser to day i see what you guys mean 2 small bolts to hold it in place after ajusting it rinkey dink i see took off the side of action and grinded away the 22mm and 11mm scope mounts on top of action i going to do mine like yours looks so much nicer i wish hatsan would get some more of the solid rails in stock i used a weaver rail from my bulley on the flash pup its hollow in side i like the solid mounts better 

[mackeral5]

82fpe!  those long barrels do amazing things. Nice work! 

Show us some more pics of your FX liners, maybe some step by step?

[fully torqued]

i took off my cheak riser to day i see what you guys mean 2 small bolts to hold it in place after ajusting it rinkey dink i see took off the side of action and grinded away the 22mm and 11mm scope mounts on top of action i going to do mine like yours looks so much nicer i wish hatsan would get some more of the solid rails in stock i used a weaver rail from my bulley on the flash pup its hollow in side i like the solid mounts better

Wow, that's some pretty aggressive surgery, looking forward to seeing how you put it back together.

[fully torqued]

1045 fps for 82 FPE  I will say, I backed out the HS after that and did 6 shots with all of them over 1000 fps and averaging 1015 fps.  That tells me a 10 shot 70 fpe tune is certainly feasible, and really makes me wonder what kind of 20 shot power tune I could get.  Next, I turned the HS back up and I stuck an H&N 30 grain slug in it, and it was 1081 fps!  These brief numbers will conclude my quest to see what the max power out of a Flashpup can be  
 

Wow, that puts you close to .22 rimfire territory energy wise.  A 40gr .22 at 1000FPS is 89FPE.

[fgwhite]

i liked how you did you rifle is this right 82 pounds energy from a 25 cal I MODED THE BULLEUY ALSO ITS HEAVY

[Rallyshark]

Donny, do you think that the pop that you are hearing could be the pellet breaking the sound barrier? The speed of sound is about 1100 FPS but can be faster in thick air, or slower in thin air. The 1045 FPS was after you backed off the hammer spring?

Hunter

I wish that was the problem, but it isn't.  The 1045 fps was with the 34 grain Beasts at full tilt.  I still had the pop at 1000 fps, but not quite as bad.  I'm pretty sure the valve/HS combo is the culprit.  I also took the valve seat to borderline territory, so I had to use way too much pre-load to hit that speed, and it was leaning on the valve pretty hard.  I'm gonna make a more sane valve seat and put back in there, and change out the spring to a shorter one.  I think that'll take care of the problem.  I may lose a little fps on the top end, but I won't be shooting the gun that hot in real life situations anyway.  I literally just finished the barrel last night and threw it together for a "fun" test, haha.  I'll know for sure what the issue is in a day or two

82fpe!  those long barrels do amazing things. Nice work! 

Show us some more pics of your FX liners, maybe some step by step?

 

Thug liners man, thug liners,lol!  I'll try and show a little more info on how I do it when I have more time, and can take some good pics.  The short version is I make the part that fits into the breech out of brass, and bore it out to the exact diameter of the liner down to within 1/4-3/8" of the barrel port.  Then I use a combination of epoxy, and set screws to secure the liner in the brass piece.  After that I sleeve/bond carbon fiber onto the remaining part of the liner to bring the OD of the entire barrel up to 16mm(with solid carbon).  I leave the last 1.5" of the liner exposed, and machine an aluminum section that is 1/2-20 threaded to fix to the end of the barrel.  I use JB Weld and tiny set screws to secure that piece.  I make sure all machined bits fit very snug prior to epoxy or JB Weld.  They are very sturdy, and don't weigh much at all.  I also tension them when mounted with 20mm OD CF tubing.  Believe it or not, that 27.5" one probably weighs a little less than the factory 17" barrel.

1045 fps for 82 FPE  I will say, I backed out the HS after that and did 6 shots with all of them over 1000 fps and averaging 1015 fps.  That tells me a 10 shot 70 fpe tune is certainly feasible, and really makes me wonder what kind of 20 shot power tune I could get.  Next, I turned the HS back up and I stuck an H&N 30 grain slug in it, and it was 1081 fps!  These brief numbers will conclude my quest to see what the max power out of a Flashpup can be  
 

Wow, that puts you close to .22 rimfire territory energy wise.  A 40gr .22 at 1000FPS is 89FPE.

Yep, it is getting up there for an airgun   I honestly didn't expect it to make that much power, so I was pleasantly surprised!  I expected it to make it over 75 fpe, but didn't think it was gonna make 80 fpe.  Either way, I'll take it!

i liked how you did you rifle is this right 82 pounds energy from a 25 cal I MODED THE BULLEUY ALSO ITS HEAVY

It is a .22, not a .25

[Thane]

Did some accessorizing, bipod and an exceptional fit Strike Industries Viper MFS Monopod.
Remove the LDC and pods, and stow it all in a triple racquet tennis bag, keeps the natives calm...

[Rallyshark]

That's nice Thane. I like that compact setup, and the racquet bag! Grab and go right there

[fgwhite]

is that a custom ldc or is that a rocker 1 ldc looks great is it about 2 inch o/d

[Rallyshark]

is that a custom ldc or is that a rocker 1 ldc looks great is it about 2 inch o/d

I think Thane made that one himself, but I'm not positive.

[Rallyshark]

82fpe!  those long barrels do amazing things. Nice work! 

Show us some more pics of your FX liners, maybe some step by step?

Here's a bit more info Mike D   I attached a picture of the 500mm liner barrel I made, along with the 20mm carbon sleeve for tensioning the barrel.  The barrel itself is 16mm OD.  I also attached a "cutaway diagram" showing what I did a bit better.  I made all tolerances where everything fits together as small as I could get them, for a tight fit.  I also bonded it all together with 4-40 set screws.  I used the really small set screws and ground them down to surface level where needed.  I used the small set screws to avoid putting too much pressure on the liner.  On top of the set screws I bonded it with slow cure 2 ton epoxy with the tightest fitting parts and the carbon fiber.  I used JB Weld on the metal to metal bits if I could.  Between the set screws and epoxy/JB Weld, it is SOLID.  The best part is how light the barrel is.  Even the 700mm one I'm working on now probably weighs less than the factory barrel!  Let me know if you guys have any questions about the process, or if I didn't explain something well. 

[Thane]

is that a custom ldc or is that a rocker 1 ldc looks great is it about 2 inch o/d

Thanks! Good eye it is 50mm (2") LDC with alum baffles, huge volume for .25 at higher power.

The diagram is great and I'm thinking seriously about copying it. Are the set screws to hold it all in place while the epoxy cures? Did you do the final turning on the breach end brass after bonding, and cutting the 1/2-20 threads?

[Rallyshark]

is that a custom ldc or is that a rocker 1 ldc looks great is it about 2 inch o/d

Thanks! Good eye it is 50mm (2") LDC with alum baffles, huge volume for .25 at higher power.

The diagram is great and I'm thinking seriously about copying it. Are the set screws to hold it all in place while the epoxy cures? Did you do the final turning on the breach end brass after bonding, and cutting the 1/2-20 threads?

I got the idea from Knife and Hobbyman(Mike/Denis) when they were talking about making barrels with liners from Brownells.  I just applied that same thought process to the FX liners.  It seems to work quite well, and I've experienced zero issues with rigidity or sturdiness.  The set screws are for both holding it in place while the epoxy/jb weld cures, and for reinforcement too.  That reinforcement part is especially true for the muzzle end with the 1/2-20 aluminum piece.  I used 8 set screws evenly spaced on that piece, since it will get more "abuse" with threading LDCs etc.. 

I did all the final turning on the aluminum adapter prior to assembly.  It is such a snug fit, that it has no choice but to be square, and I didn't want to add stress to it after assembly by turning it then.  I haven't had any clipping issues or anything like that.  On the brass piece, I did all the work to it prior to assembly, except for the final leade in work.  Same case there with fitment.  I just make sure all the tolerances are as close as I can get them so it is square.  I did wait until final assembly and cure to do the final leade in part, because I wanted to take that up to just inside the lead edge of the liner to make sure there was a smooth transition from brass to the liner.  I didn't want to do all the turning after final assembly, because you'd be hard pressed to get carbon tubing that will be "barrel blank" straight/round. 

If you do a .25 liner, you may want to change from a brass thimble to a steel one, since the walls of the thimble will have to be thinner with a .25 liner.  The part that goes into the breech is 12mm.  The .22 liner is a hair over 8mm, whereas the .25 liners are a little over 9mm OD.  Those brass walls will be getting kinda thin with a .25 liner, even though I doubt it would make a whole lot of difference in the scheme of things.  Having a longer and lighter barrel sure isn't a bad deal though   I made another diagram to show some variations on how I did the sleeving/brass piece between the liner barrels I've done so far.  The diagram I posted earlier is how I did the 500mm liner.  This diagram shows the 600 and 700mm liners.  I basically did variations of interlocking the sleeving, or using the breech fitment to further strengthen the transition from the brass to carbon sections at the breech area.  I hope that makes sense?

[Rallyshark]

I think I got my HS and the barrel where I want it.  I already have the bushings for the shroud made.  Now, all I gotta do is get my shroud cut and put some slugs on a target   I'm using 17mm ID x 20mm OD CF tubing for the shroud. 

I ended up taking a couple of coils off the hammer spring, and now the gun is much happier.  My pop turned out to be the barrel o-ring, a 2mm cross section o-ring fixed that.  I adjusted the HS to where the hammer is just barely touching the valve with zero pre-load, and ran a string over the chrony to see where she was running.  That yielded 16 shots just under 3% averaging 950 fps with the 30 grain slugs.  At this particular tune, the efficiency is pretty dang good for a .22 at 60fpe(1.43)    If I wanted to stretch my spread to 4%, it would be very near 20 shots at 59-60fpe, and a two magazine 24 shot tune in the 55fpe range wouldn't be that much of a stretch I don't think.  All of that out of a 165cc cylinder!  The power level would be a bit higher with the 34 grain Beasts I'm sure, since they will seal better than the slugs(and are heavier).  The gun is surprisingly quiet at these levels too! 

By the numbers, this baby is humming.  All that won't matter if it isn't accurate, so I'm not counting my chickens until I get some lead on target... 

[Thane]

Thanks for the sketches, and that is an incredible yield and no regulator, solid!

Seeing less of a reason to bottle, and looking toward the FX barrel liner.

[Rallyshark]

Thanks for the sketches, and that is an incredible yield and no regulator, solid!

Seeing less of a reason to bottle, and looking toward the FX barrel liner.

Glad to help, and I'd love to see you do one of these on your gun!  I shudder to think what it would do in .25  I still think a regulated bottle would be pretty awesome, but in all honesty, the shot count ain't bad.  The longer barrels give you a lot more wiggle room in that department.  Best of all, it doesn't add weight, so the gun doesn't lose it's easy hunting character.