Sythetic Flashpup Adventure Started

[GoneShootn]

No, not determined. Just curious. And Thane made an excellent point.

[Rallyshark]

No, not determined. Just curious. And Thane made an excellent point.

He usually does make good ones  

[GoneShootn]

Hijack away man!  I don't care, as long as we're talking about Flashpups of some sort,lol!  I have a wood and a Synthetic, but the wood version got turned into the "Turkenstein"...  Oddly enough, I kinda prefer how the wood version shoulders to the synthetic, even though the  synthetic as more adjustment in the butt bad.  I like them both though.  If you wait a bit, the synthetic is going to be coming out with a side lever.  I actually don't mind the bolt as it is, since I got used to it.  If you are determined to be switching calibers, the Hydra may be worth considering too, but it isn't a pup.

What do you think about the weight difference btw the synthetic and wood models? Hatsan says .1 lb difference, and Pyramyd says 1 lb. And what do you think about the aluminum air cylinder vs. steel?

[Rallyshark]

I honestly don't think the weight difference is enough to matter.  They'll both feel like feather weights compared to the AT44s.  I like both versions, and the weight difference isn't even something I think about fwiw.

[Rallyshark]

I got some more NSA 28.5 grain slugs in today, so I decided to go ahead and see what kind of higher shot count power tunes I could squeeze out of it.  Below are the results, all shot indoors at 72 degrees:
-24 shots averaging 916 fps, or 53 fpe with 28.5 grain NSA
  High of 935 fps and low of 899 fps for an ES of 36(4%)
  Efficiency 1.40

-20 shots averaging 936 fps, or 55 fpe with 28.5 grain NSA
  High of 954 fps and low of 925 fps for an ES of 29(3%)
  Efficiency 1.47

I'm quite surprised by the shout count at those power levels out of that little 165cc air cylinder.  Obviously, we can owe a lot of that to the 700mm barrel hanging out there, but I'll take it!  Obviously, this gun and porting/seat combo are much happier in the higher power range.  The lower the speed the bigger the ES.  I think a slightly smaller valve seat/porting would tighten up the spread a bit in the lower power range.  Now, if one were to do the same mods/barrel to a Wood Flashpup and fit the BT65 air cylinder(won't fit SFP)...  That would be one heck of a power house with a very respectable shot count!  I think it would easily make over 50 fpe regulated with that cylinder too.  A 3 magazine 36 shot 50+ fpe tune is certainly in the realm of possibility.  Somebody needs to build it!   

[Rallyshark]

I got to do some more testing today, and I found out my gun likes the 28.5 NSA in .218 best when shooting in the 960+fps range.  When tuned below that speed, I was getting inconsistent grouping.  I did some testing with the 24.8 in .218 and was pleasantly surprised.  I tested them shooting around 1000 fps, and they are capable of sub MOA at 100 yards, if I do my part.  I was shooting from a chair with the gun rested on my leg, so I didn't do my part and the group was around 1.5".  I knew when I pulled shots, and every shot hit where it should.  I'm quite confident the gun could do much better from the bench(or with a better marksmen). 

Anywho, that's all the updates I think I'm gonna have with this thread for a while. Long story short, I love this SFP and the myriad of tuning that can be done with them  

[TreeburnerCT]

Thanks RallyShark, Thane and others for compiling all this valuable information in one thread!  I have been looking for a short, light PCP with enough power to bring to a real range so that my wife would have something to shoot alongside my Bulldog and reading through this thread and others sold me on a Flashpup in .22.  I'm hoping to get it shooting slugs eventually, so it's nice to know it has such a wide range of adjustment in power depending on tune and modifications.  I've never disassembled an airgun let alone modified it, but I'm looking forward to working on the Flashpup after hearing how simple the assembly is.

The SFP should be here Saturday, but since the ranges are closed at the moment and I live in a very cramped suburb I may not to get to put the SFP through its paces right away.  So after testing to make sure it works should I strip the gun down and polish all of the rough edges, and is there anything else that should be done immediately?

[Rallyshark]

The first thing I usually do is run a chrony string as it is out of the box. That way, I have a solid baseline on which to base my tubing/progress. There isn't really a whole lot of polishing that's necessary, but there is usually a little cleanup involved. These guns can be a little rough from the factory, so there are some cases where some tweaking may be needed. A lot of that really depends on the guns intended use. You definitely want to clean the barrel real good prior to any target work.

[503Manny]

Hi guys, Manny here from El Salvador.

I've been enjoying this thread for 3 days! I got a .22 WFP but I'm selling it to get a SFP and do a pretty good mod with everything I've learned here...except for the PEEK valve seat, you can't find than material here. I guess I could try some delrin or similar.

I've seen a fair amount of comments regarding a replacement for the qe shroud...

What if you bought an extra qe shroud and cut it at the muzzle end, keeping the tread to keep the barrel fixed and snug? And you can still attach an LDC of your choice!

...I'd do it if could manage to get one sent all the way here, but there's no Hatsan dealer in my country.


...just my 2cts!

- Manny

[Rallyshark]

Hi guys, Manny here from El Salvador.

I've been enjoying this thread for 3 days! I got a .22 WFP but I'm selling it to get a SFP and do a pretty good mod with everything I've learned here...except for the PEEK valve seat, you can't find than material here. I guess I could try some delrin or similar.

I've seen a fair amount of comments regarding a replacement for the qe shroud...

What if you bought an extra qe shroud and cut it at the muzzle end, keeping the tread to keep the barrel fixed and snug? And you can still attach an LDC of your choice!

...I'd do it if could manage to get one sent all the way here, but there's no Hatsan dealer in my country.


...just my 2cts!

- Manny

It would be far easier to just drop the QE shroud, and make a bushing(or tight fitting o-rings) for the barrel to fit snug though the rail support.  Of course, you could also do the 20mm carbon with bushings on each end to fit the barrel snug too.  I know Amazon sells PEEK rod, if that helps.  You can open up the factory valve seat a bit as well.

Everything I did to the SFP can be done to the Wood as well.  Also, another benefit of the WFP is the aluminum cylinder.  That's significant, because that means a BT65 air cylinder will fit the WFP valve.  In other words you could turn that 165cc into 255cc!  The down side of that is it won't work without a barrel that's at least 22.5" long, because it won't clear the cylinder with the factory barrel.  The benefit of the SFP is that a shorter barrel can be fitted due to the shorter length of the steel cylinder.  I like both versions equally, and both can be made to do the same thing.  The only difference between the two is the SFP has a steel cylinder/valve with different threading, and the WFP has an aluminum cylinder.  I don't know if you've seen the thread I did with my WFP, so here it is.  It may save the trouble of selling your WFP and buying a SFP, unless you just like the look of it better.

https://www.gatewaytoairguns.org/GTA/index.php?topic=166895.0

As a matter of fact, I will be updating this thread in a few days with my SFP wearing a WFP valve and BT65 cylinder just like my WFP is.  That is, if everything goes as planned.  It will require some modifications of the stock on the muzzle end, so I'm not sure how that's going to turn out. 

[503Manny]

Hi guys, Manny here from El Salvador.

I've been enjoying this thread for 3 days! I got a .22 WFP but I'm selling it to get a SFP and do a pretty good mod with everything I've learned here...except for the PEEK valve seat, you can't find than material here. I guess I could try some delrin or similar.

I've seen a fair amount of comments regarding a replacement for the qe shroud...

What if you bought an extra qe shroud and cut it at the muzzle end, keeping the tread to keep the barrel fixed and snug? And you can still attach an LDC of your choice!

...I'd do it if could manage to get one sent all the way here, but there's no Hatsan dealer in my country.


...just my 2cts!

- Manny

It would be far easier to just drop the QE shroud, and make a bushing(or tight fitting o-rings) for the barrel to fit snug though the rail support.  Of course, you could also do the 20mm carbon with bushings on each end to fit the barrel snug too.  I know Amazon sells PEEK rod, if that helps.  You can open up the factory valve seat a bit as well.

Everything I did to the SFP can be done to the Wood as well.  Also, another benefit of the WFP is the aluminum cylinder.  That's significant, because that means a BT65 air cylinder will fit the WFP valve.  In other words you could turn that 165cc into 255cc!  The down side of that is it won't work without a barrel that's at least 22.5" long, because it won't clear the cylinder with the factory barrel.  The benefit of the SFP is that a shorter barrel can be fitted due to the shorter length of the steel cylinder.  I like both versions equally, and both can be made to do the same thing.  The only difference between the two is the SFP has a steel cylinder/valve with different threading, and the WFP has an aluminum cylinder.  I don't know if you've seen the thread I did with my WFP, so here it is.  It may save the trouble of selling your WFP and buying a SFP, unless you just like the look of it better.

https://www.gatewaytoairguns.org/GTA/index.php?topic=166895.0

As a matter of fact, I will be updating this thread in a few days with my SFP wearing a WFP valve and BT65 cylinder just like my WFP is.  That is, if everything goes as planned.  It will require some modifications of the stock on the muzzle end, so I'm not sure how that's going to turn out.

Thanks for your reply!

I want to go Synth for 2 main reasons: I'd like to try a shorter barrel too, and I just like the looks of it!

I mentioned the spare qe shroud bc I don't like the look of the naked barrel, and the shroud serves 2 purposes: hold the barrel tight and make the rifle look good!

Maybe I'll sell my WFP without the shroud, lol! and Just add a silencer I have laying around, which gets the exact same results as the oem qe.

Have a safe weekend!

- Manny

[Rallyshark]

Let us know how it turns out! 

[darkcharisma]

the only thing you and i haven't thought about is  fitting a balanced valve. wait...i just thought about it. lol.
yes regulator and bottle for more consistent shot counts are old news. the plenum if tube is cut forward of the barrel band should yield closer to 50-70cc. thats plenty!

i am way off on my estimated plenum size. the ID of the steel tube is 1.19" and going by that, 7 inch will give over 125cc of plenum space. and guess what. bottle it will be.

the only think i dont like about the valve is the ID around the poppet is only .435...thats tiny! I am thinking about enlarging it to .460 or .499".

[Rallyshark]

the only thing you and i haven't thought about is  fitting a balanced valve. wait...i just thought about it. lol.
yes regulator and bottle for more consistent shot counts are old news. the plenum if tube is cut forward of the barrel band should yield closer to 50-70cc. thats plenty!

i am way off on my estimated plenum size. the ID of the steel tube is 1.19" and going by that, 7 inch will give over 125cc of plenum space. and guess what. bottle it will be.

the only think i dont like about the valve is the ID around the poppet is only .435...thats tiny! I am thinking about enlarging it to .460 or .499".

Now we're talking!! I've been waiting for this   That should be awesome Duy!  What kind of tune are you going for with it, and are you going to keep the factory barrel?  I can see the fun in keeping it a shorty, but a little extra barrel will wake it up a lot too.  It just depends on your intended use. 

I don't know if enlarging the base of the valve is really going to gain you much.  All that air still has to make through a valve seat that can only be .210-ish at the largest with a PEEK seat.  With the factory derlin seat, I wouldn't take it over .190-ish.  If you wanted to open the valve up to handle a larger seat and valve pin, then it may be worth it.  The problem there will be having enough hammer spring to crack that sucker.  FWIW, I was able to get over 80 fpe at 200 bar with the 34 grain Beasts in .22(1045 fps), and I only opened up the holes in the valve spring retainer with a 1/8" bit.  I did put a stiffer HS in there too.
Granted, that 700mm barrel didn't hurt either,lol.  With that straight pull bolt, I don't know that anymore HS would be very fun to cock on a Flashpup. 

I'm in the process of going a little different direction at the moment.  I got my hands on a WFP valve, so I can put a BT65 cylinder on it, and I'm going to put a reg for a Carnivore in it.  I'll be tuning it to shoot the 24.8 grain slugs at 1000fps, because that is their magic speed in that barrel.  I stuck the parts together(still waiting on the reg), just to see what it will look like.  Ignore the blue tape on the valve in the pick below.  I have it taped off to open it up, but I stuck it in the cylinder temporarily to see how it all looked.  I removed the valve and started on it tonight.  Oh, on a side note, check the alignment of the valve exit with the transfer by rotating it 180 degrees without the gauge in it, before you get too crazy.  I found the hole in the valve isn't aligned very well.  If yours is like mine, you'll find the hole in the valve is too far toward the muzzle end and 2-3 degrees off center as well!  I'm glad I checked this one prior to opening it up...  Anywho, below is a rough idea of what it will look like. 

[darkcharisma]

I am trying to see if 80 FPE is attainable with the 17 inch barrel. If not, I will swap out for a longer one. Tune for max power.

I have a hunch that enlarging the base will give more power, I will document before and after to see if that's indeed the case. however much i can get even 10fps gain will do.
  Having a larger base forces me to make a larger peek seat, so might as well enlarger all ports. exhaust will be .217 minimum with .23 or .25 throat, keeping poppet 7mm maximum. 7mm poppet and 3000psi will not be that bad to knock open.


I actually like your new configuration, it looks really good.

[Rallyshark]

I am trying to see if 80 FPE is attainable with the 17 inch barrel. If not, I will swap out for a longer one. Tune for max power.

I have a hunch that enlarging the base will give more power, I will document before and after to see if that's indeed the case. however much i can get even 10fps gain will do.
  Having a larger base forces me to make a larger peek seat, so might as well enlarger all ports. exhaust will be .217 minimum with .23 or .25 throat, keeping poppet 7mm maximum. 7mm poppet and 3000psi will not be that bad to knock open.


I actually like your new configuration, it looks really good.

What caliber is yours, .25?  With the larger valve pin(poppet), and a larger seat opened up to maybe .240-ish, along with larger porting...  I feel pretty sure you'll be able to break 70fpe in .25 with the factory barrel with that stuff, but I think 80 will be tough with that short barrel.  Some tungsten in the hammer wouldn't hurt either.  I drilled out the valve face on an AT44, but I don't know what it'll do with the flash valve.  It will be interesting to see.  You'll have to re-tap the hole where the 3mm grub screw is between the two 2.5mm ones that hold the valve in, if you want to go with porting that large(transfer).  Otherwise, .190(maybe slightly more) is about as large as you can go without damaging those threads I think.  I think you could certainly hit 80 fpe with a bit longer barrel though.  You'll also have a higher fill pressure to play with. 

I can't wait to see what you come up with numbers wise, because you'll be the first person I've seen make a larger valve pin/seat in one of these guns!  I toyed with the idea, but decided against it, with my limited tooling/ability.  I'm sure you can make it happen  

My new configuration looks better than that broom stick and tiny cylinder at least,lol.  The real question will be if I can make a better shot count regulated vs unregulated.  That's going to be the big unknown for me.  The gun can make the 1000 fps with the 24.8 grain slugs pretty easily, and the plenum will be big enough, but it will be a balancing act on the tune. 

[darkcharisma]

I played with Bobs lofty formula. which is as below for .25 cal.

port X caliber X pi/4 X psi=fpe

.217x.250x3.14159/4x3000psi=127fpe

then take that and calculate with the barrel length. divided by the foot

127x17.7/12/2=94fpe.

and throw in some 20% loss.

94-18.8=75fpe.

I am thinking it will be close to 75fpe with .218 exhaust port and bridging 80fpe with .250 port. we will see.

I am not too worried about the screws. ill find a workaround.

If you have a mininlathe you can do it. I am thinking a stainless steel seat and peek poppet with 2mm stem or less. should even be easier to do vs making a metal poppet and peek seat. 

i am sure you can tune it for efficiency, given if you have a big plenum. thats why i am going with 125cc from the tube. i can swap for 22/25/30 caliber later on. if the HS cant open it. balance it will be. there is enough room...

[Rallyshark]

That is about where I was figuring you'd be on power.  Just think what it would be capable of with a 700mm barrel!  The steel poppet is one of the main reasons I didn't attempt it myself.  It never even occurred to me switch it around with a steel seat and PEEK poppet    Plus, the gun is making enough power for most any lead I'll be shooting, since I won't be going larger than .22 anyway. 

I have a larger than average plenum, but I don't have 125cc of plenum, but it sure would be nice   I made a plenum extension real quick, in case I need a larger one though.  I actually just got done "resizing" the reg, since it is for a pre 2018 BT cylinder, and I was only able to get a 2019 cylinder(slightly smaller ID of the cylinder).  I have a PEEK seat with a .214 opening ready for the valve too.  I don't think I'll get it finished tonight, but I should be able to get some shots over the chrony tomorrow, barring any surprises...

I look forward to finding out what that little monster of yours is capable of!

[Rallyshark]

Well, it looks like the reg is going to be a no go for this situation...  I went ahead and put the gun back together with a reg set point of 155 bar, and 992 is the best it could do with the 24.8 grain slugs.  I could turn the reg up a little and make that 1000 fps, but being limited by a 200-ish bar fill and remaining space in the cylinder, the math isn't there for it to work.  I know that, now that I have the reg and plenum in hand to measure the space it is taking up.  Due to the size of the plenum and the reg, I have to take up 55cc to get 27cc of plenum.  If I added 10 more cc of usable plenum, I'd be taking up around 70cc, so I'd have to get an efficiency of 1.6 if I'm being generous.  I've never gotten much over 1.5 out of one of these guns on a lower powered tune, so I don't see a reg happening with this setup and power level.

I think it is time to go back to unregulated, and gain a few shots that way.  I should still be able to make 25-30 shots with a pretty decent ES that way.  On the bright side, I can change to a full beast 70+ fpe power tune with just the turn of an allen screw without the regulator.  Oh well, I gave it a go at least   

[Rallyshark]

I had to wait a while for some parts to come in for work this morning, so I went ahead and pulled the reg and set about re-tuning the gun without it.  I also decided to stick a big chunk of rubber tubing in the cylinder to de-ping it.  That takes away from the volume a little, but not too much.  I decided to tune for 24 shots, since that is two magazines. 

Starting at 200 bar and ending around 140 bar(going by little crappy gauge on gun) I got an average of 1019 fps with an ES of 36.  I was using JSB Monsters 25.39 grain to tune it, since they run pretty close in speed to the 24.8 grain slugs. That comes out to around 3.5% at 58 fpe.  I can live with that tune I think.  I may back it down a hair, but it is pretty close to where I want it for the slugs.  The ES would be under 3%, if not for the first and last shots being right at 1000, and may be closer if I dropped the power slightly.  If I was a stickler for super tight ES, I could put a little smaller valve seat in it and tighten the string up some more.  I doubt I will though, since I can shoot around a 3.5% ES pretty easily.  Besides, a 24 shot 58 fpe tune on a 200 bar non bottled .22 ain't exactly bad   I do know, there's no way I could have gotten that tune regulated. 

The gun is probably capable of bit more power on the top end with the new valve.  I found some minor things with the alignment vs the other valve.  It showed on my hammer spring adjustments, but I didn't see the point in finding out if it makes 3 more fpe, haha.  I'll try and post a picture of the finished gun in a day or two after I get it all put back together.