Sythetic Flashpup Adventure Started

[DLP]

Fred
 Like mentioned, sanding the ID would really help. I think I would put the drill motor in a vice with a 3/8 wood dole with stick on sand paper. Might be easier to handle sliding the tube back and forth verses the drill motor.

[fgwhite]

you got it right i may try that i know on the m14x20m would work perfect do like thane did sand the hole thing down on in side why he did would haft to make barrle stiffer

[DLP]

I slowed it down just a bit. A lot easier to cock. I drilled all 3 ports at 13/64s. The HS is 3/4 ccw. I am shooting the 26.54 Hades with a 3200 fill. Starting at 882 working up to 898 and back down to 827 over 20 shots. Shot 19 was 841 so it could look a little better. But I called it like it was. Giving me an avg of 874 at 45 fpe. And it’s accurate.

With the same tune, I have the JSB 33.95 Starting out at 797 working up to 821 and back down to 756 over 20 shots. Again, shot 18 was 778 so it could look better too. But it gives me an avg of 798 at 48 fpe.

[Rallyshark]

I slowed it down just a bit. A lot easier to cock. I drilled all 3 ports at 13/64s. The HS is 3/4 ccw. I am shooting the 26.54 Hades with a 3200 fill. Starting at 882 working up to 898 and back down to 827 over 20 shots. Shot 19 was 841 so it could look a little better. But I called it like it was. Giving me an avg of 874 at 45 fpe. And it’s accurate.

With the same tune, I have the JSB 33.95 Starting out at 797 working up to 821 and back down to 756 over 20 shots. Again, shot 18 was 778 so it could look better too. But it gives me an avg of 798 at 48 fpe.

That's a good solid hunting tune right there, especially if it is accurate as you say!    ....but, did you do the valve seat?  If you make a PEEK valve seat with a .210 opening, that will wake the little pup up for sure   You can open up the factory seat to probably .190 safely, and that will help as well.  The PEEK seat won't require as much HS though.  The biggest improvement on most of these Hatsans is in the valve seat, along with good porting. 

[DLP]

I have to admit that that is something I haven’t played with. Not really sure how to go about it.

[Rallyshark]

If that is the case, you may want to start with opening up the factory valve seat a little bit.  The guns come with a spare one, so it isn't the end of the world if you mess up   Just take a 3/16" bit and drill it out, then take some rolled up sand paper(400 grit) and move it in and out of the hole to smooth it out, until the shank of the bit fits through it without much resistance.  That will put you close .190  

[DLP]

Thanks for the info. Do you drill it while it’s in the valve, or take it out? I wasn’t sure how to pop it out. I thought you guys were making your own, not modifying the stock one. I do have a few of the spares. Are the .22 and .25 the same size?

[Rallyshark]

Thanks for the info. Do you drill it while it’s in the valve, or take it out? I wasn’t sure how to pop it out. I thought you guys were making your own, not modifying the stock one. I do have a few of the spares. Are the .22 and .25 the same size?

We were making our own out of PEEK, and that is still the best way to go, but the factory one can be opened up a little and provide some decent improvements.  You need to pop it out of the valve to do what I mentioned.  Just take the valve, remove the valve spring and pin.  Then you can insert something(like a small flat head) through the hole in the valve where the valve pin goes so you can catch the bottom edge of the seat and push it out.  Once you pop it out of position, it will come put the other end of the valve pretty easily.  I actually use a piece of 14 gauge utility wire, that I put a slight bend on the end of and flattened.  That little bend and flat tip helps it catch the bottom edge of the valve seat better, but I imagine the edge of a little flathead screwdriver would work too. 

They all use the same seat, regardless of caliber.  Some may have a little larger/smaller opening, but any of them can be used.

[DLP]

Thanks for the info. I have it shooting pretty good for now. Next tear down, I will give it a go.

[VaporTrail]

Figured I'd stop by to see what kinda shenanigans are going on. Apparently a 40FPE .177 is what's been happening! Holy smokes! 

That's going to be one heck of a terminal pill. Bummer the Griffins didn't work out. Maybe they're too long and are starting to wobble?

Really excited to see how this little hammer performs!

[Rallyshark]

Figured I'd stop by to see what kinda shenanigans are going on. Apparently a 40FPE .177 is what's been happening! Holy smokes! 

That's going to be one heck of a terminal pill. Bummer the Griffins didn't work out. Maybe they're too long and are starting to wobble?

Really excited to see how this little hammer performs!

That is on the Turkenstein (Flashpup XL) thread.  This is the the Synthetic Flashpup thread, haha.  Actually, I was able to get it up to 52fpe, but I currently have it regulated for about 29 fpe with the 15.5, and around 30 fpe for the 18 grain NSAs   I was able to get a dang solid 45 fpe tune unregulated too!  I'm just working out barrel tensioning(or not) to deal with harmonics.  It is funny, because a little plastic spacer between the barrel and the cylinder can mean the difference between 1/4" groups and 1/2"+ groups depending on where I put it  But I'll carry that on on that thread   https://www.gatewaytoairguns.org/GTA/index.php?topic=166895.new#new

[DLP]

I got the 2 shroud/barrel spacers from Hatsan today. I want to add them to the 20/18 mm shroud tube I have on the rifle now. But I have it shooting quarter size groups at 75 yards. I hate to start over. If I end up using the spacers, I plan on using 1 in the back and 1 in the front. I may file down the ring on the third one and glue it in the tube right where the barrel band is. I think 3 spacers that far apart would take up any slack.  I am also waiting on the 20/14mm CF tube to get here. I may tear the rifle down and ream the valve seat at that time too. Right now, I am working on a cheek riser to replace the factory one. The 2 screws stripped out and no longer hold the riser in place. Looking at making one out of a picatinny Mount that would bolt to the reciever behind the mag well.

[fgwhite]

hey d i cut me 2 peces about 1/2 or 5/8 long glued them in each end of the m18x20m tube then i used a 1/2 drill to open up the i/d just a little so it slide over barrle worked great got the length off about a 32 of a inch on shroude used a black o ring on barrle and when i sunuged up the ldc it pinched the o ring again action worked slick as a ribbon i can see adding a spacer in tube where barrle ring for weaver rail would help but best set up what thane did used a 14mm i/d sand it out and the 20mm o/d was perfect if i was doing it a gain i do what he did

[DLP]

Ya. That’s what I think too. Just waiting on the new tube.

[VaporTrail]

Figured I'd stop by to see what kinda shenanigans are going on. Apparently a 40FPE .177 is what's been happening! Holy smokes! 

That's going to be one heck of a terminal pill. Bummer the Griffins didn't work out. Maybe they're too long and are starting to wobble?

Really excited to see how this little hammer performs!

That is on the Turkenstein (Flashpup XL) thread.  This is the the Synthetic Flashpup thread, haha.  Actually, I was able to get it up to 52fpe, but I currently have it regulated for about 29 fpe with the 15.5, and around 30 fpe for the 18 grain NSAs   I was able to get a dang solid 45 fpe tune unregulated too!  I'm just working out barrel tensioning(or not) to deal with harmonics.  It is funny, because a little plastic spacer between the barrel and the cylinder can mean the difference between 1/4" groups and 1/2"+ groups depending on where I put it  But I'll carry that on on that thread   https://www.gatewaytoairguns.org/GTA/index.php?topic=166895.new#new

That it is. Whoops. 

Still though...52 FPE? Hammer time!

[Rallyshark]

I got the 2 shroud/barrel spacers from Hatsan today. I want to add them to the 20/18 mm shroud tube I have on the rifle now. But I have it shooting quarter size groups at 75 yards. I hate to start over. If I end up using the spacers, I plan on using 1 in the back and 1 in the front. I may file down the ring on the third one and glue it in the tube right where the barrel band is. I think 3 spacers that far apart would take up any slack.  I am also waiting on the 20/14mm CF tube to get here. I may tear the rifle down and ream the valve seat at that time too. Right now, I am working on a cheek riser to replace the factory one. The 2 screws stripped out and no longer hold the riser in place. Looking at making one out of a picatinny Mount that would bolt to the reciever behind the mag well.

I don't blame you there.  I've always been hesitant to fix things when they aren't broken   I had picatinny covers on my Bullboss a while back where the cheek rest used to be.  On that gun the cheek rest was way too wide, so I removed it completely.  You could always re-tap the holes for a slightly larger screw to hold that cheek piece on too. 

On a side note, where'd Thane go? 

[Thane]

Working on my shooting skills...

... 57FPE out of an 19.4" barrel with a bullpup center balance is proving difficult , 44 fpe no issues, so I am backing it down or have to install a longer barrel, but we all know what that leads to...

Also tried a picatinny  cantilevered rail, bust, cockeyed and not as solid. The original dovetail to picatinny adapter to picatinny cantilever engaged the odd Hatsan rail and is far more solid. So they are both tight now.

[Rallyshark]

Haha, it does take some getting used to for sure. Unless you've changed out the factory barrel, it is 17" and change, not 19.4". I know it is incorrectly listed in a few places.  You should measure it to confirm though. 

I do know what installing a longer barrel leads to... More fun

[Thane]

I'm just repeating bad info.

17" seems correct, 500mm carbon shroud and I cut a few inches off.
Makes me wonder if it's making 57FPE from 17" what would an additional 5" provide?

[Rallyshark]

I'm just repeating bad info.

17" seems correct, 500mm carbon shroud and I cut a few inches off.
Makes me wonder if it's making 57FPE from 17" what would an additional 5" provide?

An additional 4-5" would provide a pretty good boost!  I have little doubt that 57 fpe would jump to 60 fpe+   A few extra inches makes quite a difference on how easy these little guns make power.  It is hard to make big power out of a 17" barrel, so when you start making that kind of power, you will get a pretty good jump in power with some more barrel.  I didn't know the lengths were listed wrong myself, until someone mentioned to me, and I started looking.  I think I even remember it being wrong on Hatsans's site for one of the Flash versions?