Hatsan Flashpup .25 60 FPE possible with Huma XXL plenum?

[DarkRattle]

Sorry if this is the wrong section. So I just recently purchased an airgun again after selling my Huma regulated Wildcat that I had years ago (I miss that gun, it was amazing…). Any who I really wanted to build something on a budget that could generate near my wildcat's powers to shoot some slugs out of it. My wildcat was tuned shooting 60 FPE with 33.95 JSBs for a ton of shots I don't remember exactly how many but close to 35 if I recall. Now I'm not looking for the wildcat's accuracy nor it's shot count as I know I won't get it. What I am looking for is to shoot these NSA 33.9g slugs that I bought @ near 60 FPE (58-60). If I can get even 10 shots with it with a low spread I'm happy and that's not a joke haha. So I purchased a huma regulator in the XXL plenum and I'm hoping to set it and forget it. Anyone with experience with this rifle want to let me know around what bar I should be setting it to? Hammer tension wise how many screws in? I know it's all relative every gun is different but a set point would be nice, I heard a guy reached 80 FPE so I know it's probably possible. Probably.. haha. Thanks everyone! The reason I'm asking is because from past experience I don't want to keep tearing this gun up to adjust it 1000 times haha (even though I prob will end up having to haha).

[Cableaddict]

Some good info here:

https://www.gatewaytoairguns.org/GTA/index.php?topic=113962.20

My personal numbers are a bit iffy, as I'm going by memory & sketchy notes, but the other guys seem to really know what they're talking aout.

Why don't you post there, and continue the discussion?
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Also, if you REALLY want to boost fpe but still have a consistent shot-string,  instead of using an internal regulator, consider using an external buddy bottle.
The output of that regulated bottle keeps pressure even inside the gun, and your entire 165cc air tube (If you have a wooden stock Flashpup) becomes the plenum.
Now you can have even strings with any pressure up to 2900 psi.   The HUMA limits you to about 2600.

If you bore out the ports to the max (3/16" IIRC) and mode the probe, you should be able to equal any other gun with a ~ 19" barrel.

See my current thread on some options:

https://www.gatewaytoairguns.org/GTA/index.php?topic=184781.0

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Also,  for slug accuracy with the Flashpup's heavily-choked barrel, you need very soft slugs, with a pliable skirt.  I'm getting incredible results with the Griffin 36gr cup-base hollows, but they are really expensive.

One of our members here swapped both the barrel and the air tube on his pup,  and I believe he might have even used a slug liner at one point. It can be done, but the cost is rather prohibitive.  Plus, you end up with a 4" longer gun,  which for me is a deal-breaker.  The Flashpup can never become a Prophet, not even a Maverick, because the trigger is too close to the breech.  Well, I suppose even THAT could be modified, but it would be a ridiculous endeavor.

[DarkRattle]

Some good info here:

https://www.gatewaytoairguns.org/GTA/index.php?topic=113962.20

My personal numbers are a bit iffy, as I'm going by memory & sketchy notes, but the other guys seem to really know what they're talking aout.

Why don't you post there, and continue the discussion?
---------------------

Also, if you REALLY want to boost fpe but still have a consistent shot-string,  instead of using an internal regulator, consider using an external buddy bottle.
The output of that regulated bottle keeps pressure even inside the gun, and your entire 165cc air tube (If you have a wooden stock Flashpup) becomes the plenum.
Now you can have even strings with any pressure up to 2900 psi.   The HUMA limits you to about 2600.

If you bore out the ports to the max (3/16" IIRC) and mode the probe, you should be able to equal any other gun with a ~ 19" barrel.

See my current thread on some options:

https://www.gatewaytoairguns.org/GTA/index.php?topic=184781.0

---------

Also,  for slug accuracy with the Flashpup's heavily-choked barrel, you need very soft slugs, with a pliable skirt.  I'm getting incredible results with the Griffin 36gr cup-base hollows, but they are really expensive.

One of our members here swapped both the barrel and the air tube on his pup,  and I believe he might have even used a slug liner at one point. It can be done, but the cost is rather prohibitive.  Plus, you end up with a 4" longer gun,  which for me is a deal-breaker.  The Flashpup can never become a Prophet, not even a Maverick, because the trigger is too close to the breech.  Well, I suppose even THAT could be modified, but it would be a ridiculous endeavor.

A lot of good info here thanks! I didn't even know about external regulators until now... As far as boring out and using a longer probe I feel like that would be too much of a hassle for powers like 60 FPE (I've done it before I believe with my marauder it was a while back) but never the less awesome info thanks!

[Cableaddict]

A lot of good info here thanks! I didn't even know about external regulators until now... As far as boring out and using a longer probe I feel like that would be too much of a hassle for powers like 60 FPE (I've done it before I believe with my marauder it was a while back) but never the less awesome info thanks!

You can hit 60 fpe without touching the probe, but not without some drilling of the ports.
But going much higher than that supposedly requires all the little tricks.  (About which I am absolutely NOT the guy to explain it all. I'm in the process of learning it, just like you.)

A nice benefit of port drilling, as you obviously know, is that the hammer spring can be loosened a bit, which lowers the gun's noise.  For me, that's almost the main reason to do it.   

[DarkRattle]

A lot of good info here thanks! I didn't even know about external regulators until now... As far as boring out and using a longer probe I feel like that would be too much of a hassle for powers like 60 FPE (I've done it before I believe with my marauder it was a while back) but never the less awesome info thanks!

You can hit 60 fpe without touching the probe, but not without some drilling of the ports.
But going much higher than that supposedly requires all the little tricks.  (About which I am absolutely NOT the guy to explain it all. I'm in the process of learning it, just like you.)

interesting, what do you reckon 50 FPE possible without drilling the ports?

[Cableaddict]

what do you reckon 50 FPE possible without drilling the ports?

I can't say for sure, since my gun had already been ported by the first owner.

However, I was curious about this, and I found two believable reposrts online, for the .25 cal Flashpup:

First guy reported:

JSB King Heavy 33.95gr  averaged 752 fps
JSB King 25.39gr  averaged 825 fps

Another guy,  After hammer spring adjustment:
28.24 gr. H&N Baracuda @ ~ 840 FPS   


So no, not even close to 50 fpe.

Just do some mild porting.  You don't have to do the supposed maximum of 3/16".  Every little bit helps.
Then set your regulator, if you have one,  to 180 bar.
Then runs strings through a chrony, and adjust the hammer from light towards hard, until you see the velocity stop rising. That's the point at which you're just dumping excess air out of you barrel.
---------------

Of course, once again, it you use an external regulated buddy bottle, and no internal regulator,  then who knows?  I've never tried it.
But porting is still a good idea, as it saves wear & tear on your hammer & valve.

[DarkRattle]

what do you reckon 50 FPE possible without drilling the ports?

I can't say for sure, since my gun had already been ported by the first owner.

However, I was curious about this, and I found two believable reposrts online, for the .25 cal Flashpup:

First guy reported:

JSB King Heavy 33.95gr  averaged 752 fps
JSB King 25.39gr  averaged 825 fps

Another guy,  After hammer spring adjustment:
28.24 gr. H&N Baracuda @ ~ 840 FPS   


So no, not even close to 50 fpe.

Dang that's depressing haha, I've found so many mixed things about this gun maybe i should have done a tad bit more research before buying it. My first choice was that new Air Venturi Avenger but sadly airguns are ALWAYS out of stock haha. Thanks for all the good info though my good sir.

[Cableaddict]

what do you reckon 50 FPE possible without drilling the ports?

I can't say for sure, since my gun had already been ported by the first owner.

However, I was curious about this, and I found two believable reposrts online, for the .25 cal Flashpup:

First guy reported:

JSB King Heavy 33.95gr  averaged 752 fps
JSB King 25.39gr  averaged 825 fps

Another guy,  After hammer spring adjustment:
28.24 gr. H&N Baracuda @ ~ 840 FPS   


So no, not even close to 50 fpe.

Dang that's depressing haha, I've found so many mixed things about this gun maybe i should have done a tad bit more research before buying it. My first choice was that new Air Venturi Avenger but sadly airguns are ALWAYS out of stock haha. Thanks for all the good info though my good sir.

IMO, the Flashpup is a fantastic platform for modifications.  Moreso than almost any other "low end" pcp.    Of course, that's based on my specific needs.  YMMV.

The only thing I don't like is the need for a really high scope, as with any bullpup. That's bad for pesting. - But even that can be overcome. Some members turned me on to those offset iron sights that mount to dovetail rails. I'm going to add those & use them for anything 10 yards an under. Past 20 yards,  the high scope isn't really such a big deal.  (Plus, I ground off the back Picatinny rail, which is bloody useless, so my cheek now rests at barrel level.

I'd really like to be having this discussion on that other thread, so I'll stop now.  lol ...     
 

Read my other thread carefully, I haven't done too much yet, but the end result should be equal or excel any other sub- $1,100 bullpup with a sub 20" barrel.   I believe that 100%.

[DarkRattle]

what do you reckon 50 FPE possible without drilling the ports?

I can't say for sure, since my gun had already been ported by the first owner.

However, I was curious about this, and I found two believable reposrts online, for the .25 cal Flashpup:

First guy reported:

JSB King Heavy 33.95gr  averaged 752 fps
JSB King 25.39gr  averaged 825 fps

Another guy,  After hammer spring adjustment:
28.24 gr. H&N Baracuda @ ~ 840 FPS   


So no, not even close to 50 fpe.

Dang that's depressing haha, I've found so many mixed things about this gun maybe i should have done a tad bit more research before buying it. My first choice was that new Air Venturi Avenger but sadly airguns are ALWAYS out of stock haha. Thanks for all the good info though my good sir.

IMO, the Flashpup is a fantastic platform for modifications.  Moreso than almost any other "low end" pcp.    Of course, that's based on my specific needs.  YMMV.

The only thing I don't like is the need for a really high scope, as with any bullpup.  Read my other thread carefully, I haven't done too much yet, but the end result should be equal or excel any other sub- $1,100 bullpup with a sub 20" barrel.   I believe that 100%.

Right right, good points. I had a $1000 scope on my wildcat not sure what it was now some Vortex or something but I got a $300 Athlon Argos (I believe?) 6-24 FFP on it, I think that's justifiable. Once you go FFP you can't go back is the case with me.

[Cableaddict]

And I said I would continue on this thread.  LOL .....

I'm with you. I think it makes more sense to put a lot of money into your scope, than into your rifle.  (up to a point.)

I'm kinda' dreaming of the MTC SWAT 12x50,  which is $750.  The only thing holding me back is that you just KNOW they're going to come out with something better by the time hunting season rolls around again.   This is exactly the wrong time to buy anything.

[DarkRattle]

And I said I would continue on this thread.  LOL .....

I'm with you. I think it makes more sense to put a lot of money into your scope, than into your rifle.  (up to a point.)

I'm kinda' dreaming of the MTC SWAT 12x50,  which is $750.  The only thing holding me back is that you just KNOW they're going to come out with something better by the time hunting season rolls around again.   This is exactly the wrong time to buy anything.

Yeah let's bounce on that thread right after this final scope topic LOL! I just have to tell you I tried my friends MTC SWAT 12x50 and the clicks on it feel amazing! I'm BIG on PRECISE clicks. 

[Rallyshark]

If you're wanting a 60 fpe tune out of a Flashpup, you're best off going UNregulated for sure.  It will do a pretty good string unregulated at those power levels for 10-15 shots.  Of course, it will require opening up the valve and porting to do so.