BSA Ultra

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I regulated my .177 Ultra SE. There is plenty of power hidden in these guns but your problem in .25 is air capacity. I boosted my .177 to 840fps for 35 shots. If you decide to go for it you will need a Huma reg, larger transfer port, lighter hammer spring, and build a HDD. You will also need to get the cap apart on the back of the gun to make HS adjustments easy while you tune it.
 
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HDD is hammer de bounce device, which for the BSA it would easily be accomplished by making a "Blast Tamer"



Here is a polst of mine from the yellow a few years ago -

https://www.tapatalk.com/groups/yellow/help-increasing-power-on-a-bsa-ultra-se-25-cal-t237550.html

The Ultra is a real nice little gun. Light weight and great trigger. VERY easy to mod. Remove the valve restrictor, drill out the TP and adjust the hammer spring. Reg’s are also simple. I used a HUMA on mine. Just degas, and screw it between the tube and air gauge. I took my .25 from 10fpe to over 30fpe for 16 shots(2 mags) w/i 4%. I then regged it and now it’s 16 shots at 28fpe w/i 1%.

With the shroud I made it’s very quiet and just a tad over 36″ long
7d2bcb66e122fc8f5675fc8d472d3d8d.jpg

 
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I also have a Scorpion SE .25 the gentleman on here that I bought it from messaged me and said there was a Hi Flow transfer port and spring in the package with the Scorpion that I can use on the Ultra
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That would be correct. The "Hi Flow" tp is just a drilled out one I think to 4mm. You probably don't need the extra spring, but you will need to disassemble the valve and remove the spacer.
 
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So I finally got around to this. I removed the ant tamper plug and disassembled the cap and turned the adjustment a half turn at a time reassembling the rifle each time and test fireing with a chrono when I started out I only had 380 FPS after about 100 times taking it apart and adjusting and putting it back together I'm maxed out on the adjustment plus I installed a washer to make the spring even tighter so I'm at about 480 FPS 100 more FPS than when I started but I've just now reached 12 FPE will installing the Hi Flow TP get me a lot more Foot Pounds I'm after at least 20 FPE can I add more washers do they make a heavier spring if so where can I get one STUMPED 😠
 
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So I finally got around to this. I removed the ant tamper plug and disassembled the cap and turned the adjustment a half turn at a time reassembling the rifle each time and test fireing with a chrono when I started out I only had 380 FPS after about 100 times taking it apart and adjusting and putting it back together I'm maxed out on the adjustment plus I installed a washer to make the spring even tighter so I'm at about 480 FPS 100 more FPS than when I started but I've just now reached 12 FPE will installing the Hi Flow TP get me a lot more Foot Pounds I'm after at least 20 FPE can I add more washers do they make a heavier spring if so where can I get one STUMPED 😠
Click to expand...


If you remove the spacer inside the valve and use the High Flow port, yes. If you just do half it's doubtful. Not sure how else to say it. I'm my first post I told you what to do.
 
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Did you install a reg? Did you remove the spacer BigTin mentioned? Your hammer spring is way stronger than you are going to need. There is no need to shim it. You are trying to take shortcuts to get the power you want. It isn’t going to work. When you do what was suggested, along with the bigger transfer port, you will see everything come together. It will be a nice gun with a decent shot count for how small the air tube is.
 
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I have one in .25 cal, an 180 bar fill gives me the tightest spread FPS wise over 36 shots. 447 FPS to 432 FPS or 11.27 FPE to 10.52 FPE using JSB Match Diabolo Exact King 25.39 pellets, these are also the most accurate pellets out of the ones I tested. The other pellets I tested were: JSB Match Diabolo Exact King MKII Heavy 33.95, Predator GTO 16.54 Grains Lead-Free, H&N Baracuda 30.86 Grain, H&N Field Target Trophy 20.06 Grain and H&N Baracuda Green 19.91 Grain, I couldn't get over 10.30 FPE with any of them. I would also like to get some more power out of it but not that much more, maybe 13-15 FPE. If possible some instructional photos would be great.

 
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The valve in that img doesnt take you to the valve parts Click on the valve in the link below. Theyre the same valve.

http://www.airgunspares.com/store/category/64/360/BSA/Scorpion%2BSE/

The image above posted Vetmx is the knock off restirctor that needs to be removed. If you don't endeavour to remove it you are just pissing in the wind.

You need to remove the cylinder to get to the valve. Here's a video of how to get the valve out once you get the cyclinder off. R10 and ultra share the same valve. 





https://youtu.be/kcDlwBOezxU




 
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