JSAR .257 HP Raptor Arrived

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Loren

Loren

Member
Jan 28, 2018
1,125
912
Kansas, United States
Here is my vision for the Raptor.









Shooting a 60gr cast bullet, all I can get out of the gun 126 FPE at 975 FPS. That is with regulator set to 3500 psi. For tuning I did degas the gun, crank the reg to max and then used my tether regulator to adjust pressure up from 3000 psi up to 4000 psi. The tether regulator has big gauges, and is easy and accurate to make small changes in pressure. Way easier than using the reg on the rifle.

From what I could determine the gun is really at a point of diminishing return past 3500 psi and even at 3500 psi the gun is not real "happy", and working pretty hard, so to speak. and the regulator seems to have a slower refresh rate. My goal was just to see how much power I could get out of the rifle. See if you could get to that 160 FPE advertised power. Right now I do not think the gun has that in it. 

Here is a shot string from a 4300 psi fill.

953
958
965
935
960
962
956
942
960
AVG 955 FPS. After 9 shots it fell off the regulator set pressure.

Continued shooting of the reg and kind of group the shots based on FPS range. This was from below the 3500 down to about 3200.
939
932
935
921
944
914
921
AVG 929 FPS At this point it is stacking rounds in one hole (indoors 15 yards in my shop)

This is below 3200 down to maybe 2800 psi
907
893
884
888
888
870
893
898
856
865
861
884
858
851
AVG 878 FPS 

From shooting this string and listening to and feeling the rifles response to be fired, I thing the sweet spot is around 3300-3400 PSI...Need to do more work on it. 

I had hopes of being able to push a 60-65gr bullet to 1050 FPS. Just don't think that is going to happen. :-\
 
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Damn that is one sweet looking rig. Sad to hear its not delivering what it should. 257raptor is near perfection what Iv always wanted from airgun and I was really hoping it could sling 85grainers 920-950fps. That surely is low and really far from what was stated. I quess 257texan is still the way to go if want to have enough umph to throw bigger slugs alltho raptor on paper looks like a winner especially if dont want to hang on hose. You should defo ask from JSAR whats up because if its like that its just BS! 126FPE is nothing with that high pressure so surely there must be something wrong.. That plenum space and barrel lenght just should be able to deliver more. 
 
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Well texan have alot longer barrel and different type valve so not really comperable. But yes u can hit 200fpe with texan using heavy bullets. Im shooting 85-89grainers about 1000-1010fps but im shooting from bench with exteral regulator.

But back to topic. I hope this is just something wrong with that raptor maybe miss aligned port or something or else thats flop of the year and totally not suitable for heavy bullet caliber. 
 
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Just needs to be tuned properly.
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So how do you tune gun properly if its running absolutely on its max and still only capable of shooting about the smallest bullet available to your caliber? How about if that dosent work on your barrel? Next up you are already close to 70gr and speed at high 800's..
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The balanced valve im sure has a learning curve. As well as the hammer buffer set up. I do believe it's just a matter of getting it tuned right. 

Example, if you grab a Impact of the shelf and turn everything wide open, is that where you get your best fps? Lets see how this pans out before we call BS on there advertisement of 160 fpe.
 
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I talked with Travis at JSAR earlier today. He said the barrel transfer port is the choke point currently and it would have to be opened up to get more power. I told him my tuning method and he said that is exactly how he does it, so I'm not lost in the woods with that. He agreed that the gun is happiest and most accurate at around 930 fps. I'm going to bring the regulator pressure down a little and just shoot it for a while. Really have no interest in tearing my brand new rifle apart and start machining on parts. I do have a 52 grain bullet that it was pushing past 1000 FPS, so I will have to do some more testing with it along with some other .257 bullets in the 60-65 grain weight range.
 
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Well balanced valve is just for easy opening and what we can see from Lorens shotcurve its instantly going down when reg preassure drops that indicates valve is opening properly. There might be a change that valve regulates its self well with heavier bullets giving alot more FPE and staying open longer but I cant see how it could produce promised 160FPE that would equal about 915fps with 85gr bullet so atm it seems likely it wont hit that mark. But Im sure Loren know what he is doing and will give us some more info when testing more. Oh and you really cant compare pelletgun to Raptor completely different animals and raptor is way above Impact power wise and structure is way different. I surely hope it dose deliver.. Like I said design wise raptor is like dream come true to me but since Im only interested about bullet shooting 257raptor was only option for me but I kinda feared it would not hit that mark I was hoping it would. 
 
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I talked with Travis at JSAR earlier today. He said the barrel transfer port is the choke point currently and it would have to be opened up to get more power. I told him my tuning method and he said that is exactly how he does it, so I'm not lost in the woods with that. He agreed that the gun is happiest and most accurate at around 930 fps. I'm going to bring the regulator pressure down a little and just shoot it for a while. Really have no interest in tearing my brand new rifle apart and start machining on parts. I do have a 52 grain bullet that it was pushing past 1000 FPS, so I will have to do some more testing with it along with some other .257 bullets in the 60-65 grain weight range.
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Oh thanks! You made it before me lol. Weird that they leave TP as choking point cant really see point of doing that? As far as Im aware of that only eats performance and effiency. 
 
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Travis said to load my desired bullet with the bolt and then disassemble to confirm elongating the transfer port and not creating a situation where the bullet wants to "fall" in the transform port. I think they are being conservative on the transfer port size so as to not have that problem on a "production" rifle.

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Yeah that makes sense alltho there is many ways to get full bore size porting without having any loading problems. I still think tho that if manufacturer says 160fpe it should get up there without having to mill ur ports. Anyhow if that is only that its good to know because thats easy to get past. Some restricted valve problems etc would be alot bigger problem. Hope you post some 100+yd groups soon :) i really hope this gun turns out to be Impact killer cause I think it offers alot more with alot less. 
 
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I had hoped to be able to open the box, put a scope on it, fill with air, and load a 60gr bullet and have 155 to 160 FPE right out of the box.
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So it's "advertised" as a 160fpe gun, it is the HP - (High Power) model, but YOU have to do machine work to get it there? Sorry that would be unacceptable to me. What would you do if you have no tools?
 
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Wow - this is just the most disappointing thread to read after placing my order for a Raptor .257 on Sept 9 and waiting patiently now, what - 5 months? In my conversation with JSAR I was under the impression 120 fpe would be possible with the reg set at 150bar or under. I am honestly getting a little concerned after this long a wait. And - how on earth did you get a Raptor HP before I got my Rapor? I ordered when a Raptor .257 HP wasn't even an option on the website. 
 
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