Author Topic: JSAR .257 HP Raptor Arrived  (Read 985 times)

Loren

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JSAR .257 HP Raptor Arrived
« on: February 05, 2020, 06:13:42 PM »
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.   :-\

HUGE thanks to the Guild and Utah airguns for the FX Chronograph !!!  It is a really cool device and made keeping track of data easier, and is easy to use.


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Loren

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Re: JSAR .257 HP Raptor Arrived
« Reply #1 on: February 09, 2020, 12:51:14 PM »
It's blowing 16-18 mph this afternoon and I only have 50 yard distance I can shoot here at home. But this is what it can do in the Kansas wind.
60gr cast bullet from NOE mold.




This is a shot string from how I have it tuned right now with the 60gr bullet.
Shot count: 22
Low: 926
Hi: 946
Avg: 933
Spread: 20
STD Dev: 5.1
942
935
935
928
928
939
928
926
937
932
926
935
930
935
932
932
928
932
928
932
932
946
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Alan

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Re: JSAR .257 HP Raptor Arrived
« Reply #2 on: February 09, 2020, 01:52:25 PM »
I'm convinced that regulators are getting better all of the time. While I understand the bullet weight and size can vary, those can be dealt with for the most part. But regulators?

The bottled Marauder I have, was lousy in maintaining repeatable pressure. I finally messed with it, and found the washers weren't stacked like they should be (Bob Sterne recently had a Guild post addressing this issue). Once corrected, and the addition of a larger port (.162), made a whole-new gun out of a kludge. Instead of 2,100 PSI, it is now ≈1,825, and the velocity and efficiency went up. Perhaps JSAR has (also) learned that consistent regulator pressure is an essential ingredient to consistent groupings.

Just wait until the wind stops "shouting"!
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Alan

I have an Omega compressor. If you're a fellow Guild member, and you pass through Roswell, NM, I'll fill your portable tank as a courtesy.

steveoh

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Re: JSAR .257 HP Raptor Arrived
« Reply #3 on: February 09, 2020, 03:18:14 PM »
Good stuff Loren. I’ve been very interested in seeing what JSAR could do with a .257. I’m kinda hoping that JSAR and Airforce and others will continue to push this caliber.

I fiddled around for a bit earlier in 27mph winds gusting up to who knows what. I was experimenting with resizing some of my 257420 bullets down to see how they faired in the Sumatra .25 Carbine. Turns out the smallest Noe Die I bought was .253. Sumatra did not like that at all. So I slugged the barrel and found it to be .250. So I figure a .251 slug should do fine. Will size some of your green meanies and other small bullets to see how how the Sumatra likes these slugs. The last slugs I shot were Rat Killer’s slugs and some Hunters Supply. Sumatra hated them all and they jammed up the magazine. Bah. A feller on the GTA is modifying magazines to more reliably shoot slugs. I have one coming. As much as I love the Texan I hate carrying it around. The Sumatra is light even with scope.

So I keep looking at your Raptor and thinking this might be a perfect slug hunter.

I also keep scratching my head about the .257 Citrus I own, and lamenting the fact I haven’t been shooting it. Compared to the Texan it’s not quite as powerful and less efficient but it’s purty. It’s also a bear to carry around and is muzzle heavy. Of course then I wonder if FX will offer a .257 barrel. Maybe convince Alan to jump on the .257 platform and get a barrel for his Impact. :)

Good grief the obsession about a caliber that’s not that much larger than a .250. Where’s the men with butterfly nets?

Back to the Raptor.

I kinda thought that a 160fpe might be optimistic for the Raptor. This is based on what the Texan and  Citrus are producing. Both will give 160 FPE. The Texan does so at 2800-3000 psi. The Citrus needs a good 3600psi to give 160fpe. Of course that thing sucks down the air.
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Alan

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Re: JSAR .257 HP Raptor Arrived
« Reply #4 on: February 09, 2020, 05:17:42 PM »
I have the barrel! But... I am leery to get used to it, unless I find an area with less housing. And there is another issue.

If I got interested in doing slugs, I wouldn't replace the setup I have now. Rather, I'd drop the bucks and set up a separate Impact to shoot slugs. I sort of doubt I'm going to do that, as the current Impact (.250 shooting JSB Exacts) has been able to extract quite a number of Eurasian and Rock doves from the local population. After all, 25+ grains at almost 980 FPS, has a devastating effect!
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Alan

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steveoh

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Re: JSAR .257 HP Raptor Arrived
« Reply #5 on: February 09, 2020, 05:46:42 PM »
I have the barrel! But... I am leery to get used to it, unless I find an area with less housing. And there is another issue.

If I got interested in doing slugs, I wouldn't replace the setup I have now. Rather, I'd drop the bucks and set up a separate Impact to shoot slugs. I sort of doubt I'm going to do that, as the current Impact (.250 shooting JSB Exacts) has been able to extract quite a number of Eurasian and Rock doves from the local population. After all, 25+ grains at almost 980 FPS, has a devastating effect!

You do? A .257? Or are you talking .25 slug barrel? Oh the gears are turning.
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Loren

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Re: JSAR .257 HP Raptor Arrived
« Reply #6 on: February 09, 2020, 06:13:06 PM »
....
Back to the Raptor.

I kinda thought that a 160fpe might be optimistic for the Raptor. This is based on what the Texan and  Citrus are producing. Both will give 160 FPE. The Texan does so at 2800-3000 psi. The Citrus needs a good 3600psi to give 160fpe. Of course that thing sucks down the air.

Yes, I think JSAR was overly optimistic about what the rifle could produce. 

I have a .30 cal Impact X that I was considering doing the Power Plenum upgrade to, but hadn't seen any numbers on the FPE, so I went looking just now.  Although great power, it is not BIG TIME slug power.  Also the big draw back on the Impact is the magazine length is pretty short.  It would not handle the shortest of .257 bullets. :-( 



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steveoh

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Re: JSAR .257 HP Raptor Arrived
« Reply #7 on: February 09, 2020, 07:51:13 PM »
Hmmm, that’s a no go on the Impact then. You know a long .25 Sumatra is a 100fpe rifle. Accurate too.
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rsterne

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Re: JSAR .257 HP Raptor Arrived
« Reply #8 on: February 09, 2020, 09:35:34 PM »
The difference between .25 cal and .257 cal is not so much the diameter as the range of available ammo, and the twist rate required to handle it.... The .25s top out at about 60 gr., and that's were the .257 starts out.... While you can get a 14" twist in .250 from TJ's, most airgun barrels are slower than that.... That is the starting twist for a .257, and you can get barrels in 10" and even 7" twists....

Bob
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steveoh

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Re: JSAR .257 HP Raptor Arrived
« Reply #9 on: March 01, 2020, 07:16:26 AM »
I roamed back to this thread and am admiring your choice of AR furniture. Color is right and it just looks good.

Any idea what the weight is with scope and all the accoutrements?

How are your strings looking?

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FL Rat Hunter

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Re: JSAR .257 HP Raptor Arrived
« Reply #10 on: March 01, 2020, 07:25:29 AM »
I do like the butt stock and your bottle cover!  Great combination!  I personalized my .25 Mini, but when the cheap route and just taped the bottle!  LOL! 
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Loren

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Re: JSAR .257 HP Raptor Arrived
« Reply #11 on: March 01, 2020, 07:47:52 AM »
Thanks guys!  Your looks sharp too Paul.  I made the bottle cover so it was the cheap route! LOL

Steve it weighs 14 lbs.  That is with a 6" front pictiny rail extension with bipod, and rear mono-pod.  I have not done much chorongraph work lately.  One of my sons and I did make it to the range yesterday for some 100 yard shooting.  Beautiful 60+ degree day, but WINDY!  Was shooting 3-4" groups in the wind, which was okay considering the wind.  The range berms create some pretty screwy wind currents, which are hard to compensate for when aiming.
 
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steveoh

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Re: JSAR .257 HP Raptor Arrived
« Reply #12 on: March 01, 2020, 08:30:01 AM »
Thanks guys!  Your looks sharp too Paul.  I made the bottle cover so it was the cheap route! LOL

Steve it weighs 14 lbs.  That is with a 6" front pictiny rail extension with bipod, and rear mono-pod.  I have not done much chorongraph work lately.  One of my sons and I did make it to the range yesterday for some 100 yard shooting.  Beautiful 60+ degree day, but WINDY!  Was shooting 3-4" groups in the wind, which was okay considering the wind.  The range berms create some pretty screwy wind currents, which are hard to compensate for when aiming.
 

I have a bunch of heavy airguns. 14 pounds is painful to carry out in the field Turkey hunting. That’s a little heavier than my mile long Texan or the very muzzle heavy Citrus.

The .458 DAQ is heavy and front weighted too.  But the .58 DAQ short rifle with a light scope is actually a great balanced rifle. I keep coming back to this rifle and thinking that a short version in .257 or .308 would be so much nicer for hunting. The Sam Yang 909s without scope is even lighter and better balanced.

I guess I’m coming around to less is more, and that max power ain’t what is needed.


Also, it appears I’m getting weaker with age and hauling around a 12-14 pound rifle while trying not to break an ankle in the rock hard Adobe is friggen hard. Maybe a short .25 AirForce Rifle with a slug barrel?

Back to scratching my head.
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Loren

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Re: JSAR .257 HP Raptor Arrived
« Reply #13 on: March 01, 2020, 08:53:14 AM »
It's set up for bench shooting.  For stalk hunting or had any distance to hike, I would ditch the PRS stock, the mono-pod and bipod and rail extension, and the large scope.  All that would probably drop 5 lbs. 



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Re: JSAR .257 HP Raptor Arrived
« Reply #14 on: March 01, 2020, 09:46:40 AM »
To compare the Raptor HP to a Texan with a 34" barrel is not really fair, IMO.... What is the Raptor barrel, 26"?.... Right off the bat, that means you need 30% more pressure for the Raptor to match the Texan, not allowing for the latter's inline valve.... My Hayabusa 257, with a 29" barrel on 3000 psi, can achieve 160 FPE maxed out.... Tuned for a decent shot count that drops to 130 FPE....

Bob
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