GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: UnderPressure on March 13, 2020, 12:16:18 AM
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Does anyone know what the groove and land diameter of the .22 JSAR Hawk is?
.221 Groove diameter?
.220 Groove diameter?
.219 Groove diameter?
Land diameter?
I have read in several places that the barrel is not choked so the groove diameter should be the same at the breech as it is at the muzzle. Is this true?
Length of the 1 in 20" twist barrel?
Also can someone tell me what the plenum volume is? What regulator and bottle does it come with stock? And what are the factory options for bottle and regulator?
What is the maximum length .22 projectile that can fit in the 8 shot magazine?
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Anyone?
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Push a pellet through the barrel with a cleaning rod and measure those numbers yourself yourself....
You might try an unfired .22lr bullet (Just the bullet!).
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Why not call Travis?
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From my experience, this measurement can vary from gun to gun of the same, only way to truly find out is have the one you plan to shoot in hand , and do what has been said above.
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or you can spend a bunch of money getting all the different diameter .22 cal rounds and see what size works best. But it is way easier and cheaper to just slug it and measure the pushed through slug. or watch review videos and see what others are shooting
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For the Millionth +1 time. If you want accuracy with slugs, SLUG THE BARREL!!! ;) ::)
then test starting with .0001 under to .0003-6 over. It takes a while, but will show you what the bullet barrel combo likes.
Contrary to popular belief, different bullets in the same barrel will want different sizing.
In testing, My favorite hp from an NOE decked to 39 gr's likes exact to grooves. .0001 under is 25 to 30 fps faster and darned near identical in accuracy. So much for the naysayers saying too much fps will be lost by going under any at all, due to blow by. Nope.
The MP slugs like .0001 to ,0003 over. They are terrible at .0001 under or exact. But become lasers at .0001-3 over.
You simply have to test with each individual bullet.
This is why I am kinda dreading the testing I have just begun with the NSA, and AVS slugs along with a large selection of my own. It is a tremendous amount of work.
Just sticking a bullet in the breach and shooting it and saying it works well or doesn't tells you very little other than you may have very well missed the best shooting bullet you have ever seen out of pure laziness or ignorance of what is involved.
There is So Much more to it than that. A LOT More.
Knife
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ahmen to that knifemaker....+1000. cant be much better explained in my eyes
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For the Millionth +1 time. If you want accuracy with slugs, SLUG THE BARREL!!! ;) ::)
then test starting with .0001 under to .0003-6 over. It takes a while, but will show you what the bullet barrel combo likes.
Contrary to popular belief, different bullets in the same barrel will want different sizing.
In testing, My favorite hp from an NOE decked to 39 gr's likes exact to grooves. .0001 under is 25 to 30 fps faster and darned near identical in accuracy. So much for the naysayers saying too much fps will be lost by going under any at all, due to blow by. Nope. The MP slugs like .0001 to ,0003 over. They are terrible at .0001 under or exact. But become lasers at .0001-3 over.
You simply have to test with each individual bullet.
This is why I am kinda dreading the testing I have just begun with the NSA, and AVS slugs along with a large selection of my own. It is a tremendous amount of work.
Just sticking a bullet in the breach and shooting it and saying it works well or doesn't tells you very little other than you may have very well missed the best shooting bullet you have ever seen out of pure laziness or ignorance of what is involved.
There is So Much more to it than that. A LOT More.
Knife
Mike,
Not all of us have the time, resources, tooling, a place to shoot/tune the gun, then to shoot at various ranges to see what works the best at 25/50/75 yards and out.
For me to drive for +1.5hrs just to be able to shoot my gun, now if it something anything doesn't work, crony, etc. have issues or some tree huggers show up my day is done where I am shooting on Public land.
I have spent many weekends (which I work 1/3 of them) out trying to figure out a dam airgun since it came in. Just my 2 cents on this subject, not picking a fight with anyone maybe just need to look outside of the box and see other's perspectives.
Randy
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I don't have the JSAR Hawk. I was hoping one of you guys did.
P.S. The groove diameter spec for .22 air rifles is .217", but I have seen reference or mention of .214" to as large as .221".
https://www.lothar-walther.com/70/airgun-blank-stainless-no-choke-twist-17.7.22-air-od.71-l-23.82?c=273 (https://www.lothar-walther.com/70/airgun-blank-stainless-no-choke-twist-17.7.22-air-od.71-l-23.82?c=273)
https://www.airgunnation.com/topic/why-dont-gun-makers-just-disclose-barrel-specs/ (https://www.airgunnation.com/topic/why-dont-gun-makers-just-disclose-barrel-specs/)
Well, the groove diameter of the Lothar Walther 22 caliber air rifle barrel is .221". And the groove diameter of the 22 caliber TJ's, CZ, or Russian Federation barrel is .220".
https://www.airgunnation.com/topic/determining-ideal-slug-size-diameter/ (https://www.airgunnation.com/topic/determining-ideal-slug-size-diameter/)
So far the best results I get are from .2155 diameter slugs. I suspect that an even smaller diameter might even be better but finding smaller diameter slugs is not possible.
I recently pushed several slugs down the barrel and have determined that the breech end of the barrel is .2155 inch diameter sized but the choke at the end of the barrel is only .214 inches in diameter.
https://airgunguild.com/general-airgun-discussion/tjs-barrels-price-list/msg25525/#msg25525 (https://airgunguild.com/general-airgun-discussion/tjs-barrels-price-list/msg25525/#msg25525)
Interesting numbers for the airgun barrels.... IMO the .22 cal barrel is on the tight side at 0.214" groove.... I know for a fact they also have an airgun barrel that is 0.213" land and 0.217" groove, with a 16" twist.... It is a good slug barrel, but I think too fast for pellets....
This is a much larger range of diameters for caliber compared to powder burners.
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Here is the Hajimoto review of the JSAR Hawk in .22:
https://www.youtube.com/watch?v=H5otFtN2i-s (https://www.youtube.com/watch?v=H5otFtN2i-s)
Hajimoto @ 12:44 in the video said he is thinking .218 does better (regarding accuracy) in the Hawk and the .217 slugs were a little loose.
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I found out Bob's Boattails are available at a very good price from a particular seller.
(https://i.ebayimg.com/images/g/18cAAOSwmFVeILrS/s-l1600.jpg)
I wonder how well these would work? They do have a .219 drive band, but according to Kolbe twist calculator require a 1 in 16" twist because of the large meplat and small diameter boattail.
Better sizing vs. insufficient barrel twist? At 50 yards?
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You rarely can ever go by posted data. Barrels are like fingerprints. No two are the same.
If the seller is such a good deal, why did you mention it, but not post it?
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Screwy, who cannot pick up an inexpensive HF Mic. or at least dial caliper?
It is as important as a chrony for tuning. ;)
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Tofazfo sell them on ebay and I get 0.2195 on average
https://www.ebay.com/itm/AIR-RIFLE-PELLETS-SLUGS-22-CAL-28-GRAIN-HPBT-BUY-3-GET-1-FREE/164034624603?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.com/itm/AIR-RIFLE-PELLETS-SLUGS-22-CAL-28-GRAIN-HPBT-BUY-3-GET-1-FREE/164034624603?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)
here is a mic, good and cheap
https://www.ebay.com/itm/Professional-0-1-0-0001-Precision-Machinist-Micrometer-Tool-Carbide-Tips/264576544553?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.com/itm/Professional-0-1-0-0001-Precision-Machinist-Micrometer-Tool-Carbide-Tips/264576544553?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)
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If the seller is such a good deal, why did you mention it, but not post it?
I removed it because I read it was against the rules to post links to online stores---> https://www.gatewaytoairguns.org/GTA/index.php?topic=169374.msg155916836#msg155916836 (https://www.gatewaytoairguns.org/GTA/index.php?topic=169374.msg155916836#msg155916836)
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Tofazfo sell them on ebay and I get 0.2195 on average
https://www.ebay.com/itm/AIR-RIFLE-PELLETS-SLUGS-22-CAL-28-GRAIN-HPBT-BUY-3-GET-1-FREE/164034624603?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.com/itm/AIR-RIFLE-PELLETS-SLUGS-22-CAL-28-GRAIN-HPBT-BUY-3-GET-1-FREE/164034624603?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)
Yep, that is the seller I originally had posted.
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In my Sentry original version, of the Hawk the BBT shoot great as cast so worth a try for those who want to try them, and not take a gamble with no odds ;)
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Anyone know the groove diameter?
Will this gun eventually get a balanced valve?
P.S. Very impressed with the shot count (and power) of the .30 Nighthawk version (which has the balanced valve):
https://www.gatewaytoairguns.org/GTA/index.php?topic=153807.msg155704345#msg155704345 (https://www.gatewaytoairguns.org/GTA/index.php?topic=153807.msg155704345#msg155704345)
Created: 02/06/19 02:15 PM
Description: JSAR Nighthawk.30
Notes 1: 4500-2000
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 50.00
Temp: 43 °F
BP: 30.23 inHg
Altitude: 0.00
# FPS FT-LBS PF
81 803 71.60 40.15
80 808 72.50 40.40
79 811 73.03 40.55
78 810 72.85 40.50
77 812 73.21 40.60
76 812 73.21 40.60
75 813 73.40 40.65
74 811 73.03 40.55
73 813 73.40 40.65
72 811 73.03 40.55
71 809 72.67 40.45
70 808 72.50 40.40
69 811 73.03 40.55
68 810 72.85 40.50
67 813 73.40 40.65
66 807 72.32 40.35
65 811 73.03 40.55
64 811 73.03 40.55
63 811 73.03 40.55
62 811 73.03 40.55
61 812 73.21 40.60
60 813 73.40 40.65
59 811 73.03 40.55
58 813 73.40 40.65
57 811 73.03 40.55
56 812 73.21 40.60
55 812 73.21 40.60
54 810 72.85 40.50
53 811 73.03 40.55
52 809 72.67 40.45
51 813 73.40 40.65
50 812 73.21 40.60
49 813 73.40 40.65
48 811 73.03 40.55
47 813 73.40 40.65
46 812 73.21 40.60
45 812 73.21 40.60
44 812 73.21 40.60
43 811 73.03 40.55
42 811 73.03 40.55
41 811 73.03 40.55
40 811 73.03 40.55
39 811 73.03 40.55
38 808 72.50 40.40
37 810 72.85 40.50
36 808 72.50 40.40
35 807 72.32 40.35
34 810 72.85 40.50
33 810 72.85 40.50
32 809 72.67 40.45
31 806 72.14 40.30
30 810 72.85 40.50
29 809 72.67 40.45
28 813 73.40 40.65
27 810 72.85 40.50
26 812 73.21 40.60
25 810 72.85 40.50
24 813 73.40 40.65
23 811 73.03 40.55
22 811 73.03 40.55
21 809 72.67 40.45
20 808 72.50 40.40
19 809 72.67 40.45
18 810 72.85 40.50
17 809 72.67 40.45
16 812 73.21 40.60
15 807 72.32 40.35
14 807 72.32 40.35
13 808 72.50 40.40
12 810 72.85 40.50
11 813 73.40 40.65
10 810 72.85 40.50
9 808 72.50 40.40
8 811 73.03 40.55
7 809 72.67 40.45
6 812 73.21 40.60
5 812 73.21 40.60
4 812 73.21 40.60
3 810 72.85 40.50
2 814 73.58 40.70
1 815 73.76 40.75
Average: 810.6 FPS
SD: 2.0 FPS
Min: 803 FPS
Max: 815 FPS
Spread: 12 FPS
Shot/sec: 0.0
True MV: 811 FPS
Group Size (in): 0.00
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I found out Bob's Boattails are available at a very good price from a particular seller.
(https://i.ebayimg.com/images/g/18cAAOSwmFVeILrS/s-l1600.jpg)
I wonder how well these would work? They do have a .219 drive band, but according to Kolbe twist calculator require a 1 in 16" twist because of the large meplat and small diameter boattail.
Better sizing vs. insufficient barrel twist? At 50 yards?
I've opened the ports up in my Sentry 705-9K .25 prototype to 3/16", for the transfer port I made one from delrin and gave it a tryout yesterday, it's shooting the BBT's exceptionally doing about 50fpe starting at about 2600psi (the closest that I can guess) which put a big grin on my face :D
I used the BBT's right from the mold without sizing and the .252 drive band works fantastic in the barrel that came with my gun. I had previously tried some that were sized to .250 but they were too loose in the bore and the rifling was barely visible, when I pushed the raw cast BBT through that fine unchoked barrel I was very happy with the way they looked and the energy they were producing.
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Some info on JSAR Balanced Valve:
https://hardairmagazine.com/ham-columns/balanced-valves-for-pcp-airguns-theyre-here-today/
Lloyd Sikes was also involved in the latest development in the design of balanced valves for PCP airguns. Travis Whitney gave Lloyd the concept as a “back of the napkin sketch”, and Lloyd did the prototype work. Travis then continued the development, and I was privileged with enough “inside information” to allow me to build my own version. Thank you both for that opportunity!
(https://hardairmagazine.com/wp-content/uploads/2018/12/HAM-Stepped-Poppet.jpg)
This aftermarket valve is made commercially by Jefferson State Air Rifles, and sold as the “SS Valve”, in varieties to fit many existing PCPs. It looks quite different, but functions much the same.
When closed, the forces on the large diameter section of the poppet cancel out. The pressure P in the middle chamber of the poppet is atmospheric, so the force holding the valve closed comes from the small diameter portion of the poppet, (0.206 x 0.206 x PI/4) x 3000 = 100 lbs. just like in the other balanced valves above.
Remember, these are “fake” dimensions, chosen for consistency in this article.
When the valve is wide open, the pressure in the small chamber between the two poppet O-rings rises like the pressure P in the exhaust port to nearly 3000 psi. This cancels out all the forces except that 37 lbs. closing force on the valve stem area, and the valve cycles like a conventional PCP valve. Well, almost!
Travis has added a little twist, allowing the SS Valve to be “fine-tuned”. He uses replaceable jets from Mikuni carburettors to control the diameter of the vent on the inlet side of the HPA poppet chamber.
In my versions I use quite a large hole, about 1/16-inch diameter, because I am using my SS valves in big bores where I am primarily interested in easier opening to allow a lighter hammer strike. Travis has shown that by restricting the size of that inlet port, you can decrease the valve dwell, because that chamber acts like an air spring.
Truthfully, I don’t fully understand this “jetting” system, but it sure seems to work!
I can tell you that the diameter of the vent through the poppet is, once again, quite critical. If it is too large, the pressure between the poppet O-rings rises so rapidly, before the poppet has the chance to clear the seat by more than a few thou, the closing force rises and slams the valve shut, and you lose the ability to get that nice light hammer strike.
It still works, you just have to hit it harder…
On the other hand, if that vent is too small, the valve tends to blow open, like a spool valve, and it gets hard to tune. It has a definite “cycle” (like a Cothran Valve), and tiny changes in hammer strike can make it “work” or “not”.
Once you get that vent about the right size, the valve can be tuned over a decent range of velocity with just hammer strike, and can develop a normal “bell-curve” in unregulated PCPs, but much easier to knock open. It also works great in regulated PCPs.
Very interesting on how the JSAR Balanced Valve can be tuned via the Mikuni carburetor jets.
I wonder if the Balanced valve for the JSAR NightHawk (and I am assuming Xisico) will also have the same adjustability?
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I wonder how well a JSAR Balanced valve would work with the Xisico Sentry? (With and without porting)
P.S. Here are Wayne52's impressive Xisico Sentry .22 results (stock gun using 23 grain pellets):
https://www.gatewaytoairguns.org/GTA/index.php?topic=169145.msg155926879#msg155926879 (https://www.gatewaytoairguns.org/GTA/index.php?topic=169145.msg155926879#msg155926879)
A couple days ago looking through my pellet supply I decided to try turning the gun all the way up and put some 23 grain magnum hunters over the chrony. The new side lever breech does cover up most of the #5 mark but it's on there. I was looking real close through my Optivisor and could see parts of the 5. This will be the next gun that comes apart, on the .25 the hammer spring did need some deburring on both ends and I think that it did make a difference comparing before and after. I'm also curious how big the ports are. The port that was on the .25 was very small, it's now 3/16". I made a TP from delrin for it that works great.
I started with 3K and ended at 1.8K pressure.
(https://i.imgur.com/aP3DE1v.jpg)
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Here is a message from JSAR two days ago regarding the Hawk Barrel:
https://www.gatewaytoairguns.org/GTA/index.php?topic=171733.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=171733.0)
(https://i.imgur.com/uGEoajn.jpg])
(So new manufacturer for the barrel on the next round of Hawks)
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I wonder how well a JSAR Balanced valve would work with the Xisico Sentry? (With and without porting)
P.S. Here are Wayne52's impressive Xisico Sentry .22 results (stock gun using 23 grain pellets):
https://www.gatewaytoairguns.org/GTA/index.php?topic=169145.msg155926879#msg155926879 (https://www.gatewaytoairguns.org/GTA/index.php?topic=169145.msg155926879#msg155926879)
A couple days ago looking through my pellet supply I decided to try turning the gun all the way up and put some 23 grain magnum hunters over the chrony. The new side lever breech does cover up most of the #5 mark but it's on there. I was looking real close through my Optivisor and could see parts of the 5. This will be the next gun that comes apart, on the .25 the hammer spring did need some deburring on both ends and I think that it did make a difference comparing before and after. I'm also curious how big the ports are. The port that was on the .25 was very small, it's now 3/16". I made a TP from delrin for it that works great.
I started with 3K and ended at 1.8K pressure.
(https://i.imgur.com/aP3DE1v.jpg)
Russ the more inexpensive Sentry's would probably be a better candidate for the JSAR balanced valve, with the ones with the longer barrel and airtube like both of mine the airtube is one long tube, whereas with the old style there's a seperate tube for the breech, valve and gauge block then the air tube screws on to the gauge block. It might be problematic to try installing the valve going through threads on the airtube of the newer ones. I suspect that the Hawke is probably more similar to the older style Sentry with the short air tube. I watched a video of one of the new 702's and they now also have the gauge mounted on the front of the air tube which would be better yet because on those, there's still a seperate air tube and tube for the breech and valve assemblies. If I could find a source for a drop block I wouldn't mind trying putting together a bottle gun from one of them. Not sure if JSAR orders the drop blocks seperate or if they get them like that from Xisico in China ???