JSAR Hawk Groove diameter? (plus other questions)

[UnderPressure]

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?

[UnderPressure]

Anyone?

[Frank in Fairfield]

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!).

[Dbez1]

Why not call Travis?

[Back_Roads]

 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.

[scion19801]

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

[KnifeMaker]

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

[scion19801]

ahmen to that knifemaker....+1000. cant be much better explained in my eyes

[screwwork]

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

[UnderPressure]

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.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/

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

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.

[UnderPressure]

Here is the Hajimoto review of the JSAR Hawk in .22:



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.

[UnderPressure]

I found out Bob's Boattails are available at a very good price from a particular seller.




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?

[KnifeMaker]

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?

[KnifeMaker]

Screwy, who cannot pick up an inexpensive HF Mic. or at least dial caliper?


It is as important as a chrony for tuning.   



 

[jarmstrong]

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

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

[UnderPressure]

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

[UnderPressure]

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

Yep, that is the seller I originally had posted.

[Back_Roads]

 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

[UnderPressure]

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

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

[Wayne52]

I found out Bob's Boattails are available at a very good price from a particular seller.




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

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.