Heavy JSB Kings ... will they match the Kings at 200+ yards. 7 groups at 202 yd.

Jump to latest Follow Reply
Yrrah

Yrrah

Member
Apr 1, 2015
462
91
NSW, Australia
After spending a month in the Border Protection Unit of our Aussie Customs, at last the new Heavies were released and I got them yesterday ... Dangerous goods!!!
After doing a BC test earlier today, I'm hopeful they will eclipse the old from either the same rifle, John Bowkett BSA Hornet; or from the FX Elite with either the BSA barrel or its own ST barrel. In today's conditions 17d C, 54% H, 1020 hPa the BC I got with the Labradar over 5, 10, 15 and 20 yards was 0.0525 average compared to 0.034 for a JSB King; and 0.0281 for .177 Exact 10.34 gr heavies. That is by far the highest BC I have seen from a diabolo shaped pellet.

At any rate the original 25.4 gr Kings shot these 7 successive 5 shot groups at 202 yards just after they came out in 2010. There was a slight R to L air current at times but conditions were very good.
Groups #1 ctc 3.20 inches / 81.2 mm and #2 ctc 3.10 inches / 78.8 mm ... Note the aiming circle was drawn around the base of the small JSB pellet tin hence the odd size

Groups #3 ctc 3.30 inches / 83.8 mm and #4 ctc 2.80 inches / 71.2 mm

Group #5 ctc 2.40 inches / 61 mm. Note first 4 shots in 0.55 inches / 14 mm

Group #6 ctc 3.45 inches / 87.4 mm ( largest group ).

Group #7 ctc 2.3 inches / 58.4 mm. Note this is just 1.088 MOA ( MOA at 202 yards is 2.1149 inches ) or 54.58 mm.

Smallest group 2.30 inches or 1.088 minutes of arc or 58.4 mm.
Largest 3.45 inches or 1.63 minutes of arc.
Average of 7 groups 2.94 inches or 1.39 minutes of arc or 74.70 mm.
900 fps: Sight zeroed to 202 yards ( +192 clicks from 50 yard zero or +51.5 moa ). Apex of trajectory was 41+ inches above the sight line. Cards with two groups had the sight raised or lowered to accommodate two groups.

I may get a chance this next week at our farm which is 525 Km north of home. We have to trim the lavender back, going into our Aussie winter, so work comes first.
Best regards to all from a fairly excited old Aussie Long Ranger .... Harry Down Under.




 
".Dudda"Thanks for sharing! Amazing BC! What was the fps for these heavys?
Click to expand...
Just under 800 fps, 47.5 fpe, but I think I can get about 830 at 52 fpe from either the Bowkett BSA Hornet or the FX Elite with ST or BSA barrels. Today I shot the FX with BSA barrel.
At V0, 5, 10, 15 and 20 yards, one shot gave 793, 784, 775, 765, 756 fps for BC s from V0 of 0.0583, 0.0583, 0.0544, 0.0544 for average 0.0564.
An ordinary King gave 905, 885, 865, 846, 826 for BC 0.035, 0.0331, 0.0331, 0.0321 for average 0.0333. But I know that when the KIng's MV is down at 880 fps the BC for the Kings, from that rifle, is over 0.036 at similar temp and pressure. ... Kind regards, Harry.
 
  • Like
Reactions: cubo
Upvote 0
At this stage I can only make these comments in reply;
Over the last week I have done many BC calculations from data from the Labradar with .177 JSB pellets leading up to the World Championships BR. .
Example: The 10.34 ge JSB .177 Heavies are reported variously as having a BC of between 0.024 to exceptional highs of 0.030 depending upon individual barrels, ranges and chronograph set-ups. This last week I have tested that pellet with numerous 5 to 20 shot strings from 2 barrels, an LW and a FWB in my TM 1000.
This is typical from the FWB barrel: and in the middle of the reported range. The LW is giving very much the same results.
10 shots V0 to V20 yd BC 0.0283.
10 shots V0 to V 20 yd BC 0.0277.
10 shots V0 to V20 yd BC 0.0278 ... Note that the temp and pressure would have varied for each of these.
Today 0.0281.
My second comment relates to the tight barrel from which these were shot ( though it was the same for the standard King of course).
I have just shot a new Heavy King into my tube of carded raw wool for inspection. It confirmed my memory ( mentioned to BD down the page) and measurement of the groove diameter is 0.246" / 6.25 mm . The pellet was sized, as for the BC test, to 0.2500". Other barrels may of course give different results. It will be interesting to see what the FX ST barrel records from this same rifle. ... 
Don't expect the BC to be that high when shot over that range at MVs above Mach 0.75 and certainly not at 1000+ fps. ... 11:15 pm here now so time for us oldies to hit the sack. ... Kind regards, Harry.
 
Upvote 0
Harry- May I ask for a photo of the std 25.4gr, and the new heavy King, side by side? Sort of curious...

I am also interested in the accuracy at the 50yd and 100yd ranges- any info? Most of my shooting is done in this range, so I can easily make a comparison. Most of my shots are pass-throughs (on smaller squirrels) so I don't feel I need the knock-down, but the trajectory and wind factors are key on these 2x4-inch targets at longer yards.

Great post, always look forward to your post.

Good Luck & Good Shooting, hi-vel
 
Upvote 0
Hi-vel, No long range shots yet, maybe this week coming at our farm. My rifle is too noisy to bang away in suburbia - no silencing devices here in OZ, illegal.

Some one has already posted pics, I'll see if I can find them for you.
Reference "Charles"


Reference "Anthony" at Talon Tunes:


I have taken some macro pics but have as yet to download them to this computer. Our tablet is not picking up wi-fi .......... Regards, Harry
 
Upvote 0
"Ted"Thank you for this information, Harry. If the good news continues to flow re: this new pellet, I think we are going to see gun makers start creating 60 ft lb .25s. The new FX Impact's power adjustability/"programmability" will already put it ahead of the game.

Pretty serendipitious for FX, if these babies perform well from smooth twist barrels.
Click to expand...
Ted I did a repeat this morning to compare 4 different pellets to be sure things are working consistently and well according to known / accepted results. Seems OK thus far. Depending upon whose BC "standard" one can get slightly differing results of course. I am using GA which is Dave's Chairgun calculator.
Today I shot one each of these for 4 downrange velocities and so 4 (or more if one wishes to match up) different ranges.
The pellets were as shown below. The ranges wre as shown.

All pellets sized to 0.2500" which has always proved optimal in this BSA barrel (and in the other BSA barrel in the BSA JB Special Hornet).
Cnditions were : 17.5dC; 53% H; 1022 hPa.
One shot only each pellet recorded at 4 down-range distances. The MVs were as for the rifle in present tune for normal Kings at around 900 fps.

Average BCs for Velocities at V0-V5; V0- V10; V0-V15; V0-V20 yards:
Heavy King 34 gr - 0.0542 MV 787 fps 47.94 fpe
Barracuda 31 gr - 0.0456 MV 840 fps 48.56 fpe
King 24.4 gr - 0.0342 MV 897 fps 45.42 fpe
PAX Ext 30 gr - 0.0332 MV 849 fps 48.00 fpe

I know the Light Kings will give me 0.0372 BC at lower velocity and at my farm at 3,640 ft altitude; but the figures today and yesterday are pretty much what good testers get around the world for that pellet.
The more well-constructed tests done, the clearer the picture will show for other rifles and barrels etc.
The Labradar is so far trouble free. I will shortly correlate its results with my CED M11. But my old shot-up chrony shows around 5 fps fast at 880 fps.
I'm hoping the Labradar will pickup the big .25 cal pellets to at least 50 yards. Last Sunday on a competition range it succeeded 50% of the time to 40 yards for .177 Exacts with rimfires going off all around me.. ...... Best regards, Harry.
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu