JSB Knockout .251

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Chris44

Member
Dec 7, 2023
21
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France
Impact M3 .25, JSB KnockOut MKII

Weather: 18.1°C 2.6 m/s clear sky 1014hPa/mbar 29.94inHg 68%

Shot count: 5

Low: 1018 FPS
Hi: 1022 FPS
Avg: 1020 FPS
Spread: 4 FPS
STD Dev: 1.6 FPS

08-Jun-2024 12:23:51;1018;FPS;104.5;J;
08-Jun-2024 12:25:27;1022;FPS;105.3;J;
08-Jun-2024 12:27:03;1021;FPS;105.1;J;
08-Jun-2024 12:28:04;1019;FPS;104.7;J;
08-Jun-2024 12:29:26;1022;FPS;105.3;J;

IMG_1762.jpeg


This is my best grouping, at 30 m. I tried other speeds, the results are more less the same the std dev are less than 4 and spread less than 8 but the groupings are not better than this one. I don’t understand why I can’t get tighter groupings. Any idea ?

Thanks.
 
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Chris44 said:
Impact M3 .25, JSB KnockOut MKII

Weather: 18.1°C 2.6 m/s clear sky 1014hPa/mbar 29.94inHg 68%

Shot count: 5

Low: 1018 FPS
Hi: 1022 FPS
Avg: 1020 FPS
Spread: 4 FPS
STD Dev: 1.6 FPS

08-Jun-2024 12:23:51;1018;FPS;104.5;J;
08-Jun-2024 12:25:27;1022;FPS;105.3;J;
08-Jun-2024 12:27:03;1021;FPS;105.1;J;
08-Jun-2024 12:28:04;1019;FPS;104.7;J;
08-Jun-2024 12:29:26;1022;FPS;105.3;J;

View attachment 471068

This is my best grouping, at 30 m. I tried other speeds, the results are more less the same the std dev are less than 4 and spread less than 8 but the groupings are not better than this one. I don’t understand why I can’t get tighter groupings. Any idea ?

Thanks.
Click to expand...
Nice !
 
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@Chris44 See posts #8 and #11 here. https://www.airgunnation.com/threads/fx-impact-m3-25cal.1287912/#post-1483067

Edit: Also check out this thread

Finding a slug to fit my m3 .25 well.

I can start with that I use the king heavy 33.95gr as a referanse since those shoot 1 hole groups at 50m @910fps. I have tried 28gr, 33gr, 35gr and 37gr from zan in speeds 950 up to 1020 and none of them group as the pellets does at 50m. I have also tried nsa 43.5gr from 950 to 1000fps and its...
www.airgunnation.com www.airgunnation.com

I don’t shoot FX guns, but I’m confident you can find a lot of info on Impacts shooting JSB KO slugs if you search the AGN threads. More experienced members are sure to comment as well. Hang in there.
 
Last edited:
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Chris44 said:
Impact M3 .25, JSB KnockOut MKII

Weather: 18.1°C 2.6 m/s clear sky 1014hPa/mbar 29.94inHg 68%

Shot count: 5

Low: 1018 FPS
Hi: 1022 FPS
Avg: 1020 FPS
Spread: 4 FPS
STD Dev: 1.6 FPS

08-Jun-2024 12:23:51;1018;FPS;104.5;J;
08-Jun-2024 12:25:27;1022;FPS;105.3;J;
08-Jun-2024 12:27:03;1021;FPS;105.1;J;
08-Jun-2024 12:28:04;1019;FPS;104.7;J;
08-Jun-2024 12:29:26;1022;FPS;105.3;J;

View attachment 471068

This is my best grouping, at 30 m. I tried other speeds, the results are more less the same the std dev are less than 4 and spread less than 8 but the groupings are not better than this one. I don’t understand why I can’t get tighter groupings. Any idea ?

Thanks.
Click to expand...
Try shooting them farther, some projectiles take longer to stabilize. Never been the case for me, but it has been for others.
 
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JaceSpace1369 said:
Try shooting them farther, some projectiles take longer to stabilize. Never been the case for me, but it has been for others.
Click to expand...
Your right,I've shot heavies in 25 caliber that would not group well at 50 that would cut a hole at 100 yards. Strange but true,now that was in the 950 plus fps range. My panthera likes 40 grain slugs at 1000 fps.,pellets at 935 to 965 depending on liner. The twist rate is little different between the slug liner and the heavy liner. It takes the heavies farther than 50 yards to get true. I've not seen many people say that,but it's so true cause I've seen it. Thanks.
 
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Ezana4CE said:
@Chris44 Are those slugs the best diameter for your rifle? Have you slugged your barrel? I tried shooting them from a Brocock and the groups looked worse. Are you shouting from a bench? What sort of rest are you using?
Click to expand...
I don’t know what kind of slugs are best for my barel , and I’m shooting from table where I can get tighter groupings with original liner and pellets .
 
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Chris44 said:
Impact M3 .25, JSB KnockOut MKII

Weather: 18.1°C 2.6 m/s clear sky 1014hPa/mbar 29.94inHg 68%

Shot count: 5

Low: 1018 FPS
Hi: 1022 FPS
Avg: 1020 FPS
Spread: 4 FPS
STD Dev: 1.6 FPS

08-Jun-2024 12:23:51;1018;FPS;104.5;J;
08-Jun-2024 12:25:27;1022;FPS;105.3;J;
08-Jun-2024 12:27:03;1021;FPS;105.1;J;
08-Jun-2024 12:28:04;1019;FPS;104.7;J;
08-Jun-2024 12:29:26;1022;FPS;105.3;J;

View attachment 471068

This is my best grouping, at 30 m. I tried other speeds, the results are more less the same the std dev are less than 4 and spread less than 8 but the groupings are not better than this one. I don’t understand why I can’t get tighter groupings. Any idea ?

Thanks.
Click to expand...
Are you using a moderator? If so, try shooting some groups without it just to make sure.
 
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I followed all the advice, and it is a little better:

Impact M3 .25, JSB KnockOut MKII

Weather: 17.2°C 3.6 m/s overcast clouds 1015hPa/mbar 29.97inHg 63%

Shot count: 5

Low: 987 FPS
Hi: 996 FPS
Avg: 992 FPS
Spread: 9 FPS
STD Dev: 2.9 FPS

10-Jun-2024 14:17:35;991;FPS;99.0;J;
10-Jun-2024 14:19:24;987;FPS;98.2;J;
10-Jun-2024 14:20:45;993;FPS;99.4;J;
10-Jun-2024 14:22:07;991;FPS;99.0;J;
10-Jun-2024 14:23:19;996;FPS;100.0;J;

IMG_1783.jpeg
 
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Centercut said:
Did I really read above that someone’s groups at 100Y are actually better than the same gun same slugs at 50Y?
I’m not aware of these self correcting slugs but damn, I sure want some!!! 😉
Click to expand...
Laser guided slugs. Takes more distance for them to lock on target. Give it time Smart Parts/Skout will be working on slugs with micro chips in them, that communicate with targets, with microchips in them.
 
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Chris44 said:
I’m using a striker HD from delta optical 5-50x50, distance was still 30 m. By « slug the barrel » you mean polish the barrel ?
Click to expand...
@Chris44 No. We slug barrels to measure the diameter of the projectile bore rom the imprints of the grooves on the projectile. Take a look at this thread for a detailed explanation.

How to slug a barrel? 🤔

How to slug a barrel? 🤔 I keep reading how important it is to "slug your barrel" in order to play the slug game..... (And buy correctly sized slugs for the barrel.) However, two things seem to never get explained in this context: ▪ How to "slug" the barrel ▪ How to measure what you...
www.airgunnation.com www.airgunnation.com
 
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