pellet grouping

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lpellet
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Joined: Sat Apr 08, 2023 8:11 pm

pellet grouping

#1 Post by lpellet »

Hi
I am a newbie to this forum and a newbie in airgun practice. I bought a Gamo varmint 1200 FPS and the attached scope from Gamo. I recently purchased two types of pellets for targeting at 20 yards.
-HN field trophy 4.5 mm 8.64 gr
-diabolo baracuda 4.5 mm 10.65 gr

Initialy the scope was set for the HN field trophy. I have aimed at the center black target for both series of shots. The HN are grouping within the black circle while the 3 Diabolo shots are to the left of the black target closer to the orange left target. What would be the reason for such a a margin in precision when using the 2 types of ammo. is this normal or is there a problem with the airgun ? I have been using a shooting bench for both series of shots. Any comments fron experienced users. I am baffled my such a difference. Does this mean I have to recalibrate the scope each time I change pellet source and weight ???
IMG_20230408_152452.jpg
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CZ-Sniper
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Re: pellet grouping

#2 Post by CZ-Sniper »

Correct. You'll find that most pellets will have a different zero, and some pellets just won't group well in your particular air rifle.
Also, shooting a springer with consistent accuracy takes practice due to the spring piston mechanism, making them more hold - sensitive. Try holding everything lightly; even placing your cheek lightly on the rifle. Be consistent with how you hold it each time and how you breath and hold your breath, as well as how you squeeze the trigger. Everything has to be repetitive and 'robotic'.
Hth
Daryl
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Re: pellet grouping

#3 Post by Daryl »

Welcome to the forum, lpellet. The 8.64gr. appear to be more accurate than I would have thought from that rifle.
Different POI's are common when shooting different ammunition. Different weight, shape and composition
of the pellets will cause different harmonics in the rifle and barrel, as well as possibly differences in holding, shot to shot.
You need to do more testing with these same pellets. 2 groups are not enough to tell much.
Best Wishes
Daryl
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abslayer
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Re: pellet grouping

#4 Post by abslayer »

What distance are you shooting these groups from ??
NovaNewfie
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Re: pellet grouping

#5 Post by NovaNewfie »

Every pellet type will shoot differently and group differently in your rifle. It's the nature of the beast. The same pellet and weight with a different headsize will also shoot differently.
Some places sell sample packs where you get 50 or 100 of each of 4 or 5 different pellets. That way you can test without having to buy a whole tin.
The majority of .177 pellets shoot most accurately at around 800-900 fps. I would try heavier pellets in your rifle.
TX200 .177 10-50×60 Hawke Sidewinder
HW30S, Diana 280
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NovaNewfie
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Re: pellet grouping

#6 Post by NovaNewfie »

abslayer wrote:What distance are you shooting these groups from ??

He says 20 yards in his post
TX200 .177 10-50×60 Hawke Sidewinder
HW30S, Diana 280
2x FWB 700 Junior, FWB 700 Alum
Hatsan AT44 .25
Daisy Avanti 753S, 2x Daisy 953 cadet
2x Tau7
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abslayer
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Re: pellet grouping

#7 Post by abslayer »

Chezz I am blind
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HW777
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Re: pellet grouping

#8 Post by HW777 »

Different pellets will group differently, try maybe 5-6-7 types and stick to 1 so you don’t have to reset your scope.
Is there any way you can Chrony that gun, if it’s shooting above 900fps that may cause some accuracy.
A magnum gun advertised to shoot at 1200fps will have lots of vibrations when you shoot….that spring hits so hard.
If it’s shooting above 1000fps and you want accuracy I would detune the gun to shoot in the 800’s fps.
Also most likely the supplied scope isn’t very good and eventually the back and frontward action of the spring will bust that scope.
HW97
FX Impact
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CZ-Sniper
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Re: pellet grouping

#9 Post by CZ-Sniper »

HW777 wrote:Different pellets will group differently, try maybe 5-6-7 types and stick to 1 so you don’t have to reset your scope.
Is there any way you can Chrony that gun, if it’s shooting above 900fps that may cause some accuracy.
A magnum gun advertised to shoot at 1200fps will have lots of vibrations when you shoot….that spring hits so hard.
If it’s shooting above 1000fps and you want accuracy I would detune the gun to shoot in the 800’s fps.
Also most likely the supplied scope isn’t very good and eventually the back and frontward action of the spring will bust that scope.
+1 solid advice. I always use blue loctite on all my stock and scope screws.

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abslayer
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Re: pellet grouping

#10 Post by abslayer »

HW777 wrote:Different pellets will group differently, try maybe 5-6-7 types and stick to 1 so you don’t have to reset your scope.
Is there any way you can Chrony that gun, if it’s shooting above 900fps that may cause some accuracy.
A magnum gun advertised to shoot at 1200fps will have lots of vibrations when you shoot….that spring hits so hard.
If it’s shooting above 1000fps and you want accuracy I would detune the gun to shoot in the 800’s fps.
Also most likely the supplied scope isn’t very good and eventually the back and frontward action of the spring will bust that scope.
Dam good advice 8)
Atlas_cn
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Re: pellet grouping

#11 Post by Atlas_cn »

Varmint is not jumping a lot but it does jumping. My uncle (lived in USA) had one and I tried to helped him zeroed it at about 20 yards last year when I visiting him. The spring release time is not long, and the trigger is just OK--overall it is a cheap gun.

For a new rifle doesn't break in yet your result is not bad. You just need to get a chrony and find out the best pellets--usually the less fps spread the better. Also domed/hollow-point is always better than pointed. However, Gamo always over claim their velocities, it is actually about 900 fps for Daisy 7.56 gr (they are tight) and about 930 for 7.4gr Crosman pointed(we only got these two when I visiting). The grouping is OK till 50-60 yards if you didn't get a lemon--Varmint always have problem at the muzzle crown and pushing pellet side ways but as the group from your photo it seems OK for this one. Also the best zero range is 30 yards as it gives less than quarter inch up and down from 15 to 35 yards.
I noticed from thousands of shots of different power plant guns, shooting a springer from bench doesn't help much, especially for high power ones. You will actually see it jumps up from the rest and some times it makes accuracy worse. Anyway keep practicing and
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lpellet
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Re: pellet grouping

#12 Post by lpellet »

thank you all for your comments and experiences with different pellets

After reading several reviews for the Gamo1250 FPS, I think it will hard to keep zero with any scope because of recoil forces from that airgun. I wish it had fixed sights on the barrel , it might give better consistency for zeroing the riffle,. Too many variables to control for success with this airgun but I will try to achieve better results from some of your recommendations.
NovaNewfie
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Re: pellet grouping

#13 Post by NovaNewfie »

lpellet wrote:thank you all for your comments and experiences with different pellets

After reading several reviews for the Gamo1250 FPS, I think it will hard to keep zero with any scope because of recoil forces from that airgun. I wish it had fixed sights on the barrel , it might give better consistency for zeroing the riffle,. Too many variables to control for success with this airgun but I will try to achieve better results from some of your recommendations.

There are recoil absorbing scope mounts advertisements I've seen. I have no experience with them, therefore no idea if they would help.
TX200 .177 10-50×60 Hawke Sidewinder
HW30S, Diana 280
2x FWB 700 Junior, FWB 700 Alum
Hatsan AT44 .25
Daisy Avanti 753S, 2x Daisy 953 cadet
2x Tau7
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HW777
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Re: pellet grouping

#14 Post by HW777 »

Look into changing the spring with one that’s softer, doing that will bring the fps down.
Ideally keep it below 900fps, get yourself some jsb pellets exact diablos.

I think if you tre jsb in 8.6g and tune it to shoot between 800-900 you’ll be ok.

Main thing maybe google where to get a softer spring maybe even check YouTube.
HW97
FX Impact
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