Canadian Airgun Forum

I have had my Air Arms S510 for a short time now, and just added a S400f to my collection as well. The 510 is in .22, the 400 in .177.

While I haven’t had a lot of time with either, it seems that when I turn down the velocity using the transfer port adjustment screw the accuracy of both suffers. I don’t mean a shift in the poi, I mean accuracy/consistency. The 510 drops to around 400fps at the lowest setting and at the setting the groups are inconsistent at just 12 yards. The 400 only drops to about 560fps on its lowest setting and it too seems to open up the groups somewhat, though not as much as the 510.

My S200 when adjusted seems to have little effect on group sizes. So I was surprised to see this happening with the other two guns. All results are indoors and with very similar psi levels in the gun, so there’s not much left to factor in that may be causing this phenomenon. Does anyone else have similar results when varying the FPS of your gun??

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Highlights - Evanix Conquest
AA HFT 500, FX Dreamline, Diana Mod 70,
HW44, FAS6004, some other goodies.

I admit to no knowledge about this, but the thought crossed my mind when reading your post that perhaps the guns pellet preference changes with velocity.

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A mask is not a political statement. It is an IQ test.

If you have a chronograph, watch and record your extreme spreads.
Probably a consistency issue with the flow turned down that far....
I try to shoot in 10 shot strings~ it gives me a better idea of performance consistency than 5 shot strings.
It of course helps to work with a known consistently performing pellet...

-D.S.

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"Ain't no half-way"
-S.R.V.

I would suspect the pellets as well. When the air 'blast' pressure changes, pellet preferences also change.

Check out this video

https://www.youtube.com/watch?v=S_iwWYi3hIM

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"...await the right moment for one, and only one well-aimed shot" - Vassili Zaitsev

That was my first thought. I checked and surprisingly the s400 was incredibly consistent between 567fps and 571fps over 15 shots. I couldn’t believe it out of a non reg gun.

The 510 was more varied, with a spread of around 25fps but I didn’t think that would be enough to open up groups to 2 inches.

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Highlights - Evanix Conquest
AA HFT 500, FX Dreamline, Diana Mod 70,
HW44, FAS6004, some other goodies.

This crossed my mind, thanks for the link. I’ll investigate this one further.

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Highlights - Evanix Conquest
AA HFT 500, FX Dreamline, Diana Mod 70,
HW44, FAS6004, some other goodies.

When I dial down my FX Royale 400 .177 FAC from power 3 to power 2, I switch from JSB 10,34 to JSB 8,44 to obtain the same accuracy and spread.


Sent from my iPhone using Tapatalk

If you dial the velocity down too far, perhaps the skirt of the pellet is not getting "blown out" to fit the rifling the way it usually does.... like this....



It could also be other things, such as barrel harmonics being in a bad range, etc.etc.etc.... Just a thought....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

My Air Arms S510 likes between 850 and 890 fps and shoots nickel size 10 shot groups at 50 yards
Never tried it lower that 700 fps , it shot worse at 700 FPS so when up to find sweet spot

I’m away currently so I can’t test out lighter pellets at lower velocities. But, I’m wondering why this is the case. A Canadian detuned 510 will shoot just fine, why are the fac versions shooting so poorly when turned down?

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Highlights - Evanix Conquest
AA HFT 500, FX Dreamline, Diana Mod 70,
HW44, FAS6004, some other goodies.

No idea just reported what mine shot best at , also used JSB .22 15.99 gr

I have experienced the same issue with my FX Streamline. at power level 3, it shot the JSB Exacts like a laser, but on the lowest power, the groups opened up.
I tried several pellets and found that it likes different pellets at different powers. My suggestion is to try experimenting with different pellets at various power levels to rule out anything else.

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Air Arms HFT 500
FX Streamline laminate .22
Benjamin Discovery .22 (tuned)
Weihrauch HW30S .177
Weihrauch HW30 MK1 .177
Weihrauch HW40
Beeman P17
Crosman 22xx carbine (tuned)
Princess Auto Super Springer Deluxe ($34.99)

The slower the pellet travels, the more unstable it becomes. Thats why using a lighter pellet at lower power settings often restores accuracy.

So I finally had time to experiment a little bit with a few different pellets. I had 3 different weights in the jsb domed pellets, and the rifle didn’t perform great with any of them. This was a surprise as they’re generally regarded as nearly foolproof and I’ve never owned a gun that did like them. I’m still shooting indoors at only 13yds so I don’t think it’s unreasonable to expect near pellet on pellet performance.

I finally tried the meisterkugeln 8.2gr wadcutters and as if by magic the groups tightened to nearly one hole. This was the accuracy and consistency I was expecting out of the rifle.

So clearly this is more a result of pellet size than weight as the jsb’s are very close in weight to the meisters. I was disappointed to find the wadcutters were the clear favorite as once the weather actually warms up and I’m shooting outdoors they don’t have the extended range of a domed pellet. I suppose my next step is to hunt for a domed pellet with the same size as the meister’s. They’re advertised as being simply 4.5mm so there could be a range of actual sizes varying from likely 4.4x to 4.5x.

I’m half tempted to buy the pelletgage just to definitively determine the exact pellet size this rifle prefers.

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Highlights - Evanix Conquest
AA HFT 500, FX Dreamline, Diana Mod 70,
HW44, FAS6004, some other goodies.

wadcutters will never group at range over 30 feet
When you expand your range out to 30 yds /90 feet and more WELLLL