Extreme pellet drop during zeroing of scope?

[smudgie49]

So I went to zero my scope down the farm today. Using SMK TH78D (.22) with 2 x fresh 12g C02 bulbs firing Umarex pellets and a Excelvan 4-9 x 40 scope. I wasn't expecting too much in terms of accuracy but used a gun rest to at least eliminate shooter wobble.

Shot groups of 5 over a measured 25 metres and generally managed a 3-4 inch grouping. However, every so often a pellet would drop alarmingly - sometimes 6 or 7 inches below the expected POI. I though at first it might be the CO2 getting cold but then the next pellets would be back 'on target'. Wondering if it could be the quality control of the pellets? Any thoughts?

[barrel]

Not wanting to sound pedantic but do you mean a 3/4" group at 25 yards?.

Kindest regards

Barrel

[grumpygit]

Sounds like a quality control issue where the skirt of the pellet has been damaged . What pellets are you using ?

[smudgie49]

Sounds like a quality control issue where the skirt of the pellet has been damaged . What pellets are you using ?

Umarex - fresh tin from JS Ramsbottom.

[SuffolkRifle]

Try some AA field/RWS Superdomes, sounds as though the barrel doesn't 'like' Umarex pellets - must admit that none of my rifles like them - including the PCPs & springers. Also don't forget that with cold weather, the chill-down of the gun will lower the power on Co2 (magnified if you're shooting quickly)

[smudgie49]

Try some AA field/RWS Superdomes, sounds as though the barrel doesn't 'like' Umarex pellets - must admit that none of my rifles like them - including the PCPs & springers. Also don't forget that with cold weather, the chill-down of the gun will lower the power on Co2 (magnified if you're shooting quickly)

I'll try that. I've only got this rifle for some plinking but it would be good to get it shooting reasonably consistently. Thanks everyone!

[grumpygit]

Umarex - fresh tin from JS Ramsbottom.

As someone said above i would try the AA fields , H&N Field Target, Webley Accupell and my one gun likes Napier Power hunter pellets, all are good . I thought you meant 3/4" not 3 to 4 inch group , it definitly sounds like the pellets its just a case of finding the right one which doesnt seem to be Umarex.

[TORNADOS7]

Who-marex? 😂 as suggested try something a little more ummm 'quality' shall we say, Superdomes/Superfields, AA Diabolo fields etc etc, I find 'Domes' are generally a good place to start...

[smudgie49]

Not wanting to sound pedantic but do you mean a 3/4" group at 25 yards?.

Kindest regards

Barrel

I wish I did mean that! No - the group was 3-4 inches across. No wind and the rifle was clamped into a workmate.