Hw 57 pop up o ring size?

[Strimmer]

Recently bought a project hw57 as I've not felt like tinkering for quite some time due to work and health. It's got a broken spring, missing screws, cracked stock and the pop up comes out. Otherwise for a 2004 model it's in good condition with little to no rust.

I'm gradually buying all the bits I need but can't find any info on what the o ring size is on the bottom of the pop up breach. I see they sell them on eblag, but I'm refusing to pay £5 for 4 tiny orings.
Can anyone help?
Thanks
Matt

[HW777]

I bought an assortment of rubber O rings in a multi pack, pm me your address and I'll pop some in the post to you, there's bound to be one that fits.

[Black Beard]

The o ring only stops the breech from popping out all the way. It'll work fine without it if you don't turn the gun upside down.

[Strimmer]

I bought an assortment of rubber O rings in a multi pack, pm me your address and I'll pop some in the post to you, there's bound to be one that fits.

Thanks for the offer there, I've a few different assortments myself, with one being close enough but was hoping somebody knew the actual size as I'd imagine it's a common service part that would need changing.

[cptman]

Recently bought a project hw57 as I've not felt like tinkering for quite some time due to work and health. It's got a broken spring, missing screws, cracked stock and the pop up comes out. Otherwise for a 2004 model it's in good condition with little to no rust.

I'm gradually buying all the bits I need but can't find any info on what the o ring size is on the bottom of the pop up breach. I see they sell them on eblag, but I'm refusing to pay £5 for 4 tiny orings.
Can anyone help?
Thanks
Matt

Sounds like Triggers broom.