Finnish, I agree with what has already been said by the other posters regarding reaction to shot - I don't think you have much of a problem.
As an aside, and I'm only looking to give you a heads up if it is applicable, how are you fixed legally to 'buy' rounds from the guy who sold you the rifle? Is he an RFD or otherwise authorised to sell ammo and how does it get entered onto your FAC? If he is a private individual selling to you then could it be construed as doing it by way of trade? Depending on the circumstances this section of the HO Guidance might apply.
Business and other transactions
5.14 A person commits an offence, if by way
of trade or business they are engaged in the
manufacture, sale or transfer of shot guns or
firearms or ammunition to which section 1
of the 1968 Act applies and is not registered
as a firearms dealer (see Chapter 16). This
requirement extends to persons who repair,
test or prove such firearms or ammunition.
Lots of questions I know but we all have to be aware of how things can be viewed by the authorities and not put ourselves on offer. If none of it applies then ignore me and I'll crawl back under my rock.