Specna edge series gearbox

[Pewpewpetie]

Hi all, currently wanting to dmr my specna arms sa-e14. I was thinking an m120 spring as local sights limit is 420fps on .2. do you think the box is strong enough or will other upgrades be nessasary?  Many thanks

[Rogerborg]

I'd be astonished if it weren't.  What I would suggest is radiusing the corners if you're opening it up anyway.