I have a US MAGNUM scale I picked up off eBay for a very reasonable price (< $20. + shipping) that weighs up to 16 oz - 7000 grain - 500 gramand is accurate enough for archery & muzzleloading. Just compared it to my good digital scales and the results for a bullet that actually weighs 245.4 gr was 245 gr (it doesn't have tenths on it's scale).
The added capacity comes in handy for a lot of household chores.
You can do a search for US MAGNUM SCALE on eBay and you should find it.