The inn was taken by a firm calling itself John Ferguson & Co., the active member of which was Sir William Bull's brother-in-law, Captain Budden; and the business appeared to consist of dealing in second-hand scientific instruments and machinery, curiosities, antique armour and weapons, old furniture, and so forth, which were brought in very heavy cases and deposited in the yard.

For a time it proved useful, and the Maxims from Woolwich passed safely through the Hammersmith store.

But the London police got wind of the Hammersmith Armoury, and seized a consignment of between six and seven thousand excellent Italian rifles.

A rusty and little-known Act of Parliament had to be dug up to provide legal authority for the seizure.
Many sportsmen and others then learnt for the first time that, under the Gun-barrel Proof Act, 1868, every gun-barrel in England must bear the Gun-makers' Company's proof-mark showing that its strength has been tested and approved.

As the penalty for being in possession of guns not so marked was a fine of L2 per barrel, to have put in a claim for the Italian rifles seized at Hammersmith would have involved a payment of more than L12,000, and would have given the Government information as to the channel through which they had been imported.