British gun manufacturers were invited to propose designs. Of the many entries, five for the horse artillery gun and three for the field gun were selected and their makers invited to submit a "specimen". These were tested in 1902, but none was found suitable for service although they all had good features. The makers were called to a conference and agreed to collaborate to produce a composite design. This used the Armstrong gun, Vickers' recoil system, and Royal Ordnance Factory's sighting and elevating gear and ammunition carrying. Reduced wheel size from to was also accepted (it had been a matter the Equipment Committee had to investigate) which saved weight. Four Artillery batteries of the composite design took part in trials of in 1903, and the new 18-pounder design was accepted.