What calibre and length of barrel is your Hornet. The psi figures you quote cant be right
. Speaking to Bowket he tells me the hammer is quite heavy so that a weaker spring could be used for user friendliness. In production you have to allow for all. There is little bounce on a standard Hornet due to the short hammer travel of only 6-7 mm. Its easy to check yours with a fine felt marker pen and a rule. The production regulator settings he told the factory to use gave a slightly lower shot count out of the many tried but produced no spike when coming off the reg. The count was more than adequate from a 75 cc air reservoir. The standard acceptable figure he gave BSA to comply with for the carbine was 65-75 for the .177 and 90-100 for the .22". Port size doesnt matter apparently if all other settings are OK and was the same for all calibres and power levels.
The R10 hammer travel was increased to try to overcome the problems caused by the BSA designed magazine indexing system rubbing on the hammer.