exactly - go with the 1OZ RST's and enjoy it

they will drop any upland bird at a reasonable range

Mr. Armstrong, in direct answer to your question, I cannot tell you about your particular gun in its present condition, but knowing what Parker stated about guns they made like yours, consider the following facts:

1. The Parker Story chapter on barrels provides at p.715 (?) a service and proof load table for Parker guns. Your gun would have been made for a 10,800psi service load, to my recall. Present SAAMI 12ga service loads are 12,500.

2. Following is a Parker load table from the Parker produced booklet "The Small Bore Shot Gun" . The maximum 12 ga load listed is an 1 1/4oz, 3 1/2 dram load. Velocities at 100 feet are provided, backed to muzzle velocity as used today, its about 1250 fps.

3. Your gun would have been targeted and test shot with an 1 1/8oz, 3 dram load, and a hang tag made with pattern results. This load was considered a good patterning load by Parker. ( this is the hunting load I use in 12ga Parkers and has also been the standard trap load for over a century)

Others may have their preferred loads less than what Parker said, but your question asked the maximum load. Presuming you mean recommended maximum service load, Short answer: 10,800psi. The true max load is probably in excess of 20,000 psi based upon destructive tests conducted.

Thanks guys, I have lots of old (50 years or so) 1 & 1 1/8 oz shells. Any new ammo I buy for this gun will be 1 oz.