I hear you, now I need to find ammo
 

Thank you all for your help. But I’m now concerned that the ammo I planned to shoot might do damage to the stock. Any referrals to a place that sells 16 gauge shells with a 7/8 ounce load and low powder charge? Google Has been no help. My preference is #6 shot for rabbits

Try RST shells. A bit pricey, but made for our type of guns.

RST out of Pennsylvania. Buy them when they have them. I’ve broke a lot of clay birds and doves with a very similar Parker in that serial number range. Very pricy but fun to shoot and effective. Enjoy! I now reload a similar load when I have a little time. Congrats!

You could take a look at the RST thread on this forum for info, but the fact that you’re looking for 16ga ammo will cause some additional issues.

Many of us are patiently waiting for RST to run 16ga. They expect to have supply in January. Go to their website, choose desired load and click on the buy button. You will see a pop up window with "notify me" when the load is available.

I stopped buying shells from RST when they sent me a flat of 16 gauge shells for my O frame 16 gauge hammer Parker. The shells had the lousy, overly thin primers that pierced on every shot. After 4 shots I quit using them as I did not want to damage anything from the blowback. I reload using modern 209 primers with no problem. When I mentioned this to Morris at a Parker annual meeting, he did not want to talk about it so this unhappy customer went down the road.

Unfortunately although reloading isn't for everyone it's the only way I can feed my old favorite and new favorite shotguns with the exact load I want. Once you get started you will never want to buy factory shells again.

I rather doubt Morris hand picked thin primers just for you. Piercing cheddite primers on Parker hammer guns is not uncommon, but the problem lays with your gun, rather than the primers. It is a clear indication that your firing pins have, just as many Parker hammer guns, worn to a pointed profile and need to be dressed properly. You may have had better luck with another brand, which most likely had thicker Remington or Winchester primers, but pointing blame at RST is pointing in the wrong direction.
I too have pierced Cheddite primers, but only in hammer guns, and rectified the firing pins right away, never having had the problem again. I would estimate I've used more than 25,000 Cheddite primers in 12, 16, 20 and 28ga.

RST uses primed Cheddite hulls. They are what they are. Possibly you have a firing pin issue?

You’re way overthinking this.