Longshot !!!! May be worth taking a look at.
 

Gentlemen. Although I am new to shotshell reloading it seems for those who shoot vintage doubles requiring low pressure rounds. Longshot may be the ticket. The only thing I could find on the powder were in forms where people complained that it was either to loud or their shoulders couldn't stand up to the loads. Most published loads are way up there. 1350fps and up all the way to 1450fps. And heavy payloads on top of that. Something I don't want going thru my old double. Even read a couple of forms of people claiming these loads destroyed modern semi autos. None the less. I just had tested a 1 oz lead load in a 2 1/2 12 gauge shell. The results were really good. Average velocity 1233fps @6000 psi. Not sure but that sounds great to me. I also tested a 3/4 oz lead load with this monster powder and the results were amazing compared to Longshot's reputation. Although I slowed the 3/4 oz load down to slow. The six shot string only had 29fps difference from the fastest to slowest and the psi rivaled 7625 or what ever that coveted discontinued powder was. Although I need to up the charge to get 1200fps it's looks like it will still be under 5k psi, maybe way under Guys it looks like Longshot slowed down may just be the ticket. It seems to shoot fine down in the normal range. Under the speed of light. Lol Just my 2 cents worth. I placed my order for some. Precision has it on sale at a great price. AnywY Merry Christmas guys. See you in the field.

Correction. 64 fps was the difference from the fasted to slowest on thet small load. The 27 or maybe is was 29 difference was on the 1 oz load

If you are looking at 12 ga loads there are many on the Hogdon site that are 1 or 1 1/8 oz loads at 2 3/4 or 3 dre and that produce 1150 to 1200 fps. These produce pressures within factory working pressures for which the gun was made.

Look at the pressure tables in TPS. Also look at the chamber dimensions in TPS. Most Parker 12s were not 2 1/2 chambers.

There are many commercial loads as well as handloads that fall well under the 10,500 psi working pressure and well under Parker proof loads. A person can always choose to use low pressure or low recoil loads but Parkers are sturdily made,not delicate.

I do not know where a person would get an idea that Parker loads need to be kept under 5000psi unless he has a gun that is somehow compromised, and if that is the case I suggest it should not be shot at all.

I see what your saying Bruce. Good point. I have never liked the Hodgon site. It says choose then doesn't let you. Never been able to get anything good off that site. Anyway I shoot a fox and it is chambered for 2 1/2 shells. I just like to baby it with low pressures and I baby me with low recoil. It seems Longshot provides both. I actually intend to bring that 1 oz load to 1175 to 1200. Should lower the pressure to at least 5500. I think I just like experimenting with this stuff. Lol when I was a young machinist I once made a black powder cannon. It's a wonder I didn't do some damanage to something. I guess to each his own.

I don't know where you live but watch out for low pressure loads in cold weather. You may get squib or hollow sounding reports and a lot of unburnt powder in the barrels.

Pa. I've heard about that but never experienced it. How cold are you talking about?I'm in Texas. It got down to 16 degrees the other day but my buddies opted out of going hunting. Lol. Fair weather hunters. But about how cold do u mean???

The less the shot charge and less the velocity, the less the recoil and generally less the chamber pressure. A slow moving target you might get away with 1100 psi or a little less and compensate for less impact energy by using larger size shot.

As stated watch out for cold weather. I've heard that some powders such as PB lose as much as 20 percent energy at temperatures below 32F . Squibs are rare but I have heard of them happening.

Good to know. I've heard about wads not clearing the barrel and getting you into trouble. We went hunting the other day but it was only about 40 degrees but wet. I remember when I was young going and breaking 1/2 in to 3/4 in ice to put decoys out. Just started back duck hunting. It if it's real cold I would probably just stay home now. Lol. My age is catching up with me.

I've shot a lot of PB in handloaded 1oz target loads. It is far and away the worst powder for shooting in the cold. At 10deg F your barrels look like you've been shooting black powder and you have to check your barrels between EVERY shot and put a factory target load through each bbl when your done just to clean the bores out. I've shot it down to maybe -20F, where it is pretty comical in performance and not worth the squib/stuck wad chance. I will no longer shoot it below -10F under any circumstances. In warmer weather I really like it for use in very light 12ga guns and 24gr loads, which go out at 1150fps and only 4200psi. That load is really nice in my light damascus 1-frame GHE12. It's also a great grouse/woodcock load in hvy cover with that gun.

For those of us that do not have a copy of The Parker Story, is there anywhere that the pressure tables of which you speak may be looked at?