doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com A little help with 16 ga loading

1.) I load 12 ga for my vintage guns at 6700-6900 psi. It is my ( possibly incorrect ) understanding that appropriate pressure levels vary per gauge. I.e. 9000 psi in a 12 isn't the same as 9000 psi in a 20 due to the difference in diameter. If my belief that 7000 psi is appropriate and 8000 is a max for my vintage 12 ga. What would be comparable pressures in a 16 ga
2.) anyone have 2 9/16 recipes using green dot powder? I have many options in hulls but prefer to stick to the powder I have if possible.

PSI is the same, if it states 9000 psi for 12 ga. load and states 9000 for a 20 ga. load.

Join the 16 Gauge Reloaders Group and for a small fee, I think $20.00, you will have a lifetime of 16 gauge reloading data that has all been tested.

Let me restate. Of course 9000 is 9000, how is the relationship vary per gauge. Ie. Is more pressure required for comparable velocity in smaller gauges. Is more pressure acceptable in smaller tubes ?
My possible misconception comes from this situation. I received a lot of great help with my "damascus safe" 12 ga 2.5 in loads from a powder company contact. When I tried to bridge that source and info into 20 ga 2.5 info with the question: "Can I get a comparable load for a 20". The reply as I remember it was to the effect of "a functional 20 ga load will require higher pressure". It is possible I misunderstood. It is possible he had spent enough time on my project.

Just google the loaders group? 16 ga society?

Mark, yes, go to the 16ga Society here.

http://www.16ga.com/forum/viewtopic.php?t=921

Join for free and get a wealth of 16 ga. reloading data.

One of my favorite loads is a 2 1/2", 7/8oz load using green dot.

Matt

My take is you would get essentially identical velocities with identical pressures "IF" the load in the smaller gauge was proportionate to bore diameter. the "Fly in the Ointment" is that smaller gauges are nearly always loaded heavier in the smaller gauge. to be proportionate to bore diameter the loads would be equal to the squares of their diameters. Thus a 16ga shot load would be 82% that of the 12 & a 20 gauge 71%. As many "Low" pressure 1ga loads are in the 7/8 - 1oz range what you are thus looking at to maintain similar pressures is 3/4 oz in the 16 & 5/8 in the 20. Even then with each step down in gauge a higher % of the shot will have bore contact or more wad contact for the same percentage of load.
There were sound & solid reasons why with the older shells the 12 gauge reigned Supreme.

Know you have heard it several times already but there is a ton of good loading information over at 16 ga.com. Tested loads with a wide variety of hulls, powders and wads. Several loads have been tested at the expense of member of that bbs and they have a large spread sheet with all loading data. Many low pressure loads are listed. If a Green Dot load exist then you should find it there.