Soot on standing breach

[Austin J Hawthorne Jr.]

While experimenting with Green Dot in my 10 ga. hammer parker,with a step at the forcing cone, I found that I was getting some soot on the standing breach. The pressure and payload are about the same as when I use my regular load of Red Dot. I was thinking of upping the amount of Green Dot a few grains to about 7500 psi in the hope that a little more pressure might seal the case against the chamber a little tighter.
The fired primers do not appear to be the cause of gas leakage as they are a tight fit when reloading the cases.
Has anyone had a similar problem with low pressure loads?

[Bill Murphy]

You didn't specify your loads. Green Dot is too low a pressure powder to bring pressure up to a reasonable level in a ten gauge with a light shot load. Tell us what exactly you are loading, and we will tell you what your problem is. I am not surprised that you have leakage. If your gun is in good shape with good barrel wall thickness, you can't blow it up with Red Dot or Green Dot. Red Dot is my choice, because it is cheap and will keep pressures up in a big barrel. I have also used it for target loads for about fifty years and have a bunch.

[Austin J Hawthorne Jr.]

Bill,
According to an older Alliant reloading manual a 3 1/4 dram load for a federal hull in 12 ga. lists about 9000 psi using 22 gr. of Green Dot over a federal primer with an rxp 12 wad and 1 1/4 oz. of shot. I tried using 24 gr. of Green Dot over a federal primer with a rem. sp10 wad in a federal 10 ga. hull with a 1 1/4 oz. of #8 shot.
This is the load that seems to allow some gas seepage. I have also used Red Dot in my 10 ga. with good results, but my Red Dot supply is gone so I am hoping to find a satisfactory Green Dot load.

[Bill Murphy]

If you have gas leakage with a certain powder, you don't keep using it. You find a faster burning powder to solve the problem. Get on the website that shows burning rates and find a faster powder. I think I am giving good advise, but maybe I am being too critical. I don't want anyone to be disappointed in their reloading experience. My advise is to throw away your old loading manuals, ignore 12 gauge data, and find a source of Red Dot. Greem Dot is too slow for slow 10 gauge loads and you will continue to experience leakage.