I spent much of the last week refurbishing an old beater 336. While I was waiting for True Oil to dry I worked up some loads for the old girl.
The chamber in this rifle is a little oversized. I have not done a chamber casting but miking the cases that have been fire formed to this chamber tell the tale. In fact the portion of the case web just above the rim that doesn't fit up into the resizing die is stretched enough that they won't chamber in my other two 30-30s even after full length resizing. I just keep my brass sorted to the gun they are for and all is good. Also the throat in this old Marlin has plenty of free bore so case trimming has never been necessary. I decided a while back that neck sizing was the only way to fly with this old 336. The slightly oversized cases with long necks add to the case capacity by a small but noticeable amount.
My powder of choice is ww748. If I tap on the side of the case with a 60d ring shank nail(any tapping device will suffice) then I can get 43 grains of 748 in the case. With the two bullets that I load 43 grains still keeps the pressure south of 35,000 psi and very safe. The bullets are the Hornady 100 gr Short Jacket and a 130 gr SP(one in the chamber and one in the magazine..hence a twice shooter). My buddy Ty's fps machine shows the 100 grainer to be 2870fps for the average and about 2700 fps on the nose for the 130 grain pill. What this translates to this old fart is that this 30-30 is an honest 250 yard gun. The 100 grainers for coyotes and the 130s for deer. Sighted in a bit over 3 inches high at a hundred yields a shoot right at them proposition out to 250. My groups were all less than 2 inches and usually closer to 1.5 inches @ 100 so the accuracy is there to make this 30-30 a 250 yard varmint/deer rifle. I can live with that!!😉