Originally Posted by beretzs
Originally Posted by 79inpa
Originally Posted by beretzs
Originally Posted by archeratlrg
Thank you. I will probably just stick with the 160/175's in mine. I have. 26" tube so want to push it a bit. I am running right at 3400fps with h4931sc in my 7Rem mag and 140gr N. Bal tips and I'm at 3125 with 160gr partitions in that old rifle but I'm running 69.5 great of the h4831 to get it
No pressure signs, brass life is about 5 loadings so I'm good with that but have always wanted the Mashburn...read to much of Have in my youth ;-) any recommendations as to starting points with the 22 or 870 and 160/175's ?


I'd probably look at any old 7mm Weatherby data using H870.. maybe an old Speer manual would have a start. I've got no experience with it in either of my Mashburns.

I got 3200 with H1000 out of my old Mashburn and 160 Accubonds and 3250 with Partitions. 175's ran 3050 with H1000 and 3100 with Retumbo and 175 Partitions. With my current Mashburn I'm doing 3250's with 154 Interbonds and H1000. Still working the load a little though.

If you haven't gotten one yet, an inside neck reamer will be required to cut the donut out after fireforming. If you don't get it out it will play heck with pressures and with accuracy. Once you nip it once, it's done but nowadays I fireform and inside neck turn. It's made it a cinch to load for.


what is this donut in the neck that you refer to?


When the cases get run into the form and then trim die the thick part of the 300 Win shoulder becomes the neck on the Mashburn. A little ring of material forms about 3/4's the way down on the inside of the neck. I can usually feel it with the pin gauge after forming and definitely after fireforming. I never noticed it or gave it much thought until Darcy pointed out how to find them. Once I slipped a few pins down in there and they were stopped I knew what I had going on.

At first I didn't think it was any big deal but as I shot the brass with the ring concentricity went to heck and pressure would spike for no good reason. Since I've learned to clean up that little wisp of brass life has been easy again and Mashburn is back to being a mild mannered nail driver.


Scotty talked me into a pin gauge set for my Mashburn--not that it was very hard.

Great enlightenment for inside neck diameter (related to neck tension, but many variable involved, not necessarily just inside neck diameter).

I even found donuts in some several times fired 30-06 brass, that I never resized from another case.