Hornady GMX
I got in a mood to do a little expansion testing. The Hornady GMX interested me in that it wasn't pure copper, so it would be less likely to copper foul the barrel.
This is hardly the first time I've done this sort of thing. Back in 2002 I did some tests on the then new Hornady interbond. Anyway, here's some pics of 2 recovered GMX bullets fired from my Browning A-bolt 300 WSM;
Now aren't those some beautiful mushrooms? Expansion is .615 and .640, retained weight is written on the paper in the bottom pic. Which is the absence of the plastic tip for one and maybe the loss of some of the metal and the tip on the other.
The story behind this bullet is that it is built from gilding metal, the same stuff most jacketed bullets use for their jackets. Therefore it's like shooting any other bullet, as far as the fouling goes.
I loaded these with my favorite powder for my 300 WSM, H-4831 SC. I choose a mid range load, Lyman 48th said start at 65.0 to 72.0,(for 165's), I went with 68.5, loaded 15 for testing. I wrote down the chrono readings, 3077 av, for two rounds.
These were fired into water filled gallon milk jugs laid on their sides, one behind the other, @ 100 yds. The first three were lost in the grass, the bullets kept skipping out the side of the 3rd jug. Finally 4 and 5 were captured. One came to rest in the third jug, one barely made it into the forth.
The first jug was mostly blown into 4 pieces, the second was split wide open, the third simply had a hole through with the bullet laying in the bottom, the one that made it to the forth barely made a slit in the bottom.