Final range test before the pronghorn season opens in the morning....
Took the 257 Allen Mag out this morning for one final range test/bullet drop confirmation test before I head out in the morning to try to snipe a big mature pronghorn.
I have been playing with the 257 Allen Mag over the last few weeks getting her ready and have learned alot about the round as well as the limits of the rifle its chambered in as far as barrel weight and things like that.
The load I am using has the 156 gr ULD RBBT Wildcat Bullet ripping out at 3315 fps via 91.0 gr WC872. This is not a max load but its as hard as I want to push this very light weight barrel. Plus, I think this is plenty of velocity for a .800 BC bullet(Drop test determined).
Anyway, from several range testing trips I have determined that 700 yards is the max I will attempt a shot with this rifle and load combo. The load has the ballistic potential to hammer a goat at 2000 yards but this very light barrel at 30" simply is not stiff enough to offer the consistancy for anything much past 800 yards.
I can keep shots in the 8-10" range at 800 yards but just not tight enough for me to feel totally confident about taking a shot at this range. TO be honest I am looking to get a 600 yard shot to test this round out.
Anyway, this morning for the final bullet drop chart test which I finalized late this week and typed up and attached to the Weaver Tactical, I set out four water filled milk jugs at 445, 522, 567 and 612 yards.
I loaded the rifle with four rounds, three in the DM and one up the pipe. Started at the closest jug, ranged, looked up on the drop chart for the proper mil dot hold -0.7 mil and let a big 156 gr ULD fly down range. At the break of the trigger, a mist of water blew out from the back of the jug. The hit was a bit off dead center as it was about 1.5" low from center but perfectly centered horizontally.
Shot two, lined up on the 522 yard jug. Ranged it, looked up the hold which was -1.1 mil and sent another Wildcat down range. This one was a dead center hit, again the bullet seemed to impact the instant the trigger broke!
Jug three was then ranged at 567 yards. Looked up the drop hold, -1.4 mil and again the jug danced at the break of the trigger. This shot was a bit lower though. About 2" off center of the jug but again dead center horizontal.
I was thinking pretty highly of myself running 3 for 3 and now it was onto my last shot. I ranged the last jug at 612 yards and looked up the hold. -1.7 mils was what the printout stated. Lined her up and this time the big 156 landed about 1" under the jug in the loose soft dirt. it did however impact with enough force to lift the jug off the ground about a foot and roll it down the hill.
Even though I missed the last shot, I knew all four would have easily hammered any pronghorn at those ranges. In studying the hits I determined that +0.1 mil was needed to be added to the hold chart as the last two impacts were landing a bit lower then they should have been.
Anyway, I revised the drop/hold chart and taped her on the rifle so we are ready to roll at day break on a big buck from anywhere from the muzzle out to 700 yards.
If things go right I will be reporting about terminal performance of the big 156 gr ULD this time tomorrow.
Hope everyone out there has a successful and more importantly enjoyable big game season this fall and winter!!!
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
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