Got to the range today to try a new load in the Win M-70 Classic 460 G&A. Given current powder supply conditions, I decided to try a powder other than IMR-4064, because I have a small supply of that powderleft and it seems to be out of stock just about everywhere.
Looking at the powder burn rate charts, I realized that RL-15 is a bit slower that IMR-4064 and my prior data showed that an 86 grain load produces a mid-2200 fps MV. Given that the 460 G&A case has a volume to the neck-shoulder junction (measured wit BL-(C) 2) of 100 grains, I loaded the CEB BBW #13 500 grain FPSS with 90 grains of RL-15 - I have an adequate supply of this powder - and fired 6 cartridges with it today. MV corrected at 8 yds is 2410 FPS with SD = 4, max spread = 11 FPS KE = 6449. The RL-15 experiment seems to be a success, because it produces excellent MV with markedly less compression than IMR-4064 due to the small granule size.
Here’s the target at 25 yds, with successive adjustments to zero
![[Linked Image from i.postimg.cc]](https://i.postimg.cc/zLdsQVjZ/IMG-1391.jpg)
I also wanted to determine the sighting system to use. The Leupold 1-4x25 produced good groups but the rings wouldn’t hold it in recoil. I’m not totally sold on using magnified optics for elephants in herds.
The Holosun 530 produces an excellent sight picture with very comfortable cheek weld. However, the scope base loosened under recoil despite torque screws fully tightened. I believe the height of the QD mount provided wit the 530 results in significant angular velocity. I changed out the factory high mount for an aftermarket QD lever mount and will try that next week, with the torx screws Loctited in place. I’m hoping to avoid having to epoxy the base to the receiver but that may be the next step. I’ll also ry the NECG peep in a forward receiver ring base.
Once the sighting system is finalized, both the DGRs will be ready. Tempus fugit now.
