I got out yesterday to play around with the new 305gr Hammer bullets to see how they shoot. RockyMtnMT sent these to me after the 307s I bought proved to be a little too much of a good thing and didn't stabilize in a 9.3 twist barrel.
Here's the new 305 version next to a 300gr OTM. That Hammer is a sexy looking bullet!
The initial test gun is a 338 CheyTac improved (similar to a SnipeTac) with a 30" barrel. This set up has proven to be capable of spectacular accuracy when I hold up my end of the deal.
All testing was done shooting prone off of a bipod. While I can spot my own hits past about 600 yards, I record everything using a GoPro setup to record through the Swarovski and controlled from my phone so I don't have to get up. I can then review the shot on my phone and make any adjustments. This works out pretty well since I don't have any friends who are competent spotters! Ranges are taken with a Terrapin and all other conditions are taken from a Kestral.
My initial load for the 305s is 140gr of H 50BMG. This is down a couple grains from what I run with the 300gr OTM but the velocities are within 10 fps with the different bullets. The 305s are shooting at 3180 fps according to the Magneto speed and they impact 1.45" high at 100 yards when I'm zeroed with the 300gr OTMs. I set the 1.45" as my zero height in the ballistic calculator so that I could stay zeroed with the OTMs. I fired 3 shots at 100 yards to get my velocity and zero and was rewarded with a .5" group with nice round holes. It appears that these stabilize much better than the 307s which were already unstable at 100 yards from the 9.3" twist.
From 100 yards I went straight to 1380 yards using an estimated BC that Steve provided for me. These were my conditions:
Velocity: 3180 fps
Altitude: 2114 ft
Baro: 31.43 inHg
Temp: 68 F
Humidity 48.2%
The calculator predicted 7.9 MILS of vertical so I dialed and sent 3 shots. My impacts were low by about .5 MIL, but the vertical spread was less than .2 MIL so it was very consistent. Horizontal spread was greater because I was not terribly concerned with wind calls yet. I adjusted the BC value until the calculator matched up with my actual drops. Now it was coming up with 8.4 MIL of vertical which matched my impacts. The new adjusted BC was .380 for a G7.
I took this new value and went straight to 1721 yards to test it. The calculator said to come up 12.4 MIL. I sent 3 shots and was rewarded with 3 hits within .1 MIL of my POA all landing inside a .25 MIL group.
For now, I'm pretty comfortable saying that for my conditions, the 305 Hammers have a G7 BC of .380. Not bad at all for a solid copper hollow point hunting bullet! More impressive is the consistency of these bullets. I've played with the Cutting Edge solids in my 375 BME and in a 338 Edge and They were the most unpredictable bullets I've ever shot. They'd shoot well for 2 shots and then the 3rd would seem to fall out of the sky! The Hammers are not only making it to the target, but holding a phenomenal and consistent group with no load tuning. I just seated them .015" off the lands and reduced the charge I'm running for a similar weight bullet.
Next weekend I hope to get out again to test them in the rifle and also run them at a lower velocity to duplicate a 338 Edge. Since I don't have a 338 Edge, I'll do it the fun way and run them out of the 338 CheyTac Improved pistol.
I just wanted an excuse to post a picture of the pistol. LOL
Andrew
Here's the new 305 version next to a 300gr OTM. That Hammer is a sexy looking bullet!
The initial test gun is a 338 CheyTac improved (similar to a SnipeTac) with a 30" barrel. This set up has proven to be capable of spectacular accuracy when I hold up my end of the deal.
All testing was done shooting prone off of a bipod. While I can spot my own hits past about 600 yards, I record everything using a GoPro setup to record through the Swarovski and controlled from my phone so I don't have to get up. I can then review the shot on my phone and make any adjustments. This works out pretty well since I don't have any friends who are competent spotters!
Ranges are taken with a Terrapin and all other conditions are taken from a Kestral.My initial load for the 305s is 140gr of H 50BMG. This is down a couple grains from what I run with the 300gr OTM but the velocities are within 10 fps with the different bullets. The 305s are shooting at 3180 fps according to the Magneto speed and they impact 1.45" high at 100 yards when I'm zeroed with the 300gr OTMs. I set the 1.45" as my zero height in the ballistic calculator so that I could stay zeroed with the OTMs. I fired 3 shots at 100 yards to get my velocity and zero and was rewarded with a .5" group with nice round holes. It appears that these stabilize much better than the 307s which were already unstable at 100 yards from the 9.3" twist.
From 100 yards I went straight to 1380 yards using an estimated BC that Steve provided for me. These were my conditions:
Velocity: 3180 fps
Altitude: 2114 ft
Baro: 31.43 inHg
Temp: 68 F
Humidity 48.2%
The calculator predicted 7.9 MILS of vertical so I dialed and sent 3 shots. My impacts were low by about .5 MIL, but the vertical spread was less than .2 MIL so it was very consistent. Horizontal spread was greater because I was not terribly concerned with wind calls yet. I adjusted the BC value until the calculator matched up with my actual drops. Now it was coming up with 8.4 MIL of vertical which matched my impacts. The new adjusted BC was .380 for a G7.
I took this new value and went straight to 1721 yards to test it. The calculator said to come up 12.4 MIL. I sent 3 shots and was rewarded with 3 hits within .1 MIL of my POA all landing inside a .25 MIL group.
For now, I'm pretty comfortable saying that for my conditions, the 305 Hammers have a G7 BC of .380. Not bad at all for a solid copper hollow point hunting bullet! More impressive is the consistency of these bullets. I've played with the Cutting Edge solids in my 375 BME and in a 338 Edge and They were the most unpredictable bullets I've ever shot. They'd shoot well for 2 shots and then the 3rd would seem to fall out of the sky! The Hammers are not only making it to the target, but holding a phenomenal and consistent group with no load tuning. I just seated them .015" off the lands and reduced the charge I'm running for a similar weight bullet.
Next weekend I hope to get out again to test them in the rifle and also run them at a lower velocity to duplicate a 338 Edge. Since I don't have a 338 Edge, I'll do it the fun way and run them out of the 338 CheyTac Improved pistol.
I just wanted an excuse to post a picture of the pistol. LOL
Andrew
