snox801
Well-Known Member
I should add I could only get mid 2700's with cup core also.
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6.5 Grendel for whitetail
- Thread starter Tank608
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I have a grendel. It doesnt defy the laws of physics. Just about every cartridge known loses 20-25 fps per inch of barrel. The 308 is one of the most efficient cartridges ever and it's 25. Barnes lists 3250 for a 100 gr from a 24" barrel in 6.5 creedmoor. That would be 3100 in an 18". So a grendel is only 100 fps slower? I dont care what you do. That's on you. Maybe the hammer folks could verify some data. It doesnt pass the common sense test to me. An AR is not something I want to see a case failure in.
This guy is the guru in the grendel forum. Do the math and let me know what you get.
Here's a comparison with 20" down to 12" with 123gr ELD-M and 123gr SST at sea level.
Supersonic reach listed for 123gr ELD-M
Expansion threshold/900ft-lbs for 123gr SST
I've got a 10.5" and a 22" not shown.
Here's a comparison with 20" down to 12" with 123gr ELD-M and 123gr SST at sea level.
Supersonic reach listed for 123gr ELD-M
Expansion threshold/900ft-lbs for 123gr SST
I've got a 10.5" and a 22" not shown.
snox801
Well-Known Member
Well by your logical Weatherby will never get the speed either. I'm not saying that you should push 100's hard but I keep having the same arguments with people about AI cases. If you use the same methods for finding pressure as with any other case and stop when it shows. How is it good for one and not the other. When I find the eld I stoped at the same slight bolt drag as with the hammers so how would that be any different.
Plus I'm not the only one. I know a few runni g hammers at the same speed as me and higher. So either we all are dummy's or the hammers have lower engraving pressures that allow more speed.
Plus I'm not the only one. I know a few runni g hammers at the same speed as me and higher. So either we all are dummy's or the hammers have lower engraving pressures that allow more speed.
snox801
Well-Known Member
The absolute hammer is indeed 300 FPS faster that is the whole selling point. They reduce the initial pressure spike like a Weatherby but not contacting the rifling until way back on the bullet. So it's jumping to rifling like a Weatherby
sdakotaguy
Well-Known Member
Based on what exactly? swipe marks, primer flow or strain gauges? Which Hammer bullets are we referring to? all of them or a select few?
I have started playing with the Absolute Hammer in the 6mm ARC. Admittedly I am a bit uncomfortable pushing velocity to the limit with little starting data, especially with the need to go out on a bit of a limb with propellant selection due to little to no data.
Weatherbys have huge free bore but also large case capacity. Look at the end of the day we all take responsibility for what we do. I just know a 6.5 grendel is not a 6.5 creedmoor or 260 no matter what bullet you shoot.
sdakotaguy
Well-Known Member
For heavy bullets 129 grain flat base, I suspect many would be doubting what Leverevolution will yield for safe velocity in the 6.5mm Grendel. Would not rule out a similar yet faster powder choice offering surprising safe velocity with Absolute hammer offering. Though would approach with caution. Really do look forward to more well vetted data for the Absolute Hammer offerings.
snox801
Well-Known Member
Correct but I'd the bullet like and absolute hammer does not engage rifling till way back that's a big jump hence freebore. Which allows the case capacity to get higher fps. Plus the way it engraved the bullet with less contact. Same with cutting edge laser.
I just think that until you try it yourself you shouldn't be commenting on it not being possible or saying it way over pressure.
This argument has been had a lot and I've shot hammer specifically for that same reason.
By your metrics everyone pushing 6.5 creeds with 140gr bullets past 3k is grossly over pressure. Yet they do it all the time with Rl26. And many with much more experience than me reloading. We have way to many factors to consider like bullet construction, engraving pressure, and powders to say that FPS is the indication of over pressure.
I just know what I've loaded is the same pressure based on my ideas for pressure as I load every other bullet. Which is well established wag to do it for decades.
Would suggest looking at Hammer Hunter and Absolute Hammer load data on this Forum. Also some very good articles on the Hammertime Forum sponsored by Hammer Bullets. Look under Reloading section. You may be quote surprised at what they achieve
Heres the deal. Velocity equals pressure and vice versa. While you might be able to cheat some with the bullet bands and freebore there are limits to this. I am quite familiar with the creedmoor and R26 as well. I have looked at hammer data online and still think it's a stretch when your getting 6.5cm velocities in the grendel. Show me some pressure tested data not just what some guy posts online.
Heres the deal. Brass will not show pressure signs until 70k. So reading primers on a case with saami at 52k is pointless. In a bolt gun maybe. But not an ar.
My 85 grain hammer load for Grendel. 32.9 grains of Power Pro Varmit. CCI 450, 22 inch CZ 527. 3025 FPS. With 80 thousands jump. Same load in 20 inch Howa is 3060. No pressure signs. Nothing !
