12-10-2023, 08:06 PM
Scrape,
You asked what kind of MV I was getting out of my 22" grendel.
I'm a bit hesitant giving strictly fps numbers out, especially since from your posts, I have the impression you might be trying to push a medium-pressure cartridge too far. Don't get me wrong, I like speed also, especially since mono bullets need speed to work their best, and I do like several Barnes's. For the 100 ttsx I'm now shooting mostly H335, but its performance is similar to Xbr, at least from my tests in my guns.
So let me offer first of all, some caveats. First off, the most important thing is what can your barrel shoot safely for you, irrespective of what someone else's barrel does. I always start with book data, and work up. Just because a book says so, doesn't mean that your barrel will respond the same. You could run into a max before you get to book max. Like Clint says, "a man's got to know his limitations."
You have an 18" barrel, I'm guessing it's an AR frame, since most bolt-actions either the poster will call it that or they are 20"+. So Saami limits to an AR frame is 52ksi.
The grendel doesn't show overpressure until you are already way over, so you can be over and brass etc doesn't tell you that. This is a key difference compared to other more standard calibers.
Also your post does not say whether you developed the load with benefit of a chrony, over a ladder of powder loads, so that's a flag to me that leaves me concerned too. Changes in MV vs changes in powder loads, And how they might accelerate as you approach or exceed max book load, for your barrel, are important trends to have for yourself, before you can adequately say what's going on with your shots.
Finally, I have gone over-pressure a couple times with the grr, but had enough info to see it and back off before I caused any kabooms. So I concentrate not on whatever max MV I can get, but what is a good and fast enough MV, on a NODE (ie, repeatedly accurate), under max, so I can shoot it and have an expectation that it will perform its job on target. I know this sounds like a lot of philosophical stuff but I think it is important to get out on the table.
My 22" bolt action rifle I can get 2725-40 fps on a node, with the ttsx, and that is admittedly over saami max of 52ksi but I have a bolt action, and it is below the 58ksi (est) that I stay under, for bolt action grendels. Thus it is still not a load to recommend for an AR frame, and I do not shoot that load in my AR frame grendels. This would translate to ~2615 fps (under 52ksi) in an 18" AR frame and depending on other specifics, such as using your OAL of 2.200".
What would 2615 ttsx MV deliver downrange? 1000 ft-lbs at 200 yds under nominal elev and temp conditions; and estimated 2162 fps, which indicate it would have an acceptable speed to open up properly in medium size game.
One more thing, I would strongly recommend that you pick up the Grendel handbooks, vols 1 and 2, from the vendor section on this forum (I get no $$ for saying this); they have a wealth of grendel specific information along with real gel tests and speeds of most of the useable grendel bullets, as well as lots of load data that some good grendel shooters got -- keeping in mind that your MMV. LOTS of good info.
I hope this is helpful. Shoot well and stay safe.
You asked what kind of MV I was getting out of my 22" grendel.
I'm a bit hesitant giving strictly fps numbers out, especially since from your posts, I have the impression you might be trying to push a medium-pressure cartridge too far. Don't get me wrong, I like speed also, especially since mono bullets need speed to work their best, and I do like several Barnes's. For the 100 ttsx I'm now shooting mostly H335, but its performance is similar to Xbr, at least from my tests in my guns.
So let me offer first of all, some caveats. First off, the most important thing is what can your barrel shoot safely for you, irrespective of what someone else's barrel does. I always start with book data, and work up. Just because a book says so, doesn't mean that your barrel will respond the same. You could run into a max before you get to book max. Like Clint says, "a man's got to know his limitations."
You have an 18" barrel, I'm guessing it's an AR frame, since most bolt-actions either the poster will call it that or they are 20"+. So Saami limits to an AR frame is 52ksi.
The grendel doesn't show overpressure until you are already way over, so you can be over and brass etc doesn't tell you that. This is a key difference compared to other more standard calibers.
Also your post does not say whether you developed the load with benefit of a chrony, over a ladder of powder loads, so that's a flag to me that leaves me concerned too. Changes in MV vs changes in powder loads, And how they might accelerate as you approach or exceed max book load, for your barrel, are important trends to have for yourself, before you can adequately say what's going on with your shots.
Finally, I have gone over-pressure a couple times with the grr, but had enough info to see it and back off before I caused any kabooms. So I concentrate not on whatever max MV I can get, but what is a good and fast enough MV, on a NODE (ie, repeatedly accurate), under max, so I can shoot it and have an expectation that it will perform its job on target. I know this sounds like a lot of philosophical stuff but I think it is important to get out on the table.
My 22" bolt action rifle I can get 2725-40 fps on a node, with the ttsx, and that is admittedly over saami max of 52ksi but I have a bolt action, and it is below the 58ksi (est) that I stay under, for bolt action grendels. Thus it is still not a load to recommend for an AR frame, and I do not shoot that load in my AR frame grendels. This would translate to ~2615 fps (under 52ksi) in an 18" AR frame and depending on other specifics, such as using your OAL of 2.200".
What would 2615 ttsx MV deliver downrange? 1000 ft-lbs at 200 yds under nominal elev and temp conditions; and estimated 2162 fps, which indicate it would have an acceptable speed to open up properly in medium size game.
One more thing, I would strongly recommend that you pick up the Grendel handbooks, vols 1 and 2, from the vendor section on this forum (I get no $$ for saying this); they have a wealth of grendel specific information along with real gel tests and speeds of most of the useable grendel bullets, as well as lots of load data that some good grendel shooters got -- keeping in mind that your MMV. LOTS of good info.
I hope this is helpful. Shoot well and stay safe.
"Down the floor, out the door, Go Brandon Go!!!!!"