Just had my rifle re-barreled from a factory SPS 20" 1:12 twist to a 24" Rock Creek 5R 1:10 twist. I'm going to break it in with my go to load of 178 Amax and 44 grains of RL15.
However, with the longer barrel, and tighter twist, I bought the fixens to experiment with the 208 Amax. Here comes my question. My max chamber length is 2.964" to the O give. I was going to try to load them to mag length, with AI mags, at 2.890"...but ran into compression immediately at 45gr.
So I figured I would go the tried and true method and just single feed the rounds to make the most of cartridge space. I started loading them at 44gr at 2.965 COAL, measures about 2.242 to the O give. Doing that I can hear powder moving in the case at 44 grains. I start to hear a little crunch up through 45 and 46 grains, but can still hear a little movement after seating the bullet. Not until about 47.5 or so do I hear a little crunch and no movement afterwards.
So here is the question, I'm starting at 44 grains and moving up in half grain increments, really just looking for pressure and a rough idea of velocity at this point. As long as I'm working up if the compression increases to a point where its going to give the rifle a problem, I'll start seeing the common warning signs right? Flattened/Cratered primers, sticky bolt lift, ejector marks, etc.?
Looking at other guys' data on here it seems everybody with a 24" or better barrel starts breaking into the 2600FPS threshold right around 47-48 grains, which is right about where I'm not hearing movement in my cases. Its not heavily compressed, I don't have to put much effort into seating the bullet, but I do hear a little crunch as a few of the sticks of powder break while seating.
Is it any more dangerous if you move up incrementally like we always do? Should you scrap the rounds if you hear any crunch at all? Logically it doesn't seem like it would matter if you break a few sticks during seating, as long as its not totally smooshed. Even then I would think you would be ok with an incremental workup. If you get the pressure warnings because the load is starting to compress, stop.
I can't imagine that Montana Marine and some of you other guys loading upwards of 50-51 grains, even at a COAL of 3.000 aren't getting a little crunch on seating. We're talking a difference of 0.036. Does 36/1000ths make that huge a difference? Any thoughts? Suggestions?
Rich
However, with the longer barrel, and tighter twist, I bought the fixens to experiment with the 208 Amax. Here comes my question. My max chamber length is 2.964" to the O give. I was going to try to load them to mag length, with AI mags, at 2.890"...but ran into compression immediately at 45gr.
So I figured I would go the tried and true method and just single feed the rounds to make the most of cartridge space. I started loading them at 44gr at 2.965 COAL, measures about 2.242 to the O give. Doing that I can hear powder moving in the case at 44 grains. I start to hear a little crunch up through 45 and 46 grains, but can still hear a little movement after seating the bullet. Not until about 47.5 or so do I hear a little crunch and no movement afterwards.
So here is the question, I'm starting at 44 grains and moving up in half grain increments, really just looking for pressure and a rough idea of velocity at this point. As long as I'm working up if the compression increases to a point where its going to give the rifle a problem, I'll start seeing the common warning signs right? Flattened/Cratered primers, sticky bolt lift, ejector marks, etc.?
Looking at other guys' data on here it seems everybody with a 24" or better barrel starts breaking into the 2600FPS threshold right around 47-48 grains, which is right about where I'm not hearing movement in my cases. Its not heavily compressed, I don't have to put much effort into seating the bullet, but I do hear a little crunch as a few of the sticks of powder break while seating.
Is it any more dangerous if you move up incrementally like we always do? Should you scrap the rounds if you hear any crunch at all? Logically it doesn't seem like it would matter if you break a few sticks during seating, as long as its not totally smooshed. Even then I would think you would be ok with an incremental workup. If you get the pressure warnings because the load is starting to compress, stop.
I can't imagine that Montana Marine and some of you other guys loading upwards of 50-51 grains, even at a COAL of 3.000 aren't getting a little crunch on seating. We're talking a difference of 0.036. Does 36/1000ths make that huge a difference? Any thoughts? Suggestions?
Rich