Now it's possible that the two separate pounds (from different lots) I've tried of 8208 are both on the very slow end of the burn distribution, but I didn't see pressure in my rifle until I was just bonkers above the load data Hodgdon shows for 8208 with heavy bullets in .223. Like more than 2 grains over max.
I'm running 80gr ELD at somewhat long lengths (~2.45" OAL), but shorter than most 80SMK data should show (2.55"). I didn't see pressure signs until I was over 24gr. Yes, 24gr. Book max is 21.0.
The rifle is an AR-15, standard Nato chamber. And it will show pressure with AR Comp and RL15 in about the expected charge weight range. So I don't think it's my gun.
As a cross check, Hornady shows 8208 with a max of 22.8gr for 75 ELDs. Dropping nearly two grains down to 21.0 for an 80gr SMK in the Hodgdon data seems a bit excessive. And the 75 is loaded much shorter than the 80SMK in this instance. (2.39" vs 2.55")
Comparing weight changes with other powders is useful. Take RL15, the max charge only drops 0.8gr when you jump from 75gr to 80gr. 24.1 of RL15 for an 80gr .223 makes sense. So does 23.2 of AR Comp for an 80 (most places AR comp and RL15 are about a grain apart in a given bullet weight).
One or both of two things must be true: 1) The 80SMK generates more pressure than an 80 ELD-m does for a given charge weight 2) Hodgdon is sandbagging their 8208 data in 80gr.
The only data I can find for 80s and 8208 is with an SMK and from Hodgdon. But is it not intriguing that Hodgdon shows a max of 23.2 for 77 SMK at maglength but drops you way down to 21.0 going three grains heavier with an 80SMK at a much longer OAL of 2.55"?
I wonder if it isn't more than 80SMK than it is perhaps the 8208 powder? But if that was true, why does Alliant show a HIGHER max charge of AR Comp for the 80smk (loaded long) than it does for the 77smk (mad length)? I think we know it's because of the OAL difference.
Which forces the conclusion that the 8208 data in a few places is just very, very VERY conservative. There's no reason to think you should drop way down in max charge going from 77smk to 80smk given the very different OALs.
And--sanity check-- when you actually test 8208 with 80s, you'll find pressure about where you'd expect it if you where just guessing at a max charge looking at 77gr data and going longer on OAL.
HMMMMM.
I'm running 80gr ELD at somewhat long lengths (~2.45" OAL), but shorter than most 80SMK data should show (2.55"). I didn't see pressure signs until I was over 24gr. Yes, 24gr. Book max is 21.0.
The rifle is an AR-15, standard Nato chamber. And it will show pressure with AR Comp and RL15 in about the expected charge weight range. So I don't think it's my gun.
As a cross check, Hornady shows 8208 with a max of 22.8gr for 75 ELDs. Dropping nearly two grains down to 21.0 for an 80gr SMK in the Hodgdon data seems a bit excessive. And the 75 is loaded much shorter than the 80SMK in this instance. (2.39" vs 2.55")
Comparing weight changes with other powders is useful. Take RL15, the max charge only drops 0.8gr when you jump from 75gr to 80gr. 24.1 of RL15 for an 80gr .223 makes sense. So does 23.2 of AR Comp for an 80 (most places AR comp and RL15 are about a grain apart in a given bullet weight).
One or both of two things must be true: 1) The 80SMK generates more pressure than an 80 ELD-m does for a given charge weight 2) Hodgdon is sandbagging their 8208 data in 80gr.
The only data I can find for 80s and 8208 is with an SMK and from Hodgdon. But is it not intriguing that Hodgdon shows a max of 23.2 for 77 SMK at maglength but drops you way down to 21.0 going three grains heavier with an 80SMK at a much longer OAL of 2.55"?
I wonder if it isn't more than 80SMK than it is perhaps the 8208 powder? But if that was true, why does Alliant show a HIGHER max charge of AR Comp for the 80smk (loaded long) than it does for the 77smk (mad length)? I think we know it's because of the OAL difference.
Which forces the conclusion that the 8208 data in a few places is just very, very VERY conservative. There's no reason to think you should drop way down in max charge going from 77smk to 80smk given the very different OALs.
And--sanity check-- when you actually test 8208 with 80s, you'll find pressure about where you'd expect it if you where just guessing at a max charge looking at 77gr data and going longer on OAL.
HMMMMM.
