So I bought 8lbs. ea. AA4100 and AA1680 to load .300BLK, the 4100 for supers and the 1680 for subs. I have new "Mast" marked brass (Gemtech?) and it was GTG out of the box, measured perfectly in Wilson gauges. I only have military white box CCI primers, which I know in addition to having a tougher cup, also have a magnum priming.
So the data for 4100 supers was for 16.4 min. to 18.4 max., maybe .1grain less, using standard RP primers IIRC. Max velocity listed was 2200fps. I loaded in .2grain increments from min. to max and hit the velocity stated for a 16"bbl. (what I was using) somewhere around 17.2grains or so. No signs of pressure, so I kept testing. I got data all the way up to 18.2 with no signs of pressure and velocities of up to 2400fps. All loads were pretty consistent with little variation in velocity. I'm used to seeing M855 clones using 24.9gr. H335 in LC brass nearly flatten these primers so I know they weren't experiencing too much pressure, but I have no way of testing that. My COAL was ~2.194 using Sierra MK 125gr. OTM's; Sierra data calls for COAL of 2.210. And again, I'm using the military primers.
So for the supers, should I extend my COAL to 2.210? Go to weaker primers? Or should I select a load from my data list, and which one? The higher velocity ones that don't show pressure signs, or the ones that match the book velocity? I'm not used to seeing gains of 200fps with no noticeable signs on the brass, it looks just like the min. loads. I don't have a comparator so I have to figure out the COAL for SMK's using averages (due to how the tips are formed, they are all a bit different and give false readings). I'm still about .016 too short I think but they are just loading into the mags.
With the subs, similar problem: with the military primers, I'm getting 1200fps or so from a 16" bbl. using the only listed subsonic load, 10.9grains of 1680. I loaded some to 10.8 and 11, 11 was obviously supersonic moreso than the 10.9. The 10.8's were right at 1050-1074. I'm wondering if 10.7 may work. COAL was ~2.094, which is about .005 longer than book data (and required no adj. of the seating die, FWIW).
With a 10.5" bbl., supers were ~200fps slower but subs were about the same, more or less. All rounds cycled regardless of barrel length and the actions were even a bit dry, supers and subs, suppressed and unsuppressed and I use no adj. gas block, all functioned just fine and locked back when empty. The subs seemed a bit sluggish without a can but still functioned, and I got near perfect patterns of ejection, supers to the 4:30 about 6 feet away and subs to the 3:00 about 5 feet away.
I'd like to keep using the military primers, I get good ignition and I have perfect reliability regardless of load it seems. No noticeable signs of pressure. What should I do, select a load that clocked ~2200fps, or perhaps 2350? The brass all looks the same. Should I work up a sub using 10.7 or 10.8gr. and a military primer? Or should I start over with weaker primers on one or both?
If I had to guess, I'd pick the most accurate load of the ones I tested, probably one of the faster ones since they seem to me to be okay, and just rework the subs using 10.7-10.8gr..
So the data for 4100 supers was for 16.4 min. to 18.4 max., maybe .1grain less, using standard RP primers IIRC. Max velocity listed was 2200fps. I loaded in .2grain increments from min. to max and hit the velocity stated for a 16"bbl. (what I was using) somewhere around 17.2grains or so. No signs of pressure, so I kept testing. I got data all the way up to 18.2 with no signs of pressure and velocities of up to 2400fps. All loads were pretty consistent with little variation in velocity. I'm used to seeing M855 clones using 24.9gr. H335 in LC brass nearly flatten these primers so I know they weren't experiencing too much pressure, but I have no way of testing that. My COAL was ~2.194 using Sierra MK 125gr. OTM's; Sierra data calls for COAL of 2.210. And again, I'm using the military primers.
So for the supers, should I extend my COAL to 2.210? Go to weaker primers? Or should I select a load from my data list, and which one? The higher velocity ones that don't show pressure signs, or the ones that match the book velocity? I'm not used to seeing gains of 200fps with no noticeable signs on the brass, it looks just like the min. loads. I don't have a comparator so I have to figure out the COAL for SMK's using averages (due to how the tips are formed, they are all a bit different and give false readings). I'm still about .016 too short I think but they are just loading into the mags.
With the subs, similar problem: with the military primers, I'm getting 1200fps or so from a 16" bbl. using the only listed subsonic load, 10.9grains of 1680. I loaded some to 10.8 and 11, 11 was obviously supersonic moreso than the 10.9. The 10.8's were right at 1050-1074. I'm wondering if 10.7 may work. COAL was ~2.094, which is about .005 longer than book data (and required no adj. of the seating die, FWIW).
With a 10.5" bbl., supers were ~200fps slower but subs were about the same, more or less. All rounds cycled regardless of barrel length and the actions were even a bit dry, supers and subs, suppressed and unsuppressed and I use no adj. gas block, all functioned just fine and locked back when empty. The subs seemed a bit sluggish without a can but still functioned, and I got near perfect patterns of ejection, supers to the 4:30 about 6 feet away and subs to the 3:00 about 5 feet away.
I'd like to keep using the military primers, I get good ignition and I have perfect reliability regardless of load it seems. No noticeable signs of pressure. What should I do, select a load that clocked ~2200fps, or perhaps 2350? The brass all looks the same. Should I work up a sub using 10.7 or 10.8gr. and a military primer? Or should I start over with weaker primers on one or both?
If I had to guess, I'd pick the most accurate load of the ones I tested, probably one of the faster ones since they seem to me to be okay, and just rework the subs using 10.7-10.8gr..
