Low load density 110 sub loads

[dellet]

Run you numbers through JBM with a 5 yard zero, and yardage increments of 5 yards or less out to at least 150 yards. Then change you muzzle velocity 50 fps.

What you will find is a vertical difference at 50 yards is less than .200”, at 100 2”, and probably 6-8” at 200 or more.

[martin_impact]

The moment I wrote it I had another idea. I Did yard/meter increments, took average V0 at 55y/50m and looked for the first intersection of line of sight and bullet path, which happened to be at 30m. Kept that as zero for calculations with max and min V0 and had 6mm/0.24" of vertical difference which is pretty close to your numbers. Not perfect but better than the parallel bore (sight height zero and zero range 1).
Havent checked the numbers on further distances thought, but you confirmed my feel that they increase significantly with distance.
Any suggestions where to look next to decrease ES, after probably trying other primers?
Powder charge consistency, Combustion chamber volume consistency, neck tension consistency. In this order? (without changing bullets or powder type)

[dellet]

The moment I wrote it I had another idea. I Did yard/meter increments, took average V0 at 55y/50m and looked for the first intersection of line of sight and bullet path, which happened to be at 30m. Kept that as zero for calculations with max and min V0 and had 6mm/0.24" of vertical difference which is pretty close to your numbers. Not perfect but better than the parallel bore (sight height zero and zero range 1).
Havent checked the numbers on further distances thought, but you confirmed my feel that they increase significantly with distance.
Any suggestions where to look next to decrease ES, after probably trying other primers?
Powder charge consistency, Combustion chamber volume consistency, neck tension consistency. In this order? (without changing bullets or powder type)

Sort brass by headstamp and lot if possible
Powder charge, you're probably already doing
Neck tension
Case volume, generally takes care of itself if you use the same headsatmp and lot of brass. if not you might sort out 10 and see if it makes a difference.

If you sort brass by Headsatmp, lot, number of firings, generally on decent brass volume and neck tension take care of themselves. It just depends on how many so called advanced, precision, bench rest techniques you want to use.Basically to more quality control, which is all it is, the smaller the groups.

What makes subsonic shooting so challenging is you are kind of combing rimfire and longrange shooting problems in your loading. So draw from any experience you can, and find a way to apply it.

Rimfire shooters rely a lot on barrel tuners, long range shooters or really any center fire precision shooters, look to different velocity nodes to help tune a load. Subsonic shooting has a fixed velocity for the most part, and I have never seen a tuner used.

It will test what you think you might know about loading, I learned a lot from this cartridge.

[martin_impact]

Sort brass by headstamp and lot if possible
Powder charge, you're probably already doing
Neck tension
Case volume, generally takes care of itself if you use the same headsatmp and lot of brass. if not you might sort out 10 and see if it makes a difference.

If you sort brass by Headsatmp, lot, number of firings, generally on decent brass volume and neck tension take care of themselves. It just depends on how many so called advanced, precision, bench rest techniques you want to use.Basically to more quality control, which is all it is, the smaller the groups.

What makes subsonic shooting so challenging is you are kind of combing rimfire and longrange shooting problems in your loading. So draw from any experience you can, and find a way to apply it.

Rimfire shooters rely a lot on barrel tuners, long range shooters or really any center fire precision shooters, look to different velocity nodes to help tune a load. Subsonic shooting has a fixed velocity for the most part, and I have never seen a tuner used.

It will test what you think you might know about loading, I learned a lot from this cartridge.

Thank you, Sir.
Yeah, it's definately a very interesting and challenging cartridge. Also trying to run both hot supersonic and subsonic loads effectively in the same platform makes it even more interesting. Personally, I don't really have much of a "proper" practical use (like hunting with subsonic ammo) for the 300 aac but I found the catridge so interesting I needed to own one.

Tuners are interesting, I feel they are gaining a lot of popularity lately because Eric Cortina is marketing his tuners/tuner brakes quite effectively it seems.
Regarding rimfire, what I understand consistent ignition is also very important. I got a adjustable primer pocket reamer on its way. Not sure if it will do anything measurable but I was keen to give one a try.
Flashholes are chamfered on my brass from the inside. In ohter calibers I haven't found a large difference with good brass, however at least the decapping pins seem to find their way more easily...