Disclaimer: Do not use this as load data. This not from a pressure tested and published source. Purely for entertainment purposes and discussion.
I got my hands on some Vihtavuori N120 and 250 gr Hornady SUB-X bullets. The goal was to come up with a subsonic load that would cycle my AR15. It is a 13.5" barrel with pistol gas and suppressor.
357 Maximum has some data for 200 gr bullets and N120. 357 Max is very close to Legend in case capacity. However, a 250 gr bullet is quite a bit different than a 200 gr.
www.vihtavuori.com
Hornady has some data for 350 Legend and the 250 gr, but no N120
With no data, but some anecdotes about N120 being case capacity limited rather than pressure limited (for this application, not in general), I decided to forge ahead.
I estimated that ~16.0 gr is the max you can fit in a case with a seated bullet. Decided to start at 10.0 gr. I don't have a good reason for that starting point.
Anyways here's what I got.
10.0 gr was too low. Interestingly, the powder seemed to ignite and burn clean though clearly things didn't get rolling until north of 11.0 gr. N120 is a stick powder which I suspect makes it behave better. I stopped at 16.0 gr because they started going supersonic. No idea what the pressures were but never observed any pressure signs to include primer signs, and or extrusion into the extractor pocket. Haven't loaded the cases yet to see if the primers pockets are still tight, but I suspect they are.
Hopefully Hornady or somebody tests this powder in the future.
I got my hands on some Vihtavuori N120 and 250 gr Hornady SUB-X bullets. The goal was to come up with a subsonic load that would cycle my AR15. It is a 13.5" barrel with pistol gas and suppressor.
357 Maximum has some data for 200 gr bullets and N120. 357 Max is very close to Legend in case capacity. However, a 250 gr bullet is quite a bit different than a 200 gr.
Handgun reloading data | Loads for pistol calibers | Handloads | Pistol powders | Reload your own ammo - Vihtavuori
Vihtavuori offers handgun reloading data for competitive or recreational purposes. Pistol calibers range from 7 MM TCU to the .500 S&W Magnum.
www.vihtavuori.com
Hornady has some data for 350 Legend and the 250 gr, but no N120
With no data, but some anecdotes about N120 being case capacity limited rather than pressure limited (for this application, not in general), I decided to forge ahead.
I estimated that ~16.0 gr is the max you can fit in a case with a seated bullet. Decided to start at 10.0 gr. I don't have a good reason for that starting point.
Anyways here's what I got.
10.0 gr was too low. Interestingly, the powder seemed to ignite and burn clean though clearly things didn't get rolling until north of 11.0 gr. N120 is a stick powder which I suspect makes it behave better. I stopped at 16.0 gr because they started going supersonic. No idea what the pressures were but never observed any pressure signs to include primer signs, and or extrusion into the extractor pocket. Haven't loaded the cases yet to see if the primers pockets are still tight, but I suspect they are.
Hopefully Hornady or somebody tests this powder in the future.
