coaspen wrote on Aug 31^st, 2017 at 7:30pm:

Since I have a short barrel, 18", I am considering 4895 for it's faster burn rate. Should I reduce the powder? I think this will yield a muzzle velocity of about 2,000, and 33,000 in chamber pressure, well below the SAMI 40,000.

I have a 30" barrel rolling block. I get 2000 with the 220 using 35.0 gr of 4895, a load selected using Lyman's pressure tested data. This is about 33,000. At this pressure you will not get 2000 from 18". You will need closer to the full 40,000 for that. Lyman's data indicates 4895 or 4064 can get about 2000 from 18 at nearly 40,000, but I'd switch to 4350 or Reloder 19 to lower the pressure some.

Hornady's data is not pressure tested and dates to before 1973. It was, though, tested in an actual Krag military rifle. My rolling block has the modern SAAMI chamber, as does Lyman's data, so it's not an exact comparison. With 4895, Hornady was not comfortable going beyond 2000 for the 220 from 30", so you will not get it from 18". In their data, 4350 would be the better choice for your goal. (The most recent Hornady data is even milder. They chose to chop 100 fps from the the maximum across all powders, with no explanation given.)

You didn't state what is your fps goal with the 180 gr bullets.