have been using 4320 for 30 years in my 1959 Savage 99 Featherweight.... 300 Savage with 150 gr Hornady Interlocks. Startted with it back then because that was what the data i had was using. Never tried anything else in that rifle. Will shoot 2 MOA or a little bit better often especially if the ballistics gods are with me that day. A Chrony test showed velocity about 2550 f/s. Took my share of deer with that load in east central minn brush places.
the small 'stick' size of 4320 makes it easy to measure. Goes thru a powder measure nicely.
When i started reloading a 223 first powder i reached for was the 4320 because that was what i had on my bench. Currently a consistent load is that powder pushing 55gr Sierra Varminters. Wont tell you my loads.....work up your own. My loads NEVER are at maximum.
Sporterized an old Mauser in 7 x 57 and i feed that one 4320 also. Have worked up respectable consistent mild loads with 140 gr Sierra ProHunters, 150 gr semi pointeds [ dont know if they are Winchester or Remington], 150 gr Partitions, and 165 gr Remington RN. Tried pushing the 150 grainer types with IMR4350. They did not play well together.
My current hunting load uses the 150 gr Partitions in a load which pretty much duplicates the 300 Savage load above. Will do MOA most of the time.
Even those ugly RN Remingtons will do 2" or 3" groups. And i havent really spent much time working up a load. [only reason i have these RN things is that a friend gave me about 200 of em, and i am too cheap to NOT use em. ]
right now I am hoarding what 4320 i have since lately its hard to find,. As are primers.
