Wanted: Load for 223 Rem w/ H-4198

Welcome to Gun Loads.

Well, we know you're starting with an exceptionally accurate rifle. I have two of them now and have owned half a dozen. With their 1:12 twist, you have chosen the optimum bullet weight, though they do well with anything down to 40gr, with individual rifles having different preferences as to their favorite brands and profiles. I usually start with Sierra bullets and often end up there, but yours may well prefer Hornadys or Noslers, or it may even do very well with cheaper bulk Remington or Winchester bullets. You just have to try them and see what it likes best. With its preferred bullet, a rifle may do very well with several different powders, but with the wrong bullet you will be testing powders from now until doomsday without much success.

It's the same way with powders. Yours may do best using H4198, or IMR4198, or any of a dozen or more others with its preferred bullet. I do not believe in pet loads, as every pet load is "the load" for exactly one rifle, the rifle the load was worked up for. Testing in your own rifle is the only way to find what it shoots best.

Looking in three different manuals, Sierra, Lyman, and Lee, I see no listed loads for H4198. This tells me that although the powder is within the optimal burning rate range for that bullet weight, none of the testers had good enough results with it to publish the data. Your rifle may like it though, and no experiment is a wasted effort, even if it only eliminates the powder from consideration.

Hodgdon's website lists the powder with a 55gr bullet at a starting load of 19.0gr to a 21.0grMAX, 2841-3150fps. This tells me that the powder reaches maximum pressures well below the optimal velocities for the bullet/cartridge combination. It does NOT mean that it is impossible to come up with an accurate load, it just means that for extremely long ranges (and 300yds is an extremely long range for the .223) that you are going to have significant bullet drop to compensate for "out there". With such a small working charge range, I would work up in .5gr increments from START and see if you get decent accuracy at 100yds at any of those five charge levels in your rifle. If you find a good one, then you will have to test at progressively longer ranges to tweak the charge weight and OAL to optimal accuracy.

FWIW, I have had very good luck with IMR4198, RE7, H335, Varget, IMR3031, IMR4895, and IMR4064 in various .223's, but every rifle is different in its preferences, and to get your rifle's opinion you will have to do some testing and see what it tells you. IME for every dozen really good loads at 100yds, only one or two will be accurate at really long ranges. Sometimes you get lucky and hit on a good combination right away, and other times you have to go through a lot of components to find the load you're looking for. If it were me, I would try Sierra 55grGK's and two others of the same weight with the powder you have on hand. That will give you a good idea of which bullet to go with, then if I needed to I would next try the best choice with IMR4198 and H335.