40 cal. 4198 loads

Congrats on your new build, I think you're going to like it. Is it IMR or H4198?  I would suggest you do a measured check of your powder chamber to confirm actual volume of the powder it holds and then start above that to be safe. I would then work up one grain at a time to find what shoots acceptable. You might not be able to go up very far to be within the limits of that barrel contour, especially with anything more than the 225-228 gr bullets.

I have a heavy contour Brux 26" 16tw barrel (no powder chamber, HIS) and my load is 56 gr of H4198 with the 228HC Pittman, no wad, at 2800 fps that has preformed very well for me. The only group I have shot with this load at 300 yds was 1.403". I have not shot any heavier bullets in my 40 cals. 

I would also suggest you ask Hank what he thinks would be a safe max load of 4198 in your barrel. I hope this helps.

Look through everything .40 cal here, keep in mind you need to stay on the lower pressure side of loads given the barrel profile, above all stay safe and don't push it.
You didn't mention if you will be shooting modules or Direct Ignition, if direct reduce loads by 10 percent or so, if you are using brass modules they will be good to the low 50s before they start stretching primer pockets so keep a close eye on them, they are a pressure indicator of sorts but don't rely on that, Direct will not blow til you are well past the danger zone.
The .40 bore builds pressure MUCH faster than the .45s so go slowly.