What is the best round to put a 400 grain .410 or .416 round downrange at subsonic velocity?

I have a 416 Rem and see that there is a Trailboss loading but that seems to be a lot of cartridge for this application.

I currently use about 10gr of Trailboss in my suppressed 308 with 180gr bullet and it is very quiet. I would like to find a larger, heavier bullet to do the same.

Thanks,

I have given this a lot of thought, and put money into it. I had a 458WM built with the thought of messing with subsonic loads, as well as real hunting loads. It's set up for using 45-70 bullets, with a short throat just like the 45-70 throat, just on a 458 case. Factory ammo will not chamber.

There were several reasons, the first of which is feeding. It must feed, and it does feed very well indeed. Actually the 458 is quite versitile for handloading. I have tested subsonic loads. I don't know why, but Trail Boss produced poor accuracy. However SR 4759 produced excellent accuracy, and offered more versitility in FPS. I could easily go from 1000 fps to 1600 fps by just adding powder. I don't know what the top load is, because for anything faster than 1600fps, I'll just use H4895, and that can be worked up to real thumping loads.

Another reason for choosing the 458 and 45-70 bullets is because pointed bullets are practically worthless if used subsonic. At the ranges for such use, the soft nose 45-70 bullets are best. So far some of the best accuracy is from the Remington 405gr jacketed flat nose bullets.

I calculated that if the Rem bullet starts subsonic, it still has the energy at 100yds that a 44 mag has at the muzzel, or just abouts.

I'm thinking that perhaps the ideal is the 458 SOCOM. I also think the 458WM subsonic loads using SR4759 would produce good results. I would like to try it and find out. I think a 458 SOCOM can would be just right. The 458 WM may be quiter in a bolt gun, since the noise of the AR action working wouldn't be a factor.

Naturally, there are 458 cartridges that may be better suited for subsonic loads than the 458WM, such as the 458x2" or perhaps the 450 Marlin, but the feeding issues are critical to me. The 458WM is far more versitle anyway. Comparing the various 458 cartridges, the difference in the powder gasses and charge in my estimation would not make much difference in effect, if using subsonic loads. Full charges loads would probably be a different story.

If anyone knows a source for a 458 SOCOM suppressor, I would like to read about it.

KB

Thanks for the reply. I've thought about the 458 because I shoot BPCR 45-70 in my Shiloh Sharps and with black powder, the velocities are all subsonic with the 535gr bullet. This killed a lot of buffalo in its day.

I'll have to check out the 458 SOCOM as well as see how accurate my 416 Rem is when loaded down.

For a 458 suppressor, take a look at
AWC Thundertrap. I have three of their suppressors (however not a 458) and am very satisfied.
http://www.awcsystech.com/