I have been reading all the threads I can find on the 458 SOCOM.  It seems that it might make a nice gun to backpack in with when I go elk hunting.  It seems that all the information I'm finding about performance is based on a 16" to 17" barrel.  This is resulting in large muzzle flashes and velocity seems a little slow although probably still adequate since the I am usually shooting less than 50 yards.  Does anyone know what kind of velocity would be possible with a 22" to 24" barrel.  Maybe a better question is what barrel lenght would provide the best performance for this size cartridge.  

Thank you.
Kevin

Shoot Marty an email @ teppojutsu. He had an excel file with different barrel lenghts and calculated velocities.

When I had my upper built by Tony (Tromix) we discussed barrel length at length.  It seems the .458 SOCOM gains very little velocity past 16-17 inches.  Some sure, but not enough to offset the inconvenience of the longer barrel.  My 17" barrel throws 300 gr. X bullets at 1755 fps and 250 gr. X bullets at around 2060 fps.  By going to a 20 or 24 inch barrel you would be lucky to gain 150 fps, but look at what you lose in portability.  I also want to point out that I am one of those lucky guys that seem to get the "slow barrel."  In regards to the vels others have gotten out of their .458s with the same load and same length barrel, mine seems to be about 100 fps slower than others.  Just one of those things that cannot be predicted and is totally the luck of the draw even with the premium barrels that Tony and Marty use.  Accuracy, much more important IMO than velocity, is outstanding, easily shooting between 1.250 and 1.750" five shot groups at 100 yards and that with an EOTech sight.  With the 6.5-20x scope from my M15-A4(T) it has broken MOA many times.

The very first prototype .458 SOCOM upper had a 24" barrel and was getting 2100fps from a 300gr Rem bullet.  I later tested the same load in a 16" barrel and it ran right at 2000fps.  Each barrel is obviously going to be different, but in this test, that extra 8" didn't do much.

Thank you.  This is exactly what I wanted to know.  I agree accuracy is more important and a 17" barrel would be much easier to carry but not if I had to give up a significant amount of velocity.   I think the 20" barrel is supposed to be the optimum lenght for the .223.   Looks like the 458 socom is not much different.