Currently I have a Tromix 16 inch barrel and it’s great.  I also have a Bowers Vers 458 suppressor (11.25 inches).  Both of those combined makes a long long package.

So, only shooting supersonic ammo.  Around 300-350 grains (or even 405g supersonic).  I am not set up for reloading yet.

What’s the minimum useful barrel length and twist rate I should get?   My ultimate goal is to transition this upper to hunting hogs under 150 yards.

Edit.  I did ask on Tromix’s email off the website.   Must not have received it, so I ask here.

I have a 12.5 inch barrel and it’s about the perfect length size wise and performance wise. Doesent give up much from a 16 but has enough over a 10.5 to make it worth it.  Twist rate I’ll have to get back with you on that.

That's odd.  I personally respond to every e-mail.....and it's a shit load.

With our barrels, at 12" or longer, the 1:14 twist will stabilize big subsonic bullets no problem.
Our 10.5" and shorter barrels may or may not stabilize big subs depending on the exact bullet and the suppressor you are running.  For that reason, we offer the 10.5" and shorter barrels in 1:10 twist as well.
However, our most accurate barrel for shooting big subs is still the 1:14 twist 12".

Tony Rumore
Tromix

Thanks Tony.  Must have gone to your junk folder.

I understand what you are saying and it’s mirrored on your website.  However, I do NOT want to shoot subs.  That is my question.  Seems like all the shorter barrels are designed for subs, I want to shoot supers from a short barrel.

Don’t get caught up in the twist.  The standard 1:14 is good for any supersonic bullet.  Even my 6.750” to 28” .458 with 1:14 twist stabilizes everything from 250 gr. Monoflexes at 1700 fps and 2250 fps respectively to 500 gr. Interlocks at 1050 fps.  And the 1:10 twist is no more or less accurate than the 1:14” twist in a 10” bbl with all bullet weight.  Since you are wanting supers only, pick your length and go with it.  Twist isn’t going to affect anything.

My 10.5" Tromix is the most fun gun I own. I shoot mostly 325gr FTXs. If I remember correctly, they are doing around 1600 fps at the muzzle. 1-2 MOA. Perfect for bushwacking for hogs. Wish I had a suppressor for it.....

Why do 1:10 and 1:14 twist barrels made?  Why not a single twist rate?  On Tony’s web site, the shorter barrels specifically state the barrels excel at stabilizing subsonic ammo.  No mention at all on the use of supers.

Semi related question.  There are 12, 10 and 8 inch barrels.  From a pure over all length (barrel and suppressor), I want the 8 inch.  What am I realistically giving up going from 12 to 8 inches when I m shooting supers?  Going from 8 to 12 is only 4 inches, well going from 12 to 16 is only 4 inches.  That is exactly what I have now.

Can you see how this is a little confusing to a beginner?  I do understand that I am making a trade off.  I am trading velocity and sound suppression for a more maneuverable rifle.  Tom Bowers said absolutely that a 16 inch barrel would be best for suppression and he only runs that in his 458 SOCOM rifle, I talked to him.

edit.  @tonyrumore You know I’m attempting to do, point me to the correct barrel.

A bullet does not stabilize just on twist alone, but on RPMs.  This is based on speed as well as twist.  For shooting big subs, 500 gr. and up, the faster twist gives better stabilization and reduces chance of a baffle strike when shooting long suppressors.  If you shoot the fast twist with lighter bullets at super sonic speeds, you get into a condition where the bullet is theoretically over stabilized.  In short, that means the bullet will travel all the way to the target with the point up.  At extreme distances, well over 500 yards, the point up attitude will cause the bullet to start tumbling.  This is not a concern with the .458 SOCOM.  By the time the point up attitude could cause a problem, the bullet would dropping about a foot for very foot of forward travel.  Of course I am exaggerating some but not much.

Plus, those wanting to shoot cast bullets in ranges from 525 up to 600 or even 700 gr. really need the fast twist to stabilize bullets that are starting at only 900-1000 fps.  As I think I said before, I saw zero difference between my two 10", 1:10 and 1:14, barrels in accuracy or velocity shooting bullets from 250 to 500 gr.  I got the fast twist to see if it would make cast 525s shoot more accuratgely than the 1:14 twist, and it did not.  I have not had any success shooting any cast bullets and being able to get the kind of accuracy I insist upon.  At best I can get 3-5 inch groups at 100 yards and that's not good enough for me.  I have abandoned cast bullets.

If you go to the .458 SOCOM forums, you will see where both Tony and I have posted velocity results from barrels of different lengths.  You might have to search but going off the top of my head, from 12 to 18 inches you lose very little fps, maybe 50 fps tops because the powder is mostly burned in 12 inches.  Of course that varies with powder but something like H110 or Lil-Gun, which gives top velocities, the loss beyond 12 inches is minor.  Going down from 12 to ten inches you lose somewhere around 75-100 fps, then from 10 down to 8, maybe another 50-100 fps, then 8 to 6, another 75-125 fps.  Those are not hard figures because different powders and different bullets can cause different velocity loses.

1-22 twist will give you optimal accuracy with various 300gr hunting bullets. We usually get 1" or less with the Barnes 300gr TTSX which in my opinion is the best overall hunting bullet for the SOCOM. I've killed Cape Buffalo with the SOCOM using this bullet, it just works!!!

Slightly off-topic, but this thread is probably a great place to ask.

I have a 16" 458 upper from DTT, and the threading is 5/8x32. What options are there for adapting this thread to 5/8x24? I would like to shoot subsonics through my obsidian 45.

This barrel seems to do fine with both 300gr Hornady hollow points as well as 500gr cast 459 boolits.

Also, thinking about sending this barrel to C3 machining to cut to 12.5", which would of course obviate the need for a thread adaptor.

Why didn't they thread these barrels to 5/8x24 in the first place??

TROMIX makes muzzle devices in 5/8 x 32.

Them and a whole lot of others did queer threads to keep rubes from screwing on .308 muzzle devices then wanting to sue when the rifle blows up. Pretty much the same as those using 11/16 x 24, 3/4 x 24, and other oddball sizes.  They will feed you all kinds of BS stating the reason is something else but the truth of the mater is they assume you are an idiot and cannot figure out for yourself that you cannot pass a .458 bullet through .308 M.D.

While 1:22 might give you sub 1" groups with the 300 gr. TTSX, I get the same sub one inch groups with the 300 gr. TTSX with my various lengths of 1:10, 1:14, and 1:18 twist barrels.  It's the bullet, not the twist.  Maybe by the time you go out to 500 yards or more you MIGHT see a difference in accuracy regarding twist, but you'll never see it within the ranges the .458 SOCOM is normally used.
And when shooting heavy subs, the faster twist has got to be better according to the charts, but I have shot 500s at 1000 fps and they stabilize just fine out of 10, 14, and 18 inch twist and just as accurate out of one as the other.  The only reason for the really fast 1:10 twist is for getting into 570-600 gr. bullets and beyond.  And for slower twists, no reason for them what so ever.  Those super slow twist might look better on paper but in the real world they get you nothing, other than being able to claim you are different for what ever BS reason you want to claim.

Another claim I have heard for slower twist is that they are faster.  B.S.  I have shot too many loads through too many twists and the velocity variation is well within what you see if you shot the same load out of two different same length, same twist barrels.

The only thing I have seen that seems to boost velocity is polygonal rifling, but it does so at much increased pressures, dangerously so IMO.
The same loads that shoot a 250 gr. Monoflex to 2000 fps out a 16 inch conventionally rifled barrel scream out of a 16 inch polygonal rifled barrel at 2200 fps but the primers are well beyond flat.  By the time you down load the rounds to give you those safe round primer edges you are back down to the conventionally rifled barrel speeds, namely 2000 fps.  In all three of my polygonal rifled barrels the conventionally rifled loads have to be segregated from them and if I use a polygonal load in the conventional, they are waaaaay slower.

Contrary to what some might say about Polygonal barrels being faster AND lower pressure has not been proven my experience.  Quite the opposite, they are faster with the same load but pressures are way higher.  Getting them down to the same pressures and they are not any faster than the conventional rifled barrels, but they do use less powder, about two grains less.

I would have bet $100. that Big Bore would have a different opinion to mine!!! Personally I don't have any need for a bullet over 300gr in the SOCOM and every 1-22 bbl I've shot is more accurate with 300gr bullets than the 1-14s. There is a reason benchrest shooters pick a twist that doesn't over stabilize their chosen bullet.

However if you want a one size fits all the 1-14 will shoot plenty good enough with all bullet weights for most applications.