Anyone have one?  Thoughts?

Have two, an 18 and a 24.  24 for maximum range and the 18 for better handling in tighter places but I give up about 100 fps.  As much as I love the .458, and I have 7 of them with 6 being ARs, the .375 is IMO a more versatile round for deer, boar, and other large game for ranges out to 300 yards with supersonic rounds but the .458 is still king for heavies and subsonic out to 100-150 yards and supersonic use with 250-300 gr. bullets out to 150-200 yards.

Be sure to check out the section on the .375 SOCOM on the .458 SOCOM Forums.  There is also some load data in the Load Data section. This round gives honest to God 2400 fps velocities with 200 gr. bullets with pressures only in the 36-36.5K psi range which means you don't beat up your rifle and cases last forever.  Brass and loaded ammo can be purchased from SBR or you can easily form it yourself from .458S brass.  Dies are available from CH-4D and TROMIX.

Thank you I was hoping for a boar rifle out of it.  My .458 is an SBR that I really enjoy but I am yet to hunt with it.  j

I roll my own so I'll check out the load data on those sites.  

One more Q, does the ejection port need relieving like the .458?

Yes since the .375 is formed from .458S brass, the port needs to be enlarged just as with the .458S.  To build the .375 the process is the same, only barrel, bolt, and enlarged ejection port is needed.  Standard buffer and buffer spring, rifle or CAR, is used.  However, the .375 works beautifully with midlength and rifle length gas systems.  18" barrels are midlength and my 24" is rifle length.  I am not sure what gas length Tony uses on his 12.5 inch .375 barrels but he has all that worked out.

We have two versions of the short barrel 375's.  An 11" carbine gas 1:12 twist for super sonic shooting, and a 10.5" pistol gas 1:10 twist for sub-sonic shooting with powders like Trail Boss and Tin Star.

Tony

I was looking at your 18" upper.

This seems like a much more capable cartridge than .458 SOCOM, just looking at the projectiles and speeds.

Would be sick suppressed.

That picture you posted is one of mine and depicts a 235 Speer (not at all accurate but M.O.Deer out to 150 yards), then the LBT 255 gr. spitzer GC that is also not a bench rest bullet, but certainly minute of plinker, cheap, and a whole ot of fun (size to .376 and seat deep enough to chamber) and then the 270 gr. Hornady RNSP.  It too is not a great round because it needs 1800 fps impact velocity to expand so its usable expansion range is very short, but it is VERY accurate and a 270 gr bullet, even if it does not expand, packs a hell of a wallop.

The .375 shines IMO with bullets 200-235 gr. range.  They get the velocity and the range and pack a heck of a punch for anything one might hunt with it in NA.

The Vollmer 200 gr. FP and the Sierra 200 gr. FP are incredibly accurate and good to 250-300 yards and will expand, but the flat points don't help to keep the trajectory all that flat.  Then the cherry on top is the Vollmer 200 gr. Spitzer which which is quite a bit flatter shooting than the flat points and their higher B.C. Helps keep their velocity and energy quite high.

Maker, and soon Vollmer, has/will have 175 gr. Spitzers and Vollmer is working on 235 gr. Spitzers that will have strong enough jackets to be accurate at SOCOM speeds and not be damaged during feeding through an AR.  I think the jacket is too thin on the Speer 235 gr. bullets and were being damaged during feeding which contributed to the poor accuracy.  Vollmer is also working on skivs in their jackets to aid expansion at lower velocities, therefore increasing the usable range of the bullets.

I totally agree, thhe .375 SOCOM is a better longer range round than the .458 but it is really hard to top the incredible knock-down power of a 400-525 gr. subsonic .458 hammer.  On one level I wish I were not retired because the reduced level of discretionary income limits building more .375s in shorter barrel lengths to play with like I did with the .458S.

Tony just posted this on the .458 SOCOM forums regarding the .375S with 325 gr. Maker Monster EXPANDING subsonic bullets in a 10.5 inch, 1:10 twist barrel.
DAMN!  This is some serious kick-ass power in a tiny package!

I'd been looking at the 45 raptor but just doesnt look like the support is there and the brass is uber expensive.

Thinking of picking this up as an alternative to doing 300blk build for subsonic use.

It certainly would pack a hell of a lot more punch than the .300 BO, no question about that.  If you are limiting your velocity to 1050 fps to keep everything subsonic then the only way you can get more oomph is to increase bullet size.
A .300 BO 220 gr. bullet (539 ft-lbs energy, a little less than a 115 .357 SIG at 1500 fps) pales in comparison to a 325 gr. .375 (796 ft-lbs energy, about the same as a .357 magnum with a 140 gr. bullet at 1600 fps), which then pales to a 500 gr. .458 SOCOM (1224 ft-lbs energy, almost the same a .44 magnum with a 240 gr. bullet at 1500 fps).  You can't go up in speed for more energy so you have to go up in weight.

Yeah, I don't mind using a big bullet and shooting short distances because a lot of what I hunt is within 100yds so its plenty.  If i need supersonic and distance, i have a few 6.5CM for that.

Also looking at the 375 Raptor as well, since it uses the much more accessible 308 brass

Just a word about the Raptor.  It operates at MUCH higher pressures than the .375 SOCOM so the brass is not going to last anywhere near as long.  On the Raptor, you must form it yourself so far as I have heard.    There is also going to be less stress on the bolt and barrel extension with the SOCOM and the .375 SOCOM is ready to ship NOW at prices the Raptor cannot approach from what I have seen.
To form the .375 SOCOM brass out of .458 SOCOM brass (68 cents a case from Maker Bullets, the best way is to anneal, chamfer the outside well, run it through an intermediate form die which necks it down to .40 caliber, then through the .375 SOCOM size die.  Done.  You can run it straight into the .375 die but you might loose some brass, especially if you do not anneal first or chamfer well.  Using the intermediate die I have never lost a case.
Also, SBR sells loaded ammunition as well as marked brass for the .375 SOCOM but not as cheaply as you can buy .458 SOCOM brass.  SBR's price is 84 cents each sold in lots of 100.
Just like the .458 SOCOM, brass seems to last forever.  I have some with ten loadings on it and it is still going strong.  Also, one must compare apples to apples.  Looking at the Raptor load data linked here, they claim higher velocity than we get with the SOCOM but the SOCOM used COALs that fit in an AR-15, the COALs I see listed for the RAPTOR and their higher velocities are two things, loaded to a COAL that will not fit in any AR platform and loaded to 60K psi or more, not the 36500 psi the SOCOM is loaded to.  That means the SOCOM will have less wear and tear on the bolt and barrel extension as well as the brass.  Here is a link to the Raptor data that is most often quoted from what I have seen.  It even says in the FAQs that you cannot use it in the AR-15 since the cartridge is too long and the pressures are too high.  Load that down to pressures that will not destroy an AR-15 and lengths that fit the magazine and the .375 SOCOM out performs and at lower pressures.  With the bigger case of the SOCOM, if you load the same charge of powder in both the Raptor and the SOCOM, the SOCOM will give lower pressures and slightly less velocity.  But when you up the charge so that both are operating at the same pressures which will not wreck an AR, like 36500-37500 psi, you get higher velocity with the bigger case since it is using more powder and creating more gas.
And another thing is the magazines, the SOCOM uses unaltered GI type mags, just like the .458 SOCOM.  The .308 size case does not like to be stuffed in unaltered AR-15 magazines.  You can make it work but the mag usually will need to be altered and more than likely the mag will not work with 5.56 anymore, or at least not as reliably.
Just something for you to think about before making the plunge.