458 Socom upper build. I finally committed or should be committed

[edslhead]

Nice!. The difference between cycling and jamming was about the thickness of a piece of scotch tape on my tromix 375. All the new brass ran just fine. Good luck with that, they are a hoot

 

[Ura-Ki]

Ok, YOU SUCK! How did you know I have been looking at a big bore AR build?
Seriously, @Tully Mars and @3M-TA3 have been on my case about doing a big bore. I'm on the fence though, the Bushmaster, and the .45/70 rimless look pretty darn good, and I have been looking at the .375 as well! Gonna be watching this thread closely, Want your views and honest reports!

 

[etrain16]

Ok, YOU SUCK! How did you know I have been looking at a big bore AR build?
Seriously, @Tully Mars and @3M-TA3 have been on my case about doing a big bore. I'm on the fence though, the Bushmaster, and the .45/70 rimless look pretty darn good, and I have been looking at the .375 as well! Gonna be watching this thread closely, Want your views and honest reports!

I'm secretly pining for one too...

 

[edslhead]

Ok, YOU SUCK! How did you know I have been looking at a big bore AR build?
Seriously, @Tully Mars and @3M-TA3 have been on my case about doing a big bore. I'm on the fence though, the Bushmaster, and the .45/70 rimless look pretty darn good, and I have been looking at the .375 as well! Gonna be watching this thread closely, Want your views and honest reports!

I'd go with a straight wall case. No hasells reloading and very similar performance.

 

[Ura-Ki]

I'd go with a straight wall case. No hasells reloading and very similar performance.

That's whats got me thinkin the rimless!

 

[osprey]

What's the hassle with a case with a shoulder? Been reloading them for years in all sorts of cartridges. Sounds like maybe you got a finicky chamber on the 375 version. Head spacing off the shoulder is preferable to me. Don't get me wrong that 45-70 looks sexy as hell but it has big $$ written all over it. Call Tromix and talk to Tony about your issues and remember don't be an a**hole lol. He may be able to help you out.

 

[osprey]

Ok I have to come clean even though it is contrary to what I said in the "who else hates hornady dies thread". I started with my go to Redding dies for this cartridge and stuck the first case which was new. I was trying to unscrew decapping setup out to drill and tap primer pocket for extraction like usual. Only problem is it will shear off at expander ball due to case geometry. Call Redding and great customer service as usual and had a new one in a couple days with instructions to put expander/decapper assembly much lower than usual to prevent. Ok lubed once fired cases well with new assembly adjusted per Redding. Going ok but still awful amount of force needed. 5 cases in I stick another, Fuuuuudge. Same deal shear off decapp assembly at expander button trying to remove for drill tap maneuver. So took a chance on Hornady dies and they have been great so far with the socom. So here I sit tonight dining on crow

 

[Ura-Ki]

^^^ It happens^^^

Been there, Done that!

Pro Tip,,, Good BBQ Sause for that Crow masks the nasty just enough!

 

[edslhead]

What's the hassle with a case with a shoulder? Been reloading them for years in all sorts of cartridges. Sounds like maybe you got a finicky chamber on the 375 version. Head spacing off the shoulder is preferable to me. Don't get me wrong that 45-70 looks sexy as hell but it has big $$ written all over it. Call Tromix and talk to Tony about your issues and remember don't be an a**hole lol. He may be able to help you out.

I did call Tony and ask about 375 ( I got the dies from him ) he said they need to be just shy of the gauge. He even recommended resizing new brass, said they were that finicky. Like I said just a piece of tape down into the gauge , any more and they wouldn't extract. I reload about 20 different shouldered cartridges myself and these are a bugger The 50 wolf and 450 bushmaster cause no problems at all.

 

[titsonritz]

I'd go with a straight wall case. No hasells reloading and very similar performance.

Personally I prefer tapered/shouldered cases over straight wall cases in semi-automatics for an extra measure of reliability.

That's whats got me thinkin the rimless!

Why would I want to spend a lot of time and money ruining my 45-70 brass?

From a design standpoint, the 45 SOCOM has always made the most sense to me regarding big bore cartridges for an AR-15 style weapon. As mentioned above, I like the shape of the case for AR type guns and using common 250-600gr projectiles that are actually designed for rifle use rather than pistol use is so full of win.

 

[osprey]

Well anorher range session in the books with 7 different loads. This thing is far from picky. It cycled all but my lightest sub loads comprised of a Maker 500gr bullet and 11gr of AA #9 which olny got me 500 fps lol. I had to check and make sure the first one cleared the barrel as I didn't see the bullet strike as it was way low. The rest of the loads cycled the action feeding the next round into full battery and locked back on empty mag. I did have one failure to feed with one wide meplat 420gr cast precision bullet but the other 9 rounds using this bullet fed and extracted great. I did not shoot past 50yds as I was mostly doing chrono work but the best group of the day went to the 500gr Acme rnfp load using 29gr of A 1680 and clocking 1310 fps avg. All 5 shots were touching for a 3/4" group at 50yds. 1680 burns pretty damn clean in both sub and super loadings and is a very versatile powder. I think I can get 1500-1600 fps out of a 405 grainer with this powder without pushing too hard and load 500 gr subs that cycle with it as well. Some loads were with new brass unsized, some were new but run through full length sizing die and some were once fired and fl sized. It did not seen to matter to the function as it ate them all up with the noted exceptions. I am very happy at this point and will continue to hone in on my loads but it seems to be a very straightforward task at this point.

 

[MDL]

@osprey, Good to hear on the 1680 powder and I guess there are no over pressure signs...I have only been shooting 300-350 grain bullets.

 

[osprey]

I finally got back to wringing out some more loads with my Socom. I also have a fishing problem so it has been taking up most of my spare time lately. I have a good idea where I am with super loads so I dedicated this session to subs. I broke out the supressor this time as I am satisfied all my subs are flying true so as not to have a baffle strike. Here are the results of three different powders all with a 500gr. Subsonic expanding bullet by Maker bullets. All loads used cci 350 primers and had a coal of 2.270"

18.2gr H110 gave an average speed of 1011fps and a 8.6sd. All bullets touching at 50yds and action cycled and locked back on empty chamber.

15gr AA#9 gave an avg of 840 fps and a 17.6 sd. Two bullets in one hole and one not touching the other two for around a 1" group. Action cycled and locked back on empty chamber. This load was a bit quieter than the others.

22.2gr AA1680 gave an avg of 979 fps with a sd of 7.8. Group was about 1.25"at 50yds. Action cycled and locked back. From testing I know this load will cycle action suppressed or non suppressed. Loads using this powder have varied in speed and accuracy more than the others but since it cycles action without the supressor I am inclined to work on it a bit more to see if I can refine it a bit more. This chrono string was actually very consistent with low sd but this is not always the case with this powder.

I had no failures of any kind through 30 rds of subs all through my hybrid can. I am very pleased to date with this setup and may try to harvest a deer with it next month.

 

[osprey]

And fast forward a year and here we are. The Tromix barreled 458 socom and 500gr subsonic expanding bullets are a lethal combo on deer with a drt result.

 

[titsonritz]

And fast forward a year and here we are. The Tromix barreled 458 socom and 500gr subsonic expanding bullets are a lethal combo on deer with a drt result.

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Nobody hunts with an AR.