AR Sponsor
Joined:
May 2024
Posts:
891
EE: 0% (0)
VA, USA
Posted: 9/1/2026 8:08:07 AM EDT
|
I want a thumper. Short bbl, suppressed. Will also shoot supers but never more than 200 yards and the primary use is suppressed out to 100 yards. What are the important things to know here for each round? Feeding reliability, ammo availability, mag issues, etc. The straight wall hunting requirement is not a consideration for me. Thanks! |
|
450 Bushmaster seems the more common pick and more likely to be around long term. Starline makes brass for it. The 400 Legend is another to consider if total round count in the magazine is of any importance. The 400 Legend is a.40 like 40SW & 10 mm and just like the 350 Legend fires .355 (9mm ammo) in a pinch one could likely single load either 40SW or 10 mm in the 400 Legend chamber and while not ideal or recommended could be of interest. The 450 B is .451 like .45ACP but I think the bolt face is smaller. If you want a real thumper the .375 Ruger or .375 H&H would be my suggestion in a bolt action or the 45-70 in a lever action. If you want a subsonic gun .45 acp is all subsonic and there is no real advantage to running longer more expensive cases one is struggling to reduce velocity in. If you hand load 45-70 is more versatile because it’s not gas driven cycling and mag reliablility is not an issue. Even then the 44 Mag running shorter 44 Special cases to get subsonic could make more sense. 44 mag in a lever action is a lot of fun and easy to reload. Look at a reloading book to compare each option. Your other options in semi auto is go to a .308 based gun or a NEMO 300 WIn Mag. Subsonic Suppressed and high energy Thumper are both big heavy bullets but there is a huge difference between a 300 gr 375 H&H with over four thousand pounds of energy and a 250 gr subsonic bullet from a 450 B |
USAF (Ret) 2003-2024
Joined:
Oct 2025
Posts:
477
EE: 100% (2)
CO, USA
|
Originally Posted By Urimaginaryfrnd: 450 Bushmaster seems the more common pick and more likely to be around long term. Starline makes brass for it. The 400 Legend is another to consider if total round count in the magazine is of any importance. The 400 Legend is a.40 like 40SW & 10 mm and just like the 350 Legend fires .355 (9mm ammo) in a pinch one could likely single load either 40SW or 10 mm in the 400 Legend chamber and while not ideal or recommended could be of interest. The 450 B is .451 like .45ACP but I think the bolt face is smaller. If you want a real thumper the .375 Ruger or .375 H&H would be my suggestion in a bolt action or the 45-70 in a lever action. If you want a subsonic gun .45 acp is all subsonic and there is no real advantage to running longer more expensive cases one is struggling to reduce velocity in. If you hand load 45-70 is more versatile because it’s not gas driven cycling and mag reliablility is not an issue. Even then the 44 Mag running shorter 44 Special cases to get subsonic could make more sense. 44 mag in a lever action is a lot of fun and easy to reload. Look at a reloading book to compare each option. Your other options in semi auto is go to a .308 based gun or a NEMO 300 WIn Mag. Subsonic Suppressed and high energy Thumper are both big heavy bullets but there is a huge difference between a 300 gr 375 H&H with over four thousand pounds of energy and a 250 gr subsonic bullet from a 450 B You may have missed the part where OP saod "short barrel suppressed". 375 h&h? Lulz. OP, while not a sbr my 20" 450 Bushmaster is loads of fun with both supers (elk/deer) and subs. Unsuppressed, a short barrel is gonna thump both directions.  We carry 450bm factory ammo at my shop (i think 5-6 different loads as of sunday, had yesterday off) and no 458. The socom is a fantastic round but the BM got adapted quickly with lots of factory support. Sadly the socom didn't (but definitely deserved it). Both are excellent but the 450 being more widely available (and a clearance on chrome lined barrels from bushmaster several years back  ) pushed me that direction. I'm getting three supers in about an inch and a half at 100 with a 1-4 lpvo. Plenty for what I'm using it for.
|
Joined:
May 2024
Posts:
893
EE: 0% (0)
VA, USA
|
Originally Posted By Tamarit_167: You may have missed the part where OP saod "short barrel suppressed". 375 h&h? Lulz. OP, while not a sbr my 20" 450 Bushmaster is loads of fun with both supers (elk/deer) and subs. Unsuppressed, a short barrel is gonna thump both directions. We carry 450bm factory ammo at my shop (i think 5-6 different loads as of sunday, had yesterday off) and no 458. The socom is a fantastic round but the BM got adapted quickly with lots of factory support. Sadly the socom didn't (but definitely deserved it). Both are excellent but the 450 being more widely available (and a clearance on chrome lined barrels from bushmaster several years back ) pushed me that direction. I'm getting three supers in about an inch and a half at 100 with a 1-4 lpvo. Plenty for what I'm using it for.How is feeding reliably? Special mags? Purpose built upper? |
USAF (Ret) 2003-2024
Joined:
Oct 2025
Posts:
478
EE: 100% (2)
CO, USA
|
Originally Posted By IIA: How is feeding reliably? Special mags? Purpose built upper? I opened the port of a standard keyhole 5.56 stripped upper with a dremel. I just use a couple DH 4 round mags i snagged with my discount at brownells. Function has been flawless for about 400 rounds or so now. |
Member
Joined:
Dec 2023
Posts:
11787
EE: 100% (7)
USA
|
They are pretty similar, and you'll probably be happy with either. I like both. If I had to pick one, it would be my Tromix 458 SOCOM. I use it with a Hybrid 46 silencer, it's a 12" barrel, I use Lancer magazines without modifications. My 450 Bushmasters have been less well tested. |
I don't see no Americans. I see trespassers.
|
Originally Posted By ELittlefield: They are pretty similar, and you'll probably be happy with either. I like both. If I had to pick one, it would be my Tromix 458 SOCOM. I use it with a Hybrid 46 silencer, it's a 12" barrel, I use Lancer magazines without modifications. My 450 Bushmasters have been less well tested. How's the Hybrid? My brother went w/ the Lane on a 16" Rock River and wasn't happy w/ how loud it was w/ subs. Takes a lot of gas to throw heavy bullets. |
Member
Joined:
Dec 2023
Posts:
11788
EE: 100% (7)
USA
|
Originally Posted By backbencher: How's the Hybrid? My brother went w/ the Lane on a 16" Rock River and wasn't happy w/ how loud it was w/ subs. Takes a lot of gas to throw heavy bullets. Originally Posted By backbencher: Originally Posted By ELittlefield: They are pretty similar, and you'll probably be happy with either. I like both. If I had to pick one, it would be my Tromix 458 SOCOM. I use it with a Hybrid 46 silencer, it's a 12" barrel, I use Lancer magazines without modifications. My 450 Bushmasters have been less well tested. How's the Hybrid? My brother went w/ the Lane on a 16" Rock River and wasn't happy w/ how loud it was w/ subs. Takes a lot of gas to throw heavy bullets. I haven't dipped into subsonics with it yet, but I'm delighted by how it suppresses even 325 grain supers. I've even run it with an FRT, and that doesn't gas me out. Overall I'm extremely pleased with the Hybrid 46. It's one of few cans which I actually move around different guns, because it's so versatile. It does get pretty gassy on a fixed front sight base 14.5 5.56, but that's really pushing it to the extreme. |
I don't see no Americans. I see trespassers.
Joined:
May 2024
Posts:
896
EE: 0% (0)
VA, USA
|
Originally Posted By ELittlefield: They are pretty similar, and you'll probably be happy with either. I like both. If I had to pick one, it would be my Tromix 458 SOCOM. I use it with a Hybrid 46 silencer, it's a 12" barrel, I use Lancer magazines without modifications. My 450 Bushmasters have been less well tested. That is the exact same setup I am favoring. Question - since that setup is geared toward suppressed, I assume you're shooting some subs? What weight and have you had any issues with stabilization from a 12" 1:14 twist rate? Also did you go regular weight bbl or lightweight bbl? Standard or "upgraded" billet upper? Any thoughts on that? ETA - just saw you haven't shot subs yet... |
Joined:
Aug 2023
Posts:
10149
EE: 0% (0)
NC, USA
|
I dont have either, but I do have a 375 Socom . The fit in a std mag and feeding is excellent . One thing that always made me hesitant of the 450B , 400L , and 350L is the almost second thought nature of the mag fitment . To me its worth a few extra bucks . Myself , I would give 458 Socom a good look if I were going a bit bigger. |
Joined:
Aug 2023
Posts:
10150
EE: 0% (0)
NC, USA
Joined:
Sep 2025
Posts:
1449
EE: 0% (0)
NV, USA
|
I went 450 bushmaster for my thumper. Reason was ammo avalaibility and standardization across the board. Never liked that alexander arms doesn't warranty their stuff if you shoot any ammo but theirs and 458 socom was fringe ammo manufacture only. Yes, there were 12.7x42 options, but i didn't want to run into compatibility problems. The 458 socom's ability to feed from a regular mag is damn nice, but nowadays you can get or make magazines with higher capacity than 7 lrds as well. |
|
Go over to 458SOCOM Forums and spend some time reading. Time spent there could save you buyers remorse from buying something that is not what you really want. Feeding is smoother with the .458 S. because you have a .458 bullet trying to go into a considerably larger chamber opening (bottle necked case), unlike the straight walled cartridges where the case head (opening to the chamber) is just slightly bigger than bullet diameter. NOTHING needs to be done to the mags but with full length loads, 2.250", PMags don't work too well due to that stupid rib down the front. I pretty much use Lancer Gen 2 and 3 magazines only. You do NOT need a sled type follower or modified followers, not in a properly built upper. Radical or BCA, all bets are off, but that is not the fault of the .458 SOCOM. Subs or supers, there is nothing wrong with a 1:14 twist but if you really want to go heavy with 550 gr. + bullets with sub loads, TROMIX has a 1:10 twist. I have never had any problem stabilizing any bullet from 250 gr. to 500 gr. with my 1:14 barrels, supers and subs. I cannot comment on suppressors because I don't shoot any, yet. Now that the Form 4 is going away (?) and the tax is gone, that is about to change. I personally would not give a second look at the .450 BM, but then again, I only shoot loads I make myself. If I did not load my own, then I reluctantly would say the .450 BM has the edge there with easy to find factory loads. But that is the ONLY advantage I see with the .450 BM ,or its use in states that do not require straight walled cases for deer hunting, which you said is not a concern. If you reload, brass lasts forever. I quit over a decade ago counting how many loads I have on my brass. Once I got to 15 or so loadings, why bother? If I feel the primer pockets loosening up while depriming or priming, then I retire the lot. |
Join the N.R.A.
Beware speaking with a sharp tongue as you are apt to cut your own throat.
My name is John Wick, you killed my puppy, prepare to die.
Beware speaking with a sharp tongue as you are apt to cut your own throat.
My name is John Wick, you killed my puppy, prepare to die.
|
I built a 458 socom, and just barely got it running last year, not good enough for me for deer season. Would like to remedy that this year, but as always running out of time. If I had to do over, I would more strongly look at 450 BM - because someday I might want to hunt in a straight wall rifle state. But I am happy with the 458, and Tromix all the things! |
AR Sponsor