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Posted: 6/4/2026 11:54:17 AM EDT
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Pondering a .300 for a truck gun while shopping short suppressors. I have a 9mm AR pistol that’s been flawless & the kids really enjoy. Wondering if juice is worth squeeze or maybe just run 147’s in the 9? |
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Originally Posted By funnelcake: Pondering a .300 for a truck gun while shopping short suppressors. I have a 9mm AR pistol that’s been flawless & the kids really enjoy. Wondering if juice is worth squeeze or maybe just run 147’s in the 9? My $0.02: - If you want subsonic at range (longer than self-defense ranges), a .300BO can make sense. - If you want subsonic at close range, a 9mm is probably about as good, and a .45ACP would have all the energy of the .300BO, a larger diameter, and a much wider variety of bullets proven to perform at subsonic velocities. - If you want supersonic and a short barrel, sure, the .300BO can make sense. It's nearly straight-walled, so it takes a lot more advantage of a short barrel than a highly bottlenecked round would. |
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Originally Posted By alacop: Something you leave in your truck to get stolen. Originally Posted By alacop: Originally Posted By voyager3: What is a truck gun? Something you leave in your truck to get stolen. There is truth to this. .300 makes a lot of sense to me in a barrel shorter than 11-12", suppressed or unsuppressed. I would personally use a cheap 14.5" or 16" 5.56 gun for my truck gun. If I had a truck gun. Ahem. |
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A lot of people seem to poo poo it. But I think its pretty versatile out of a short barrel, supers with can surely pack more punch than 556 out of a 10 inche barrel or less. I pack a long gun in my car or truck daily, but its usually 556. But not because i dont like my 300 or feel it isn't capable. |
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Yes. .300blk subs crush 9mm. They lose very little velocity compared to 9mm and are effective out to ~200yd … basically drop-limited because ~10mrad or 30-35MOA is about 200yds of range and most LPVO or prisms aren’t going to show more vertical holdover than that. And .300blk supers offer legitimate AK/AR rifle performance if needed. Lop no  I would say if you only interest is shooting quiet subs and with no interest in supers, .338ARC or a PCC makes sense. The moment you want to consider supers too, the .300BLK takes the win. |
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Yes and no. I don't see the point of an AR-9 with 147's since it will basically be a larger, heavier version of the CCW you may have on you. But, since you already have the weapon.....how deep is your wallet? What are you trying to achieve? If you are going to exclusively subs...NO, the just isn't worth the squeeze unless you have a very specific use case. While 300blk has more power and range, from a cost perspective, it is hard to beat the value of 147gr HST's for serious work, or 147gr fmj's to shoot piles of dirt compared to 300blk gucci rounds or fmj. If you are going to run supers (or both super and subs), then YES, it isn't even a close comparison. An 8"ish inch barrel running 110's (up to select 125's) absolutely crushes anything of similar size and function. A lot of popular brass 110's are running at roughly 2100fps. That is about 1077ft.lbs. In 5.56 you would need a 77gr round to run roughly 2500fps (1069 ft.lbs) or a 55gr round to running 2975fps (1081 ft.lbs) to have similar muzzle energy on target (assuming good/like projectiles). |
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I shoot subsonic 147’s and 150’s for practice. Attached File 50 yards, rested over ammo can, red-dot sight Palmetto 8.5” upper. Quietbore FORM 1 suppressor. Attached File Avoid using your NFA-configured “TRUCK GUN” unlawfully in some shit that the feds might take jurisdiction. Attached File |
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They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety. - Benjamin Franklin, 1775
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety. - Benjamin Franklin, 1775
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I have settled on 300BLK because I like its variability and most importantly it works out of short barrels. I run subs and supers depending upon what my current purpose is. I'll steer clear of the truck gun conversation, but I think all will agree that you only have truck guns for dispatching problems. People or critters, so I'd run supers as being quiet is less important than being effective. Knocking back the sound however is always a good thing so "suppress all things" is my mantra. All that being said, one can use a truck gun for fun when there are no threats, and running subs is definitely fun. I have firearms tuned to subs and others tuned to supers. If you want a fun quiet gun, tune your truck gun for subs and enjoy it when you can, but when stashed, keep it loaded with supers as they will run fine on a gun tuned for subs and unless you are expecting extended gun fights, a mag or two of supers in a gun tuned for subs won't wreck it. |
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Originally Posted By W_E_G: I shoot subsonic 147’s and 150’s for practice. https://www.ar15.com/media/mediaFiles/105614/IMG_6116_jpeg-3777529.JPG 50 yards, rested over ammo can, red-dot sight That’s interesting. I had tried to work up a subsonic 147 gr. load that would cycle back in (checks notes) 2011 but was unsuccessful. I don’t think CFE-BLK was around back then. I’ll have to try that. I think I even have the same PSA upper that you are using. |
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Originally Posted By stiglitz_actual: Yes. 5" w/ 110gr TacTX will deal with pretty much anything  https://distortion.io/i/IMG_1500.jpg @stiglitz_actual Wow. Would you share build details? Thanks. |
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Originally Posted By Steamedliver: @stiglitz_actual Wow. Would you share build details? Thanks. Parts bin special  Aero lower w/ AZR, LWRC UICW stock/buffer Troy upper w/ SLR 5" 1:5 300blk barrel & AGB, chinesium ohhunt "mk12" 4" handguard And a Wolfpack Armory recessed night howler planB adapter w/ Resilient Putnik |
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Originally Posted By stiglitz_actual: Parts bin special Aero lower w/ AZR, LWRC UICW stock/buffer Troy upper w/ SLR 5" 1:5 300blk barrel & AGB, chinesium ohhunt "mk12" 4" handguard And a Wolfpack Armory recessed night howler planB adapter w/ Resilient Putnik Thanks. Mostly curious on the barrel. How you like the 5 inch barrel with subs? From my reading 300 subs do not gain anything of merit going from 5 inch to 16 inch. I do not know of that’s correct. So I plan on getting the best 5-6.5 inch barrel I can deal with. |
Words fall from your mouth like shit from ass.
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Originally Posted By Steamedliver: Thanks. Mostly curious on the barrel. How you like the 5 inch barrel with subs? From my reading 300 subs do not gain anything of merit going from 5 inch to 16 inch. I do not know of that’s correct. So I plan on getting the best 5-6.5 inch barrel I can deal with. For subs, that is mostly correct. Heck, going to a 16" barrel might actually make your subs go supersonic. But as a few other have also noted, ignoring the supersonic side of 300blk is leaving a lot of meat on the bone. |
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Originally Posted By akethan: I've found it better out of a short bolt gun with subs for critters of all kinds. Originally Posted By akethan: I've found it better out of a short bolt gun with subs for critters of all kinds. I don't know if I'd call it "better", but the realization on how much sense a shorty bolt-action in 300blk makes was the inspiration behind my BCA build with a LAW folder. It solves a couple of major issues with 300blk (no more trying to tune or choose between supers and subs, suppressed or not.....and if you have a can, less noise shooting subs) Originally Posted By akethan: If I'm keeping a gun in my truck it's gonna be a cheap 556. From cost standpoint, outside of the bullets themselves, the cost of the weapon and mags (if using 5.56 mags) is the same. And depending on the ammo you are using, there isn't even a huge gap there. When ACA was making ammo, their 77gr SMK wasn't much more expensive than their 110gr Vmax. Same upper, lower, bolt, mags. A cheap 10.5" 300blk barrel is the same price as a cheap 10.5" 5.56 barrel. (Each $62.93 on BCA's website). PSA is running a 4th of July special right now. Both are $299 https://palmettostatearmory.com/psa-10-5-carbine-length-5-56-nitride-9-lightweight-mlok-upper-mbus-vortex-sparc-w-o-bcg-or-ch.html  Only way to visually tell them apart (without looking down the barrel) is the short gas tube on 300blk. https://palmettostatearmory.com/psa-10-5-pistol-length-300aac-blackout-nitride-9-lightweight-m-lok-upper-no-bcg-or-ch-with-mbus-sight-set-vortex-sparc.html 
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Originally Posted By GarrettJ: That’s interesting. I had tried to work up a subsonic 147 gr. load that would cycle back in (checks notes) 2011 but was unsuccessful. I don’t think CFE-BLK was around back then. I’ll have to try that. I think I even have the same PSA upper that you are using. Requires PISTOL-LENGTH gas system. |
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They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety. - Benjamin Franklin, 1775
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety. - Benjamin Franklin, 1775
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Not to start a shitshow in here, but I highly recommend using 300BLK-specific mags. They make them for a reason. Any time you’re adopting a new caliber it’s the ammo costs that are the biggest factor. Luckily the cost of 300BLK has come down, but is still ~30% - ~50% more than 223/556 and always will be. That said, I loves me some 300BLK. |
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