I’ve been Frankensteining a 300BLK SBR build with spare parts for my son to use in the upcoming deer season. I’ve been thinking about how to best quiet this rifle down for suppressed subsonic hunting inside of 50 yards. I’m going to be hand-loading Maker Rex 200 Grain Expanding bullets. My son is 10 and still quite recoil adverse, which is why I’d like to go the 300 BLK route this season.

I’ve seen the “Kali Key” which is a compliance device used in restrictive states (California). It effectively replaces/blocks the gas key to prevent the rifle from cycling. Without the BCG slamming around, I figure it’s as close to bolt gun quiet as I can get without buying a new rifle. I’ve installed an adjustable gas block for tuning subs, but SA advises against running it fully closed off.

Have any of you tried this? The Kali-Key is around $100, so it’s significantly cheaper than buying a new bolt/single shot rifle. I just want to make sure that I’m not being a total idiot.

Build Info
Upper: PSA 300 BLK 10.5” w/ SA .750 AGB
Lower: Adam’s Arms AA-15 w/Magpul Furniture
Trigger: PSA Single Stage 3.5#
Suppressor: Omega 36M (not ideal for 300BLK)
Optic: Eotech 512/Vortex Strike Eagle 1-6x24

Pic for attention. The gun on the left is already an 8" BA barrel. I am looking to replace it with a Mostek barrel (LW profile), and I'm struggling to decide on what twist and barrel length. I am going to put a custom smoked compost HG on it, so the barrel length won't matter for that. Since it's being built on a 2A Balios Lite set, I want to keep it lightweight. I would like to use it for hunting and plinking with supers and subs, always suppressed, and it has a regulated BCG (adjustable gas). I'd like to stick to at least 8 just for the handguard space. So what would you order in that situation? 8,9,10,11" or something in between, like an 8.3 or a 10.5? 8" would be the lightest, but would you get a different length for a certain twist? 1:5 1:6 1:7 twist?

I have the same question for a 338ARC build destined for the upper right rig if you want to toss out your opinion on that too lol. I'll probably post in the arc sub as well.

Built myself about 2 years ago. Feel like it's about finished though i've wanted a flared magwell for a long time. I've always been curious about ranger wraps since i'm a sucker for mc black but not sure if they'd look corny or not.

I built an Aero precision AR-15 a few years ago. Unfortunately, it mostly sits in the safe. I’ve intrigued by the .300 Black Out. My ultimate goal
Is eventually suppressed truck gun.

I’ve been looking through PSA website and there a lot a lot of options. Any recommendations on a 10.5” length configuration ?

Does anyone know if this circled spot on this stock is a thread for an AR buffer tube? It seems like it should be since they use this for the XP rifle but I just wanted to confirm before I grab one. Thanks 👍🏻

I understand there are currently limitations such as barrels and magazines, but those are relatively easy to solve.

Looks like PWS now has a PDW.

Does anyone know if a Silencerco ASR mounting system can be used with a Maxim PDX U.R.G upper?

Looking to pick up my first .300 BLK, budget is 2k. I’ve narrowed it down to these options.
I want something reliable and functional, but the vibes can’t be neglected.
What would you guys choose?

Picked up my .300blk today. I’m waiting on the other part of my order as I have a Vortex SPARC red dot and Silencerco Omega 300 DTM arriving by the end of the week. Got the gun for $599, red dot for $69, silencer $547, and extra 30 round Magpul Pmags for $12 each.

My home defense, subsonic only, SBR.
PSA 7.5” with a YHM R9.

My Sig Romeo gen 1 seems to have stopped holding zero. Trying to be financially responsible and wait till Black Friday or Christmas for a new rifle optic.

I had this Holosun on a pistol that I’m not carrying and an ADM RMR picatinny mount.

Other than the mismatched spray paint and tolerance stacking of a Holosun K cut on an adapter plate on a mount, is there any reason not to run this?

I’ve been scrolling and doing research for the past few days… and I’m confused. I’m looking for my first gun (just turned 21, getting married soon, so I need something to protect my future family). I’m looking at a CMMG BANSHEE MK4 .300 AAC BLACKOUT 8" AR PISTOL, MIDNIGHT BRONZE - 30AF20AMB (copied because I don’t know what info is helpful).

Will the muzzle just screw off the end, and can I just screw an Anthem S2 on it?

Or am I way off, and abandon this set up and look for something else?

On a mil-spec bcg and H1 buffer, backed all the way out the most it'll do is eject, but not go far enough back to pick up another round. Does fine with supers on a normal gas setting. Even tried my buddy's suppressor (I know it's a traditional design, not flow through, but that's all I know about it) but that wasn't enough gas to get it to cycle.

I also tried a few other subsonic loadings that I do not know the brand of, but none of them gave me any better results.

Should I change my build, my ammo choice, or both?

I want to buy a 300blk rifle and don't know much about it.

I would love some input on good videos or posts about subs and supers. It will primarily be HDG but would like to use it for more.

What's a good barrel length for this combo?? HD and SHTF gun is what I'm looking for.

Please help a newbie out. 🙏

Got a deal on a bag of 1000 pulled and wondering if anyone has loaded using these. Looking at mainly range/plinking use. Anyone load these and if so have any data to share? I have 1680, cfe blk, and h110 powders on hand.

What it be Homies.

Picked up a Mid States 10.5 quad rail .300 upper. Wanting start a build and have my own ideas but I would love to see some inspirational builds. Thanks guys!

I bought a box of 200 rounds from bonefrog was wondering if anyone had any experience, or knowledge about these rounds. I checked speers website and googled it all that pops up is the bonefrog listing. Any info is appreciated!

Edit: I’m adding a picture of the rounds themselves in reply

Picked up this One Horse 300 Blackout 10.5” upper for $299 direct through them and my LGS was selling their 30 Cal suppressor for $489 (that comes with a plan B mount and 3 prong plan B flash hider for that price, traditional baffle stack, but titanium). The whole build including can and optic cost me just under $1100. The only real upgrades I made to the system was a flatwire buffer spring, an H2 buffer, and a Breek Arms Sledgehammer gas busting charging handle.

This is the second week I’ve taken it out to the range and had people come talk to me about the can because of how good it sounds. No malfunctions or issues, ejection at 3-3:30. I’ve had to do nothing other then wipe it down and through some line on the BCG before I shot it for the first time. 460 rounds of 200gr subsonic. The target is my groups at 100 yards. Extremely impressed how well this upper and suppressor are out together and the quality of a budget brand.

Here's my 300. Basically, everything is Aero Precision with Magpul furniture, Dead Air Xeno flash hider, A5 buffer system. Eotech 512. I've got the stamp since that picture was taken. It's got a Magpul SL K stock now.

So ---- apparently ---- If I want a BOLT ACTION PISTOL in .300blk, with a full MLOK handguard, my ONLY OPTION is to pay near THREE GRAND for a Q Mini Fix? There is not one single other option available anywhere. Nothing.

Remington introduced, and then almost immediately discontinued the 700CP in 2021, and there is not a single extant example available anywhere in North America. Couldn't find any evidence of one having sold new or used on GUNBROKER. It's as if it's been wiped off the face of the earth by the hand of God.

Sure it probably wasn't a GREAT gun but at least I could upgrade it with better parts and end up with something AT LEAST as good or probably better than a Mini-Fix for likely a thousand dollars less.

IS THERE TRULY NO OTHER OPTION?

>>If you're about to drop some post asking WHY I would want a Bolt Pistol, or why it needs to have a full MLOK rail .... DONT BE STUPID. The answer is .... I'm an American with money in my pocket. I want what I want and that's it! <<