.300 BO advice sought...

Dale Gribble

Can't starve us out; Can't make us run
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Helped my dad with his first AR (5.56) build a few months ago. So far, he loves it and that’s from a guy who said he’d never have an AR...not that he has anything against ownership/possession of them, he’s just always been a wood/steel kinda guy.

Anyhoo, he’s looking to build an AR pistol in .300 BO. I can’t really speak intelligently and/or offer suggestions because I do not have any experience with the platform in that chambering. I have suggested the SBA3 brace. He’s got some time on my rig that’s equipped with one and he’s decided to go with the same on his build.

What he’s looking for...

A rig that:

- Is relatively compact/lightweight
- Can be kept by the bedside, carried in a vehicle or be used to take deer / other game
- Effective out to at least 300 meters
- It’ll have 75 year old eyes behind it, so I suggested he look at a LVPO as opposed to a RDS.

What barrel length would yall suggest? Any other comments/suggestions?

Thanks!
 
I would not do a 300blkout due to how easy it is to mix up one round and have a catastrophic situation in the 5.56mm. Since he is 70 years old + that is a real situation.

On the side note, a 6.5G pistol like this one:
https://palmettostatearmory.com/psa...m-lok-moe-ept-sba3-pistol-kit-5165449010.html

Prevents 100% that issues a 300blkout has, and allows you to get to 300yds + in the same size package you are looking for.

Optic,
I would skip all the LPVO and go directly to a Super Sniper 10x
https://www.swfa.com/swfa-ss-10x42-tactical-30mm-riflescope-3.html

Why make it complicated?
 
I would not do a 300blkout due to how easy it is to mix up one round and have a catastrophic situation in the 5.56mm. Since he is 70 years old + that is a real situation.

On the side note, a 6.5G pistol like this one:
https://palmettostatearmory.com/psa...m-lok-moe-ept-sba3-pistol-kit-5165449010.html

Prevents 100% that issues a 300blkout has, and allows you to get to 300yds + in the same size package you are looking for.

Optic,
I would skip all the LPVO and go directly to a Super Sniper 10x
https://www.swfa.com/swfa-ss-10x42-tactical-30mm-riflescope-3.html

Why make it complicated?

IMO the Grendel is awesomeness. Good call.
 
The old man wants 300 blackout, so let's come up with a quick and easy idea to make that possible...like build one from OD Green or Tan parts (to include mags) so he knows which is which without any chance for a mix up.

I'm planning a 300 blackout build right now as well. I'm planing to use either the Gen 2 Tailhook or an SBA3. Standard carbine buffer and spring. I'll slap an LVPO on it, probably a Steiner 1-4 I might still have laying around somewhere. I'm inclined to get a pre-built upper because I've been wanting a piston gun in the collection ( I like stuff that's a little less common) so for me it's a PWS MK109. After my first build (AR9) I'm learning about the things I like and don't like. One thing I don't like is the crappy "mil-spec" safety I installed. Spending a little on that next time seems like a good idea, maybe get one of the 1/2 throw style with a longer lever. I'd use another POF trigger or a Hyperfire in a heartbeat.
 
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I’ve an 8.5” pistol and a 10” SBR, and like them both.
The 10” (avatar) is used for hunting and HD. It’s performed flawlessly for 10 years. The inexpensive 8.5” Anderson/PSA upper is newer and hasn’t been shot much, it also has run without fail.
I rarely shoot 5.56, I reload and use a heavy Lee factory crimp to help savior a kaboom in case a 300 gets mixed in with the 5.56.
 
Definitely get vastly different mags for use with the 300 blackout. I use lancer smoke in my .223 and windowed pmags in my 300 blackout. Always get a pistol length gas system to help with cycling reliably.

Barnes tac-tx 110 grn bullets are the gold standard for hunting with 300 blackout. If he doesn't reload, the factory version is called Vortx. I have had good success on hogs with the 110 gr hornady vmax, which is sold as the hornady black packs.

Leupold mark ar or vxr patrol LPVO are excellent and very lightweight, paired with an aero ultralight mount and you are barely adding any weight.

As far as 300 yard effectiveness, it won't be for hunting. Hitting a man sized target to wound sure.
 
tailhook mod 2 is a pretty darn good brace that actually works as a brace (and doesn't feel like crap if it accidentally escapes your cheek and touches your shoulder)
keep in mind that a 300 subsonic is a lot like 45acp, but with a different shape
supersonics are more like AK-ish.
like many, i would recommend CLEARLY marking your 300 gun, mags, and ammo so no mistakes are made.
 
If I had to do it over I'd have done a 9mm pistol instead of a 300 build. There's no cheap ammo around here at all and wasn't before all this mess.
 
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If I had to do it over I'd have done a 9mm pistol instead of a 300 build. There's no cheap ammo around here at all and wasn't before all this mess.

Yea if you're gonna plink with it then you kinda have to reload. You can shoot for pre-coronavirus .223 prices if you reload and don't mind shooting powdercoated bullets.
 
If you’re willing to drive towards me, I’ll loan you a 7.5” 300BLK pistol and another 10” 300BLK upper and y’all can shoot both to see what he likes.
 
Here is my solution to mixing magazines. I made these for my 300blk mags. Old tired eyes cannot see the 300 BLK from Magpul.
View attachment 200060
I opted for just making everything FDE that was 300BLK...

B149068F-3FC8-4BDE-B548-D98044E2BFB4.jpeg

Lancer makes 300BLK specific mags with FDE baseplates if you prefer them over 5.56 PMags.
 
I built my 300bo from scratch...

80% lower, and cheap 10.5 inch 300bo pistol kit from www.daytonatactical.com

But, I also upgraded some of the components like the 13 inch handguard, noveske pig hidden inside handguard, magpul furniture, etc...

I was also afraid of the 300/5.56 mixup, so I bought and installed a dust cover laser engraved with "300bo", I color coordinated it green, and my buddy gave me a couple "wwjd bracelets" that actually say "300bo". They fit on the mags to remind me what ammo is in those mags...

I love this thing! I've put about 500rds through it, and I killed a deer with it a few months ago. No problems, whatsoever (after the initial hiccups of getting an 80% home build dialed in).

20200329_143218.jpg
 
10 inch is about right for a pistol length.... I'm not a fan of rifle cartridges with short barrels, but the 300bo is an exception due to the powder it burns (Heavy Handgun Magnum). It will still achieve rifle velocity with lighter bullets with a shorter barrel, and it's plenty light and compact.

I was also not a fan of the pistol braces when they first came out, but @BigWaylon sold me on the SBA3..... If I were in the market for a pistol AR (or something else it would fit), I would gladly buy another one.
 
Wolf is producing .300 blackout ammo but I'm not sure when it'll hit the shelves...... I love the round. The Wolf ammo will make it cheap to stack/plink with and the 110gr Barnes Tac-tx is a deer hammer.
 
My little 9" is pretty golden so far... With the wide range of ammo available, you'll want pistol gas and either a little overgassed or adjustable if you want it to function 100% with big subs and little supers. Also if you want to shoot big subs go with a 1-7 twist too. If it's only for supers 1-8 is fine.. oh and 300 meters is too far for ethical hunting with 300blk.. 200yds max with supers, 100yds with subs...
 
My little 9" is pretty golden so far... With the wide range of ammo available, you'll want pistol gas and either a little overgassed or adjustable if you want it to function 100% with big subs and little supers. Also if you want to shoot big subs go with a 1-7 twist too. If it's only for supers 1-8 is fine.. oh and 300 meters is too far for ethical hunting with 300blk.. 200yds max with supers, 100yds with subs...


Im all for ethical hunting...

That's why I drink beer and sit on my back porch and shoot them from 30 yards while they are eating corn... ;)

20191119_164434.jpg
 
Wolf is producing .300 blackout ammo but I'm not sure when it'll hit the shelves...... I love the round. The Wolf ammo will make it cheap to stack/plink with and the 110gr Barnes Tac-tx is a deer hammer.

Can't wait for the Wolf stuff to come out... I'm hoping they do supers and subs...
 
I built mine off a DSG Arms kit. Looking at their website it doesn’t show anything .300 related so they must’ve got out of it.
 
After reading several posts of the danger of mistakingly shooting a .556 round and the resulting damage and possible injuries, I decided to put the rubber mag pulls on all my .300 mags. As it's main purpose is a HD gun at 7.5" I didn't want to mistake the .300 and .556 mags in low light or without my glasses on.
 
Yes...... Legitamate point above........mark the.magazines.one way or another. A coworker marks a big green X paint pen on his 300bo mags to keep them separated from 5.56 mags.
 
Yes...... Legitamate point above........mark the.magazines.one way or another. A coworker marks a big green X paint pen on his 300bo mags to keep them separated from 5.56 mags.
Paint pen sounds good, but even better if it's also tactile, so you can feel the difference in the dark...
 
Here is my solution to mixing magazines. I made these for my 300blk mags. Old tired eyes cannot see the 300 BLK from Magpul.
View attachment 200060
I like it.
I run 300BLK in Magpuls, 5.56 in metal mags.
I sprayed white paint into its cap and filled in Magpul’s “300BLK” with a toothpick so it’d stand out. After it dried a bit I wiped the surface with a thinner to get a clean look.
796D70F3-517F-4775-AB7C-4900EDCFB644.jpeg
 
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I used the aluminum sticker material that I make the UIDs out of. I just laser engraved it. It is solvent resistant, scratch resistant and supposed to last for 20 years of service according to mil specifications. I am now rethinking it since you did the white paint. The paint looks better.
 
Wolf is producing .300 blackout ammo but I'm not sure when it'll hit the shelves...... I love the round. The Wolf ammo will make it cheap to stack/plink with and the 110gr Barnes Tac-tx is a deer hammer.

The impending Wolf ammo is what made me finally build a 300BO pistol, I just jumped the gun a bit lol
 
I used the aluminum sticker material that I make the UIDs out of. I just laser engraved it. It is solvent resistant, scratch resistant and supposed to last for 20 years of service according to mil specifications. I am now rethinking it since you did the white paint. The paint looks better.
Your solution is easy to see with old man eyes.
 
I think him having one as a rifle in 5.56 and the .300 in a pistol will help differentiate.

They sell AR magazine wraps with all sorts of cool stuff on them, just order him some .300AAC mags and a few of those wraps. I have never really worried about getting the two mixedup, I keep my .300 in its own case with its own magazines. The man was smart enough to raise you, and survive until his 70's. I feel he is probably smart enough to keep magazines separate. Heck, paint them wood colored and tell him just to use the old wood magazines with his .300 pistol.
 
my advice is to skip a .300blk unless you reload or already have a stash of ammo. It's a rich man's caliber during the good days. That being said, I have an 8.5" BLK pistol that is my wife's fave. But my latest build is a grendel because steelcase Wolf is still available at decent prices.

I have a feeling the wolf 147gr .300blk is vaporware at this point
 
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