Which AR cal, noob Reloader

[Hueco]

I've got a builder kit coming with a 9" hand guard and I'm wanting to do an SBR.

My OG thought was to do a ~9" 300blk with a suppressor for some light, maneuverable, quiet(ish) fun.

But, before committing to anything, am asking all y'all what caliber shorty AR you would build or avoid? The rub here is: I'm a reloading noob and whatever caliber this ends up being, I'll be loading for it…does that promote/discount any options?

The only thing I'm dead set against: I don't want another .223/5.56 gun…other than that, I'm not married to anything at the moment. What do you think?

(Weapon purpose: home defense rifle, range toy, fun, maybe some competition use, fun, etc.)

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[slimmer13]

I'd probably stick with the 300blk. You can make brass with a harbor freight chop saw and it's pretty much designed to do what you describe.

 

[jjfitch]

6.8 Rem. SPC was designed for your application!

Smiles,

 

[Member 34319]

300 black. Was designed for short barrels. Suppresses well. Don't need special bolt

Or a 11.5" 556

Thats all I got.

The rest aren't worth it in short mode.

You can go nuts and look at oddballs, 338 spectre being one. If 350 legend had more support it would be an amazing suppressed cartridge. 9x39 is another great one, but ammo is not exactly readily available.

By the way, this months builder set is pretty slick! Color me a little envious!


From a reloading aspect.

300 black wins again. Tons of 30 cal bullets out there. Uses lots of different powders. Versatile, from fast light supers, to heavy subs.

6.8 bullets aren't always readily available. Brass can be hard to find.

338 spectre is likely easy to reload too, but brass must be bought from specialty shops and or made. 338 bullets aren't cheap.

350 legend sits on shelves here in the west. Uses a broad spectrum of powders. Bullets are very hard to find. Brass likely is sitting on the shelf too. Specialty bullets available but costly.

 

[Hueco]

300 black. Was designed for short barrels. Suppresses well.

Or a 11.5" 556

Thats all I got.

The rest aren't worth it in short mode.

You can go nuts and look at oddballs, 338 spectre being one. If 350 legend had more support it would be an amazing suppressed cartridge. 9x39 is another great one, but ammo is not exactly readily available.

By the way, this months builder set is pretty slick! Color me a little envious!
View attachment 1126273

Yea, that's what I got. Couldn't resist. I've got a full length of that rail and really like it - not having the rail go all the way makes for a very comfy rail.

I'm not normally the kind of guy to worry about matching my shoes with my belt, but couldn't pass these up when I saw them for this build either:

 

[Member 34319]

Don't forget the matching drapes.

 

[P7M13]

Like @jjfitch suggests, 6.8 SPC is a great cartridge, performs well in shorter barrels.
Also look at the 300 HAM'R

Not sure how well either of the two above will work when shot subsonic.

 

[jjfitch]

300 black. Was designed for short barrels. Suppresses well. Don't need special bolt

Or a 11.5" 556

Thats all I got.

The rest aren't worth it in short mode.

You can go nuts and look at oddballs, 338 spectre being one. If 350 legend had more support it would be an amazing suppressed cartridge. 9x39 is another great one, but ammo is not exactly readily available.

By the way, this months builder set is pretty slick! Color me a little envious!
View attachment 1126273

From a reloading aspect.

300 black wins again. Tons of 30 cal bullets out there. Uses lots of different powders. Versatile, from fast light supers, to heavy subs.

6.8 bullets aren't always readily available. Brass can be hard to find.

338 spectre is likely easy to reload too, but brass must be bought from specialty shops and or made. 338 bullets aren't cheap.

350 legend sits on shelves here in the west. Uses a broad spectrum of powders. Bullets are very hard to find. Brass likely is sitting on the shelf too. Specialty bullets available but costly.

LAX Ammo has Privi (PPU) ammo. $1.00 per round shipped. Reloadable and shoots nice!

Smiles,

 

[Hueco]

300 black. Was designed for short barrels. Suppresses well. Don't need special bolt

Or a 11.5" 556

Thats all I got.

The rest aren't worth it in short mode.

You can go nuts and look at oddballs, 338 spectre being one. If 350 legend had more support it would be an amazing suppressed cartridge. 9x39 is another great one, but ammo is not exactly readily available.

By the way, this months builder set is pretty slick! Color me a little envious!
View attachment 1126273

From a reloading aspect.

300 black wins again. Tons of 30 cal bullets out there. Uses lots of different powders. Versatile, from fast light supers, to heavy subs.

6.8 bullets aren't always readily available. Brass can be hard to find.

338 spectre is likely easy to reload too, but brass must be bought from specialty shops and or made. 338 bullets aren't cheap.

350 legend sits on shelves here in the west. Uses a broad spectrum of powders. Bullets are very hard to find. Brass likely is sitting on the shelf too. Specialty bullets available but costly.

What's the scale of difficulty for making brass? Seems working with 10mm mag to start isn't too bad looking:

I wonder how cycling with it is compared to 300 blk, along with perceived recoil.

 

[Caveman Jim]

If you've got 223/556 brass you can make your own ammo. That said I would go with a 300 blackout unless you've got deep pockets.
That's all I've got, good luck brother.

 

[Member 34319]

What's the scale of difficulty for making brass? Seems working with 10mm mag to start isn't too bad looking:

I wonder how cycling with it is compared to 300 blk, along with perceived recoil.

Making brass isn't the hardest thing in the word. It just requires more dies and time/process.

I can't imagine recoil on 338 specter would be any different than shooting a pistol caliber of similar bullet weight through a rifle as the speeds should be about the same. Just like subsonic 300 blackout is basically 45 acp with a better bullet coefficient, 338sp might be similar to say 44 mag with a better coefficient.

@wired has one and I never get tired of him showing it off.

 

[wired]

Making brass isn't the hardest thing in the word. It just requires more dies and time/process.

I can't imagine recoil on 338 specter would be any different than shooting a pistol caliber of similar bullet weight through a rifle as the speeds should be about the same. Just like subsonic 300 blackout is basically 45 acp with a better bullet coefficient, 338sp might be similar to say 44 mag with a better coefficient.

@wired has one and I never get tired of him showing it off.

I love that cartridge.

 

[quneur]

Grendel has better ballistics than the 300 blk even in short barrels. But reloading components are hard to find. If you're going to want to shoot a lot, 9mm is another option. Ammo is out there and straight wall cases are much easier to reload than bottle neck cases.

 

[jjfitch]

The M4 9mm is a great H/D option with a shake awake der dot. My wife laid claim to mine!
I'll use the H/D shotgun!

 

[3MTA3]

300BO is my vote:

• Designed for your application
• Uses the same bolt as 5.56
• Can be made from common brass - "so easy even an @Caveman Jim can do it"
• Uses the same magazines as 5.56

IMO the only drawback is that 300 BO will chamber in 5.56 followed immediately by disaster and since it uses 5.56 mags you need to be very careful not to get them mixed up. I strongly suggest you find a way to keep them straight like one or more of these among others:

• A different color mag used only by 300BO. Example: Black for 5.56 and FDE/Coyote for 300 BO
• Use plastic for one and metal for the other
• One distinctive brand used only for 300 BO. Example: Magpul for 5.56 and Lancer for 300 BO

 

[Caveman Jim]

300BO is my vote:

• Designed for your application
• Uses the same bolt as 5.56
• Can be made from common brass - "so easy even an @Caveman Jim can do it"
• Uses the same magazines as 5.56

IMO the only drawback is that 300 BO will chamber in 5.56 followed immediately by disaster and since it uses 5.56 mags you need to be very careful not to get them mixed up. I strongly suggest you find a way to keep them straight like one or more of these among others:

• A different color mag used only by 300BO. Example: Black for 5.56 and FDE/Coyote for 300 BO
• Use plastic for one and metal for the other
• One distinctive brand used only for 300 BO. Example: Magpul for 5.56 and Lancer for 300 BO

Thanks for the mention brother @3MTA3 as I forgot to include this very important fact in my unusually short post.
I used to use white fabric medical tape on my 300BLK magazines but found a great deal on some rubber magazine labels.
At the onset of the 300 black build I made the decision to use only polymer (lancer & Magpul) 20 round magazines and US G.I. 30 rounders for my 5.56 AR's.

 

[Sweep1308]

Grendel has better ballistics than the 300 blk even in short barrels. But reloading components are hard to find. If you're going to want to shoot a lot, 9mm is another option. Ammo is out there and straight wall cases are much easier to reload than bottle neck cases.

My vote is .300 blk also. Wherein it us true that Grendel undeniably outperforms .300blk in supersonic applications, subsonic is another story. Other factors also impact my decision.

.300blk will ALWAYS be available one way or another. Soooo many .30 caliber projectiles. Also, an almost endless supply of 5.56 brass. Powders are the largest inconvenience, and they are certainly available. The bonus of using the same bolt face as 5.56 is also an advantage. Not sure on barrel life, but I would imagine similar, if not in favor of .300blk also. The addition of some decent subsonic expanding projectiles to this caliber has also enhanced it's abilities. However, those special projectiles are both expensive and hard to find at times.

There will ALWAYS be a caliber that's better than whatever you choose in some aspect of performance. Blackout is a good, all around caliber and isn't going anywhere.

Edit: and yes, find a labeling system that works for you to keep your mags/ammo from entering the wrong host. Lots of options. One that wasn't mentioned was electrical tape. I keep my 5.56 bare, and my .300 blackout get banded with the thin, bright colored electrical tape depending on purpose. Subs, supers, ball, hunting, etc. Bottom line, if it's taped, it's blackout.

 

[BBQ Guy]

300 blk shoots well suppressed with subs and a short barrel.
IIRC that was one of the main desire goals behind the development of the cartridge.

 

[DirectDrive]

Tough choice.

300BLK
338 Spectre
375 SOCOM
458 SOCOM


375 SOCOM

 

[3MTA3]

Thanks for the mention brother @3MTA3 as I forgot to include this very important fact in my unusually short post.
I used to use white fabric medical tape on my 300BLK magazines but found a great deal on some rubber magazine labels.
At the onset of the 300 black build I made the decision to use only polymer (lancer & Magpul) 20 round magazines and US G.I. 30 rounders for my 5.56 AR's.

View attachment 1127671View attachment 1127675

Nice! IIRC you made your brass from 5.56. What did you find to be the easiest way to cut it down to 300 BO?