.300 Blk Out needs?🤔

[Deputy819]

Have to come to the LRH 'Braintrust' on this one because I'm way out of my element here. I have a .30 cal suppressor in 'jail' (blew the 90 day E-File thing) and I just sold my .300 Win Mag that it was going on. Yesterday, picked up a .300 Blk Out on a whim at my LGS and whenever the ATF decides to grace me with my suppressor it will now have a rifle to be attached to. I hadn't really planned on hand-loading for this cartridge, but components seem to be plentiful for it……and I already have plenty of small rifle primers. That same LGS I bought the rifle from has plenty of CFE Blk powder and I've found .300 Blk Out brass & bullets fairly easily online. Here's my question…..considering this is an AR platform what dies would you guys recommend should I choose to hand-load for this thing? At some point I'd also like to mess around with the whole "sub-sonic" thing, too. Thanks folks!

 

[Deleted member 115360]

They are a ton of fun to load for. I just have a set of rcbs fl dies. I full length size all of my ar cases, because I was told I should. It works fine.

A lb of powder shooting subs will last for years, and it is a potent little cartridge with the 100gr hammers, or 110gr ttsx or 110 vmax. Shooting subs suppressed is just a blast. I let my little nephews and neices shoot mine all the time. Light recoil and no muzzle blast, and they love it. Every load I've ever played with shot really well too. We have killed a few deer with them too, with the subs, and it didn't kill very well, but I'm still playing with that. It is a respectable whitetail killer with the lightweight bullets inside of 200y.

 

[waspocrew]

I'm new to the 300 BLK as well, but have been loading with the Hornady dies without issue. There are plenty of great die options, just go with your preference.

 

[Deputy819]

They are a ton of fun to load for. I just have a set of rcbs fl dies. I full length size all of my ar cases, because I was told I should. It works fine.

So, I don't necessarily need 'small base' dies? Also…..you ever load bullet weights from 190gr on up to 200+?

 

[waspocrew]

Another must have: buy a Wilson case gauge. This will help you know if you're getting everything set up correctly.

 

[Deleted member 115360]

I have done everything with my single set of dies. I use a universal seating die to seat everything, it is easier to tune than the rcbs stuff. I've worked up some 190 sub-x right now. I'm playing with them. I want to get every drop of velocity that I can without breaking that sound barrier..

 

[Mike D Texas]

I've loaded it on Lee, RCBS, Hornady and Redding. I've settled on Redding for now. Not because the others loaded lesser quality ammo, I just went through a phase of trying to consolidate to one manufacturer of dies.

That said I've not used CFE BLK I use AA1680 for subs and MP300 for supers. I gained noticeable velocity with the MP300 over H110/W296, etc….I'm running the 110 Barnes TAC-TX at 2315 fps from an 8" SBR.

 

[QuietTexan]

A1680 for subs, you might need to change the buffer weight out depending on if you have an FA carrier or not and what the gas port/block are.

I use regular Hornady dies, never needed anything fancier. The dies are not the limitation here, the barrel, chamber, and overall specs of the AR are what will hurt group size a lot more than reloading tools.

Berrys Bullets are awesome for subsonic blaster rounds. Gilded metal 200+gn cheapies that run very well and don't break the bank when you're shooting high volume.

IMO cough up the $200 for a Form 1 and SBR the lower, the 300 BLK only needs an 8" barrel for subs and that drastically reduces the overall length compared to a 16" barrel + suppressor. Don't be disappointed for how loud it is with the can on - you can't do anything about the gas port noise on an AR, but have someone else shoot it and stand 10+ yards away on the offside of the rifle and you'll be shocked how quiet it is overall.

So, I don't necessarily need 'small base' dies?

Correct, it's a very low pressure round, no blown primer pockets or expanded heads here. Only the top end of supers are going to crack 50k, and you can get similar velocities at lower pressure by changing powders.

Also…..you ever load bullet weights from 190gr on up to 200+?

That's really the point of the Blackout - subsonics through an AR-15 platform. The supersonic ballistics and rise of specialized flat base bullets like the Barnes Tac-TX are just icing on the cake at this point. It'll never be better as a super than pretty much any other .308 cal out there, but will hold it's own well enough. I prefer short action 6mms to the 300 BLK for supers, but the ability to change between the two only by changing out the mag is a big plus for the 300 BLK.

Another must have: buy a Wilson case gauge.

Would have to be their brass min-dimension gauge. Wilson's standard case gauges are for fired brass, very useful for headspacing but they're not a checker gauge. If you want to ensure function in a SAAMI spec chamber a Hornady, Lyman, Sheridan Engineering, or Dillon gauge are better choices.

 

[Deputy819]

Don't be disappointed for how loud it is with the can on - you can't do anything about the gas port noise on an AR, but have someone else shoot it and stand 10+ yards away on the offside of the rifle and you'll be shocked how quiet it is overall.

Good point and thanks for all the good info. I'll do just that.
Just ordered 5 boxes of Hornady .300 Blk Out 190gr SUB-X TAP from Mile High Shooting to get started. Now if the ATF would just cooperate…

 

[Deputy819]

Also…..would something along these lines be decent enough to slap on top of this rifle? I won't be doing anything with it other than knocking off the occasional 'varmint' (animal….non-biped ) on my property and target/steel work just for fun…

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[QuietTexan]

While that scope would be fine, I would push you a bit to get an FFP instead of a second since 1) the Christmas tree isn't really practical in SFP, and 2) the 300 BLK does have a lot of arc to it in both super and subsonic, so knowing what your actual drops are on the stadia lines is important. The SIG 1-4x is FFP, Vortex makes a 1-8x Strike Eagle that's FFP.

Re: 1-6x power - I typically use low power scopes on hunting rifles - 2-7x, 1-8x, 1-6x, and straight red dot even. Works much better IMO than too much magnification and getting lost scanning for the target.

 

[Deputy819]

While that scope would be fine, I would push you a bit to get an FFP instead of a second since 1) the Christmas tree isn't really practical in SFP, and 2) the 300 BLK does have a lot of arc to it in both super and subsonic, so knowing what your actual drops are on the stadia lines is important. The SIG 1-4x is FFP, Vortex makes a 1-8x Strike Eagle that's FFP.

"Shopping" now. Thank you, Sir.

 

[jasonprox700]

That scope would probably work well enough, but…

I have tried using the straight tube scopes for hunting, and they work just fine during daylight hunting, but when using them early morning and late evenings, they do not transmit light as well as larger objective scopes (to my eyes).

I had a 1.5-5 VX3 Leupy on my Blackout, but have since swapped it for the Athlon Helos BTR 2-12x42 FFP. It isn't much larger than the VX3, but is light years ahead for low light hunting.

 

[Okanogan]

The 300 BO is a fun little cartridge especially if you're running suppressed. I am now down to just a AR pistol which I have suppressed with a TBAC Dominus.

You haven't really said much about what your goals are for your soon to be set up. The BO isn't really a long range cartridge so for my uses I'm not looking for the same kind of things I look for when loading my 300 WMs, 6.5 SAUM, or Valkyrie. I'm just looking for plinking, target, defense and maybe deer at fairly short range. For those types of applications, I have found Hornady dies and Lock N Load progressive press save me time and produce satisfactory results. (I still weigh powder charges though) Depending on what your goals are, changing up from your long range reloading practices may save you time and money.

Here are a few comments from my 300BO experience that you can take or leave:

- CFE Blk has worked well for me for both subs and supers. However, it tends to like to have a compact load which means getting a good combination of charge weight and bullet selection might be a challenge. My favorite subsonic load is a 225g hornady match bullet seated on 12.8g. (The easiest way to determine what is a compact load seating depth is to put the charge in a fired unsized case and measure the COAL with the bullet setting on the charge.)
- A1680 is more forgiving on not being compact and so probably makes a better choice for many subsonic loads.
- I have used H110 for many of my supersonic loads and I think it will give you a little more velocity than many of the other options.
- I have had good luck with starline 300 BO brass. It isn't as soft as Hornady brass. It isn't as good as Lapua and some of the high end mfr but it gets the job done for me at a reasonable price. Normally, I buy direct from Starline but they are apparently so backed up they aren't taking back orders like they normally do. Brownells and Powder Valley both had some available earlier today.
- If you're running an AR platform, the 190 Sub-X rounds may have an issue feeding if you seat the bullets deep enough to make a compact subsonic load with CFE Blk so you may want to try a different powder if you're trying to stay subsonic.

It sounds like you are fortunate to have small rifle primers readily available. The rest of the components you need are generally available and you should be able to have some fun and save some money over the currently still very high prices for non-FMJ factory ammo.