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300 blackout help

Rowdyryno

Sergeant
Full Member
Minuteman
Dec 24, 2011
214
0
41
Wichita kansas
So I'm building a 300 blk out on a seekins billet upper and lower and have everything I need except barrel and hand guard. I picked up the new EOtech sight yesterday that's calibrated for 300 blackout and has to dots and on top of sight is a picture showing both subsonic and supersonic ranges for the dots. Sub is top dot zero 50 yards lower dot 150 yards, and then same for super but top dot 100 yards lower dot 300 yards. I wanna keep this rifle short but don't wanna completely kill the thought of the sight. If the sight is useless for a 10.5" barrel or less then ill go exchange it for a normal single red dot and just zero that and hold over if need be. So any feed back will help thanks
 
On the one I currently have, I got an AAC upper with the KAC URX2 handguard (it was built exactly as I wanted it at the time, save for the fact it had mid instead of rifle length handguards). With the thin barrel, it is quite light. The SDN-6 suppressor works well, but mount has play. It currently has a Leupold Mk.4 2.5-8x, but I may put a Browe optic on it later. Titanium, batt. illuminated reticle, ex-Trijicon guy's startup bussiness, reticle similar to the Leupold .300BLK reticle and not the useless ACOG BLK reticle. Check it out: nice, compact titanium ACOG-esque 4x combat optic, dual illum. BDC for the BLK with interesting features. NV settings so it works with clip ons. Nice caps and the ARD threads in. Uses a CR123 or 3v DC battery jack.

But the little .300BLK impressed me, it did more than I expected it to. It exceeded my expectations by far. I figured it would be primarily limited to this 200m or so range I normally shoot at, but found it shot very easily at those distances, with either supers or subs, given appropriate elevation changes on the scope --which I found I still had plenty left to go. I suspect subs peter out between 250-350ish, but the supers could go quite a bit further. So I'd like to try one built a little better, but still light. In fact, lighter.

For another I'm building, I'm thinking of going with a quality 14.7" stainless, deep and wide fluting on a heavy or medium contour, twist to be determined, but barrel should weigh in at around 1 pound and with a blind pinned Wilson GI type flash hider/mount, PRI carbon fiber handgaurds (or possibly a carbine length KAC URX3) and a 17 oz. Wilson Combat titanium suppressor. I like the VLTOR uppers for strength, but for lightweight, I'm gonna stick with a good, quality forged upper and lower. Maybe a Mega, they are local (and I have one laying around). CTR stock. I like JP Ent. Full Mass BCG best of any other, period, but may try their low mass setup in this one. That about does it, the rest is sort of user specific, like triggers (some Geissele I'm sure) and grips and bipods and other accessories.

I'm building a light 6.5Grendel to these specs too, but with the VLTOR upper and Satern barrel. It'll use the same suppressor and have a USO 1-6x DFP scope/dot. Should have it done... In about 2 years.

I'll probably go with the Browe on this .300 too unless someone else comes up with another one I like better, or if I don't like the first one I get. Right now there are two reticles it seems: the ACOG and Browe/Leupold (which is much better IMO). There is the EOTech one, but also doesn't take full advantage of this cartridge like the ACOG, and you literally have to determine what range that second dot is for by trial and error with subs once you get a super zero. With the Browe (or Leupold) you can zero one side or the other and it works with most light supers and 220 subs.

Now if you can get an SBR, well, then things open up quite a bit. That is what I wanted, but we can't have that here, hence the blind pinned mount to save the extra inch or so (which doesn't interfere with barrel removal, only the gas block). Good looking SBR .300bbls. look, to me, to be the heavy Noveske barrels by far. AAC makes one as well, a light 8.5"? and it isn't too bad either (the 16" light barrel is pretty accurate so far) but it uses their SDN-6 mount, unless you take that off. The flash suppressor mount itself works very well too. Personally, I'd use a different suppressor, a lighter one that either threads on or has a stable QD mount that locks up tight. Probably that EOTech you mention, maybe another, maybe an Aimpoint Micro (T1?). .300Blackout is really good for a PDW type weapon, it doesn't lose too much velocity in the short barrels compared to 5.56, but functions just like the familiar M4. Wish we could have SBR's, there are only a couple I want and this is one of them. Only thing better would be a side folding stock...
 
I've just about finished a build for a .300 blk out myself. ( missing a scope and a by-pod ) My question is that I have seen a lot of websites saying that .300 whisper will work in .300 black out, is this true?
also anyone have a good line on some reasonably priced SS Blk Out? or is reasonably priced ammo just a relic of my past like 98 cent gas?.. It's to the point where I'm considering looking into the feasibility of purchasing automated machinery to make my own ammo.
 
I've just about finished a build for a .300 blk out myself. ( missing a scope and a by-pod ) My question is that I have seen a lot of websites saying that .300 whisper will work in .300 black out, is this true?
also anyone have a good line on some reasonably priced SS Blk Out? or is reasonably priced ammo just a relic of my past like 98 cent gas?.. It's to the point where I'm considering looking into the feasibility of purchasing automated machinery to make my own ammo.
depends on who made the whisper reamer and to what spec, often the only difference in in the throat but the only way to know for sure is to look at the reamer print or make a chamber salting and measure it, nobody can tell you for certain over the Internet...
 
I've just about finished a build for a .300 blk out myself. ( missing a scope and a by-pod ) My question is that I have seen a lot of websites saying that .300 whisper will work in .300 black out, is this true?

300 Whisper ammo will work in a 300 BLK barrel but not the other way around.
 
So I'm building a 300 blk out on a seekins billet upper and lower and have everything I need except barrel and hand guard. I picked up the new EOtech sight yesterday that's calibrated for 300 blackout and has to dots and on top of sight is a picture showing both subsonic and supersonic ranges for the dots. Sub is top dot zero 50 yards lower dot 150 yards, and then same for super but top dot 100 yards lower dot 300 yards. I wanna keep this rifle short but don't wanna completely kill the thought of the sight. If the sight is useless for a 10.5" barrel or less then ill go exchange it for a normal single red dot and just zero that and hold over if need be. So any feed back will help thanks


The dots are calibrated for 220gr, subsonic. Easy enough for a 10.5" barrel. I would think you would be fine at least for the sub's.

I haven't found any info on the supersonic calibration of the dots for velocity, or specific bullet weights.

It may be a little bit of wishful thinking on the part of Eotech that your unknown supersonic load will match their dots / ranges.

They might be close enough unless your shorter barrel doesn't quite deliver the velocity Eotech calibrated their sight for.
 
300blk makes very little extra velocity over 11.5. It is fast burning. You will lose a bit in a 10.5, but I'm not sure if it is enough to throw off the sight drop compensation.
 
Very little difference. We shoot the 300 blk subs to 650m regularly. It still has .45acp power at that distance. You just have to get an optic that will do it.
 
Well I looked and looked for what I wanted to go with and came across the Houston armory integral suppressed 8" barrel 12" hand guard total package and really leaning towards that as a all in one package. So should I ditch that 300 black out EOtech and just go with a single dot set up?
 
If you reload AND shoot mostly subs then no.You can just add powder to bribg the subsonic velocity back up to factory load specs ananthe bdc will work again.
 
The king, I do reload but have never reloaded 300 blackout I just reload for long range stuff due to that's all I shoot at the moment but will def reload of the 300 blackout of need be. I just want the shortest package possible and the internal suppressor cought my eye and from what I've heard from the people there they say it performs like a 12" barrel due to it being all internal.
 
The sorter barrels with standard suppressors are quieter.

The only issues with the HA is that it's louder than an 8" with an SDN-6 and its a 1 trick pony.

I have handled one at Shot show and talked to the owner and a customer who has one.

That said, the HA is shorter, I.e. an 8" bbl and a 4" can. It's a special purpose weapon and it is good if you need a short relatively quiet weapon.

The options with a secrete 30 cal can are more versatile as you can use the can on other rifles.
 
Texasguntrustlawyer I have many cans but wanted the in the hangars look and all my cans are QD cans so kinda makes that hard. I run a SD-300 titanium can from AAC on my 30 cals now. All and all what did you think when you handled the HA?
 
After immersing myself in the caliber for a while I have a few suggestions.

1) Get a 1-4X Mildot illuminated optic with a zero stop(Vortex PST)-perfect for going from sub to super. Set your zero stop for subsonic zero if thats what you shoot the most. Know your mils for supers. Done. The dual reticle thing is silly and my supers are 110 grain bullets at 2400 fps. I like magnification for that.
2) Get some Lancer 20 rd mags. This cartridge makes a 30rd loaded mag heavy. Fast.
3) Get a good sizing die (I prefer Forster). I didn't feel the Hornady was that great.
4) Build a gun around your can. If you have a really large/long can, try the shorter barrel. I really like the 8.2" size with the can on the gun.
5) Try more than just 220 subs. I really like subs in the 190-208 grain range. I like Nosler 190 match bullets (cheap) use magnum primers and 11.3-11.5 gr of 1680 powder. My gun shoots 1" groups at 150 yards with subs.
 
I run hornady 225s for subs and the leupold 1-6 multigun for optic. Has a ton of drop compensation between knobs and reticle.
 
there is alot of good info here . I really like the idea of the leupold 2.5 x 8 mk 4 . I am not a big fan of bdc because you are so limited with what you can do.
I have an 8.5 inch pistol build I plan to sbr soon and use a yhm stainless phantom suppresor . short is definatly the way to go with these guns . I mounted an aimpoint pro on the rifle simply because it fits the mission of the rifle . I am limited on distance due to terrain and vegitation so most shot would/ will be under 100 yds . I do have a 16 inch blackout with a should not work but it does simmons 3x9x40 that I have decided to just zero for supers and lwt it go at that . I also have a 700 remington in 300 blackout and have mounted a weaver 1x6 on it .
reloading is the only way to go with this round , like the king above I also use the hornady 225 grain bullets for subs and the outlaw state 220 grain low velocity expanding bullets for hunting .
good luck and have fun.