Need to finally pick a cal please help, looking for barrel  from 8 to 10.5
Thanks

In that range, 300BLK is the best bet. That's about the length it was designed around.

I'd be willing to bet 762x39 is going to have more velocity than the other two when comparing similar weights.

For HD it really doesn't matter.  Any center fire rifle round is going to ruin someone's day.  If you already have a 5.56 rifle and just want something different I'd go 300blk.   You can load some 110 varmageddon that would be nasty.

Well, it's just not as simple as that.

I had a chart and some numbers of 300BLK and 7.62x39, out of 8" barrels all the way up to 16" barrels.

And in short configurations, the 300 pushed the same weight as fast or faster than the x39, and with less powder.

The AK round is not as efficient and will require more barrel length just to SLIGHTLY edge out the 300 in velocity, but considering the 300 uses .308 bullets(better BC's) that slight advantage the AK had is more or less nulled out rather quickly.

I'll see if I can find some of that data and post it in this thread soon.

With a 16" barrel the 7.62x39 can push the 125 grain nosler BT(308 bullet but accurate in most guns) or the hornady sst to 2400 fps also most factory 7.62 is faster than whats on the box, tula wolf etc will be around 2400 fps and Sellior and Bellot is typically around 2400 also.  Or 150 fps faster than the 300 blk out.  But that advantage drops the shorter you chop the barrel, it also is increased as the barrel approaches 20".  I would think at 8" the 300 would at least be equal and 10.5 would be close as well.  In short unless you want the cheaper factory ammo option the 300 blk is best in barrels under 10.5", it burns less powder and will be just as fast.  And this comes from someone who would choose the 7.62x39 all day in barrels  16" and longer.

I would (And I did...) go with .300. I'm still not sold on 7.62x39 ARs being reliable enough for HD, even with the newer, supposedly better mags that are coming on the market. .300 was designed to reliably work in a barrel of approximately that length.

At any HD range, bc is not really gonna matter. The 300bo, 7.62 and or the hvy weight 223's will get the job done without any problems. No matter which one someone gets hit with they are gonna have a very bad day. I have the x39 and 223 in sb and would not be afraid to use either one. I have not gotten any bo's because of the cost of shooting them. Reloads cost me at least as much as what I can buy x39's or 223 for. Also, I reload some things but have not been able to find time to load as much as I used to. The fact that I can pi ck up the phone and have either of the rounds shipped to me quickly and cheaply with the x39 or 223's win out over the 300 bo. I'.m sure the bo is a good round but not at what it costs to shoot, at least for me, anyways.

Yes. The Blk cost ammo is terrible

300 blk, but I am biased

Not if you reload.



 

Reloads have gotten to be more of a time constraint with me, more so then a cost factor. I can order up a case of GT in x39 cheaper then bo reloads. If you go up to some of the hvy's in the sierra's, it can get really high dollar and still cost me in the time factor.  When I go to the range, the normal shooting is 300-400 223's and about the same in x39. If I were to shoot that much in the bo, I would have to load even more which then takes up more of my time to do. Just don't think there is much of an advantage to shooting the bo over the 39 when all the factors are added in.

ETA: For short barrel HD I don't think that there is any question that the 300BLK has the edge in efficiency / less flash.  Bolt failure in 7.62x39ARs (given less meat supporting the lugs) as well as less than optimal mags are known issues you don't have to deal with in 300BLK.

I have 300BLK in 7.5", 10.5", and 16".  

7.5" below:



I decided to go with PAP M92 pistol with Midwest Industries Rail /  T1mount in 7.62x39 (my first AK).  Think they have a 10" or 10.5" barrel.  You can buy that gun with sig brace for $550 at Atlantic Firearms right now.  Below is not mine but an example.  Might get CNC Warrior muzzle devise to tame flash.  Meaty bolt and reliable mags.

You are going to pay at least 40 cents a round to reload 300 Blk by the time you pay:
25 cents per bullet (cheapest I could find)
7 cents for brass ($28 for 100 reloaded 4 times)
4 cent for primer
~10 cents for powder

I am paying less then 25 cents a round for 7.62x39, don't have to spend any time reloading and I can find it everywhere. Granted they are not very accurate blasting rounds, but I have my Grendel for shooting tight groups. I still get 2 moa out of my AR-47 with cheap Wolf.

I am shooting my 225 grain cast lead bullets in 300BLK for less than 12 CENTS per round.

4 cents for the lead alloy mix
1 cent for powder coating
1 cent for brass (converted my own and when shooting subs they are good for AT LEAST 10 times each.....probably much more)
2 cents for primers (only need to allow 4 cents if you didn't have the "sense" to stock up before the price boom)
3.5 cents for powder (11 grains of powder that was $22 per pound is about 3.5 cents)

I am shooting my 300BLK for about the same price people are paying for 22LR.

Thats like saying it only cost 2 cents a round to shoot 22lr because you bought the ammo 20 years ago.  Its going to cost you closer to 25 cents to load with todays prices.

300 bo, though conssider 277 wolverine.  

x39 is louud as fuck, louder thhaan 5.56 in the same barrel length even, though one might think it is more efficient and would be better.

part of is, i think the powder typically used in x39.  handloaders might be able to makex39 loads with lighter bulletss and faster barrels so it will burn more efficient like 300 bo but most surplus or factory ammo really seems optomized for the stsndard barrels.  

w 300 bo, you get a shorter, better balanced less deafening gun.  def the choice of what you listed.  u want to shoot for cheap throow another upper on there and shoot 5.56 or 5.45

Why do you keep coming on and spamming a questions no one has asked? How many of the 300BLK people go onto the .277 threads and suggest they get a 300BLK even though no one even asked about it?

Please do everyone a favor and keep the posts on topic. Otherwise you might have posters with their pet cartridges chiming in and suggesting stuff like: the 30HRT or the 7.62 X 40 WT or the 30 RAR or the .308 or the 6.5 grendel or the 6.5 creedmore or the 50 Beowulf or the 450 bushmaster etc. and that would just be annoying and distracting.

Thats not correct at all.  My lead cost is still current with normal prices.  Brass is cheap as ever with 5.56 brass going for less than 10 cents each....same as I paid.  My powder price is also current.....its currently available for $150 per 8 lb keg.....which is even LESS than I quoted for $22 per pound.  The ONLY thing that I am taking advantage of is the primer costs which are now 3.5-4 cents each.  Add it up.......still only about 14 cents per shot.  

I reload my cast subs my AR15 for $.072 cents a round. and my cast reloads for my model 7 for $.05 cents a round, substantially cheaper then factory anything and that is based on today's cost.  of course I got a whole bunch of wheel weights for free  and I don't include my time simply because it is part of my hobby and a good skill to have

my super sonic cast loads run me around $.11 a round without a gas check and $.13 a round with a gas check

What boolit mold for the 225gr?

For HD ammo it's not terrible even if you don't.  Nobody blinks at paying a dollar a round for handgun caliber JHP's - so 80 cents a round for .300 shouldn't be a problem.  


If the OP wants a short barrel, then it's kind of a no-brainer.  All three rounds will work in terms of ballistics with the right ammo, but some of them are going to have lousy platforms, awful blast, or both.

10.5" 5.56 will spit M193 out pretty fast, in the mid 2700's.  Use VMAX for home defense inside the house, and M855 or Barnes 70gr TSX for barrier blind outside.

With a can, it isn't that bad in the house at all, and will have the most affordable ammo option that will run in the gun.

I personally would want something fast that will frag in the house, and not over-penetrate, so that would mean a supersonic load if I were to use 300 BLK, so that negates that for me personally since why bother if I'm going super anyway.

For training indoors or just my regular CQM, the 300 is nice because with subs, there is no overpressure at all, just a fun little package to shoot with short barrel/suppressed.

For HD the 30bo is the obvious winner.  The reasons are 3-fold:

First, the BO was designed to have a full powder burn in about 8" of barrel.  For 5.56 this takes about 18" and around 15" for 7.62x39.  What this means is you end up with a huge fireball and nasty concussion when more of the powder is burning outside the barrel than in.  What that further means is that when you pull the trigger you just flash-banged the $#!+ out of the bad guy, AND yourself, especially if you didn't think to grab the hearing protection when you heard that glass break in the middle of the night.

Second is energy.  The BO is a highly effecient cartridge, related to #1 as you get a quick powder burn.  This means that the projo gets moving faster in less time, thus generating more energy.  A 5.56 projo is little more than an icepick stick at low velocities as it can't expand much anyway due to bullet-size limitations.  BO hunting and SD projos are 50% bigger in initial diameter, and are designed to expand at the velocities generated.  This means more effect on the target.  Ballistically the BO is nearly identical to the 30/30 Winchester, out of half the barrel length.

Third, if you decide to be smart and suppress, then the choice gets even more obvious.  The BO was designed as the Whisper first, for exactly this reason; heavy bullets going subsonic but packing a punch while not deafening the user.  A 5.56 and 7.62 are still damned loud with sonic crack even when suppressed.  With a BO you can hear the action cycle when muffled.

So arguements about "ammo costs" are almost pointless here if we are talking HD.  There is no value you can put on protection.  I happily pay $1-2 a round for good defensive ammo in everything I own that can serve as such, so I do it here as well.  Personally I run the Barnes Vor-TX for HD in my BO as it is designed for quick kills on things like pigs and deer.  Sounds awfully similar to a bad guy, and they will be stopped in exactly the same fashion.  Because cost for practice does matter though, look at Freedom Muntions.  They roll their own from once-fired and converted 5.56 brass (I'm usually seeing LC headstamps) for about $.45, and I collect the brass and reload it myself.  This get's it down to a pretty bearable quarter a round.  Is it 5.56 or 7.62x39... no, but it's superior to both in this instance.

All of this.

300BLK really shines in the suppressed SBR role, especially when the distances will be short(er).  In my limited experience, it will be the "best performing" of the three options, given the role.

Also, I too have no problem dropping $1-$2/round for quality HD/SD ammo, and the 110gr Barnes is quality ammo/bullet.

Hell, if they made ammo that was proven to be even better at stopping threats (than what we have now), I'd pay more for that too.

That's my opinion and it's worth what you paid for it.

I disagree with the first two premises for the following reasons:

I'm going into this assuming that I'm going to suppress any SBR for HD anyway.  Additionally, I've shot a lot of 5.56 in the house day and night from 14.5" M4's, and don't remember the fireball.  Military ammunition is charged with propellant that has flash signature reduction, and out of a can, you don't see a lot of this especially.  Any of the calibers fired from an 8-10.5" barrel supersonic are going to be extremely loud and concussive without a suppressor, doesn't matter which one.

If your HD plan is to use an SBR without a can indoors, just know that you and any family members are going to suffer some temporary hearing loss, with high likelihood of permanent.  Even 9mm pistol indoors will cause hearing loss, been there, done that (done to me). The short story is that an 8" 300 Whisper is going to destroy some ears indoors without a can, so the statement that it is somehow advantageous over the others is not supported by the facts.

The second point about internal ballistics doesn't make sense in context of HD.  5.56 from a 10.5" SBR within the house is plenty fast to kill, has been done for decades in the real world with limited to FMJ ammunition.  With the 70gr TSX, it folds people over even at distance.  I've never seen a close range 5.56 wound that resembled an ice pick.  All of them have been pretty brutal, to include shots from close range with 14.5" M4's and Commando barreled SAWs.  Without any Hague Convention restrictions for the civilian, you can even use varmint projos like the VMAX, expanding pills like the TSX or BT, etc.

The third premise that 300 Whisper subsonic is superior indoors I fully agree with, because it's quiet, nothing to argue about there.  Is 5.56 super suppressed so bad that it is defeaning indoors?  Not in my experience.  It's more like a sharp slap, but very tolerable.

The biggest thing you have to worry about with 300 Whisper is over-penetration with subs.  Show me a sub that will expand and not exit a human chest, because these projos are in excess of 200gr, and that's a lot of bullet to slow down with that kind of sectional density.  A lot of people like to equate it with a .45 ACP, but it's really a different animal altogether in the SD department.

If we go back to lightweight expanding supers from the 300, then I lean back to the 5.56 NATO suppressed.  Where 300 makes sense for me is high volume training CQM/CQB sub/suppressed, so I don't have any over-pressure issues to deal with at all over days upon days of shooting.

Had a 10.5 300blk. Adoption has been crazy fast, and overall just a cool round to shoot. However, that said, I am back to 22lr, 556, 308 and 9mm in my life. I spend more time shooting and less time drooling over the next best thing. 300 supers with a can are better for the application you describe, so go for it. But don't do it if it means you will shoot/train less. For me, I was shooting less and that is far worse than very slightly better ammo. There always seems to be better ammo, always. Heck, folks seem to be chatting about the 277WLV being better than the 300BLK. So here we go again.

If you have two similar ARs, one 556 and one 300BLK, because why not, then you get the both of best worlds.

I do plan on getting a 762x39, but it will be in the form of an AK.

Best for what? That has to be answered first. Home defense? Hunting, etc..

Read the thread title.  We've been talking about HD the whole time.

He TL;DR it.

Why I would go - 300BO with a SBR

Theoretically you can have two guns in one- with just a mag/ammo change

Mag A -  MP5
Mag B -   AK47