From Supersonic to Subsonic

Discussion about rifles in 300 AAC BLACKOUT (7.62x35mm), hosted by the creator of the cartridge.

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WHA1949
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From Supersonic to Subsonic

Post by WHA1949 » Thu Jul 24, 2014 12:52 pm

I built my first 300 Blackout about 2 years ago, 9" Pistol set up for defensive use only, zeroed at 25yds, lite weight and handy in confined spaces. Initially loaded 110 and 125gr Supersonic ammo, loud and plenty of recoil, I decided to try some subsonic ammo to see what the difference was and if they would cycle through without any problems. Both Remmington 220gr UMC and OTM Ammunition functioned flawlessly through the action with less recoil and noise, follow up shots were quicker and more accurate. That caused me to revaluate my ammunition needs.

Most Ballistic tipped ammo most likely won't expand to its full potential at close ranges and supersonic speeds, so I thought if I hit some idiot with a 220gr OTM doing 1000fps at close range as opposed to a 125gr BT doing 2100fps, its still going to hurt.

Am I over thinking this? Realistic comments appreciated.

I won't be going suppressed anytime soon, maybe down the road, below is my 300 Blackout pstol.

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yondering
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Re: From Supersonic to Subsonic

Post by yondering » Thu Jul 24, 2014 1:02 pm

WHA1949 wrote:Most Ballistic tipped ammo most likely won't expand to its full potential at close ranges and supersonic speeds, so I thought if I hit some idiot with a 220gr OTM doing 1000fps at close range as opposed to a 125gr BT doing 2100fps, its still going to hurt.

Am I over thinking this? Realistic comments appreciated.
Your thinking is flawed. The right supersonic bullets (like the Nosler 125gr BT, and several others) do expand well, and provide terminal performance typical of a rifle.

Your subsonic loads (except the specialty stuff like Lehigh) do not expand, and essentially act like a small caliber non-expanding pistol bullet, except with much more penetration (far too much, actually). You don't get something for free here; that reduced recoil and noise comes with greatly reduced performance.

The "it's still going to hurt" comment made me chuckle. If that's the goal, forget a gun, just use a fork.

harrishmasher
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Re: From Supersonic to Subsonic

Post by harrishmasher » Thu Jul 24, 2014 3:09 pm

Barnes 110gr TSX will expand just fine from 1 to 300 yards out of a 9" barrel. Other than Lehigh there are no expanding subs on the market. Pretty much like shooting someone with a 220gr 45acp FMJ round. Not ideal for home defense. Probably go through the target and through a wall after.

I run my 9" rifle suppressed. I would prefer to use subs for home defense, since suppressed subs are hearing safe indoors. But given they don't expand, I keep a mag loaded with Barnes 110gr TSX handy and my Eotech sighted in for supers. Still loud with a suppressor, but much quieter than a suppressed 5.56 out of a 16" barrel...forget a short barreled 5.56 indoors even with a suppressor.

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MMA10mm
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Re: From Supersonic to Subsonic

Post by MMA10mm » Tue Jul 29, 2014 11:03 pm

One of the great things about the 300 in all it's itterations is flexibility. Here's some food for thought:

220-240gr HPBTs at 1000fps are going to be at least as effective as a 45ACP+P 230gr FMJ. Some think that is weak, because they desire rifle performance. Using that metric, they are 100% right. However, if you are using the 300 to replace a pistol, this load puts you up in the higher reaches of powerful handgun loads. So, it depends on how you look at it.

110-125gr, and perhaps a little heavier, will certainly expand at 300 velocities, but if you're shooting inside the house with a short barrel, everyone will soon be deaf...

There are many specialty bullets starting to hit the market too, like Lehigh Defense, who make heavy bullets which expand, so you CAN have your cake and eat it, but it will cost some $$.

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yondering
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Re: From Supersonic to Subsonic

Post by yondering » Wed Jul 30, 2014 11:48 am

MMA10mm wrote:One of the great things about the 300 in all it's itterations is flexibility. Here's some food for thought:

220-240gr HPBTs at 1000fps are going to be at least as effective as a 45ACP+P 230gr FMJ.
No, they are not. Diameter and frontal surface area matters; the 45 has lots of it, the .30 cal doesn't. The "220-240gr HPBTs at 1000fps" don't expand, and don't cause a lot of damage, and penetrate way farther than necessary.

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Re: From Supersonic to Subsonic

Post by Tophatman » Wed Jul 30, 2014 1:45 pm

Subs will 'ice pick' several feet of ballistics gel leaving about a nice clean .31" wound track. Would that hurt? Well I wouldn't want one poking a hole through me. Would it be debilitating? Maybe, maybe not, shot placement would be extremely important and you'd probably have to tbox someone to have a real off switch.

Subs have their place and can be a blast to shoot but I wouldn't use one for HD. If the noise is a concern then get a can. Recoil turn it into a SBR or put an 'Arm Brace' on it to help with recoil management.

Just my opinion and worth what you paid for it. :)

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Re: From Supersonic to Subsonic

Post by harrishmasher » Wed Jul 30, 2014 1:50 pm

yondering wrote:
MMA10mm wrote:One of the great things about the 300 in all it's itterations is flexibility. Here's some food for thought:

220-240gr HPBTs at 1000fps are going to be at least as effective as a 45ACP+P 230gr FMJ.
No, they are not. Diameter and frontal surface area matters; the 45 has lots of it, the .30 cal doesn't. The "220-240gr HPBTs at 1000fps" don't expand, and don't cause a lot of damage, and penetrate way farther than necessary.
FMJ Subs are fun to shoot, but until one of the major ammo manufacturers starts making some expanding subs that cost less than $2 a round, subs are just for fun time at the range. Obviously a sub could no doubt wound and kill someone, but there are far more effective ammo choices. A non-expanding 300blk sub would be very low on my list of defensive ammo choices. I would choose a 9mm bonded hollowpoint out of a compact pistol well before a FMJ sub out of a rifle.

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Re: From Supersonic to Subsonic

Post by jettcity1 » Thu Jul 31, 2014 7:18 am

My personal opinion is that subs for a defense round are adequate and just as effective as some personal defense pistol rounds.
Bottom line is it is better than nothing and you will put holes in somebody that will hurt very much.
If there is a badguy in my house, I want my 300 Blackout pistol with subs in it.
I wont wake up the neighbors, i am suppressed.

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JeffWard
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Re: From Supersonic to Subsonic

Post by JeffWard » Thu Jul 31, 2014 7:28 am

A 220 grain subsonic is no more effective as a man-stopper than a FMJ 32ACP.

Both will go right in one side, and right out the other.

"Just as effective as a 45 ACP." Ummmm... No! 99% of 45ACP defensive ammo is hollow-point, expands to 0.75" and stays inside your attacker.

Just because you have an uber-cool suppressed gun that won't wake your neighbors, doesn't mean it's effective for self defense. Get some high quality 115-125gn supersonic hollow-point/ballistic-point bullets that expand!

JeffWard
Guns are tools designed for dirty work both competitive and defensive. If I meet someone with a well worn gun, I hope their barrel is pointed the same direction as mine if the lead starts flying...

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Re: From Supersonic to Subsonic

Post by golfindia » Thu Jul 31, 2014 8:16 am

12g 00 buckshot.

Why shoot one 30cal hole in something when you can shoot 9 30cal holes in something?

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