Hey everyone -

So without getting into any "ULTIMATE AR CALIBER!!" or "WHICH IS BETTER?!?" discussions.... we have all seen charts like this one:



But what I can't seem to find is a chart like this with ratings for SUBSONIC .300BLK. Ideally, I'd be looking for the SAME chart or metrics but for subs, comparing various barrel lengths to same in 5.56 supersonic.

Any help is sincerely appreciated!

Outstanding, thank you.

What specific info are you looking for?  Muzzle energy?  Velocity?

Energy is fairly easy to calculate with velocity and projectile weight, although energy is a fairly dubious metric in the realm of terminal ballistics.  

Velocity will help you determine if a specific projectile will be within its operating envelope, so good info.  Someone would have to shoot a specific load, through a bunch of different barrel lengths, to get you round about velocity numbers useful in a chart like that.

It doesn’t help that’s there’s not a “universal” defensive ammo standard for subsonic .300BLK like you have with 110gr Barnes.  I’ll also throw in that basically all defensive expanding .300BLK specific sub projectiles have a fairly narrow operating envelope.  Usually somewhere between 950-1050fps.  

A 190gr Sub-X at 1050fps is generating 465 ft lbs of energy.  Numbers obviously go down from there, so there’s not a ton of comparing to do, because subsonic .300BLK and supersonic 5.56 aren’t really comparable in the first place.  Different tools for different jobs.

Depending on what you’re trying to compare or learn, that chart may be missing a lot of critical info as well.

That's because there is no comparison.

I'm not following.  Are you comparing 300blk subs to 5.56 supers?  

There are a couple of issues with that.
One (as someone mentioned) is there this is no universal sub round.  Some folks run The popular ones are 190gr, 194gr, 200gr, and 220gr.  

The other is that barrel length does not play nearly as much of a factor in subs.....other than sometimes subs can go super in really long barrels.  The difference between a 6" barrel and 16" barrel might only be 200 fps (depending on round)...and that might be the difference between 950 fps and 1150 fps....maybe.

Exactly.  My favorite subsonic reloads with a 220 gr bullet goes from a muzzle velocity of 1040fps in my 16-inch carbine to 980fps in my 9-inch pistol and down to 870 fps in my 5-inch pistol.  170 fps in 11-inch of barrel length change.

Also the long heavy 30 caliber bullets almost always have really good BC values and combine with the subsonic velocity means they carry their energy down range pretty well.  Even a lowly .4 G1 BC means a 220gr bullet at 1040 fps (528 ft-lb) still has 945 fps (436 ft-lb) at 200 yards.  It carries the energy/velocity well it just does not start out with much.  It's roughly the same energy as common self defense pistol rounds but has a bit better ballistics down range.

Yeah, I don't see the point of such a chart for subs.  Subs are subs because, well, they're subs.  1050 FPS seems to be the commonly agreed on target speed for the round, so in that regard, what's left?  Energy is a function of bullet weight and velocity, of course.  Beyond that, I don't see where or why barrel length matters.  You can get/load subs that'll shoot 1050 FPS in a 16" barrel as well as a 7" or even 5" barrel.

That's a very interesting chart. Thanks OP.

What are Delta ft lbs.?

Since I can't seem to quote more than one post at a time, I'll try and address several questions here.

First - for any of this to make any sense we need to stipulate a median "average" of different loading, bullet weights, etc. We're looking at wide approximates here.

Second - the chart I posted allows me to surmise, as an example, that my SIG RATTLER has approx the same muzzle energy as my DD MK18, all other things being equal*

Third - I want to know how this same comparison would work with SUBS. In other words, given the same target at the same range would my Rattler still be the equal of my MK18 in that one measurement? Less? How much less?

Fourth - for most of us, in the real world, this data has no REAL practical application.... much like a lot of the so-called "Data" gun guys tend to get really REALLY excited and argumentative about....

The American version of Lufthansa ft lbs.

No really, I have no idea

The answer is no, it’s not.

Heaviest sub available (220gr, AFAIK) at 1050fps (which is optimistic out of a Rattler with factory ammo) is generating 539 ft lbs of muzzle energy.

THANK YOU!

That's pretty much as expected. About the same as my 1911 running .45 +P Speers.

From this I can surmise (again, approximately, and very loosely & inaccurately equating muzzle energy with terminal "effectiveness" at close range) that a suppressed Sig MCX Rattler running .300blk subs isn't SIGNIFICANTLY more effective than say a Sig MPX Copperhead 9mm. And is also heavier. And more expensive. And has heavier recoil. And more expensive to run.

From THIS I can surmise that, the only advantage to upgrading from a Sig MPX Copperhead to a Sig MCX Rattler would be if I limited the use of subs to strictly practice scenarios. Oh and the fact that magazines go from being $50 to $10... which does not quite offset the fact that range-fodder goes from something like $0.22/rd to something like $0.65/rd  


FROM THIS I can FURTHER conclude that in owning a PDW or SBR chambered in .300blk, the ONLY practical benefit of subsonic ammo is noise reduction and at the expense of reducing one's rifle-caliber PDW to the relative "effectiveness" of a Pistol Caliber PDW or PCC.

Or... in short; Subs for show, Supers for a pro.

These conclusions are all examples of laughably flawed gunboy logic, but they're at least as real-world useful to me as the conclusions drawn by these trigonometry professors who inevitably weigh-in on these matters

Charts are good for comparison. The other thing which is very needed is reload data in reloading manuals. Everything they list is for 16” barrels for 300 BLK subsonic. They have to know reloaders are reloading for SBRs.

Charts do not translate to the field. If killing shit is what you are after.

300BLK is a shitty 75 yard caliber.
Just like a 30 carbine.

But it is fine for CQB. In fact, it is optimized for that. Will any of us here be kicking doors and entering to clear a house? No. But if someone - or more than one - has broken into my house, I feel pretty confident that my 300 BLK subsonic SBR will get the job done.

This is where I started for my subs:  https://hodgdon.com/wp-content/uploads/2020/07/subsonic-data-final.pdf

Not a lot of data out there specific to subs.  You can also search for 300 Whisper data.

If you want to pay for a subscription, there are online sources that have data as well.

ETA: And since it is suppressed, I will come out with my hearing not being completely FUBAR.

I appreciate you sending this. I have my data worked up fairly well. But getting there took plenty of trial and error. Thanks!

Delta is the mathematical term for change. If you look at the chart, the difference between the previous number and the next line is the "delta". Or where I retired from

Yes and no.
Subs are subs, so they are always going to be limited.  However, the BC's and SD's are completely different, so 300blk will have more range.  Non expanding 300blk can penetrate bulletproof glass and level II armor.  While expanding 300blk can't really do that, you are talking about really big (and expensive) holes with deeper penetration...much bigger than 9mm.

But technically, the same logic applies to your MPX...or any other weapon that can easily shoot both supers and subs.
What is the point of using 147's over 124+P's except for noise (unless you have a very specific scenario)?

Not understanding the comparison. 30 Carbine is a supersonic round.  Are you comparing 30 Carbine supers to 300blk subs or supers?

Since this is tech:

30 carbine shoots a 110gr round at 1990 fps out of a 17.75" barrel (967 ft.lb).

Hornady Black 110gr V-Max is listed at 2375 fps out of a 16" barrel (1377 ft.lb) with a much slicker BC of .290
Barnes 110gr Tac-Tx is listed at 2350 fps out of a16" barrel with a BC of .289 (1349 ft.lb) with a BC of .289.
Underwood loaded Nosler 110gr Varmageddon is listed at 2400 fps out of a 16" barrel (1407 ft.lb). These rounds have a BC of .293.
Underwood loaded Lehigh 115gr Controlled Chaos is listed at 2360 fps out of a 16" barrel (1422 ft.lb).

The 110gr Tac-Tx/V-Max/Varmageddon rounds are probably the most common "good" rounds shot out of 300blk, although we usually shoot them out of shorter barrels.  

A great round for the 16" is the Nosler 125gr Ballistic tip.  While the muzzle velocity is "only" 2250 fps (1404 flt.lb), the .366 BC allows it to keep keep that energy up at a greater distance.  It is 926 ft.lb at 200 yards, which is close to what 30 Carbine does at the muzzle.

But just to drive this point home.  Sig 120gr SBR ammo (the SBR label for their 120gr Elite HT) is listed at 1897 fps out of a 6.75" barrel (959 ft.lb).   That backs up GBB's point of 300blk being made for "shorter" ranges.  For a caliber that is centered around barrels often in the 8-9" range, how far are you expecting to shoot to "kill" things?   Are you grabbing the right tool for the job?
My Wilson Combat loaded 110gr Tac-Tx (I really wish they would make that again) is listed at 2400 fps out of a 16", and I chrono'd it at 2213 fps out of my 9" and 2261 fps out of my 10.5".  Do you think the rounds suddenly magically lose all momentum at 76 yards?

Interesting side note.  My 10.5" shooting WC 110gr Tac-Tx at 2261 fps at the muzzle (1249 ft.lb) would be 1987 fps at 100 yards (964 ft.lb).  My 9" shooting WC 110gr Tac-Tx at 2213 fps at the muzzle (1196 ft.lb) would be 2008 fps at 75 yards (985 ft.lb).

Since you mentioned 30 Carbine being a 75 yard gun to "kill" stuff and given what 30 carbine does at the muzzle.  Does that make my 9" a 150 yard gun and my 10.5" a 175 yard gun?

Are you saying something like a Sig Rattler (5.5" barrel) is "only" a 75 yard gun when shooting 110's?  
https://www.ar15.com/forums/armory/Sig-Rattler-300-BLK-Ballistics-Question-/45-541897/
Using your own criteria, what are your expectations of range for any gun to "kill stuff" with a 5.5" barrel? What are you shooting?

Blackout subs carry a given energy twice as far as 9mm or 45acp subs and generally with twice the precision/half the group size. Especially in wind.  May not be a practical feature but they are fun to consistently lob in and connect on steel at 2-300 yards.  

For expanding subs at point & shoot ranges (no holdover needed) the 9/45 pistol ammo/bullets are much cheaper.

300 BLK subsonic is between 147 9mm and 230 .45 ACP for energy.

Supers are effective terminally out to ~300 yards if shooting 110 Barnes Black tip, depending on barrel length.

With my 300 BLK I can hit 5 for 5 on a 6" target at 300 yards with factory Barnes 110 black tip. Past that the bullet dives like crazy, gets tossed by wind, and fails to perform well terminally.

Subs will shoot sub MOA. The limit for practical drop/drift/moving targets for subs is in the 125 to 150 yard range. Past that you can have EXTREME vertical errors with small errors in judging distance and/or vertical angle and huge wind drifts or leads on moving targets.

But if you stick to 300y supers and 125y subs you can have some spectacular results!

Also, 300 BLK shoots much flatter than 5.56 from the muzzle to ~110 yards with a 50yard zero using a cowitness or lower 1/3 optic height IME. It is truly point and shoot from 25-105y staying within an inch of your 50y zero POA.

There are NO sub MOA PCCs, not even a Sig MPX, or even sub MOA 9mm factory ammos that I am aware of. If you want a silent semi auto sub MOA rifle you have no choice but 300 BLK as far as I know of... if someone knows of a viable alternative let me know.

Sounds like you are debating if a .300BLK MCX is worth it if you already have a MPX.

I've had an MPX since it was released and recently picked up a Spear LT .300BLK.

Comparing them side by side, subsonic .300BLK is noticeably quieter suppressed than subsonic 9mm.

Subsonic .300BLK recoils much less than supersonic and is comparable to the MPX.

.300BLK is more accurate than 9mm, and higher BC subsonic .300BLK retains velocity much further than 9mm.

However, even though .300BLK is objectively better than 9mm, if you're just going to shoot only subsonic then .300BLK probably isn't worth the extra ammo cost unless that isn't a factor for you.

Personally, I got the Spear LT mostly to shoot supers but be able to go super quiet with subs when I wanted to. And it looked really cool.

BC doesn't mean much for subsonic loads.  There is very little difference in external ballistics between a 178 Amax at 1050 and a 240 VLD at 1050.

ETA: I reread your post and realized you are comparing it to pistol bullets.  I have not compared external ballistics of .300blk to pistol bullets.  You very well may be correct.

That is very interesting, and aligns with my perceptions on supers.
I have a 50 yard zero, and I shoot (for the most part) the same type of supersonic rounds.  
110gr Tac-TX
110gr VMax
110gr Varmageddon
All three are 110gr, ballistic tipped, flat based spitzers.  All three have similar BC's (.289, .290, and .293 respectively).   Depending on the loader, all three range from a box listing of 2325 fps to 2400 fps  (Underwood, Wilson Combat, Barnes, Hornady, and AAC are what I have).
I hoping AAC will list the BC of their 110gr Sabre round, as I might be able to add that to the stable.
 
Over a variety of barrel lengths between 7.5" and 10.5", I expect roughly a 50/125 zero.  Some are shorter than 125 yards, some are longer, it just depends on the load/barrel combination.

If I would rate "ranges" by color in 50 yard segments for my longer-ish 300's, it would be:
0-50  Dark Green
50-100 Dark Green
100-150 Green
150 - 200 Yellow-Green
200-250 Yellow
250-300 Orange
+300 Red

Subs would be half of the above unless you are running dedicated magnified optics.   Obviously supers can go past that as well, but that isn't 300blk's forte.

Let's compare a 300 BLK 190 grain Honady SubX (G1 BC .437)  to a 9mm 147 grain Hornady XTP (G1 BC .212) and a .45 230 grain Hornady XTP (G1 BC .275) All fired from a 2.5" height over bore at 1040 fps for the 9mm and 1000 fps for 300 BLK and 45 ACP, all with a 50y zero. I bump the 147 to 1040 because it tends to run that hot in factory loadings from PCCs and the 300 BLK and 45 ACP tend to run slower from SBRs in factory loadings. The 300 BLK so it is not supersonic in 16" barrels and factory .45 230 runs slower even in PCC barrels unless it is +P loaded. Plus 9mm just needs help LOL.

Statistics for the: 147 XTP / 190 SubX / 230 XTP
Muzzle energy: 353 / 422 / 511
Drop at 100y: 6.42" / 6.61" / 6.84"
Drift at 100y: 2.72" / 1.31" / 2.00"
Energy 100y:  292 / 386 / 446


Drop at 150y: 22.57" / 22.72" / 23.66"
Drift at 150y: 5.84" / 2.8" / 4.31"
Energy 150y:  269 / 371 / 420

So while 300 BLK does "carry the mass better to distance" and has less wind drift, it still does not deliver any more power than a 230 grain .45 at any range you would actually shoot something. The .45 is still over 900 fps at 150 yards, so well within the ideal velocity for expansion and would produce the larger wound.

IMO the real benefit iof 300 BLK is 4-10x smaller group sizes vs pistol calibers, a little less noise suppressed in some platforms, and a little less windage to take full advantage of that precision.

At 200y the 45 has ~49" of drop and 300 BLK has ~45" of drop. That is a really extreme change for a 50 yard difference that close and it gets even crazier past 200y. At 300 yards even the 300 BLK drops over 10 feet from POA with almost a foot of drift in a 10mph crosswind and a 10 yard ranging error is a ~10" error in elevation either way.