The Carbine and the Rifle at Unkown Distance: The Value of Velocity

The Carbine and the Rifle at Unkown Distance: The Value of Velocity

I read about plenty of shooters who pat themselves on the back for hitting a target at 400-500-600-700 yards with their SBR in 5.56 or .300 blackout. These shooters have come to the conclusion that their beloved SBR can do anything a rifle can do. I would venture to say *most* shooters understand the limitations of their chosen system. Some shooters are quick to point out that their SBR, Pistol, or blackout can shoot just as far as a full size rifle and will do so while being shorter, lighter, and 20% cooler. I will admit that for self defense, these compact systems make lots of sense.  However at extended ranges… short barrels just don’t stack up against a musket. No matter how you slice it, they will be inferior in performance on real world unkown distance targets. Let’s set the stage:

Shorter and Shorter

Compact weapons are handy. With the .300 blackout SBR craze, and the Sig brace,  short-barreled rifles and pistols have exploded in popularity. Until recent years, short-barreled 5.56 ARs were hampered by limited ammo choice, but that has been partly corrected by heavier loadings such as 77 grain Mk 262. These heavier loadings make the SBR a far more capable machine and no one will argue that these heavier projectiles don’t improve performance at all distances.

With the intro of .300 Blackout, we have witnessed yet another surge in the popularity of this versatile caliber in the AR platform. These guys too, are very proud of that the .300 blackout can reach 600-700-800 yards. “Why, we can all be like Travis?! Sign me up!”

Click the 7 minute mark to start the shenanigans:

There are plenty of similar videos on YouTube just like Mr. Haley’s demo here. More minds become convinced that SBRs can hit targets at any distance, and that long guns, you know the thing we used to call rifles, are not necessary and antiquated. Well, let’s cut to the chase: Your short gun is not as good as a rifle at those same distances. Both hit the target right? So what gives?

Assumed Capability and Unkown Distances

Elmer Keith is alleged to have hit a target at 600 yards with his classic revolver. Jerry Mikulek hit a target at 1000 yards with his 9mm. Should I argue that a 9mm pistol caliber SBR is a great tool for 0-1000 yard shooting? Many guns can hit targets at great distances with shooter skill or known distance with calculated shots.

At known distances, modern optical sighting systems allow you to dial in dope with an extreme degree of precision and repeatability. Punch in your data, and your I-phone can tell you exactly how many clicks to go up in order to hit that silhouette at 900 yards… Likewise, bdc systems give you instant satisfaction from hitting steel in perfect conditions.

The difficulty comes when the shooter is in a field scenario where he (or she) is under a time constraint to hit a target of varying size presentation at an unknown distance. At this point, if our target is going to present for only a few seconds, there is little to no time to dial in dope or to accurately estimate the exact target distance. The target may be oblique, down low, or may not fit our BDC at all (such as a person at the extremes of height, or a deer, hog, etc). Our chance of hitting that target at unkown distance will be highest with a projectile that shoots as flat as possible, and that is a balance of ballistic coefficient and velocity. So… what does a flat shooting load get us?

The Benefit of Velocity:

The perfect projectile would be a laser. It shoots in a perfect line neither affected by wind or gravity. A laser would have the same point of aim and point of impact at 100-200-300-1000-2000 yards. It would intersect a target at every distance with one zero. The closer we get a physical projectile to the flat shooting ideal hypothetical projectile the further the bullet will travel while still intersecting our target.

Since we don’t have laser rifles, we want to shoot bullets with the highest aerodynamic value launched at the highest velocity we can. This means we should shoot cartridges with a high ballistic coefficient from the longest barrel we can effectively use for our purpose. Let’s look at Mk 262 the 77 grain SMK for our first example. It has great terminal performance and fragmentation capability out of even shorter weapons. The picture below illustrates the advantage of velocity and trajectory from a rifle vs a SBR.

Short Barreled Rifles vs Musket

The longer our bullet remains inside the vertical axis of the target, the more forgiving our gun will be to shooter error. In the above example, I have to estimate that the 9 inch target is within 33 yards of its actual distance to get a hit with higher velocity, while with a carbine my estimate must be within 23 yards of accuracy for the 10.5 inch gun.

“My error has to be within 25 yards? I can do that” Yes, I guess you could depending on how much time and experience you have. Time vs shot performance is the key here. If our target presents itself only for a short moment of time, there will be precious little time to adjust dope or to calculate distance, and precious little time to set up the shot. Reticles with built-in bullet drop stadia are a quick solution, but the highest likelihood of intersecting the target is to choose a flat shooting projectile / barrel length combo that will keep the bullet flying for the longest period aloft in the space occupied by the target at X distance.

The shorter you go on barrel length, the lower the velocity, and this directly translates to more bullet drop. The lower velocity also directly relates to longer flight time to target. The longer the bullet is in the air, the longer the wind has to push it off target. There is precious little room for error as we extend the range with shorter and shorter weapons, *especially .300 blackout*. Again, I recognize that this is not what these weapons are designed for, and many shooters understand that, but there is always that *ONE GUY* who thinks his SBR can be a sniper rifle. “See! Haley shot something at 750 yards with his blackout!!11!! What can’t this round do?”. Well… let’s see how the guns and bullets fare compared to each other with another test. What test? MPBR.

Maximum Point Blank Range:

MPBR is a method of setting up your gun to take maximum advantage of bullet trajectory vs the size of the target. In the above example, I used a 9 inch tall “headshot” model. Lets tighten that up to 8 inches which equates well with a hit in the vital zone of this silhouette. This means we will sight in so that our bullet rises no higher than 4 inches above our point of aim, and stops being the maximum as soon as it drops 4 inches below our point of aim. The goal here is to aim at consistent spot on the target (in this case, center of mass), and give our bullet the best chance of staying in that defined zone for the longest distance. Sound familiar?

maximum point blank range

MPBR: the 8 inch sweet spot on this IDPA silhouette is a great setup for sighting in a defensive rifle. Barrel length and bullet choice directly equate with how “long” your MPBR is. The longer distance our bullet travels while staying in the vital zone, the better since we don’t have to correct our aim.

So take that 8 inch vital zone and apply it to 10.5, 14.5, 16, and 20 inch barrels using several popular civilian / military loadings. What do you get? A chart. A chart that shows you how much distance a bullet will travel while staying inside our defined MPBR for defensive shooting.

Maximum Point Blank

Regardless of which projectile you choose, barrel length and velocity play a key role in how flat the trajectory is. The longer the MPBR, the further your target can be before you have to make corrections to elevation. The 16.5″ should read 16″ but the data was not affected.

With any setup, you want the flattest shooting projectile for your uses, and in making a choice before settling on a rifle, you *should* ask yourself how long can I go without sacrificing portability for my needs? Trajectory is directly related to your velocity and bullet construction. Whats interesting to see is just how flat M193 shoots: while it has a poor ballistic coefficient, it is by far the flattest shooting projectile for shooting at less than 400 yards with m855 a close second.

The chart also shows how barrel length imparts a longer MPBR regardless of ammo choice or which bullet you choose. More velocity means less deviation from your target via wind *and* drop regardless if you shoot 5.56 77 grain, 55 grain, or even .300 aac.

The less time the atmosphere has to influence the bullets path, the better. Let’s say you are dialed in on a 600 yard man-sized silhouette. There is a *mild* 5 mph wind. Take a look at the chart below. With each shortening of the barrel, more wind drift is introduced and you will be near 26 inches with the 10.5 inch barrel. Then there is .300 blackout…  39 ish inches of drift? It takes a longer time for .300BLK to reach the target and thus it’s more affected by wind.

Wind drift is kept in check with Mk 262, but with every step down in velocity, we combat more drift. The better the round fights the wind, the longer it will stay in the targets horizontal box. The .300 AAC blackout is supersonic and in no area did I substitute subsonic .300 AAC in any of these slides.

So while Travis Haley was able to throw rounds downrange at 750 yards on a windless day, we can see that it would take substantial hold overs or optic adjustment to get a consistent drop on a target with the blackout on a *mildly* windy day. It’s important to choose the right system for your shooting. If you really wanted to push your AR15 to intermediate ranges, 6.5 would be the best choice while still fitting into the AR15 magazine well. It is capable of shooting flatter than .308 and also has less wind drift than any of the discussed loadings.

Wrapping Up:

It isn’t about the accuracy, we know mechanical accuracy in the SBR platform is just as good (if not better than) their rifle based counterparts… it’s about the amount of user error each kit allows, and how that plays into the sum of everything that goes into the shot. It’s about giving yourself the greatest chance to hit the target with the natural error that comes from being human. Don’t trust that little SBR to do everything you see on the internet. Keep it in its place, and keep it inside its performance envelope. Right tool for the right job.

That said, practice does make perfect. Ash Hess, former army marksmanship instructor, recently received accolades for running his 11.5 inch pistol and winning a 0-400 yard DMR match.

However, even he admitted that the rig was at the edge of its performance envelope. His skill ousted the statistical gains on drop and drift other rigs may have had over him. For you and me, who can’t dedicate 20 years of our life to shooting every day, build a rig that gives you the advantages you need for your shooting environment in mind, and train with it as often as possible.

Build a dedicated rig for longer shots and you will find it much more forgiving of distance error and wind error. We aint perfect, and if things go south, our shot won’t be a white silhouette at 100 yard intervals.

Written by lothaen


  1. William · April 4, 2015

    This is my new favorite gun blog for sure. I appreciate that there’s enough technical detail in each post to explain things concisely without being over my head. It’s just good practical information. I’ve learned a lot. Thank you.

    • lothaen · April 4, 2015

      Hey thanks for the kind words. If I could blog and shoot full time to teach others what I know about shooting… I would do it. 🙂

      That said I’m still a student of the rifle myself. Hence this blog follows me with things I learn as I go along.

  2. Wayne Anderson · April 5, 2015

    Thank you! I’m wrapping up my third AR build as we speak – the first was an 18″ SPR with a White Oak barrel, the second a CQB 16″ built as an exercise on a sub-$600 budget. This third has the budget increased to $800, with the theme being Melonite and ultralight, and so far I’m thinking it’s the rifle I’d choose to carry a long distance.

    I keep seeing pistol lowers and pistol kits being sold and pushed, and I know a 10″ pistol barrel will lose about 400 fps compared to the same round from a 16″ barrel. A 20″ barrel will add about 300 fps more than the 16″. What you say about relative accuracy is spot on, but there’s also more to consider. There’s kinetic energy, spin rate, and wear and tear.

    Obviously, a given mass hitting at higher velocity will deliver more impact to the target. But if you’re shooting the M855 round, that bullet is designed to fragment at the cannelure within the target, creating a wound cavity the size of your fist. It does this if it’s spinning at speeds over about 200,000 rpm – like a 1:8 twist will deliver from a 16″ or 14.5″ barrel, but not at the reduced velocities of a 10″ pistol barrel.

    Without the extreme spin induced by at least a carbine barrel, the bullet will tend to pass through a target intact, minimizing its lethality. So if you’re considering a rifle (vs SBR or pistol), that’s another factor to consider.

    And here’s one more: The pressure created by M855 at the gas port on a rifle length barrel is about 19,600 psi. A mid-length is 26,500 psi, and a carbine is about 33,000 psi. With a pistol barrel, that increases to 48,300 psi – 2 1/2 times the rifle gas system’s pressure. All that translates into a weapon that’s harsh to shoot, and stresses every part of its gas system far beyond the designed specs. In short, the less pressurized rifle system will fatigue you less and serve you reliably much longer.

    For me, I don’t see that the macho factor of an SBR or pistol is worth all that.

    • lothaen · April 6, 2015

      Purely personal preference, but if I were to buy something below 14.5 inches I would likely switch cartridges to something like .300 AAC blackout. Not to say 5.56 isn’t lethal in SBRs with the right ammo, but I prefer to reduce concussion and blast by choosing a round more optimized for the barrel length.

      I have been beside many 5.56 SBRs at the range, and when we are under the roof I feel like my teeth are rattling depending on what comp the shooter is running.

      I shoot my rifle into a shoot bucket in the basement when testing cartridges and the concussion isn’t half bad. I don’t know how I would feel about touching off a 12 inch gun indoors though. A suppressor is on the shopping list… one day. 🙁

  3. Ryan · April 6, 2015

    The reason SBRs are gaining popularity is because they are used by the high speed face shooters. For the jobs they need them for they are ideal plus they are quite usuable at 5/600 yards with 77grain bullets. So people want what that community use.

    That 8 yard wiggle room with range estimation isnt that big of a deal in a gunfight.

    Most citizens use SBRs for home defense and with heavy bullets works very well and the shorter length makes a big diference with manuverabiliy, especially if used with a can. The most likely distance a citizen will use a rifle is closerange where a SBR shines, and still works ok longer out.

    Shooting at midrange 5/600 yards is fun and challenging with a SBR.

    • lothaen · April 6, 2015

      I agree, the likelihood of shooting something small as discussed in the article is really low on the probability scale of self defense.

      Civilian shooters can utilize the rifle as it sits for a variety of purposes other than self defense, and small targets are plenty when it comes to harvesting small game.

      I fully agree with the place and the practicality of the SBR, but I have argued with people who dismissed the ballistic superiority of longer rifle platforms simply because they shot something at 780 yards with their blackout and that was good enough for them to *know* they can shoot it that far.

      As with everyone, I think the importance is that we master our firearms up close and out far, my blog just happens to concentrate on the “out far” at the moment since I have been shooting and studying distance work.

      I will get a chance “up close” with the competition season starting up to see how my new rig plays out.

      I am seriously lacking on my pistol work, and with my situation I think if there is a gun I will be using for self defense it would be my pistol when I am outside my home. The probability of never having to use a rifle defensively past 25 yards is high, but I want to pass on to my children the skills I learn to shoot well beyond that.

      You just never know when another Tulsa Race Riot will happen, or a Battle for Blair Mountain, or a Hurricane Katrina, or a Civil War will occur. These things happen… hence why we all want a SHTF gun and the skills to use it. 🙂

      • Ryan · June 11, 2015

        My kids will absolutely be taught how to sling up, estimate range, and shoot irons out to at least 500 yards. It is their birthright imo.

        Id rather have a shorter rifle and work a little harder at longer ranges then have a longer rifle and struggle indoors, which ive done with both a SAW and a m16a2.

  4. Wayne Anderson · April 6, 2015

    “Most citizens use SBRs for home defense…?” And what world is that in? SBRs may be fun to shoot, but they’re not all that common yet, even among gun owners. Last time I checked it was usually a handgun or shotgun. Like rifles, SBRs still run quite a risk of overpenetration in a home defense scenario, and in many places they’re not even legal.

    I won’t say they don’t have a place among competition shooters, like you say. But I’m pretty sure it’s not correct to say that “most citizens” use them for defense.

    • Ryan · June 11, 2015

      Lol, I meant most of those with a sbr have them as home defense rigs. Not that most people have them.

      Id agree that 99% of self defense shootings are solved with a handgun.

  5. Jack Bnimble · April 13, 2015

    You did not even mention the tumble and frag factor of the 5.56 round.

    The 55 grain was designed to tumble and frag creating a lethal would channel that would quickly bleed out a target, as long as the round was traveling at 2600-2700 fps. This gave an effective range of 200 yards from a 20 inch barrel, the M16. From 200-400 yards the tumble/frag factor decreases and by 400 yards it is gone, making a 22 hole in the target.

    Past 400 yards bullet placement (penetrate a vital organ) becomes critical for a kill.

    As you shorten the barrel you shorten the effective range for the tumble/frag. 16 inch give you about 150 yards, 14.5 inch about 95 yards. This is with M193.

    I have read that with a 10inch barrel you only get about 2500 FPS leaving the barrel, so unless you are using some premium ammo, m193 ball wont tumble and frag properly.

    Personally I dont get the SBR craze other than the look cool factor for 95% of people. Unless you are a professional door kicker (SEAL, Delta, etc) where a SBR allows you to drive up to a building, get out of the vehicle real easy and fast, kick in a door and do your CQB thing, then a SBR is a disadvantage in so many ways.

    They are loud as hell because the powder does not have enough barrel length to burn up properly. New rounds help this but its still bad. They have a huge flash for the same reason. Lots of SBR civilians then put a break on then end of these gimped rifles making them even louder. A can helps, but honestly I am not sure if a can brings the noise level down past that of a 20 inch AR. Combine, noise, flash and reduced effective range (tumble/frag) and you get a very gimped 5.56 rifle. But hey its short and looks “Operator”!!

    • Ryan · June 11, 2015

      Why would we bring up m193? There is some incredible new bullets out there. I dont care what my barrel length is, i still want the most effective bullet available. Dobt get me wrong, Ill train with m193, but my mags stay loaded with 77 grain bullets.

      If we’re talking home defense then even that crap ammo will work inside 50 yards quite well. If we’re talking warfare then we have 77 grain bullets. And beyond their effective range we use machine guns, mortors, arty, and CAS.

      The fantasy of laying in your fighting hole, moistening your front sight, with a tight sling as you pop hadji is just that, a fantasy.

      Fwiw, my home defense carbine has a 14.7″(with a permanent a2 fh) so not an sbr

  6. Wayne Anderson · June 11, 2015

    Actually, I addressed the whole “tumble and frag” issue in my first comment on this post – where I discussed the speed and the fact that a 10″ barrel won’t spin an M855 round up to the speed at which it was designed to fragment.

    In Lothaen’s reply to that he said he’d probably go to .300 AAC if he were using an SBR. Which makes sense given those parameters.

    • Ryan · June 12, 2015

      And tumbling and fragging are not all that important now a days with much better ammo out there. Barnes bullets, bonded softpoints, 77hpbt bullets all out class m855 by a WIDE margin. Id rather have a 12″ barrel with 55 grain barnes bullets then a 16-20″ rifle with either m193 or m855.

      If we’re talking about putting down threats either overseas or home defense why are we talking about m193 and m855?

  7. Joshua · October 10, 2015

    Who ever said their sbr would do at distance what a full sized rifle would?

    • lothaen · October 17, 2015

      You would be surprised how many people argue that the ballistics of a SBR don’t matter and that they are just as capable as a rifle at x, y, or z distance.

      • Colin · October 19, 2015

        I’ve heard that one before. A guy at work told me his 10.5″ pistol, with a brace of course, is just as capable as my 20″ three gun rifle to 500 yards. I didn’t argue, but I did suggest a match to see who whose AR was more capable. Just for fun. He declined… Funny how that worked out.

  8. Wordmahn · May 3, 2017

    This is a very informative and well written article. Thank you. I would add however, that…

    In ANY fighting scenario esp SHTF, good long shot capabilities are of dubious value. Especially is this true for those who live in wooded areas. Afganistan was a special case, But even in wide open desert where I live, I’m thinking that a 14.5, even a 12.5, might be ideal for general carry. Even the long range marksmanship oriented USMC has mostly conceded this and switched over to the M4 for general issue. THAT should tell us something.

    Military stats tell us that most small arms shooting occurs inside of 300. Good general isssue optics like the ACOG and better 5.56 ammo are pushing that out, but it’s still mostly true. If I shoot at bad guys at 700 with my carbine and miss, I’m still suppressing them. If I wing an attacker, he’s degraded and there’ll be time to shoot him again. Choosing a smaller, lighter weapon makes it more likely that I’ll have it on me all day and ready in a pinch. It means I can attach a short suppressor and it won’t become unwieldy and allow me to deploy it inside a vehicle, something that might be of critical value in a fluid, SHTF environment.

    Static defense would be different. Dealing with snipers, and defeating hard cover are more specialty situations. I may still keep one 7.62 long gun for the these things. But for the majority of individual SHTF, defensive purposes, a 14.5 or even shorter carbine is hard to beat, even with its known limitations.

  9. Joe · August 29, 2017

    Technically, laser beams are affected by the Earth’s gravity.

  10. willford · April 16, 2019

    Get SEVERAL for many ranges. SBR’s are for close work, UNLESS, Never mind.

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