When it comes to choosing between a 10.5-inch and an 11.5-inch barrel for a 5.56 rifle, the debate often revolves around performance, reliability, and intended use.
While the difference of one inch may seem negligible at first glance, it can have implications depending on the shooter’s needs.
Let’s break it down based on input from industry professionals and experienced shooters.
Performance Differences: Muzzle Velocity and Terminal Ballistics
One of the most significant factors influenced by barrel length is muzzle velocity. A general rule of thumb is that every inch of barrel length adds or subtracts around 20-30 feet per second (fps) to the projectile’s velocity. This increase in velocity affects the terminal ballistics, meaning how the bullet performs upon impact.
- 11.5” Barrel: Provides slightly higher muzzle velocity, which improves fragmentation, penetration, and accuracy at longer distances. This is particularly beneficial when shooting heavier rounds like 62-grain and 77-grain bullets.
- 10.5” Barrel: The lower velocity slightly limits fragmentation and overall ballistic effectiveness, particularly beyond 200 meters. However, at close quarters, it remains lethal and effective.
For shooters looking to maximize range and effectiveness, the 11.5-inch barrel is the superior choice. If compactness is the main priority, the 10.5-inch barrel still performs well in CQB scenarios.
Reliability and Recoil Management
Dwell time—the time the bullet spends in the barrel after passing the gas port—affects the rifle’s recoil impulse and cycling reliability. A longer barrel increases dwell time, which can make a noticeable difference in performance:
- 11.5” Barrel: Smoother recoil impulse, improved reliability, and reduced wear on internal components. Less finicky with weaker ammo.
- 10.5” Barrel: Snappier recoil, increased wear on parts, and sometimes more finicky with lower-powered ammunition.
A longer dwell time helps with smoother cycling and reduces the risk of malfunctions, making the 11.5-inch a more forgiving option across different ammunition types.
Compactness and Maneuverability
One of the key advantages of a shorter barrel is increased maneuverability in tight spaces. In close-quarters battle (CQB) situations, a compact rifle can make a real difference.
- 10.5” Barrel: Better suited for vehicle use, home defense, and confined spaces where every inch matters.
- 11.5” Barrel: Still compact, but offers a better balance between size and performance.
As one industry expert put it: “An inch less snag and an inch less drag can make all the difference in tight spaces.” However, in practical applications, the additional inch doesn’t drastically impact maneuverability unless extreme compactness is the priority.
Suppressor Considerations: Gas Blowback and Fouling
For those running suppressed setups, the extra inch can influence gas pressure and overall shooting experience.
- 10.5” Barrel: Tends to have more gas blowback, which can lead to increased fouling and a harsher shooting experience when suppressed.
- 11.5” Barrel: Less gas blowback, making it a better choice for suppressed shooting.
If you frequently shoot suppressed, the 11.5-inch barrel is the preferred option due to better gas management and reduced fouling.
Ammunition Considerations
Ammunition selection plays a role in how much of a difference the extra inch makes. If using MK262 (77-grain) or heavier bullets, the extra velocity from an 11.5-inch barrel helps maintain ballistic stability. Conversely, if using standard 55-grain or lower-quality bulk ammo, the benefits of the longer barrel are slightly less pronounced.
- High-quality ammo (e.g., MK262, 77-grain OTMs): Performs better in an 11.5-inch barrel.
- Lower-quality bulk ammo: More noticeable performance drop in a 10.5-inch barrel.
Final Verdict: Which One Should You Choose?
So, does an extra inch really make a difference? The short answer is yes, but how much it matters depends on your priorities:
- If you want the most balanced option with improved performance, reliability, and suppression, go with the 11.5-inch barrel.
- If you need maximum compactness for CQB or vehicle use, the 10.5-inch barrel is still an effective choice.
- If suppressor use is a factor, the 11.5-inch barrel is the better pick due to reduced gas blowback.
For most shooters, the 11.5-inch barrel is worth the extra inch. The slight increase in length provides noticeable benefits in reliability, ballistic performance, and overall shooting experience, making it a well-rounded choice for a variety of applications.
What’s Your Take? Do you prefer a 10.5-inch or an 11.5-inch barrel for your 5.56 rifle? Let us know your thoughts in the comments below!
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The recipient of the bullet will not know or care about the super-slight difference of muzzle velocity between the two. For me, a 5.56 is to be used in a 16″ to 20″ barrel. 10.5″ is optimum for .300 BLK. But TEHO.
The article above opens with the statement that the focus is on rifle config. This would center around SBR and NFA, which I think 99% of everyone doesn’t want to go through. I think the 10.5″ is considered the max length that a reasonable person would see on a build and still accept it as a pistol (using the proper buffer tube accessory, of course), so…
I appreciate the article. Presently I do not own any long guns and am shopping for and AR15 and this discussion of barrel length solidifies my decision relative to barrel length.
If you’re purchasing lower receiver/fire control housing as a stand alone component see that the FFL fills out the transfer form as a ‘pistol’ . You can assemble a pistol length barreled AR and be OK as a pistol, -and- you can always fit a rifle length barrel at any time & be legal.
You can NOT put a pistol length barrel on a lower that is 1st time-around transferred as a ‘rifle’, and then fit a pistol length (sub-16.5″) barrel without filing a Short Barrel Rifle Form4 so that you can be considered ‘legal’ if something untoward were to occur with the firearm.
Pile-on charges can have horrific consequences.
Again, -always- transfer from manufacture as a ‘pistol’ and NOT a ‘rifle’ , it opens up beneficial usage avenues for you, and can keep you out of -further- trouble, if any were to arise.
Actually the FFL cannot list a frame or receiver as a “pistol” on the form. Years ago they could do that but not anymore due to ATF “rulings”. A stripped frame or receiver can be built into a handgun or long gun. However, once it is built into a long gun it cannot be made into a handgun. Only a Class 2 manufacturer could make it into a AOW or restricted post sample machine gun. A individual could Form 1 the frame and manufacture a SBR. I’ve been a FFL since 1999.
A lower receiver can (and should) be transferred as a “receiver” not as a pistol or rifle.
You start to run into problems with a complete lower, because if it has a stock it must be transferred as a rifle, not a pistol.
I bought a sack of lowers a couple years ago, and the FFL put “Receiver” on the 4473 so I could go either way with them. Ok to do that then, but may be different today. Also at that time, if the first build of an unspecified lower was a pistol, you could “rifle” it and convert back to pistol as often as you liked, as long as you didn’t mix the two formats. Short barrel with no shoulder stock, ok. Long barrel with no shoulder stock, ok. Long barrel with shoulder stock, ok. Short barrel with shoulder stock, not ok—SBR. I think a vertical foregrip comes into play here also—I think it’s ok on a rifle but would SBR a pistol. May be wrong on that point.
M16’s had 20inch barrels.
The 5.56×45’s claim to fame is its speed.
M16’s had 20 inch barrels, the 5.56×45’s claim to fame is its speed
are previous comments made for articles prior this ‘upgrade’ coming back?
yes. We’re working through a ton of issues at the moment. One of them being comments going straight to moderation; which they should not be.
I approve of the new look(so far!) Barrel length is merely academic for me living in ILLannoy🙄
Does one inch really make a difference?
Ask her!
Probably not much of a difference.
Shorter than 10″, I have no doubt it would.
I have an 8″ AR pistol in 5.56 and after plugging in some numbers, it’s weak, especially after 100 yards. Keeps dropping from there.
What would of made this a interesting read if you actually shot 62grn and 77grn out of both barrel lengths and published the actual FPS. Enter those numbers into a ballistic app and publish the down range results.
Then compare the DI with other similar length barrels using firearms with short stroke gas piston and then compare the recoil between the two.
Does an 11.5″ barrel push it into SBR territory?
I’d still go either 14.5 inch or 16 inch for 5.56 for a general purpose or home defense rifle.
hey, my comment posted…the other test comments didn’t and went to moderation. So it seems the site is working. Thanks 😁
If this one here posts, it’ll be only the 2nd out of 8 total attempts since the site’s re-launch to the new format. I’m trying a different username now, but even that has been rejected twice. Participating in the comment section is the main reason I’ve been part of TTAG for 10 years. If this keeps up, there will be no incentive to come here instead of the many other sources of gun-related news.
can’t imagine it makes much diff.
That’s what I said. My wife remains skeptical.
This is where bullpup rifles become viable especially suppressed.
Also it avoids an additional tax stamp.
If you are focused on a short length barrel, you should really consider a caliber change – .300 blk was made for the shorter barrel: pistol configuration, suppressed, subsonic ammo, the works. Price differential has been greatly reduced since 556 has remained high. Terminal ballistics of the .300 far surpass that of the 556 in this barrel length scenario.
I’m sorry, but saying that with 55gr ammo the extra inch of barrel length doesn’t make much difference is absolutely incorrect. It makes MORE of a difference than it does with heavier bullets.
This would of been a interesting article had you actually clocked the FPS at the muzzle of 62grn and 77grn ammo then plugged that information into a ballistics calculator to get the down range performance between the 11.5″ and 10.5″ barrels.
A more realistic comparison of recoil would of been shooting same length barrels out of short stroke gas piston firearms and comparing them to DI.
Get whichever one you want.
Search high and low. Seek out the sages on the mountain top, the operationally operating operators, the nerds with their spreadsheets and all the bro-science guntubers you want and the answer will always be a convoluted word-salad of “it depends” backed up by fractional numbers that may or may not mean anything in the real world.
If you find a good deal from a reputable manufacturer on a 10.5″ or an 11.5″ just go for it. It’s not worth giving yourself an aneurysm trying to min/max like some loser arguing about video games or cape shit from his moms basement. You’re either putting holes in paper, ringing steel or harboring fantasies of sending rounds into Dude Badguy and any barrel length will do that just fine.
Unless you are going to suppress you will lose whatever hearing you have to the noise. The 16″ barrel lets the powder burn in the barrel instead of past the front sight.
Remember 10-16″ guns won’t penetrate level 3 AR500 with M193 or 855, 18 and 20″ will…short guns also have short gas systems and are less reliable. Gun was designed to have 7″ of barrel after the port. Short guns have deeper penetration because they lack the required energy to fragment with ball…get a rifle, not a pistol if you’re not going to the range to look like a Delta Unit. Or get both? Bad guys wear body armor…so focus on bullet performance then get a weapon to support that.
“No gun is so short and useless that a soldier wouldn’t love it.”
For many of Scott’s comments, the length of the gas tube is as important as the barrel length. Gas tubes come in several lengths – pistol, carbine, and rifle. You might not get much choice when buying an assembled rifle, but when specifying or building your own, you have that option.
A friend of mine was the lead firearms instructor at the N FL Institute for Public Safety. After the N Hollywood shootout everyone was jumping on the patrol carbine concept. Mark is teaching the classroom phase and is pointing out the difference in barrel length of the M-4, 16.5″, and the more common 16″. He made the comment that an 1 1/2″ doesn’t make much difference anyway. (He was speaking of handling, not ballistics.) The lone woman in class said, “Oh, you’d be surprised.”
The 5.56×45’s claim to fame is its speed.
It started life as a .222Magnum because many varminters liked the extra fps gain over the .222
Reduce the fps down and you’ve not got much more then a .22Magnum.
—– I like this new TTAG format. ——