Anyone who turns up at a rifle match with a muzzle-braked rifle will be highly unpopular with the men shooting beside him

Thursday, March 28th, 2019

Dunlap talks about muzzle brakes and “flashhiders”:

In any reference to foreign military weapons, muzzle brakes and flashhiders come into the conversation. Flashhiders are nearly always just an open-front metal cone attached to the muzzle of machine guns, and I could never see that they were ever very effective in confining the muzzle blast. Both Russians and Germans had very efficient combination flashhiders and smoke-dampers for use on sniping rifles, but these were large cylindrical attachments, not suitable for automatic arms.

Muzzle brakes were designed to reduce recoil and take some of the load from the recoil mechanisms of artillery pieces. Who originated the large gun application I do not know, but the first real small arms brake* was the American “Cutts Compensator” designed by the U.S.M.C. officer Cutts. It has been used to a small extent on commercial rifles, to rather wide use at one time on Thompson submachine guns and today is literally a “must” on the twelve gauge autoloading shotguns favored in skeet shooting. In the latter application varying removable tubes are provided for use in the front of the compensator, which regulate the choke. Recoil is reduced as much as 40% in some cases. The model devised for the submachine gun was not so satisfactory. Theoretically its main purpose was to “hold the muzzle down,” but in reality it had little effect on controlling either recoil or climb, and was dropped from use early in the war. It helped some, but not much.

The model designed for .30 caliber rifles was and is very effective, cutting the recoil as much as 50%, and two or three men who have used them on .30-06 rifles state they take even more, reducing recoil to almost nothing. Cost was low, and I have often wondered why the device did not become more popular for use on the heavy recoil hunting rifles.

(*Springfield Armory experimented with muzzle brakes before the 1st World War — but their first application of such attachment was on the Lewis Aircraft machine guns about the years 1917–1918.)

The Cutts rifle compensator achieves its braking action in a different manner than the usual European muzzle brake, in that it is tapered to a smaller diameter at its front than at its center, and is slotted vertically for most of its length. The foreign small arms brake was usually a plain recoil-reducer, but some submachine gun models were also compensating types for aiding in overcoming the tendency of the muzzle of the weapon to climb, or rise during firing.

Those used on anti-tank rifles were strictly brakes for counteracting the direct back thrust of the barrel under recoil force. Braking action was developed by force against a plate or series of plates at right angles to line of bore, and the attachment was largest at the forward extremity.

The principle of a muzzle brake is simple, being to erect a partial barrier to the escaping gases while naturally permitting the bullet or projectile to pass. The gases forcing the bullet out of the barrel are of course expanding and moving at high velocity, coning out as they leave the bore; if a plate is placed a short distance from the muzzle, with an aperture for the bullet to pass through, a large portion of the moving gases will blast against it, forcing it forward, so if the plate or barrier is attached to the barrel, it has a strong pull forward on the gun. Since the force of recoil exists and is moving the gun to the rear at the same time, the opposing forces tend to neutralize each other, with the result that recoil can be reduced to a large degree.

Muzzle rise can be reduced by setting the blast plate at an angle, as if it is over ninety degrees from line of bore (vertically, of course) above line and less than ninety below, the forward pull of the brake is also slightly downward. Usually the braking area is square to the bore and the gas escape ports are larger on the upper portion of the brake body, or sides, to serve the same purpose of keeping the muzzle down, by allowing the gas to escape easier at the top than at bottom.

For shoulder rifles a brake need not be very long or large in diameter, since the blast of gas does not cone out or spread too greatly immediately upon passing from the barrel, and its force is powerful enough to act upon even a small area effectively. I have not yet had an opportunity to experiment, but believe that an inside diameter of 1″ will handle even the .375 H. & H. Magnum cartridge very well. The sides, or body of the brake are very important, since they must control the final escape, release and dissipation of gas. Narrow slots, wide slots, small holes, large holes, wide opening, large and small tolerances on the bullet port — all have different effects on recoil reduction.

The simplest muzzle brake I ever saw was that used on the Solothurn 20mm AT rifle and consisted of just a block of steel threaded to the end of the barrel, bored straight through for passage of the shell, and having horizontal holes drilled straight through from side to side for gas escape. They came in three, four and five-hole sizes — the more holes the more brake effect, and no baffle or blast plate was used, the only thing to catch and divert muzzle gases being the holes at right angles to bore which received a portion of the expanding blast.

The universal effect of all muzzle brakes is to increase the report and flash as they splash the noise and gas sideways, close to the shooter. Anyone who turns up at a rifle match with a muzzle-braked rifle will be highly unpopular with the men shooting beside him. I will guarantee that.


  1. Sam J. says:

    Looking at your article on MG got me to looking around and I found this page I’ve read before. Lots of good stuff on guns, ammunition, grenades, etc. Interesting. Maybe some will like it.

  2. Isegoria says:

    Anthony Williams’ work has shown up here before, in a discussion of a potential magic bullet.

  3. Kirk says:

    Williams does a lot of good work, but I have my doubts about the whole concept of a single-cartridge solution for the needs of the combat soldier.

    All too much of what goes into the decision-making process in this regard is based on theory and supposition. There’s very little real knowledge or data to back anything up–From the data we have, you could argue that the 5.56mm/7.62mm NATO dual-caliber solution we have today is flawed, or you could argue that it is nearly perfect.

    What I can say, from the evidence, is that every time we’ve tried the unified cartridge idea, it’s been blown up by reality. The 7.62mm NATO was supposed to be the one cartridge that did it all, from MG down to the submachinegun PDW role. It manifestly did not, and we got our asses handed to us in the dense jungles of Vietnam. So, they tried for another solution, the 5.56mm, and while it was acceptable as an individual weapon cartridge, it was not workable for the support role. So, by accident, we recapitulated the German experience with the StG44 and MG42, and the Soviet experience with the 7.62X39 and 7.62X54R families. Dual-caliber is what practice teaches us is necessary, and none of the unified cartridge ideas have really worked worth squat down on the line. No matter which direction we’ve approached it from…

    While I think the 5.56mm is flawed, and not lethal enough, I also think that if you go much past it in terms of power that you’re going to start having problems actually using the damn thing in individual weapons. Likewise, I feel like the 7.62mm NATO is underpowered for its role in the support weapons, and would prefer us to go to something a bit more substantial–But, not that freakin’ .338 Lapua Magnum. That’s a bit much, to my mind.

    And, of course, I’ll freely admit I can’t back any of that up with data. Nobody can, because nobody has really bothered to do a lot of the fundamental research, and frankly, we really don’t know what the hell is going on in direct-fire small unit combat these days.

    All too much of the thinking in this area is specious, poorly thought-out, and badly sourced. There’s a lot of magical thinking about things, and mis-attribution of effects. If you really wanted to answer these questions, you’d have to wire a unit for sound, monitor it in a real action, then recover the enemy bodies for analysis. Do that, and you might begin to get to actual ground truth, but anything short of that…? You’re gonna be doing mostly wishful thinking.

    I used to think we had a really good handle on what goes on in battle, but after a tour working as an observer/controller at the NTC, and observing combat from the vantage point of the divisional HQ for the 101st Airborne for a year, what I’m convinced is that we mostly really don’t.

  4. Paul from Canada says:

    I am with the group that really wants to believe in the “one cartridge to rule them all”, and I still think the Brits came closest with their .270 and .280 rounds, but I have to admit that in practice it never quite works out.

    The idea is seductive, one related weapons system to simplify logistics and training, and one cartridge, and everyone tries it, and everyone abandons it. Even the U.S. with the laughable “M-14 for every role”.

    Canada tried it with the C1(FN FAL) rifle, and C2 (FN FALO Automatic Rifle), and it might have worked with an intermediate calibre, but the C2 was too light for 7.62, and despite the doctrine, GPMGs got borrowed from the Support Company and put down to the platoon level almost immediately.

    The Russians tried it with the AK rifle and RPD/RPK. but whenever they actually fought (Afghanistan/Chechnya), the PK/PKM would show up in the infantry squad/section.

    The Brits tried twice, first with the EM-2, for use by the Infantry Section/Squad, with a belt fed Bren Gun derivative for the support Company and vehicle roles, but Studler put paid to that. Later, they tried again with the SA-80 program, but that failed with the poor quality of the system, and even then, like the Russians, whenever the Brits actually went into combat, L7 GPMGS suddenly and mysteriously appeared at section level.

    The Marines are trying something similar again, and we will see.

    The Chinese are also trying, but they are producing cartridges with different loadings for different purposes. A bad idea in my opinion, since Pvt. Snuffy (Pvt. Chin?), will end up stuffing the heavy ball machine gun round in his rifle, out of ignorance, stress induced error, or because that is what showed up in the combat re-sup with predictable results. The logistics of a common round size and common large scale packaging (i.e. pallet size), are desirable even with different loadings, so I can see the appeal.

    I did suggest in a comment elsewhere, that this approach might work if the weapons were made more adjustable. The previous Japanese service rifle was chambered for 7.62 NATO, but the Japanese used a lighter bullet and charge in their cartridge, but the gas regulator had a setting for using the NATO round, by venting more gas to the atmosphere so the heavier round didn’t damage the gun. A similar approach might work for the Chinese. Have a gas regulator that would vent off more gas if a heavy ball machine gun round needed to be used in a rifle, for example.

    On the other hand, I have to agree with you that increasing the 5.56mm by too much would make it ineffective as an individual weapon, and a 6.8 SPC or whatever , would not be nearly powerful enough for support use. Given the relative un-importance of the individual rifle in modern combat, I think the two cartridge solution is here to stay.

    I think the 5.56mm is fine as it was originally intended, for use as an assault rifle cartridge, mostly in Western Europe, against the Soviets, and with a maximum effective range (2-300 meters),dictated by terrain and iron sights.

    However, lately, doing a lot of counter-insurgency, in arid and desert terrain, with the almost universal adoption of optics, practical effective range is now more than 2-300 meters, and the power and lethality is being called into question, and an increase in size and power is probably justified. Unfortunately, the current 6.8 solutions are constrained by keeping the costs down, so keeping the same magazine well, receiver length etc, and I am not sure the juice is worth the squeeze.

    Also, I have to admit, the logistics advantages are mostly theoretical. Small calibre small-arms ammunition is a small fraction of logistics, in terms of weight and volume. Even if you managed to make one cartridge do it all, you would still have different packaging and different loadings. Belted ammo for MGs (mixed ball and tracer, or mixed AP, API and tracer), rifle ammo (cartons or bandoleers of stripper clips), sniper/match ammo, etc. etc. and that would be dwarfed by the quantities and varieties of grenades, mortar ammo, HMG and auto-cannon ammo, Automatic grenade launcher ammo, radio and NVG batteries etc. etc. etc.

    Nobody had any difficulty in WWII/Korea providing the front line troops with the various ammo required back then, even with coalition warfare and the non-standardization prior to NATO. Even the Japanese with their more than on kind of 7.7mm and Italians with similar problems managed. The only issue I ever heard of was the Germans not able to deliver 7.92 Kurtz after initial allocations, but that was due to strategic supply and manufacturing, not to the inability to do the combat logistics.

    Despite all the lobbying for the 6.8, and the new telescoped semi-caseless concept,I think economics and logistics will mean that we will have 5.56mm and 7.62mm for the foreseeable future. We will add .338 Lapua and perhaps a couple of other varieties of grenade cartridge/small auto-canon cartridge, but until the phased plasma rifle in the 40 watt range shows up, what we have is “good enough”.

  5. Sam J. says:

    “…Brits came closest with their .270 and .280 rounds…”

    I think you’re right. I believe that you need a heavier machine gun round also but a longer range round is necessary for the individual soldier. A lot of this can be obtained by making the bullet more streamlined without raising the weight too much and using new case design. The link I posted earlier has a lot of examination of this.

  6. Kirk says:

    I think the Swedes were on to something with their 8X63mm M/32 cartridge for their medium and heavy MG units. That caliber strikes me as being a better MG round, and were it I, the individual weapon would look a lot like the Swedish 6.5X55mm loaded down to enable controllable full-auto fire.

    I do not like the 5.56mm/7.62mm NATO mix we run now. It works, but I think we could do better. Caveat being that before I blew the cash on replacing them, I’d demand that real research be done to either validate my ideas or prove me wrong.

  7. Bruce says:

    A guy fired an AR-15 at the next table at the range a couple years ago. It was a real slap in the face, and my face broke out in blisters afterwards. Hearing seems okay though.

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