Muzzle brake pull off , what is it and is it real ?

[Metal god]

Hey guys and gals . I was debating on where to start this thread Because this is both internal and external ballistics and decided here instead of the reloading sub forum .

Several years ago I read and or watched a video about something called "muzzle brake pull off" and although the theory seem possible I never really gave it much thought .

So what the heck am I talking about you ask ? Muzzle brake pull off as I understand it is the effect/movement of your muzzle caused buy the air/gasses being pushed/forced out of the barrel and engaging the muzzle brake BEFORE the bullet exits the bore . The theory is that there is at minimum air in the bore in front of the bullet . When the bullet engraves into the lands that seals that end of the bore forcing everything out the other end ahead of the bullet . Well air compresses and the bullets movement forward actually compresses the air in the bore as it's pushed/forced forward . The forward compressed air exiting the bore and hitting a muzzle break and really any muzzle device can and does move your muzzle and creates POA to POI shifts or worse inconsistent groups .

I hope I explained that well enough for it to seem like a reasonable theory to all of you . I had never gave all that much thought until last night when I saw this video of the shock waves of a bullet in flight .
https://www.youtube.com/watch?v=BPwdlEgLn5Q

On the whole the video is pretty cool at first but when the video reaches the 6:51 mark when they looked at the muzzle blast . OMG I can't believe how much air and gasses come out of the bore BEFORE the bullet exits ! Not only air but am I seeing actual blast coming out before the bullet ???

If so , then this would seem to confirm something Unclenick has talked about many times here at TFL . That is gasses passing by the bullet BEFORE it engages the lands .

Anyways I just wanted to get your guys thoughts on this and If I'm seeing what I believe I am seeing . Which is in fact enough air and or gasses exiting the bore in front of the bullet to cause your muzzle device to pull you off target ? You can see it much better on the revolver being fired but I suspect the rifle has quite a bit too.

[Art Eatman]

Any pull-off has already been taken into account by the sight-in process.

Easy enough to test: Sight in either with or without the brake. Then remove or add and shoot again.

[Metal god]

Art that is the plan . The revolver part of the video is what surprised me . I think you can clearly see blast coming out before the bullet , as apposed to just the little bit of air that would be in such a small bore . That really does seem to show gasses from the powder actually goes around the bullet and gets ahead of it ???

[big al hunter]

Easy enough to test: Sight in either with or without the brake. Then remove or add and shoot again.

Maybe....but I think you will notice vertical change in POI due to recoil. Probably not much, depending on caliber. I would be curious to see the results. I added a muzzle brake to my daughters rifle. I didn't notice a great difference in group size, but I only shot a few groups sighting it in before deciding she needed the break.

I would think that, if the load is consistent and accurate, then the muzzle device would channel the gases ahead of the bullet consistently as well. Therefore the device would not change accuracy, only POI. If the load is inconsistent enough to cause a change due to the muzzle device, then it would likewise be inaccurate in both conditions.

Perhaps I am simplify this a bit too much. I have never studied the theory you mentioned.

[RC20]

Your muzzle brake is going to affect the harmonics as well.

How much? Flip a coin.

Don't over think it. As long as you know it changes, you can decide to blast your fellow shooters at the range or not, but you might not want to go hunting with it.

Get as spaced as you can from the next shooter and sight it in with the brake if you plan to hunt with it.

The brake also affects the guy next to you in his shooting. Just as you are pulling the trigger tends to be highly disconcerting.

I have just left off shooting and hid behind the shed as I saw one of those guys getting ready to lay a shot down range.

[reynolds357]

Most rifles are more accurate with a brake than without. A brake affects harmonics. I have had to tune the brakes on a couple of my 1k rifles. No brake, tack driver. Brake, shot like crap. Keep putting brake back in late and removing material until shot better than they did without brake. Now, if your brake needs to be heavier, you just wasted a brake.
Watch a brake in high speed and you will quit worrying about "pull off."

[Metal god]

FWIW , I’m in no way worried about the effects of a muzzle brake . This tread was to show that there is infact air and or gases ( with the revolver ) leaving the muzzle before the bullet and to provoke conversation about that phenomenon . I have many rifles that have muzzle brakes and have no problems with them .

[Art Eatman]

Photos of the little puff of gas which precedes the bullet have been around for several decades.

[Brian Pfleuger]

Don’t know about the muzzle brake thing, but do know that the puff of gases is both long since known and not as simple as “all that”, a lot depends on cartridge and chamber designs, OAL, etc

However, that video is really cool. It is, by far, the clearest ultra slow-mo video I’ve seen of guns/bullets. Most are terribly grainy and dark.

[Bottom Gun]

I'm not a fan of the blast enhancers called muzzle brakes.
I bought an AR that had a brake installed and got tired of the blast so I took it off. It was then not only more pleasant to shoot but my groups became considerably smaller without it.

[reynolds357]

I'm not a fan of the blast enhancers called muzzle brakes.
I bought an AR that had a brake installed and got tired of the blast so I took it off. It was then not only more pleasant to shoot but my groups became considerably smaller without it.

Shoot a 460 WBY or a 50BMG with and without a "blast enhancer" and get back to me.

[Bottom Gun]

Shoot a 460 WBY or a 50BMG with and without a "blast enhancer" and get back to me.

I'm talking about normal hunting rifles. I'll never have a need for anything larger than .338 Win so I still don't like muzzle brakes.

[dgludwig]

My Savage Model 116 SE bolt-action rifle, chambered in .338 Winchester Magnum, has a muzzle brake that can be turned on or off with a flick of the wrist. I don't have a chrono so I don't know if there's any significant difference in ballistics when the brake is on or off but I can say that I've seen no change in poa vs poi when fired from the bench with either position.

[reynolds357]

My Savage Model 116 SE bolt-action rifle, chambered in .338 Winchester Magnum, has a muzzle brake that can be turned on or off with a flick of the wrist. I don't have a chrono so I don't know if there's any significant difference in ballistics when the brake is on or off but I can say that I've seen no change in poa vs poi when fired from the bench with either position.

I have the same rifle. That brake is aggressive. It's the ONLY brake I have ever shot that blew powder in my face.

[handlerer2]

It is my understanding that some powder gas will escape before the bullet swages to seal the bore. Like Art said this has been observed ever since the development of high speed photography.

[reynolds357]

A brake also has to be balanced. If you vented all your gas at the 3 o'clock position, I am sure you would observe slight poi shift.

[BeeShooter]

I took aerodynamics courses in college. I understand the principles of sonic and subsonic air flow. Now that I'm retired, I build and shoot quite a few rifles. I'm leaning towards the speed of gas expansion transversal around the bullet before the bullet seals in the barrel bore. A lot of my testing seems to support this and thus possibly contributing to a wider range of muzzle velocities. Obviously the throat,bullet weight, and fuel are determining factors. One more thing- I set-up a .300 WM to shoot a 185 gr. hybird at over max published loads. This is a 1.25" straight 26in krieger 5r shooting inside a .3 moa at 100yds. with a Holland 30 degree 'up' break. Same rifle w/o break shoots a 3. plus moa / 100. I don't lose a lot of sleep over things like this but it's a very interesting to think about. Thanks Metal God.

[Picher]

Gases escape before the bullet engages the bore, not the start of the rifling, since some gases can bypass the bullet while it just touches the rifling.

[reynolds357]

I took aerodynamics courses in college. I understand the principles of sonic and subsonic air flow

Have aeronautical engineers ever figured out how a bumble bee flies? When I was in college, my professor said "It is mathematically impossible for a bumble bee to fly."

[Brian Pfleuger]

That’s an urban legend that never was rooted in reality.
https://www.snopes.com/fact-check/bumblebees-cant-fly/

[reynolds357]

Join Date: June 25, 2008
Location: Austin, CO
Posts: 19,399
That’s an urban legend that never was rooted in reality.

That's odd. He did the equations showing that the bumble bee dis not have enough wing surface area to generate enough lift for its mass, given the amount of power it could produce. You can always count on Snopes to be full of Bravo Sierra. August Magnan published story of the physics defying bumble bee in 1913. High speed photography solved the problem in 2005. A bumble bee does not move its wings up and down, it moves them forward and backwards. The equation of impossibility proves true for up and down motion.

[Brian Pfleuger]

In other words, except for one quote in a book by one dude 85 years ago... no one ever thought it "impossible" for bees to fly and references to it never really more than an insolent response to claims of knowledge.

It's even called The Bumblebee Argument... "Unfortunately (for the pseudoscientists), the laws of physics do not in any way forbid bumblebee flight; there are no papers that deny bumblebee flight, and no scientist has done so in a lecture, except, perhaps, ironically. To put it simply, it is possible to "prove" that a bumblebee cannot fly if you perform an extremely crude calculation (like forgetting to take into account things like the rate of flapping, the rotation of the wing, or the action of vortices), but a full aerodynamic calculation (to say nothing of getting all empirical and watching a bumblebee fly) will show that the bumblebee's flight works perfectly well."

Not that it ever had anything to do with the OP, except as an occasion for snark.