Muzzle breaks

[jhunter1010]

well hardpan, muzzlebreaks work by diverting the gasses to the side of the barrel reducing the jet effect(recoil) of the escaping gasses.on an unbraked rifle, the gasses coming out the end of the barrel should(in my opinion) speed up the bullet
in a braked rifle, the gases are pushed back to the sides, so they cannot continue pushing the bullet after it has left the barrel

-however, i doubt it would make any difference in hunting circumstances, or any shooting within resonable ranges-

i had a hard time thinking of how to explain this :roll: , hope it makes sense to everyone

does anybody else agree or disagree with my idea??

afterall, i could be wrong :shock:

 

[hardpan]

thanks JD,
Agreed on how they work. Just not sure how the gas can drive the bullet much after the bullet leaves the end of the barrel. The gas would have to push against air, and the resulting volume increase should greatly decrease pressure very quickly. I have done some measurements where brakes slow the bullet, but also some where they have no impact. I even hear from some people that state that they increase velocity... I could spend a few hours and model the gun reasonably well, but I am not sure about a practical solution other than just measuring with a chronograph. I am going to run that chronograph test in the next 2 weeks on guns with a brake and without. Let you know what I find, but I am guessing that the design of the brake, the velocities, and even the cal. will all be real factors.

Anyway, I sometimes shoot from a very enclosed chamber, with baffling starting just inches from the barrel, and then every 2 feet for 10 feet. Grouping from that situation is very difficult with a .257 with a brake on. But, the same gun groups fairly well in an open range. Hence, my interest.
Hardpan.


afterall, i could be wrong :shock:[/quote]

 

[jhunter1010]

i look forward to seeing the results hardpan

my guess would be that the smallbores (257wby) would have more of an increase , due to the higher pressures generated by such cartridges, and the lighter bullet to push on.


could a boat tail vs flat base make a measurable difference, afterall the gases are hitting the flat base head on, (assuming the gasses travel fast than the bullet), maybe they would deflect of the boat tail of the bullet, reducing the effect

 

[jhunter1010]

maybe even try the chrony right in front of the barrel, as close as you can, and then maybe at 5 and 10 feet, to see if the bullet accelerates at all from muzzle, to 5 feet(or 10)

i also found this today on yahoo ansers ( i googled the accelerating bullet question)

Bullet acceleration after leaving the barrel?
How many people do not realize that the friction of the bullet sliding against the barrel is greater than that of the "air pressure" outside the barrel and that the "air pressure" inside the barrel IS the same or MAY be greater than that of the "air pressure" outside of the barrel when constrained by the walls of the barrel and by the force of a rapidly moving bullet?
2 years ago
Additional Details
That's exactly my point. That once free of the friction from the barrel the bullet enters the significantly less friction atmosphere of the outside air. Also, for those that know a little about aerodynamics, since thrust opposes drag, and there is little drag or negative pressure behind the bullet because the gas is also rushing out of the barrel and is still expanding in a forward direction with some loss to the sides of course the bullet will continue to accelerate in feet per second from the end of the muzzle.

Someone brought up a good point, some cartridges do meet their maximum pressure inside the barrel. Others do not and the gas pressure is still pushing and expanding just as a bomb does after it leaves its casing. In fact it is the unrestrained pressure wave that gives a bomb it's concussive force.

Have any of you who seem to already know this answer ever gotten out to the range with two chronographs and tested it?
2 years ago

"the friction of the barrel is lost while the force driving the bullet remains"

That would be incorrect. The force driving the bullet overcomes the friction of the barrel. Once the barrels friction is lost, i.e. the bullet leaves the barrel, the acting force has less resistance to overcome therefor more of the energy is used to accelerate the bullet and none is used to overcome the friction. plus the bullet has little drag due to the air rushing out behind it.

 

[Antelope_Sniper]

Velocity goes one direction once the bullet leaves the barrel.
Down.

If you port the barrel, i.e. drill holes in the barrel it self, this results in a release of gas, and reduced velocity. If you add a muzzle break onto the end of your barrel, if might result in a small marginal increase in velocity, but I would expect it to be insignificant.

 

[remingtonman_25_06]

If you put a crony 5 feet in front of a muzzle brake, I would bet it would break it. If anything, it will give false readings. Its not designed to work that close with rifles.

I like brakes on big rifles that are used for LR shooting, or for LR shooting in general. They make it easy to spot your own hits when you dont have a spotter, plus you can shoot them all day long. You cannot become proficient at LR with a gun that kicks the crap out of you if your scared of it. There are ways to tame down recoil, but none are as effective as a brake, and they surely dont keep the muzzle flip down which is what allows you to see your hits with a brake. As for the noise, wear ear plugs when practicing and when your in the field dont worry about it unless you have time, 1 or 2 shots isn't even noticable with your adrenaline going and everything.



I've had brakes on a 25-06, on my 7 RM, and 338 EDGE. All were used for LR shooting/hunting.

 

[hardpan]

The gases might cause a problem with the Chrono, but it works on light and not sound. I usually measure at the muzzle to 5 feet out, no problems yet. If I get time this weekend, will take some measurements and post the results.
Hardpan

 

[Greg Nolan]

I agree with all the theories but the timing and position of the bullet will limit much acceleration beyond the seal caused by the base of the bullet leaving the barrel. There could be a increase in velocity as more of the bullet leaves the friction of the barrel but the pressure of the gasses pushing the bullet would be lost almost instantly once that seal was lost and the friction of the air has already started it's resistence on the point and sides of the bullet. A bullet that has gone past it's peak pressure could of course already be slowing down before the end of the barrel. (A pretty rare situation with normal length barrels.)
We are speaking of variables that are pretty minor. IMO :roll:
I will be interested to see how your tests come out. I may be missing some very important facts.
Thank You
Greg

 

[Ridge_Runner]

OK, the pressure has reached its peak and starts to decrease before the bullet exits the muzzle, so how can a bullet excellerate after it exits the muzzle and the gasses driving it can get around it?

Not a rocket scientist and have no way to prove it, but just my line of thinking. This opinion is just from a dumb country boy who shoots some, is worth what it cost ya!


Yes a chrony works with light, but the muzzle blast will change the light enough to give you a false reading, and will in not much time break the skyscreens when shooting a big boomer from less than 5 yards, Don't ask me how I know this but for awhile I had PACT on speed dial.
RR

 

[DrMike]

Pressure peaks at or before the crown. There is no further acceleration after the bullet leaves the bore. A muzzle brake will not affect velocity negatively because velocity cannot increase once the bullet has left the muzzle, which is at the base of the brake. Of necessity, once the seal between the bullet and the barrel is broken by the exit of the bullet from the barrel, pressure dissipates rapidly.

 

[jhunter1010]

Not a rocket scientist and have no way to prove it, but just my line of thinking. This opinion is just from a dumb country boy who shoots some, is worth what it cost ya!



RR

did you just call me a dumb country boy?

 

[Ridge_Runner]

Not a rocket scientist and have no way to prove it, but just my line of thinking. This opinion is just from a dumb country boy who shoots some, is worth what it cost ya!



RR

did you just call me a dumb country boy?

Nope but if ya was I'd know it, I been one for a long, long time!!
RR

 

[Woodycreek]

What brakes would you guys suggest for a 300 RUM Sendero slinging 200gr AB 3220 fps? The rifle groups around .4-.5 with 200gr ABs at 100 yards but the recoil is brutal!

 

[YoteSmoker]

I had a KDF brake installed on my 300 rum 700 CDL. It is the same brake Weatherby puts on their rifles called the Accumark. Pushing a 200 grain AccuBond with 95 grains Retumbo, I would liken the recoil to a 30-06 sporter shooting a 165 grain bullet. It does not kick too bad, but I am still cautious how close I put my eye to the scope. I will definitely be wearing hearing protection this fall! The blast is something else, but much more noticeable at the range vs when I shoot steel out in the wide open plains. It is an excellent cartridge and I have mine zeroed at 300 yards. My last two shots were within an inch of a .308 dimple I was shooting at on the steel plate at 300 yards, so I guess that makes it 1/3 MOA accurate! P.S. The steel is half inch heat treated, actually a side of a form baking bricks, and at 300, the 200 AccuBond cracks the backside of the plate where it strikes. That's a whole lotta energy right there!

 

[Woodycreek]

Just talk to a local gunsmith about brakes. He said he could put a Vais brake on for $160.

 

[YoteSmoker]

That's not a bad price if it includes the brake and installation. I paid 180 for mine. Have not heard anything bad on the Vais.

 

[Woodycreek]

Thats the brake, install and a good smith. The brake cost $95.