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wilit
08-09-2009, 11:17 PM
I've seen many discussions on how these types of muzzle brakes which replace the barrel bushing are useless because the the slide is already moving before the bullet leaves the barrel. Here's the brake I'm talking about.

http://cn1.kaboodle.com/hi/img/2/0/0/15e/7/AAAAAjLhDJkAAAAAAV5y2g.jpg

I recently ran across these vids on youtube and as you can see, the slide is stationary until the bullet has completely left the barrel. Please watch and discuss.

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cmace22
08-09-2009, 11:39 PM
No info on your break, but thats cut a way 1911 video was awsome!

Josh
08-10-2009, 1:45 AM
even in the videos it shows the slide moving before the bullet exits.

But the main reason these brakes dont work as well as a screw on brake is that they allow too much gas to escape out the front instead of through the ports.

HCz
08-10-2009, 1:54 AM
I don't think the slide is moving before the bullet gets out, at least from 2nd and 3rd video. But as pointed out already, I think the gas escapes to front a lot faster than via ports.

B Strong
08-10-2009, 6:42 AM
I've tried barrel bushing brakes before.

They are limited value, but the real problem they present is that none of the ones that I've tried were heat treated to the point were they'd hold up to extended use - depending on the model, most of them peened the locking lug within 500 rounds - and you'd have to improvise a method of removing the comp from the gun to take down the pistol, and then re-shape the lug to get the thing back on the gun.

Waste of money and time imo.

J-cat
08-10-2009, 8:27 AM
I don't think the slide is moving before the bullet gets out, at least from 2nd and 3rd video. But as pointed out already, I think the gas escapes to front a lot faster than via ports.

You need to watch closer. The third video clearly shows the slide moving to the rear before the bullet leaves the barrel. Reference the slide against the edge of the frame's dust cover seen in the lower part of the video. Look immediately right before the first puff of air. The barrel and slide begin to recoil to the rear as a unit.. This is called dwell time. The bullet is still in the barrel at that point. It also depends on the caliber. A 230gr 45 bullet @ 800 FPS stays in the barrel longer than a 115gr 9mm bullet doing 1400 FPS.

wilit
08-10-2009, 7:08 PM
You need to watch closer. The third video clearly shows the slide moving to the rear before the bullet leaves the barrel. Reference the slide against the edge of the frame's dust cover seen in the lower part of the video. Look immediately right before the first puff of air. The barrel and slide begin to recoil to the rear as a unit.. This is called dwell time. The bullet is still in the barrel at that point. It also depends on the caliber. A 230gr 45 bullet @ 800 FPS stays in the barrel longer than a 115gr 9mm bullet doing 1400 FPS.

Okay, yeah, it moved like 2mm. However, the bullet and 90% of the gasses have left the barrel before the slide would move enough for the cuts on the brake to be covered by the barrel.

Gunaria
08-10-2009, 7:15 PM
I've tried barrel bushing brakes before.

They are limited value, but the real problem they present is that none of the ones that I've tried were heat treated to the point were they'd hold up to extended use - depending on the model, most of them peened the locking lug within 500 rounds - and you'd have to improvise a method of removing the comp from the gun to take down the pistol, and then re-shape the lug to get the thing back on the gun.

Waste of money and time imo.

A flat head screw driver works fine with me. I got one of them dragon's fire breaks on mine and I like it.

Sheldon
08-10-2009, 8:52 PM
Because it is a modified barrel bushing, the inner diameter clearance has to allow for the barrel to ride thru it. That is way over the diameter of the bullet and as such allows most of the escaping gasses to go out the front of the brake/bushing instead of being diverted thru the ports of the brake where they'de be doing anything toward reducing the recoil. A true compensator would be mounted to the end of the barrel and the port size would be just enough bigger than the bullet diameter to allow the bullet to get thru it without interferance. That way, the bullet acts as a seal of sorts and divert more of the gasses thru the other ports in the comp to reduce recoil/muzzle flip.

J-cat
08-10-2009, 9:27 PM
Okay, yeah, it moved like 2mm. However, the bullet and 90% of the gasses have left the barrel before the slide would move enough for the cuts on the brake to be covered by the barrel.

No, it moved about of an eigth of an inch. Yes, I agree, the vents were not blocked by the barrel.

BigDogatPlay
08-10-2009, 11:28 PM
A true compensator would be mounted to the end of the barrel and the port size would be just enough bigger than the bullet diameter to allow the bullet to get thru it without interferance. That way, the bullet acts as a seal of sorts and divert more of the gasses thru the other ports in the comp to reduce recoil/muzzle flip.

A barrel mounted compensator generally has an expansion chamber inside of it. Once the bullet is in the compensator's expansion chamber, for that brief instant, the seal is gone. In reality it's gone the instant the bullet leaves the rifling at the muzzle crown.

I'm not a master of fluid or gas dynamics but common sense tells me that regardless of how the compensator / brake is mounted the venting of the gas is going to happen far faster than the mechanical cycling of the action. The linked video in the OP seems to prove that on the compensated gun that was shown. In that respect the bushing mounted compensator / brake should have some measure of effectivity in recoil reduction which is it's intended purpose.

Maybe this is one for Mythbusters? :cool2:

CRTguns
08-10-2009, 11:36 PM
The problem with bushing comps...

the comp is bored to allow the whole damn barrel through. Because of this they are never very effective- the gasses are not adequately constrained abd controlled behind the bullet- the hole is too big!

BigDogatPlay
08-10-2009, 11:43 PM
And if there is an oversized expansion chamber inside a barrel mounted compensator... same thing, no?

J-cat
08-11-2009, 8:41 AM
It would be far better to sharpen the comp into a spike.

xxdabroxx
08-11-2009, 9:38 AM
And if there is an oversized expansion chamber inside a barrel mounted compensator... same thing, no?

small hole at the end though. i think that is what the difference is, the gasses are not allowed directly out the end.