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Muzzle Brake and Scope Movement

 
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  #1  
Old 08-16-2005, 08:54 PM
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Muzzle Brake and Scope Movement

Just noticed that scope has moved ahead about 3/16th of an inch after 35 rounds and muzzle brake installation.

Scope had not moved w/more than 100 of same rounds prior to the brake?

What don't I know? [img]/ubbthreads/images/graemlins/confused.gif[/img] Or should I chew out the fella that installed the scope (me) [img]/ubbthreads/images/graemlins/blush.gif[/img]
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  #2  
Old 08-16-2005, 09:36 PM
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Re: Muzzle Brake and Scope Movement

I'm no pro but it may be a ring issue.
I assume your talking about the 338 in some of you other posts.
I don't know what the recoil is like on it.
I have limited experience with brakes ( only one holland QD )but my scope has not moved and I have put 75 rounds down the tube since it was added. I mounted the scope on it new after brake installation with Burris signature rings with a 6X24X50 Burris Black Diamond in them( which is not a light scope )and no movement yet. Thats on a 7Rum but recoil is 243 level or less since brake job.
Thats all the help I can be but keep us posted on what you find out.
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  #3  
Old 08-17-2005, 08:54 AM
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Re: Muzzle Brake and Scope Movement

Roy,

Keep in mind that while you feel less "felt recoil", the scope and rifle are acutally having more stress and strain placed on them with a brake. Let me explain why before I am called a crazy loon!!

Recoil is the resulting force you feel from the bullet being forced down the barrel, that who opposite and equal action deal!!

Well, a rifle will gain teh exact same amount of recoil energy from firing a round with or without a brake. this is because the recoil energy is produced while the bullet is in the bore. From the time the bullet begins to move until it reached and is released by the muzzle, the rifle gains "X" amount of recoil energy.

This is true for a rifle with a brake on it as well. The only thing the brake does is try to fight the resulting effects of the recoil energy on the rifle. So we have two rifles, one with a brake one without. When the bullets leave the muzzle on each, both rifles have the same recoil energy in theory. Both rifles and scopes have experienced the same stress from the same recoil energy.

With the Non braked rifle this is the end of things as far as g-forces are concerned, not so with the braked rifle.

Now with a braked rifle, the rifle is in rearward motion and then the expanding forces of the gas escaping the muzzle hit the muzzle brake with tremendous energy which produces negative G-forces. SO not only does the scope have to handle the positive recoil forces generated by simply shooting a round, but it also, in a split second is hammered with negative forces generated by the brake.

This is why a top quality scope and mounting system are a nessesity with a large caliber rifle fitted with a brake. I recommend Burris Signature rings with all my brake fitted big game rifles at least.

That said, it may simply be a freak thing that just happened to occur. If your not using Burris Signatures, get some and your problem will go away. Also, if your using a standard base with windage adjustable rear screws make sure the rear screws are not slipping. Again, the Burris Signatures will generally solve this problem.

Have a good day,

Kirby Allen(50)
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Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #4  
Old 08-17-2005, 02:02 PM
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Re: Muzzle Brake and Scope Movement

ah ha! Poop!

So that's why the recoil seems much "sharper" and "shorter" even though it is a bunch less than before the brake.

And that's why the windage mount screws looked off center.

Using Leupold 2 piece bases w/single allen (pun) screw rings. Guess they gotta go. [img]/ubbthreads/images/graemlins/crazy.gif[/img]

Will switch to Sig rings. What base do I want? Shudda bot that IOR base for 80 bucks, huh? [img]/ubbthreads/images/graemlins/confused.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img]

Its just money [img]/ubbthreads/images/graemlins/blush.gif[/img] No patience, SWH here I come... Gotta shoot Friday [img]/ubbthreads/images/graemlins/tongue.gif[/img]

We'll see how the Alaskan Guide [img]/ubbthreads/images/graemlins/frown.gif[/img] scope holds up. [img]/ubbthreads/images/graemlins/confused.gif[/img]
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  #5  
Old 08-17-2005, 04:45 PM
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Re: Muzzle Brake and Scope Movement

Fifty,
i'm certainly not gonna call you a crazy loon,but i am gonna disagree with you.you use the term recoil energy.i'm not sure what that means but i think you're trying to explain primary recoil.that is simply the bullet accellerating from zero fps to whatever.this accounts for maybe 5% of the felt recoil.secondary recoil is when the bullet exits the barrel and now you have 15K or whatever the pressure is on the inside pushing on the bolt.a brake is simply an extention of the barrel to "bleed off" the pressure from inside the barrel over a longer period of time so the felt recoil is less because much less pressure is pushing against the bolt.the escaping gases pushing against the diaphrams of the brake simply lessen the push against the bolt even more.in a nutshell, i simply do not believe that a scope has anywhere near the same amount of "felt recoil" with or without a brake! it's much less with a brake on.
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  #6  
Old 08-17-2005, 05:24 PM
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Re: Muzzle Brake and Scope Movement

Dave,

I would respectfully disagree with your comments. Talk to anyone in the 50 cal shooting world and you will see what I am talking about. Most scopes are designed to withstand rapid acceleration in only one direction, from the scopes perspective, rearward very quickly. With a muzzle brake there is this initial reward movement but also a substantial forward force, or should I say a very quick Deceleration of the scope.

This is why all scopes designed for 50 BMG rifles and air rifles have lens locks on both sides of the scope lens, not just one like many scope designs.

This is also why a pneumatic air rifle is one of the best things to destroy a scope, negative g-forces.

Felt recoil is basically not recoil energy at all, its the momentum of the rifle that you have to physically stop with your shoulder.

If your theory were true, you could take say a 300 RUM loaded with a 125 gr Ballistic tip to 65,000 psi and a 250 gr ULD loaded to the same 65,000 psi and recoil would be basically the same because there is the same amount of pressure forcing its way back against the bolt face. This is not true.

The second the bullet breaks the seal of the muzzle the bore pressure drops to basically 0 psi extremely fast with or without a brake.

In fact depending on the brake design, a rifle with a brake fitted like a Vias or similiar brake will have a higher bore pressure reading, longer then a naked muzzle or a partition style brake.

This has been proven time and again and is the main reason why a Holland or similiar style brake reduces felt recoil more efficently then a Vias style. They allow the gas to vent quicker. Also why they are louder.

Still, a bare muzzle will reach 0 psi in the bore the fasted of all three. Now we are talking milli seconds here so keep that in mind.

On this one my friend I would again have to respectfully disagree with your theory.

What do some of the other guys think??

Kirby Allen(50)
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #7  
Old 08-17-2005, 05:36 PM
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Re: Muzzle Brake and Scope Movement

Found this little tid bit on Lilja's website. Hope it helps. It is basically what Kirby is saying.


Eric Williams, the former editor of the Fifty Caliber Shooters Association's magazine VERY HIGH POWER, reports on another potential problem with scopes on muzzle braked rifles. According to Eric some of the brakes on today's fifties are so efficient that for a moment they are actually pulling the rifle forward. It is a very brief but forceful jolt and it seems as though it puts the scope into a kind of reverse recoil situation. Some of the target type scopes are not designed to take this forward thrust and soon develop loose parts inside. Eric did say that the Leupold Mark 4 seems to hold up, at least so far. It was Eric's fifty, with a Mark 4 on top, we used to shoot the tank hull at 2000 meters. This rifle had one of the type of brakes on it that can cause the forward thrust I mentioned. The scope seemed to be working just fine for me and it takes a lot of clicking to get on at 2000 meters.
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