do it yourself muzzle break

Discussion in 'Gunsmithing' started by gohring3006, Apr 22, 2014.

  1. gohring3006

    gohring3006 Well-Known Member

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    met a guy today that threaded his own break with a die and a mandrel that went inside the bore that was proper fit (.308) with threads that helped center the die with the barrel my question is how precise does it have to be his looked completely strait I had no way to measure if it was completely straight but by my eyes it looked good and he said it shot great to 400yrds so I'm asking how much does the break influence the bullet after it exits the crown of the original muzzle as far as uneven influences by not being completely strait I mean the naked eye couldn't detect it?
     
  2. FearNoWind

    FearNoWind Well-Known Member

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    Defining "straight" is a matter of acceptable variable over a given distance. Perfectly "straight" allows for 0 variable tolerance but even some of the better lathes can have an error in the order of .0005 or a bit less over some range of distance along the lathe bed, depending on how far the carriage travels and how accurately the tail stock adjusts. My lathe (not a gunsmith lathe) will vary .0003 over twelve inches. To obtain better runout than that I have to spend a lot of time tweaking the feeds. From your description I assume your friend threaded a counter bore into which he screws a muzzle brake. Machining a counter bore to repair a damaged muzzle is not uncommon but I've never seen a muzzle break installed that way.
    Bottom line - if the rifling at the muzzle is properly machined I see no reason why a muzzle break installed that way wouldn't work - but, IMO, it'd be a lot more work and sets up the potential for greater chance of error than the traditional method used for screw on breaks.
    A properly designed and installed muzzle break should have no adverse affect on the bullets path.
     
  3. gohring3006

    gohring3006 Well-Known Member

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    it was basically a .308 in. Dowel that slipped in the muzzle about 1.5in long then it increased to a 5/8in x 24 threaded top that rested on the crown then you screwed the die onto it and it traveled on it for approximately 3/4in till you got to the crown then the die continued off of it onto the barrel till the desired length you want to thread the whole process probably took 5min.it was pretty slick I want to try it but don't want to turn a .5 moa rifle into a piece of crap
     
  4. J E Custom

    J E Custom Well-Known Member

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    I do not recommend doing any threading on a firearm with any die or tap. Site bases can be done with a fixture but muzzles brakes should not be done this way.

    If a brake is installed properly (True to the bore centerline) it has no effect on accuracy. If installed improperly, It can cause uneven harmonics and can be dangerous if the bullet can/does strike the brake.

    I fix brakes that have been installed this way all of the time because they are not straight and the brake has to be bored out to assure that the bullet does not strike the brake.

    Brakes need to be bored .010 to.020 larger than the bullet Diameter.(.005 to .010 clearance from the bullet) More than that, reduces the effectiveness of the brake. Any error in alignment can be catastrophic. It is very hard to see .010 much less .005 thousandths of error.

    As long as the bullet does not hit the brake it is safe but can have a major effect on accuracy.

    It is simply not the correct way to install a brake and the person that does brake installation this way is taking on a lot of liability if things go bad.

    There are many things that a person can do it yourself (like bedding) that may not work but would
    not be dangerous. But some things require proper tools and skill to perform safely.

    I can not stress how important it is to have a real gunsmith do this type of work.

    Would you hire a veterinarian to do open heart surgery on your father ? if a vet screws up the patient dies and he apologies.

    Take this warning for what it is worth.

    J E CUSTOM
     
  5. gohring3006

    gohring3006 Well-Known Member

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    I was hoping to hear from you JE. And I will head your warning it looked to good to be true but I thought I would ask on this forum I have to say that this site is the best place to get answers from people that are not trying to get your business by telling you what they want you to hear I think I will tell my friend that you warn against it for safety reasons or I will let him read this post thank you for your advice I trust it...
     
  6. gohring3006

    gohring3006 Well-Known Member

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    thank you also your technical data is always complete and comprehensive I love this f@#%in site lol.
     
  7. J E Custom

    J E Custom Well-Known Member

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    You are welcome.

    I know it sounds like a gunsmith wanting more business but I am retired and don't have to make a living at it (It is just a hobby)

    I am a do it your self person and understand when someone wants to do it there selves, but some jobs are better left to people with the know how and equipment.

    I can only warn or advise, They can do what they want but they must be prepared for the consequences.

    Normally when I fix a brake that has been hand installed, I have to cut the barrel tenon off, losing approximately 3/4" , re-thread the tenon and re crown the barrel.

    So the person has not saved anything and has shortened the barrel.

    I hope the person that did his muzzle brake is not upset with my recommendations and has good luck with his brake installation.

    J E CUSTOM