1/2x28 30cal side port muzzle brake

[WYO300RUM]

If you have a muzzle on a .30cal with 1/2" threads have your muzzle gauged after firing a box of shells and I'll bet you an unpleasant surprise. The bore as deep as the threading will be looser than the bore deeper in the barrel than the threads. A number of people have demonstrated that even 5/8x24 is a bit on the small side. From .243 to .338 I much prefer 3/4x24. Added meat at the muzzle helps keep it from belling out. I had the muzzle on a few barrels I was running 5/8x24 brakes on gauged. All came out looser under the threads than deeper than the threads even with .243cal. About a year later I found the video below and decided right there and then to go 3/4x24 on all future barrels of .24cal to .338cal. On my .223's I now do 5/8x24.

I suspect the effect is more pronounced on stainless barrels than on chrome-moly barrels. I run almost all barrels in stainless anymore.

Yes, thousands of people did smaller threads for decades. We also used to think rotary dial telephones were a pretty useful thing.

I fired probably 2k rounds through factory barrel with a 1/2 magnabrake from Magnaport . No problem at all. Non so far with new barrel and APA Answer . Your mileage may very . Also , you are limited by your barrel diameter on what size / thread break you can install. There's no way to thread a 1/2 in. pencil barrel 9/16 or 5/8, etc.. Just saying.

 

[kgunz11]

If you have a muzzle on a .30cal with 1/2" threads have your muzzle gauged after firing a box of shells and I'll bet you an unpleasant surprise. The bore as deep as the threading will be looser than the bore deeper in the barrel than the threads. A number of people have demonstrated that even 5/8x24 is a bit on the small side. From .243 to .338 I much prefer 3/4x24. Added meat at the muzzle helps keep it from belling out. I had the muzzle on a few barrels I was running 5/8x24 brakes on gauged. All came out looser under the threads than deeper than the threads even with .243cal. About a year later I found the video below and decided right there and then to go 3/4x24 on all future barrels of .24cal to .338cal. On my .223's I now do 5/8x24.

I suspect the effect is more pronounced on stainless barrels than on chrome-moly barrels. I run almost all barrels in stainless anymore.

Yes, thousands of people did smaller threads for decades. We also used to think rotary dial telephones were a pretty useful thing.

So that's not always the case. With any tubular bore style object, many machining processes can change the bore dimension. Some of that due to the process in which the material is made.

In the application of a rifle barrel, some of us know how to machine the muzzle in a way that doesn't change the ID of the bore in a measurable manner. I can tell you that heavy passes and hogging the material WILL change the dimensions. Going slow and easy, with sharp carbide tooling, proper work holding, a good threading insert, and you won't get tight or loose spots.

I have a 300WM #5 contour barrel in the lathe right now that I took a little video of that confirms this.

I remember a time when people said fluting a barrel was detrimental to accuracy. There are very few absolutes in this world, and a lot of voodoo.

 

[8x68s]

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American Precision Arms

American Precision Arms manufactures high end tactical, target, and hunting rifles, as well as the most popular muzzle brakes in long range competition. Known for having the best muzzle brakes, scope rings, trigger guard, bottom metal and most accurate rifles in the industry.

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