November 27, 2022. For the best accuracy with threaded-muzzle barrels, use a larger muzzle thread diameter. Robert Whitley, ARX Enterprises LLC, has discovered that some barrels are threaded 5/8. The muzzle may not be accurate at 24 TPI. Because too much steel has been removed, the barrel’s end can sound a bit like a trombone. This is especially true for barrels of.30 caliber, but it can also happen with barrels of smaller caliber (even 6mm). Robert demonstrates the phenomenon in the video below. The video is recommended for all gunsmiths and anyone who plans to thread a barrel. Robert gauges a 5/8 at 1:00 -1:30. x 24-threaded,.30-Caliber barrel. The belling effect is evident as day. “When we set up a commercial barrel in our lathe, the maximum-sized bushing that would fit into the bore at the chamber’s end was almost.0015” smaller than what would fit at the muzzle. I started pin-gauging a variety of commercial barrels that were threaded for 5/8” x 24 TPI. This is what I found. R. WhitleySolve Problem With a Larger Thread Size
What if 5/8? Is 5/8? You can leave a little more steel in the barrel. (See Video at 02:40. Frank Green from Bartlein barrels says: “We get these kinds of questions all the time. I recommend that you run the largest thread diameter possible. Robert Whitley found that a 3/4” thread is sufficient. The “belling effect” is not caused by threading that is 28 TPI x 3/4? Robert recommends 3/4? If you need to thread your barrel for an muzzle brake, or suppressor, use a 28 x 3/4 inch. Robert explains that we only make 3/4″ x28 TPI muzzle brakes, and that’s what customers recommend to us. “See how much more meaty the 3/4? Threading vs the 5/8?. 3/4? The 3/4? threading allows for more metal around the bore. The bore will not become bell-mouthed …”. This is why threading is so important.
The 5/8? The 5/8? x 24 TPI threading was never created by any accuracy-based think tank. It’s a military.30 Cal threading for barrels that are heavy. They had to make the barrel lighter so that it was smaller in diameter, and the threading had the ability to work with that situation. People have assumed that because the military uses this threading for certain purposes, it must also be suitable for highly accurate rifles. However, that is not true. We do muzzle threading so that there is no relief cut behind threads on barrel (i.e. The relief cut should be placed on the jam nut or brake, but not on the barrel’s muzzle. Many people have difficulty understanding that the muzzle of a rifle’s rifle is sacred metal. You should not reduce it more than necessary. A tiny threaded nub at the barrel’s end with a diameter of pencil is not ideal for accuracy, especially if it’s threaded or you need to torque it. I cringe when I see barrels with MTU or Heavy Varmint contours, but then find a tiny threaded nub at the muzzle. This is so that someone can “screw it on a can” or a brake. Lessons learned over the years
Craig Kostyshyn was a big player in the 30BR game. He made some of the most impressive 30BR rifle barrels for benchrest competition. When I started the project, I wanted a medium-heavy Palma contour barrel that I could use as well as a muzzle turndown to allow me to use a front sight band. He was shocked to learn that I wanted the muzzle to be turned down. The muzzle bore dimension would open up. He did this by rough contouring the barrel with the turndown, before he lapped it. After that he worked more on the barrel’s back. Although I thought he was a bit too concerned, the barrel shot great and I didn’t mind arguing with him. After all, he was shooting groups in one. I just put it away and didn’t think about it until recently, when Fred from Sabreco did some chamber rework on a commercial.30 caliber barrel I had. Fred noticed that the maximum size bushing that would fit into the bore at the chamber’s end of the barrel was almost.0015 when he set it up in the lathe. He noticed that the maximum-sized bushing that would fit in the bore at the chamber end was almost.0015? and he shared it with me. This prompted me to pin-gauge a variety of commercial barrels that I had that were threaded for 5/8” x 24 TPI. What I came up with is what you can see in the video. AccurateShooter.com has given written permission for you to not reproduce or re-link more words than 75 words.
Similar Posts:Tags :Barrel Flare Barrel Threading Crown Muzzle Muzzle Brake Robert Whitley, Suppressor
