Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Learning to neck turn
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="Fiftydriver" data-source="post: 35857" data-attributes="member: 10"><p>Bravo2zero,</p><p></p><p>I tell my customers to follow these steps. This for turning to fit a tight necked chamber.</p><p></p><p>Take a fired case from your chamber. Measure the expanded neck diameter, say for example you have a 6mm-06 with a fired neck diameter of .2755".</p><p></p><p>Now take a dumby round loaded with the bullet you have decided to try. With this bullet loaded in an empty, unprimed case, measure the neck diameter with a seated bullet.</p><p></p><p>Say that measurement comes out to .2750".</p><p></p><p>Basically you have 0.0005" total clearance for your case to release the bullet on firing. Total clearance is not the real figure we want to look at, we want to know how much actual distance will be between the bullet and the case when fired.</p><p></p><p>To find this you simply divide the total clearance by two and this will give you the actual clearance all around the bullet and case neck when fired.</p><p></p><p>So in this case it would be 0.00025". Much to tight. As a rule of thumb, the absolute minimum actual clearance youwant is 0.00075" between the bullet and case.</p><p></p><p>This translates to 0.0015" total clearance. Anything tighter then this will result in possible pressure problems from bullet diameter variations as well as variations in the necks you cut. While small there will be variations.</p><p></p><p>Like I said, I believe this is the absolute tightest you should have.</p><p></p><p>I much prefer to have 0.001" clearance on each side of the bullet and on big game rifles 0.0015" to 0.00175" is preferred as hunting bullets are generally not held to the strict tolerances of match bullets.</p><p></p><p>If you have to remove alot of brass, remember that you will get more accurate cuts if you take off a little at a time. This will depend onteh turning tool you have but I prefer to take off 0.00075" to 0.001" at the most per cut. Makes for a much more accurate case neck.</p><p></p><p>If you are just turning your necks to improve concentricity and neck tension from load to load. Find the thinnest neck in the lot of brass you have. Use some common sense here. IF you have 500 rounds of brass and 475 of them are 0.015" thick or more in teh neck but there are a couple that are 0.012" thick. DO NOT TRIM THE ENTIRE LOT TO 0.0115" to true all of them up.</p><p></p><p>USe the thin necked cases for sight in loads or something else. This will save you hours on teh bench as well as save on your turning tool as well.</p><p></p><p>When you do turn jsut for better consistancy, take off, 0.0005" at a time. Remember that there will be 0.0005" taken off both side for a total of 0.001" off the total diameter of the neck. </p><p></p><p>Only cut enough to jsut true up the case necks.</p><p></p><p>If you take off to much with a SAAMI spec neck, you will actually negatively effect the accurcy of your load because the neck will be very loose. Only take off enough to true the neck up and thats it.</p><p></p><p>Also, if you make the neck to thin in a standard chamber, you will increase the work hardening of the case neck as a result of the greater stretching on firing and necking down when resizing. This will result in premature case neck splitting.</p><p></p><p>Something youreally do not what when you jsut spent all that time carefully turning your necks.</p><p></p><p>Hope this helps some,</p><p></p><p>Good Shooting!!!</p><p></p><p>Kirby Allen(50)</p></blockquote><p></p>
[QUOTE="Fiftydriver, post: 35857, member: 10"] Bravo2zero, I tell my customers to follow these steps. This for turning to fit a tight necked chamber. Take a fired case from your chamber. Measure the expanded neck diameter, say for example you have a 6mm-06 with a fired neck diameter of .2755". Now take a dumby round loaded with the bullet you have decided to try. With this bullet loaded in an empty, unprimed case, measure the neck diameter with a seated bullet. Say that measurement comes out to .2750". Basically you have 0.0005" total clearance for your case to release the bullet on firing. Total clearance is not the real figure we want to look at, we want to know how much actual distance will be between the bullet and the case when fired. To find this you simply divide the total clearance by two and this will give you the actual clearance all around the bullet and case neck when fired. So in this case it would be 0.00025". Much to tight. As a rule of thumb, the absolute minimum actual clearance youwant is 0.00075" between the bullet and case. This translates to 0.0015" total clearance. Anything tighter then this will result in possible pressure problems from bullet diameter variations as well as variations in the necks you cut. While small there will be variations. Like I said, I believe this is the absolute tightest you should have. I much prefer to have 0.001" clearance on each side of the bullet and on big game rifles 0.0015" to 0.00175" is preferred as hunting bullets are generally not held to the strict tolerances of match bullets. If you have to remove alot of brass, remember that you will get more accurate cuts if you take off a little at a time. This will depend onteh turning tool you have but I prefer to take off 0.00075" to 0.001" at the most per cut. Makes for a much more accurate case neck. If you are just turning your necks to improve concentricity and neck tension from load to load. Find the thinnest neck in the lot of brass you have. Use some common sense here. IF you have 500 rounds of brass and 475 of them are 0.015" thick or more in teh neck but there are a couple that are 0.012" thick. DO NOT TRIM THE ENTIRE LOT TO 0.0115" to true all of them up. USe the thin necked cases for sight in loads or something else. This will save you hours on teh bench as well as save on your turning tool as well. When you do turn jsut for better consistancy, take off, 0.0005" at a time. Remember that there will be 0.0005" taken off both side for a total of 0.001" off the total diameter of the neck. Only cut enough to jsut true up the case necks. If you take off to much with a SAAMI spec neck, you will actually negatively effect the accurcy of your load because the neck will be very loose. Only take off enough to true the neck up and thats it. Also, if you make the neck to thin in a standard chamber, you will increase the work hardening of the case neck as a result of the greater stretching on firing and necking down when resizing. This will result in premature case neck splitting. Something youreally do not what when you jsut spent all that time carefully turning your necks. Hope this helps some, Good Shooting!!! Kirby Allen(50) [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Learning to neck turn
Top