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
Reloading
Let's talk about the "dreaded donut"
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="Michael Eichele" data-source="post: 486843" data-attributes="member: 1007"><p>A thought on 'flow' or brass moving forward.</p><p></p><p>If you take a brand new case, measure it's length, fire it and measure again, you will find that the length changes very very little if any at all (assuming the chamber is within good tolerences. The shoulder may move depending on headspace etc....But the overall length very little. After you full length size, you will find that the case is now longer. It is the resizing NOT the firing that causes the majority of any length increases. In fact, resizing has such an affect on case demensions, many shooters think that they are 'bumping' the shoulder when in fact they are setting it back conciderably even if it only measures .001 back from when fired. This is because the shoulder moves forward during FL sizing. If you run a fired case up your FL die and stop .010 short, pull it out and try and load it into your chamber, you will find that it likely will not fit. This is because the shoulder has moved forward. To bump it back .0005-.001, it actually has to be bumped several thousandths because it has moved forward several thousandths while being resized. Now there are exceptions to this rule. If using a tight chamber where the case cannot expand much or at least spring back to at or near specs, you may not see any forward movement or very little of it. For factory chambers and full on SAMMI spec chambers, you will see alot of forward 'flow' if you will. In this sense, Mikecr is right.</p><p></p><p>Do-nuts are often times caused by improper neck turning. If you dont turn enough brass at the neck shoulder junction, the excess brass on the out side of the neck has to go somewhere during resizing and firing. This is when it goes inside the neck. Brass needs to be turned so that a small cut goes onto the shoulder. Not too much though. When neck turning, a good mandrel should be used to run inside the neck to get the inside of the neck right. Then any flaws will be outside. When you push the flaws from inside the neck to the outside, then they can be turned and the flaws will be cut away. I like the K&M set because the neck guide has teeth in the bottom to remove any do-nuts when the neck walls are touched up. The upper end of the shank is smooth for smooth, uniform turning. </p><p></p><p>This is on main reason I like to neck turn. It isnt always about making a neck concentric with the bore but rather I prefer to have a smooth uniform neck for consistent neck tension.</p><p></p><p>If neck turing is done right, you should hardley ever, if ever see any do-nuts. I have in factory chambers when FL sizing over and over but not is good custom fitted chambers be it FL sizing or neck sizing. This maybe one instance where using an expander ball during resizing may be of any benefit as it would push a do-nut out of the way. I still prefer to neck turn and either use a body die and sperate neck die or neck size only since expander balls tend to cause runout.</p><p></p><p>M</p></blockquote><p></p>
[QUOTE="Michael Eichele, post: 486843, member: 1007"] A thought on 'flow' or brass moving forward. If you take a brand new case, measure it's length, fire it and measure again, you will find that the length changes very very little if any at all (assuming the chamber is within good tolerences. The shoulder may move depending on headspace etc....But the overall length very little. After you full length size, you will find that the case is now longer. It is the resizing NOT the firing that causes the majority of any length increases. In fact, resizing has such an affect on case demensions, many shooters think that they are 'bumping' the shoulder when in fact they are setting it back conciderably even if it only measures .001 back from when fired. This is because the shoulder moves forward during FL sizing. If you run a fired case up your FL die and stop .010 short, pull it out and try and load it into your chamber, you will find that it likely will not fit. This is because the shoulder has moved forward. To bump it back .0005-.001, it actually has to be bumped several thousandths because it has moved forward several thousandths while being resized. Now there are exceptions to this rule. If using a tight chamber where the case cannot expand much or at least spring back to at or near specs, you may not see any forward movement or very little of it. For factory chambers and full on SAMMI spec chambers, you will see alot of forward 'flow' if you will. In this sense, Mikecr is right. Do-nuts are often times caused by improper neck turning. If you dont turn enough brass at the neck shoulder junction, the excess brass on the out side of the neck has to go somewhere during resizing and firing. This is when it goes inside the neck. Brass needs to be turned so that a small cut goes onto the shoulder. Not too much though. When neck turning, a good mandrel should be used to run inside the neck to get the inside of the neck right. Then any flaws will be outside. When you push the flaws from inside the neck to the outside, then they can be turned and the flaws will be cut away. I like the K&M set because the neck guide has teeth in the bottom to remove any do-nuts when the neck walls are touched up. The upper end of the shank is smooth for smooth, uniform turning. This is on main reason I like to neck turn. It isnt always about making a neck concentric with the bore but rather I prefer to have a smooth uniform neck for consistent neck tension. If neck turing is done right, you should hardley ever, if ever see any do-nuts. I have in factory chambers when FL sizing over and over but not is good custom fitted chambers be it FL sizing or neck sizing. This maybe one instance where using an expander ball during resizing may be of any benefit as it would push a do-nut out of the way. I still prefer to neck turn and either use a body die and sperate neck die or neck size only since expander balls tend to cause runout. M [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Let's talk about the "dreaded donut"
Top