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
Sinclair Concentricity Gauge
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="TRexF16" data-source="post: 2375903" data-attributes="member: 108912"><p>Thanks Mikecr, I think I see what it is you are concerned with. Do I understand you right that you believe bullet runout is caused by the entire case having a gentle curve to it - the "banana" you referenced? If that were the case (no pun intended) I could understand your argument versus the way I am describing fixing runout in loaded rounds. But I have never encountered that opinion regarding the source of case runout. My experience and everything I have gathered from others over the decades is that cases with runout get that way during the sizing process, and the culprit is the sizing of the neck, usually the expansion step after the neck has been sized down already. In normal full length dies this happens when the case is entirely unsupported as it is pulled over the expanded ball on the way out of the die. This is easy to test by checking straightness after a trip through the sizing die with the expander ball removed and compare it to a "normally" FL sized case. The former is almost always straighter. It's also the reason traditional neck sizing dies sometimes produce more runout than FL dies - the case body is unsupported both when sized down and expanded back up. Collet dies and bushing dies avoid these risks by the nature of how they work, and tend to produce straighter cases. Many of us FL size with no expander, then run the case necks over an expanded mandrel so they get expanded on the upstroke, and avoid much runout that way.</p><p></p><p>I'll reiterate I am not discussing straightening a <em>bullet</em>. The bullet never touches the tool and the bullet's position in the case neck is unaltered. You simply secure the neck in the precision hole, and nudge the case body in the right direction to eliminate the misalignment of the case body to the case neck. Then you roll it in the v-block (concentricity gauge, in this case) to confirm the correction, and repeat until it meets your needs. (I always got for .001 or better since it's easy to do so). There is no way to tell, using the concentricity gauge, the difference between a case that came out of the sizing process straight and a case that was a little off but got straightened the way I am describing. I have not encountered cases with the body having a curve to it but I have not spent a lot of time looking for it either.</p><p></p><p>I'm not trying to argue, but rather to understand your point since it doesn't match my experience or knowledge.</p><p>- If the reason a case (and the subsequent loaded cartridge that was made from it) has runout is that the case neck got misaligned with the case body during sizing, and I eliminate that misalignment, why isn't that a legitimate fix?</p><p>- Is it your belief that it's not case neck misalignment that is the primary cause of measured case neck runout, but rather a gentle banana curve that runs the entire length of the case?</p><p></p><p>Looking forward to better understanding your point.</p><p></p><p>Cheers,</p><p>Rex</p></blockquote><p></p>
[QUOTE="TRexF16, post: 2375903, member: 108912"] Thanks Mikecr, I think I see what it is you are concerned with. Do I understand you right that you believe bullet runout is caused by the entire case having a gentle curve to it - the "banana" you referenced? If that were the case (no pun intended) I could understand your argument versus the way I am describing fixing runout in loaded rounds. But I have never encountered that opinion regarding the source of case runout. My experience and everything I have gathered from others over the decades is that cases with runout get that way during the sizing process, and the culprit is the sizing of the neck, usually the expansion step after the neck has been sized down already. In normal full length dies this happens when the case is entirely unsupported as it is pulled over the expanded ball on the way out of the die. This is easy to test by checking straightness after a trip through the sizing die with the expander ball removed and compare it to a "normally" FL sized case. The former is almost always straighter. It's also the reason traditional neck sizing dies sometimes produce more runout than FL dies - the case body is unsupported both when sized down and expanded back up. Collet dies and bushing dies avoid these risks by the nature of how they work, and tend to produce straighter cases. Many of us FL size with no expander, then run the case necks over an expanded mandrel so they get expanded on the upstroke, and avoid much runout that way. I'll reiterate I am not discussing straightening a [I]bullet[/I]. The bullet never touches the tool and the bullet's position in the case neck is unaltered. You simply secure the neck in the precision hole, and nudge the case body in the right direction to eliminate the misalignment of the case body to the case neck. Then you roll it in the v-block (concentricity gauge, in this case) to confirm the correction, and repeat until it meets your needs. (I always got for .001 or better since it's easy to do so). There is no way to tell, using the concentricity gauge, the difference between a case that came out of the sizing process straight and a case that was a little off but got straightened the way I am describing. I have not encountered cases with the body having a curve to it but I have not spent a lot of time looking for it either. I'm not trying to argue, but rather to understand your point since it doesn't match my experience or knowledge. - If the reason a case (and the subsequent loaded cartridge that was made from it) has runout is that the case neck got misaligned with the case body during sizing, and I eliminate that misalignment, why isn't that a legitimate fix? - Is it your belief that it's not case neck misalignment that is the primary cause of measured case neck runout, but rather a gentle banana curve that runs the entire length of the case? Looking forward to better understanding your point. Cheers, Rex [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Sinclair Concentricity Gauge
Top