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
Finding Jam - I thought I knew how
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="Les in Wyoming" data-source="post: 2070548" data-attributes="member: 115820"><p>I used Eric Cortina's method, which is what I always used to do. He said it doesn't matter if you get different readings, but if I have a large difference from different shells, how do I know if I my load is going to be .010 off jam or .020 into the rifling? </p><p></p><p>I used 3 different de-primed cartridges and they were all different. So I did them over and over again. It looks like each cartridge comes out the same each time - but each are different. Hmmmm. So I checked cartridge length. Each are different. In my pea brain, it seems to me it would not matter what the cartridge length is, because we are going for base of cartridge to ogive. That figure should be the same and the bullet jump should therefore be the same when you measure the OAL. Am I right? </p><p></p><p>It looks like my fired cases measure differently. I have a Lee case hand sizer. It sticks into the primer hole as a pilot and you spin it which cuts to size. But it looks like the length is different. </p><p></p><p>So, it could be that I am going to reveal some ignorance here, but I am here to learn. Does the actual case length make a difference in how deep the bullet sits from the lands when you measure CBTO?</p><p></p><p>Secondly, does cartridge length make a difference in accuracy if they are all seated the same CBTO? If so, what would the tolerance be? within .001? .002? or .009? etc. I will appreciate any input. Thanks</p></blockquote><p></p>
[QUOTE="Les in Wyoming, post: 2070548, member: 115820"] I used Eric Cortina's method, which is what I always used to do. He said it doesn't matter if you get different readings, but if I have a large difference from different shells, how do I know if I my load is going to be .010 off jam or .020 into the rifling? I used 3 different de-primed cartridges and they were all different. So I did them over and over again. It looks like each cartridge comes out the same each time - but each are different. Hmmmm. So I checked cartridge length. Each are different. In my pea brain, it seems to me it would not matter what the cartridge length is, because we are going for base of cartridge to ogive. That figure should be the same and the bullet jump should therefore be the same when you measure the OAL. Am I right? It looks like my fired cases measure differently. I have a Lee case hand sizer. It sticks into the primer hole as a pilot and you spin it which cuts to size. But it looks like the length is different. So, it could be that I am going to reveal some ignorance here, but I am here to learn. Does the actual case length make a difference in how deep the bullet sits from the lands when you measure CBTO? Secondly, does cartridge length make a difference in accuracy if they are all seated the same CBTO? If so, what would the tolerance be? within .001? .002? or .009? etc. I will appreciate any input. Thanks [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Finding Jam - I thought I knew how
Top