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
7MM RUM/WC872 and the chrony ...
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="steve smith" data-source="post: 27412" data-attributes="member: 110"><p>I wouldn't be to worried about the velocity increase. I found the same thing in my 30" barreled 270-300 RUM. I was using the 135MK with 98gr WC872, pretty much max load. The rifle has a .300" neck, all case necks turned to .0105" per side. Loaded round mics. out to .299" +.0"-.001". Anyhow, I started the load @92gr, If I remember correctly, and ended @103.5grs. The velocity started around 3600fps at 92gr, jumped up to 3680fps by the 96gr mark, by the time I hit 103.5gr the velocity was just over 3800fps. in the first 4gr the vel. increased 80fps, but in the last 7.5gr it increased 120fps. The problem is with the case capacity, to the brim of the neck is around 113gr. of WC872. You and I both are in the realm of extremely overbore rifles. We are pushing small projectiles with very large amounts of propellant at relatively fast velocities. The more capacity you add the less effect the added capacity has. Where as an additional 2gr. in a 270win might give you an extra 100+fps, but the same additional 2gr in my rifle hardly even shows a difference. It took 11.5gr to make 200fps difference. But the velocity was a little more predictable when using 5010. I've achieved the earlier mentioned velocity of 3800fps @97gr, and much better accuracy. With wc 872 my best groups weren't much better than 1-1.5". with 5010 the groups dropped to below 1".</p><p></p><p>[ 06-17-2003: Message edited by: txhunter ]</p></blockquote><p></p>
[QUOTE="steve smith, post: 27412, member: 110"] I wouldn't be to worried about the velocity increase. I found the same thing in my 30" barreled 270-300 RUM. I was using the 135MK with 98gr WC872, pretty much max load. The rifle has a .300" neck, all case necks turned to .0105" per side. Loaded round mics. out to .299" +.0"-.001". Anyhow, I started the load @92gr, If I remember correctly, and ended @103.5grs. The velocity started around 3600fps at 92gr, jumped up to 3680fps by the 96gr mark, by the time I hit 103.5gr the velocity was just over 3800fps. in the first 4gr the vel. increased 80fps, but in the last 7.5gr it increased 120fps. The problem is with the case capacity, to the brim of the neck is around 113gr. of WC872. You and I both are in the realm of extremely overbore rifles. We are pushing small projectiles with very large amounts of propellant at relatively fast velocities. The more capacity you add the less effect the added capacity has. Where as an additional 2gr. in a 270win might give you an extra 100+fps, but the same additional 2gr in my rifle hardly even shows a difference. It took 11.5gr to make 200fps difference. But the velocity was a little more predictable when using 5010. I've achieved the earlier mentioned velocity of 3800fps @97gr, and much better accuracy. With wc 872 my best groups weren't much better than 1-1.5". with 5010 the groups dropped to below 1". [ 06-17-2003: Message edited by: txhunter ] [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
7MM RUM/WC872 and the chrony ...
Top