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
300 WM with 20" need advise...
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="Lefty7mmstw" data-source="post: 663470" data-attributes="member: 48043"><p>Yes a longer barrel will give you lower muzzle pressure, to a point. If you use powders that are on the fast side for your given combination, you can get along with a lot shorter barrel than if you're using a compressed charge. </p><p>I pulled out some pressure graphs from my old 7mmstw, and though the pressure was still dropping as the bullet exited, the pressure was below 20,000psi at 1.5 milliseconds, while it has only dropped to 12,000 psi at 2.5 milliseconds. Neither pressure is doing much to move the bullet. The load was 81 rl25, 140 sierra fb, 215, rem. brass. The pressure peaked at 60,000 psi at .6-.7 milliseconds. </p><p>I highly doubt he'll notice any difficulty shaving down to 20" from the normal 24" of a lot of the factory 300win's out there. 100-150 fps would be a lot with equal or better accuracy if he watches his powders. I wouldn't burn ball 50bmg powder or retumbo in this one, though. That would CREATE problems on its own. Stick to the idea that the pressure needs to be off by exit, and use mid-speed powders.</p></blockquote><p></p>
[QUOTE="Lefty7mmstw, post: 663470, member: 48043"] Yes a longer barrel will give you lower muzzle pressure, to a point. If you use powders that are on the fast side for your given combination, you can get along with a lot shorter barrel than if you're using a compressed charge. I pulled out some pressure graphs from my old 7mmstw, and though the pressure was still dropping as the bullet exited, the pressure was below 20,000psi at 1.5 milliseconds, while it has only dropped to 12,000 psi at 2.5 milliseconds. Neither pressure is doing much to move the bullet. The load was 81 rl25, 140 sierra fb, 215, rem. brass. The pressure peaked at 60,000 psi at .6-.7 milliseconds. I highly doubt he'll notice any difficulty shaving down to 20" from the normal 24" of a lot of the factory 300win's out there. 100-150 fps would be a lot with equal or better accuracy if he watches his powders. I wouldn't burn ball 50bmg powder or retumbo in this one, though. That would CREATE problems on its own. Stick to the idea that the pressure needs to be off by exit, and use mid-speed powders. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
300 WM with 20" need advise...
Top