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
Hunting
Long Range Hunting & Shooting
7 rum
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="NZ Longranger" data-source="post: 428788" data-attributes="member: 14"><p>I've been shooting big 7mm's for many years now and have taken many 100's if not 1000's of big game animals with them. The RUM is the biggest factory 7mm by some margin and will outrun the STW by 100 to 150 fps or so with 160gns and heavier. </p><p></p><p>The biggest issue with the factory 7mm RUM's is the throat is way too long on most of them. You can't seat 180gn Bergers out anywhere near the lands without the bullet falling out of the neck. I have only found one factory 7mm RUM of the many I've worked with that would shoot the Bergers jumping. The rest shot way better with the 175SMK, which is far more forgiving of the 100 thou plus jump necessary in the factory chamber with the 175 SMK seated only 100 thou into the neck. Any less in the neck and the ammo will be too fragile and the bullet will fall out too easily if you drop it or suchlike. The 175gn SMK is the go-to long range bullet in factory 7mm RUM's with too long throats in my experience.</p><p></p><p>Now, a custom 7mm RUM with a shorter throat is a different story. With something like 100 thou freebore, you can easily touch the lands with the 180gn Berger, and drive them at around 3200fps out of a 26" barrel with H50BMG or even faster with US869. Out of a 30" barrel, you can get well over 3300fps, but if shooting bare bullets, you may start to blow bullets up in flight at this velocity as the throat roughens up. Moly bullets seem to handle this issue for longer, before you have to change back to the thicker jacketed 175 SMK or similar. The Berger is the best long range bullet in our experience though, killing quicker and better in the wind. The old 200gn Wildcat ULD's performed similar to the 180gn VLD, but didn't really offer much more ballistically. They were accurate but only a tiny smidgin better in the wind and dropped more, so when Richard stopped making them we switched back to 180's and 175's. And at sea level they need an 8" twist to stabilize them out to 1000 yards. I know Kirby can stabilize them with a 9" at his altitude, but we do most of our range work at not far above sealevel before hunting up to 6000' or so, and its a pain when you can't shoot them on the home range. Your factory 9" twist probably won't stabilize the 200gn ULD's at sealevel. </p><p></p><p>As to barrel life, it all depends on what powder you use and how hot you drive it. The most temperature consistent powder H50BMG (or 2218 as its called down here) is harder on barrels. I'd expect 600 to 800 rounds. US869 will give you nearly double the barrel life with more velocity but more temperature sensitivity. You can minimize this by keeping your ammo at a consistent temp by carrying it against your body or something similar, or if you want to get really high tech, having different drop charts or PC inputs for different ammo temps. Another way we've dealt with a very temperature sensitive powder like H870 was to have different loads for different temperatures, but you need to be on the ball to work this system.</p><p>This is all only an issue beyond 800 yards on big game, as inside 800 its not really an issue if you pay a little attention to not letting your ammo get too hot or cold. </p><p>Good luck, short of the big 338's there's nothing beats a big 7mm!!!<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /></p><p>Greg</p></blockquote><p></p>
[QUOTE="NZ Longranger, post: 428788, member: 14"] I've been shooting big 7mm's for many years now and have taken many 100's if not 1000's of big game animals with them. The RUM is the biggest factory 7mm by some margin and will outrun the STW by 100 to 150 fps or so with 160gns and heavier. The biggest issue with the factory 7mm RUM's is the throat is way too long on most of them. You can't seat 180gn Bergers out anywhere near the lands without the bullet falling out of the neck. I have only found one factory 7mm RUM of the many I've worked with that would shoot the Bergers jumping. The rest shot way better with the 175SMK, which is far more forgiving of the 100 thou plus jump necessary in the factory chamber with the 175 SMK seated only 100 thou into the neck. Any less in the neck and the ammo will be too fragile and the bullet will fall out too easily if you drop it or suchlike. The 175gn SMK is the go-to long range bullet in factory 7mm RUM's with too long throats in my experience. Now, a custom 7mm RUM with a shorter throat is a different story. With something like 100 thou freebore, you can easily touch the lands with the 180gn Berger, and drive them at around 3200fps out of a 26" barrel with H50BMG or even faster with US869. Out of a 30" barrel, you can get well over 3300fps, but if shooting bare bullets, you may start to blow bullets up in flight at this velocity as the throat roughens up. Moly bullets seem to handle this issue for longer, before you have to change back to the thicker jacketed 175 SMK or similar. The Berger is the best long range bullet in our experience though, killing quicker and better in the wind. The old 200gn Wildcat ULD's performed similar to the 180gn VLD, but didn't really offer much more ballistically. They were accurate but only a tiny smidgin better in the wind and dropped more, so when Richard stopped making them we switched back to 180's and 175's. And at sea level they need an 8" twist to stabilize them out to 1000 yards. I know Kirby can stabilize them with a 9" at his altitude, but we do most of our range work at not far above sealevel before hunting up to 6000' or so, and its a pain when you can't shoot them on the home range. Your factory 9" twist probably won't stabilize the 200gn ULD's at sealevel. As to barrel life, it all depends on what powder you use and how hot you drive it. The most temperature consistent powder H50BMG (or 2218 as its called down here) is harder on barrels. I'd expect 600 to 800 rounds. US869 will give you nearly double the barrel life with more velocity but more temperature sensitivity. You can minimize this by keeping your ammo at a consistent temp by carrying it against your body or something similar, or if you want to get really high tech, having different drop charts or PC inputs for different ammo temps. Another way we've dealt with a very temperature sensitive powder like H870 was to have different loads for different temperatures, but you need to be on the ball to work this system. This is all only an issue beyond 800 yards on big game, as inside 800 its not really an issue if you pay a little attention to not letting your ammo get too hot or cold. Good luck, short of the big 338's there's nothing beats a big 7mm!!!:) Greg [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Hunting
Long Range Hunting & Shooting
7 rum
Top