338 rum and barrel length vs. velocity

[grouse]

working on a 338 rum and trying to determine Barrel length. I'm wanting to keep somewhat short 26+- but everything that I keep reading says 28-30 is minimum. I ran across this article on the lapua. Think this would be similar for the RUM? If so I think I can get away with 26" for a hunting rifle.

https://rifleshooter.com/2017/03/338-lapua-magnum-barrel-length-versus-muzzle-velocity-30-17-inches/

 

[LA50SHOOTER]

working on a 338 rum and trying to determine Barrel length. I'm wanting to keep somewhat short 26+- but everything that I keep reading says 28-30 is minimum. I ran across this article on the lapua. Think this would be similar for the RUM? If so I think I can get away with 26" for a hunting rifle.

https://rifleshooter.com/2017/03/338-lapua-magnum-barrel-length-versus-muzzle-velocity-30-17-inches/

I wouldn't go Any shorter than 26" and every inch you can afford to have beyond is going to increase velocity. - The powders your going to be seeing the best performance with are on the slow end of the scale (unless your planning on light bullets at hyper velocity). - Retumbo & H-1000 like long barrels.

Good Luck & Good Shooting

 

[284winner]

working on a 338 rum and trying to determine Barrel length. I'm wanting to keep somewhat short 26+- but everything that I keep reading says 28-30 is minimum. I ran across this article on the lapua. Think this would be similar for the RUM? If so I think I can get away with 26" for a hunting rifle.

https://rifleshooter.com/2017/03/338-lapua-magnum-barrel-length-versus-muzzle-velocity-30-17-inches/

Yes. While I'm no expert, others here hold that title. I read that as well as I'm building a 338 lapua imp with a 28" barrel. Im changing my barrel length to a 30". Lots of opinions and experiences to listen too. Sort them out but most are spot on. 26 at the shortest but looks like the 28-30 is ideal for the standard 338 lapua or RUM. Seems like 30-36" is what many run on the improved cartridges.

 

[grouse]

It looks like 34FPS is lost from 30" to 26" when using the heavy stuff. I would run 250-275

 

[284winner]

It looks like 34FPS is lost from 30" to 26" when using the heavy stuff. I would run 250-275

Not alot of difference. With the 300s it's about 74. Still not alot.

 

[grouse]

With the 300's I read 2833 at 30" and 2799 at 26" from the chart. Seems hardly worth the extra 4 inches to me

 

[284winner]

With the 300's I read 2833 at 30" and 2799 at 26" from the chart. Seems hardly worth the extra 4 inches to me

Sorry I have it reversed. A bigger difference with the 250s. Still not really much difference.

 

[dkhunt14]

With the 300's I read 2833 at 30" and 2799 at 26" from the chart. Seems hardly worth the extra 4 inches to me

That depends how far you want to shoot. The 300 grain hits hard way out there. It is also a great killing bullet. I also believe from all our testing those numbers are off. On the one load, more barrel had less velocity. Depending on chronograph, till they cut the barrel off that many times, the light changed and so did the numbers. Usually you can figure about 30 fps per inch average. Matt

 

[86alaskan]

I've got a RUM in progress and I'm going with a 28" plus big beast brake/suppressor. I figure, this is not the kind of gun I'm gonna build for short range close quarters handling. If you want to hammer with 338 bullets and a short barrel, just save the money on brass and powder and build a 338wm. If you're going RUM or Lapua sized cases, why handicap yourself with a shorter barrel that brings your performance down to 338wm levels. Those big cases deserve the long barrel for max performance.

 

[grouse]

I've got a RUM in progress and I'm going with a 28" plus big beast brake/suppressor. I figure, this is not the kind of gun I'm gonna build for short range close quarters handling. If you want to hammer with 338 bullets and a short barrel, just save the money on brass and powder and build a 338wm. If you're going RUM or Lapua sized cases, why handicap yourself with a shorter barrel that brings your performance down to 338wm levels. Those big cases deserve the long barrel for max performance.

I hear you but if the data in the article are correct. What's the point of going that long?

 

[Evlshnngns]

You made up your mind, go 26''. If you go back a page or two there is a thread on a 18'' 28 Nosler pistol. It only has to tickle your Fancy....

 

[284winner]

I hear you but if the data in the article is correct. What's the point of going that long?

There is alot of published info on the 6.5 Creedmoor only getting a few feet per second more from a 22" to a 26" barrel. Reading on, they commented that it was Hornady factory ammo that was used. Not sure exactly how that article read but maybe the ammo selection was factory 338 lapua. Typically when guys want the most from there cartridge, they go long on barrel and full on case capacity. Then there's the seating depth etc. Can't say for sure but could be that's why the smaller jump in velocity to barrel increase.

 

[grouse]

I posted data, looking for feedback. Any other data to counter? I prefaced all my comments with "if the data are correct". I'm seeking info here from "real world" shooters. So give me some data

 

[LA50SHOOTER]

I posted data, looking for feedback. Any other data to counter?

No - None - You've made up your mind - Go 26" or what ever you want..............

 

[Evlshnngns]

I posted data, looking for feedback. Any other data to counter?

Just the Lilja article, noted in the article you posted. Or base it off the 29" velocity of 2871, 72fps gain over the 26'', 24fps per inch.

As LA50SHOOTER stated, fire up the ballistic calculator. Decide your effective range of fire, find out what velocity your bullet needs for proper expansion. Juggle it all till it fits.

 

[grouse]

I don't understand why some folks are so sensitive to this topic. It's just a discussion.

Anyone shooting anything under 28"? If so care to post your results? Just seeking feedback.

 

[dkhunt14]

I posted data, looking for feedback. Any other data to counter? I prefaced all my comments with "if the data are correct". I'm seeking info here from "real world" shooters. So give me some data

The velocity figures are too low in that article. I have seen 30 inch barrels in 338 Lapua and Remington Ultra mag shoot 2900 to 3000 with 30 inch barrels with 300 grain bullets. I know of nobody that would use 4831SC in a Lapua case even with lighter bullets. RE33 gives more velocity with less pressure. Usually 100 to 150 more with a 300 grain bullet.

Like I said before, it depends on how far you want to shoot. If your talking less then 1000 yards, it wouldnt matter near as much. When you get out there 1300 or more it matters alot. Matt

 

[Midnightmedic]

Here’s my load
Factory Remington 26” barrel with Watt’s mag conversion. 300 grain Berger OTM TACTICAL seated to a col of 3.98”. Max Retumbo load => 2830 fps with <10fps Es. Half Moa 3 shot groups out to 1300 yards verified every fall for the last 8 years and over 400 rounds down the barrel. Only intended as a stout hunting load for late fall winter hunts.
FYI 100 grains of Rl33 hits 2900 fps.

 

[wboggs]

I hunted with a custom 338 RUM for years. Used 26" Krieger barrel and got 2986fps using 250 gr barnes bullets and Norma MRP. Accuracy and killing power were amazing and rifle was easy to.handle in the field

 

[Kalitrazescapee]

I don't understand why some folks are so sensitive to this topic. It's just a discussion.

Anyone shooting anything under 28"? If so care to post your results? Just seeking feedback.

I have a factory stock rum and 85gr h4831. 250sgk does 2700 on the crony...the only change is a limbsaver pad..I probably have a 26" barrel. But unlike many ...I have ammo...I've never understood why one thinks a couple boxes is all they need