338 RUM w/ Retumbo

[JD338]

I have been starting to work with Retumbo in my as well as my nephew's
338 RUM with the 250 gr PT. Velocities are quite impressive with no pressure signs encountered.
Here are my first accuracy testing range results from 6-7-08 in two different rifles chambered in 338 RUM.

Remington 700LSS, Leupold Vari X III 2.5x8
338 RUM
250 gr PT, Federal case and Federal GM215M primer

98.0 grs Retumbo
#1 from clean oiled barrel was 2937 fps
Avg velocity 2999 fps, #2 was 2998 fps and #3 was 3000 fps
ES n/a
SD n/a
3 shot group at 100 yds went 1.592", 2 & 3 went .649"

98.5 grs Retumbo
Avg velocity 3016 fps
ES 24
SD 12
3 shot group at 100 yds went .652"

99.0 grs Retumbo
Avg velocity 3024 fps
ES 13
SD 6
3 shot group at 100 yds went .829", 2 went .159"

My nephews 700 XCR 338 RUM, Nikon Buckmaster 3x9

98.0 grs Retumbo
Avg velocity 2994 fps
ES 13
SD 6
3 shot group at 100 yds went 1.875", 2 went .940"

98.5 grs Retumbo
Avg velocity 2994 fps
ES 9
SD 4
3 shot group at 100 yds went 2.182", 2 went .991"

99.0 grs Retumbo
Avg velocity 3026 fps
ES 19
SD 9
3 shot group at 100 yds went 2.152", 2 went .500"

The 99.0 gr charge weight needs to be reshot and tweeked.
I also think there are some issues with the Nikon scope as it seems to shoot everything all over the paper.

JD338

 

[OU812]

Both the 98.5 and 99 look good, I'll bet both would come together with a seating depth tweek of .005 at a time. Can't beat the velocity with a 250 and no pressure signs to boot. Good shooting!!!!!!!!!!!!!!

 

[Desert Fox]

I'm really impressed with Retumbo. I'm currently developing loads for my 338 Lapua Improved, and Retumbo got the nudged over Reloader 25. I like both powder but I believed I can squeezed more velocity from Retumbo with less pressure although, Reloader won in accuracy department.

Here's Retumbo's 5-shot group @ 200 yards, 300 grain SMK

Here's Reloader 25's 5-shot group @ 200 yards, 300 grain SMK

 

[craiger40]

Hey fellas,

I may have to work with some retumbo. I do have to say i am more than pleased with RL-22. I don't like how sensitive RL-22 is to temp. Hodgdon powders are reportedly more temperature stable and that may mean quite a bit come November. Have you fellas worked with H1000? Check this out, in my July 08 issue of guns and ammo they have an article about bolt VS. double guns for hunting in Africa. The article was comparing power levels and one was a 458 lot vs 470 NE w/ 500gr trophy bonded bear claw bullets. The 458 at 2300 made 5,873 FT/LBS the 470 at 2150 made 5,132 FT/LBS my 338 RUM with the 3,213 fps load i had last weekend i was getting 5,156 FT/LBS or about 24 FT/LBS more than the 470. Its not so much as i would want my 338 on safari but just to be able to even compare that info really shows how outstanding the 338 RUM is. The 338 RUM is just an outstanding cartridge and i thank god every weekend mine has a brake on it. :lol:

Craig,

 

[Powerstroke]

JD,

Looks as if your just about there. That's awesome to have two guns of the same caliber there to play with.
What powder were you shooting out of it before ?
I've been playing with the Retumbo, R-25, N-165 out of my .300RUM

 

[JD338]

JD,

Looks as if your just about there. That's awesome to have two guns of the same caliber there to play with.
What powder were you shooting out of it before ?
I've been playing with the Retumbo, R-25, N-165 out of my .300RUM

Powerstroke,

I agree, testing 2 338 RUMs is going to shed some interesting facts.

Prior to Retumbo, the only two powders I have used in my 338 RUM has been RL22 and RL25. I have been able to get under .5" with the 200 gr BT/AB, 210 gr PT, 225 gr PT and 250 gr PT. The 225 gr AB has shot under .6".
For a factory rifle, it is very accurate!

JD338

 

[JD338]

Just an update on the 338 RUM with the 250 gr PT and Retumbo.
I have settled on a charge weight of 98.6 grs and have been working on seating depths.
The bottom two targets in the photo were shot with the 250 gr PTs.

I also noticed that my velocity dropped , this may be due to a different lot of Retumbo powder. Has anybody noticed any lot to lot variation in velocity with Retumbo?
I will reconfirm this load and post my results.

JD338

 

[FOTIS]

Very nice JD. Man oh man!

 

[Alaska]

I have been starting to work with Retumbo in my as well as my nephew's
338 RUM with the 250 gr PT. Velocities are quite impressive with no pressure signs encountered.
Here are my first accuracy testing range results from 6-7-08 in two different rifles chambered in 338 RUM.

Remington 700LSS, Leupold Vari X III 2.5x8
338 RUM
250 gr PT, Federal case and Federal GM215M primer

98.0 grs Retumbo
#1 from clean oiled barrel was 2937 fps
Avg velocity 2999 fps, #2 was 2998 fps and #3 was 3000 fps
ES n/a
SD n/a
3 shot group at 100 yds went 1.592", 2 & 3 went .649"

98.5 grs Retumbo
Avg velocity 3016 fps
ES 24
SD 12
3 shot group at 100 yds went .652"

99.0 grs Retumbo
Avg velocity 3024 fps
ES 13
SD 6
3 shot group at 100 yds went .829", 2 went .159"

My nephews 700 XCR 338 RUM, Nikon Buckmaster 3x9

98.0 grs Retumbo
Avg velocity 2994 fps
ES 13
SD 6
3 shot group at 100 yds went 1.875", 2 went .940"

98.5 grs Retumbo
Avg velocity 2994 fps
ES 9
SD 4
3 shot group at 100 yds went 2.182", 2 went .991"

99.0 grs Retumbo
Avg velocity 3026 fps
ES 19
SD 9
3 shot group at 100 yds went 2.152", 2 went .500"

The 99.0 gr charge weight needs to be reshot and tweeked.
I also think there are some issues with the Nikon scope as it seems to shoot everything all over the paper.

JD338

 

[Alaska]

I finally got my RUM finished.........and ready to start my load workout.
I have some Retumbo , 250 AB some Rem Brass and CCI 250 primers.

 

[jmad_81]

JD, That looks like it is working very well for you. Impressive velocity as well. I ended up settling on 88.5 Gr of RL-26 in mine with a 250 VLD. Getting 3010 fps and .4" groups with it. Very pleased.

 

[SJB358]

That is a HORSE of a load.

 

[JD338]

That is a HORSE of a load.

Yup. It is my go to load. It just hammers everything I hit with that big 250 gr bullet.

JD338

 

[bboswell]

Tag. A buddy of mine has a custom 338 RUM that I will end up loading for when he finally gives up on factory crap ammo....

 

[JD338]

Tag. A buddy of mine has a custom 338 RUM that I will end up loading for when he finally gives up on factory crap ammo....

Let me know when you are ready, I have load data for all bullet weights from 200-300 grs.

JD338

 

[big rifle man]

Jim, I've been pretty much staying with 225 grain bullets in my .338RUM. I've been using IMR4350 and accuracy has been excellent. I have a couple of pounds of Retumbo and would be interested in trying that with the 225's if you have the info.

 

[bboswell]

Thanks. I know he wants to go heavy.