Retumbo and 338 Norma Mag

Bluejazz

Sergeant
Full Member
Minuteman
Jun 8, 2009
862
3
62
IOWA
After running some quikload #'s it seems that some of the powders and loads mentioned on here for the 338 Norma Mag are over pressure.
RL22 @ 83gr= 66,380psi @ 2700fps
Ramshot Magnum 90gr=67,288psi @ 2741fps
My question is anyone using Retumbo in there 338 Norma.
It seems to deliver same speed as Ramshot Magnum, but with less pressure.
Retumbo 92gr=63,959 @ 2732fps
 

jasonk

Very Snipery
Full Member
Minuteman
Feb 23, 2007
5,767
7
Vancouver, Washington
Re: Retumbo and 338 Norma Mag

I was loading some for the 338 Norma Mag today, hope to have the rifle back from Ionbonding this week.

Interesting info since I think that based on what others were saying I've got some test loads that I've got up to 93 grains of Ramshot and 85 grains of RL22. I know that the smith tested the rifle with 84 grains of R22 and saw no pressure signs.

I know that QL isn't perfect though, according to it my 300 Weatherby is way overloaded, but I'm at or under the Barnes manual for 180 gr. bullets, so you have to take what it tells you with a grain of salt.

What bullets are you using for the calcs, 300 SMK?

What does QL tell you for R25? It seems to have speeds between R22 and Retumbo if I remember right.

Jason
 

Bluejazz

Sergeant
Full Member
Minuteman
Jun 8, 2009
862
3
62
IOWA
Re: Retumbo and 338 Norma Mag

jasonk,
It looks like quikload puts
RL 25 with 85gr @ 63594psi= 2675 fps.
Used 300gr SMK
 

jasonk

Very Snipery
Full Member
Minuteman
Feb 23, 2007
5,767
7
Vancouver, Washington
Re: Retumbo and 338 Norma Mag

Thanks...so it appears that one could equal the R22 velocities with R25 at basically the same pressure. I've got lots of R25 so I'll give it a run and see what happens.

OAL you used Blue? Does QL let you input jump to lands or other variations like that?
 

Bluejazz

Sergeant
Full Member
Minuteman
Jun 8, 2009
862
3
62
IOWA
Re: Retumbo and 338 Norma Mag

COAL used was 3.500
Previous pressures given based on loading off the lands. If you were to seat the bullet on the lands Quikload shows pressures to be very dangerous. Still looking for feedback on Retumbo.
 

Bluejazz

Sergeant
Full Member
Minuteman
Jun 8, 2009
862
3
62
IOWA
Re: Retumbo and 338 Norma Mag

After running some more #'s on quikload, it looks like Vithovouri N570 might be an even better powder for the 338 Norma. 93gr N570 @ 63,398psi = 2776fps
Any feedback from those reloading this caliber is appreciated.
 

RWSGunsmithing

Gunny Sergeant
Commercial Supporter
Full Member
Minuteman
  • Mar 26, 2006
    4,892
    217
    Manning, Iowa
    www.rwsgunsmithing.com
    Re: Retumbo and 338 Norma Mag

    Unfortunatly the n570 will not be avalible till the end of the first quarter of 2010.

    I test fire my 338 normas with retumbo powder about 93-94 grains. Unfortunatly I have not had a chance to really sit down and shoot it for accuracy or chrony it, but plan on using retumbo for now until the n570 becomes avalible.