About Hodgdon’s Retumbo
From the manufacturer’s product page:
This magnum, extruded powder was designed expressly for the really large overbore cartridges such as the 7mm Remington Ultra Magnum, 300 Remington Ultra Magnum, 30-378 Weatherby Magnum, etc. Retumbo adds 40-100 fps more velocity to these cartridges when compared to other normal magnum powders.
In addition, it is an Extreme Powder, making it perfect for big game hunting under all types of conditions.
Available in 1 lb. and 8 lb. containers.
Chances are that if you don’t shoot an “overbore” cartridge such as a 300 Winchester magnum or something similar, you may have never used Retumbo. It’s specifically intended for that type of cartridge. My first learned about Retumbo when handloading for a 300 Remington Ultra Mag, an ideal cartridge for this powder. Seeing Hodgdon’s recommendation to use Retumbo in the 25-06, I tried it and found it to be excellent with 110 and 115 grain bullets. It produced good accuracy, high velocity and commendable standard deviation figures.
Burn Rate Analysis
Retumbo falls right in the sweet spot in term of burn rate for cartridges like 300 Win Mag and 300 PRC:
Based on this burn rate, let’s take a look at some popular loads and cartidges!
Retumbo Cartridges and Loads
Retumbo is a very versatile magnum powder with some great loads we found spanning from the 25-06 all the way up to the big and bad 300 Remington Ultra Magnum and beyond. Here are some of the loads we have either tried, or are planning to try:
We would love to hear from you if you have favorite Retumbo loads that you’d like to share!
Under the Microscope
Using our 400 powder WiFi Microscope, we took a close look at Retumbo and some of the other powders we’ve previously looked at under magnification. Here’s the results:
As you can see above, the granules are similar in length when compared to Varget, but are larger in diameter for sure!
We also measured the density for Retumbo, and compared it to other powders we’ve previously measured density for:
Retumbo falls right in the middle of the density range here, interesting!
Hodgdon Retumbo is an extreme powder, making it rather temperature insensitive. It’s well suited for use in overbore cartridges.
On the limitations side, Hodgdon’s Retumbo isn’t particularly useful for milder, more efficient cartridges like the 6.5 Creedmoor or the 308 Winchester. Keep in mind this is a limitation of similar powders to Retumbo.
Hodgdon Retumbo is one of the slowest burning powders, most useful in a number of “overbore” cartridges. This includes cartridges often chosen for long range hunting such as the various 6.5, 7mm, and 30 caliber magnums available. These calibers are often favored by hunters pursuing mule deer, elk, bighorn sheep and other game species in mountainous areas or on the open plains where a longer shot might be required. Most of my use of Retumbo has been in 25-06, pushing 110 and 115 grain bullets to good velocity. I’ve used those loads primarily for mule deer and antelope hunting.