Anyone load 7MM-08 139LRX with RL-16

[USAF Ret]

Getting ready for a possible disabled vet elk hunt this year or next year in ID. Thanks to Bryan at the Idaho Wildlife Federation for sponsoring me.

I am possibly taking two rifles, both in 7mm. 280AI and 7MM-08. Specifically for the 7mm-08, I have a 1:9 twist Carbon Six barrel and plan on loading the 139 Barnes LRX. Big Game gives the most bang for the buck, but also is not as temperature sensitive as other powders (.98 FPS per degree). Still, not too bad. I love the speed, accuracy, and low SD from Alliant powders. From Barnes, they list RL-15 and RL-17 which are not great. However RL-16 is fairly temp sensitive (.34 FPS per degree), but there is little data on RL-16 for 140 grain mono bullets.

Now, RL-16 falls between RL-15 and Big Game for burn rate. So, I am not sure why it is not an option.

Has anyone loaded the 139 LRX or any mono bullets in the 140 weight.

Thanks.

 

[TX Trophy Hunter]

Here’s Alliant’s data for a 139 SST, albeit not a monolithic. If you search the internet it looks like several people have used H4350 data as a starting point for RL16. If you are comfortable in reading pressure signs it might be enough to work with to get started.

 

[Sheltowee]

I would try the 141gr. Hammer HBC or the 145gr. HHT. I've found the HHTs to be more accurate and faster than the Barnes but, to be fair, Hammer doesn't list RL 16 for those in the 7-08 either. Couple of RL 16 loads listed under the 180AI, though.

 

[Alpine01]

RL-16 is slower than Ramshot Big Game from what I can see; and RL16 and RL17 are nearly the same in terms of speed. Looking at the Barnes reloading data for the 139-gr LRX, you'll generally get faster velocities with the slower powders on their list but that is also with a 24-inch barrel. A much shorter barrel would probably prefer a somewhat faster powder burn rate if you are trying to max your velocities. As always, take what info I am giving with a grain of salt and start on the low end of charge weights for whatever powder you end up using.

While I don't load for the 7mm-08, I do load for my 7mm RM (24-in barrel). I use 150-gr Hornady CX's (mono bullet) and routinely shoot 0.5 MOA or better groups with it. Muzzle velocities are chrono'd at 3210 fps (using new Garmin chrono) with a Std Dev of 6.6 fps and an extreme spread of 18 fps over 70 rounds so far. I use H4831SC which is a bit faster than RL-22 and I haven't noticed any real temperature sensitivities with it. Hodgedon claims sub 0.1 fps/deg for its 4831SC powder. Finally, the CX-150 is nearly identical to the Barnes 150-gr TTSX BT in terms of BC and sectional density as a comparison so I would expect a 139-gr CX to be very similar to the LRX. The last critter I took with the 150 CX was a BC moose at 375 yds. Both shots were complete pass-throughs and my moose didn't move more than two steps before tipping over.