7 Mag / RL 25

TackDriver284

Handloader
Feb 13, 2016
1,859
586
Does anyone use RL-25 with 150 Ballistic Tips in the 7 Mag? I got some 150 Ballistic Tips from a fellow member on the forum. This morning I worked up with IMR 4831 to Nosler max loads and a little over but velocity is not up to par. Nosler book says 3240 fps with IMR 4831 with 65 grains. I was pushing 3080 fps with 65.5 grains. Groups was a decent .8 MOA@100. I used Quickload and tweaked the powder burn to my velocity and it shows 69.5 grains IMR 4831 max at 61k psi @ 3257 fps. I may try a ladder ( 65.8 - 69 ) and use 1 shot for each 1 inch target on a plane and see POI for each gradual charge until I see pressure, hopefully at 3200 fps. its my goal. My OAL is 3.400" and manual shows 3.290" , its off the lands @ .010"
I like to try RL-25 but there are no loads for 150 grains except 160 grains which shows 70 grains as max in the Nosler manual. Should I go for 70 grains RL 25 as a starting point?
Does anyone have decent loads using RL-25? I won't use your loads, just using them as an idea.
 

jimbires

Handloader
Aug 16, 2011
2,501
474
Mark , when I mess with burn rate , I can get it to show the correct FPS , but my pressure gets way out of whack . I do adjust the weighting factor . this seems to keep the estimated pressure at a believable number . the weighting factor number I use for a 7 rem mag is , 0.390 . maybe this weighting factor number will align your velocity , pressure , to the powder charge without changing burn rate .

I don't know your specifics , I used a 26"bbl , default water capacity , 3.400" COAL . I did adjust the weighting factor to 0.390 . it looks like 73.7 grain of RL25 , 106% case fill , is going to be a max charge at 60974psi , and 3303FPS . looking at this I'd say 70 grains would be a safe starting point . it tells me 3200 FPS should be easily obtained without using over max charges with RL25 .
 

TackDriver284

Handloader
Feb 13, 2016
1,859
586
The Norma brass I used had about 10 firings on them, pockets were getting a little loose, so I tossed them and used new Nosler brass, would not know the exact water capacity yet until I get two firings on them to make sure they expanded well enough to get an accurate measurement of H20. Of course you will squeeze a little more velocity after the first firing, I'll run a ladder soon. Thanks Jim.
 
Top