Hi, this is an update on my 7mm Mashburn Mag load testing. Around May
last year, I had my custom 700 re barreled. I went with a Douglas 25"
in the mag contour to fit my stock. And using my PTG reamer my gunsmith
re did the rifle for me. It was throated to 175 Nosler at 3.600 and 0.020
jump to lands. So up till Oct. last year I finally found several good
loads and near max or max in the loads. On 1/21/15 I finally went out
to the range to test my loads.
Bullets used in the test:
150 Nosler Solid Base (old, not made any more)
160 gr Nosler AB
160 Nosler Part.
160 Rem Bonded CL
175 Sierra BT
175 Nosler Part
175 Nosler Part Semi Pointed
25 inch Douglas barrel long throat
All brass neck reamed WW 300 Win mag once fired
All primers Fed 215
Total of 32 rounds fired, 4 round strings
175 Nosler 74 H1000 3.575 OAL 3043+, 3008-,3029 m
160 AB 75 H1000 3.580 OAL 3153+, 3116-, 3139 m
160 AB 77 H1000 3.580 OAL 3217+, 3192-, 3198 m
160 Part 78 H1000 3.550 OAL 3237+, 3230-, 3253 m
160 Rem BCL 75 RL-25 3.525 OAL 3148+, 3124-, 3132 m
175 Sierra 71 RL-25 3.565 OAL 2946+, 2929-, 2938 m
150 Nosler SB 72 IMR7828SSC 3.558 OAL 3177+, 3155-, 3167 m
175 Nosler Semi Pt. 72 Retumbo 3.510 OAL 2920+, 2904-, 2910 m
Notes: When I went to load these rounds last Nov. I had to use a
new lot of H1000 powder. The new lot is a little hotter and the
77 and 78 gr loads were a little hotter than what I got in my
load work up last year. So I will work again with the 160 Part
from 75 gr of H1000 up.
The most accurate loads fired last year were:
162 Hornady SPBT 75 H1000 3.510 OAL # 215 3/8" 3 shot pulled #4
175 Sierra BT 71 RL-25 3.525 OAL # 215 5/16" 3 shot pulled #4
160 Part 78 H1000 3.565 OAL # 215 2 shots landed in 3/8" pulled 2
it may work. In velocity test it has 3 fps spread
The 175 Sierra load had a 8 fps spread
I am leaning to the 175 Nosler as a favorite.
I really like my Mashburn rifles and the 700 is a great rifle.
