8mm Rem Mag Range Report - 220gr Sierra SBT, RL-25 and RL-22, Rem brass, Rem 9 1/2M primers, OAL 3.600", Velocity 3009fps
My initial thread on the 8mm Rem Mag was one of presentation and theory.
It was an awesome and interesting morning to say the least and the 8mm Rem Mag is a beast at both ends. Anyone who says he likes to shoot an 8mm Rem Mag at the bench for more than 21-25 rounds has something truly wrong with them. Now that said, I am use to a 340Wby without a break shooting 225gr bullets which generates 43.0ft pounds of free recoil. The velocity of recoil though is just a tad slower than the 8mm Rem Mag even though marginal I felt the difference. Here are the stats on the free recoil and velocity of recoil for the 8mm Rem Mag with a 220gr Sierra SBT moving 3009fps on the average.
Cartridge: 8mm Rem Mag
Firearm: Remington 700
Load and Firearm Info:
Bullet Dia (in): 0.323
Case Length (in): 2.850
Case Volume (gr H2O):
93.5 Muzzle velocity (ft/sec): 3009
Bullet Wt (gr): 220
Charge Weight (gr): 86
Barrel Length (in): 24
Firearm Weight (lb): 8.50
Free recoil energy is 42.1 ft-lb. (57.1 Joule)
Free recoil velocity is estimated to be 18 ft/sec. (5.4 m/sec)
(This is equivalent to dropping the 8.50 lb gun from a height of 5 feet.)
The free recoil volocity is gained in only 0.14 in (3.6 mm) of travel
Recoil impulse is 4.7 lbf-sec (21 Newton-sec)
Powder gases generate about 38 percent of the total recoil impulse & velocity
Now the recoil thing out of the way -
I found RL-25 to give me higher velocities for max load in my rifle over RL-22. Also, it gave me better accuracy, better extreme spread and better deviation.
Now this is not a bench gun, it is a purer hunting rifle. My last group was actually the fastest velocity wise and also the best accuracy. Temps were low 80's with 91% humidity and my elevation was 105ft above sea level.
Here is the average velocity and group size of the max load of RL-22 in my 8mm Rem mag. and group size was 1.2"
Here is the average velocity and group size of the max load of RL-25 in my 8mm Rem mag. and group size was .866", Extreme spread 20 Deviation 10
Note: (this was my last group shot for the day, and recoil was taking its toll and I was still getting use to my trigger, so this is in my opinion a good load for hunting)
top velocity of the day
All and all I am very excited about the 8mm Rem Mag in a fine rifle to use on big game. It is evident that anything hit with this 8mm Rem Mag will die quickly if not immediately depending on shot placement, but this beast will end the life of any beast hit with it and more than likely be DRT. Very impressive cartridge. Yes I can't wait to hunt with it.
Changed my mounts and rings. The Quad Rings were not keeping my scope from turning with the significant recoil of the Big 8 and I was afraid if I tighten them more than I had them I might strip a tread in the aluminum rings. So I went to a real traditional look with steel Leupold mounts and rings.
Well, today is revealing indeed all accept me changing my OAL and opening up my group to over twice the size it was Friday. You know, sometimes I need to leave somethings a lone. Now that said, here are my velocities from two different groups this morning and they are not over max (you can see by looking at my brass). I am going to adjust my OAL back to were it was 3.600" and continue to work up one tenth of a grain at a time till I get near or at max for my rifle.