8mm Rem Mag & Range Report
 

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

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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)

FACTOIDS:
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"
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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)
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top velocity of the day
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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.

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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.

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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.

Nice rifle in a very good caliber. Very well done range report. I've always felt the 8 MM Remington Magnum was a very underrated cartridge. I think a lack of bullet choices hurt it also.

Great report bullet.

Well done!

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.

Here are pictures of my chronograph readings, brass fired for highest velocity average and my group that needs the OAL adjusted back to where it was. This is very significant, considering I have a 24" barrel, and a greater cross section of my 200gr bullet than a 200gr bullet out of a 300Rum.

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Getting there with the Accubond bullets. Different lot of RL-25 and things looking up. Had Extreme spread of 30, Deviation of 11 and average velocity of 3133fps. Will be taking a break for a while before doing anymore work with my 8mm Rem Mag, but very pleased with where it is going.

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first three shots then I was not paying attention shot the other two in a different target right above this one.
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Bullet,

Very nice Remington! I have never shot an 8MM Mag. Great group on the first pic. As you stated anything under 1 MOA is good for a hunting rifle and as you stated. Somethings are best left alone when you are getting that type of group. The Old Saying comes to mind! If it ain't broke don't fix it! Great job!:)
03

thanks guys and 03 you are so right, if it ain't broke don't fix it.

Yes, I am ready for part two of my load work using four different groups, two different powders and two different bullets for a total of 20 rounds to be fired at the range Monday morning.


First: a five shot group using Sierra 220gr with Magnum and a five shot group using Nosler 20gr Accubond with IMR7828

Second: a five shot group using Sierra 220gr with IMR7828 and a five shot group using Nosler 200gr Accubond with Magnum

Great post. I would love to have an 8mm Rem. someday. If I get one, your data will be very useful.
cottontop

Thanks, it should get more interesting as I continue my load work. We will see.

Today was an interesting morning but you talk about hot and humid. Once again to remind everyone, this is an out of the box rifle with no glass bedding or pillar bedding and this rifle uses a pressure point up close to the end of the for end. No, I do not have any intention of changing it at the moment. But today was a very good day of discovery. First, 200gr Accubonds give me great velocities but the accuracy is very poor. I have tried now different loads with RL-25, RL-22, MRP, Magnum and IMR7828 and the groups are embarrassing to say the least. My rifle simply does not like them. I have 100 200gr Accubonds left and will trade them for some 200gr Partitions if someone is willing to do so, and if you are willing please pm me about trading.

Magnum powder preformed well, my barrel did not get as hot to the touch as with the other powders and accuracy was fair to good but average velocities were 2951fps with the 220gr and that was disappointing. Now IMR7828 did very well in velocity with the 220gr SBT and accuracy was good and this was with one grain under book max. I am very please with this powder and the Sierra SBT. I will be soon testing 250gr bullets and also some 200gr (forgive me for even using these words and don't remind me of my dislike for terminal results I get with the :mrgreen: - Barnes TSX).


220gr SBT, 83.0grs IMR7828, Rem brass, Rem 9 1/2M primers, 3016fps, OAL 3.600" .964 minus first round which was first round out of a clean barrel. After ten shoots this group should tighten up a little more once the barrel is fouled good.

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