My 308 Norma Magnum is smoking!!

Eagleye

Eagleye

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I have a 308 Norma Magnum built on a commercial mauser action with a Benchmark 1-9" twist barrel [25.5" long]
Have been busy developing an Elk load for the fall.

I found a good shooting load, [ .6-.7 moa] but when I chronographed it, the velocities were below what I would
expect from this combination. [200 Partition, 73 grains of Alliant Reloder 25 - 2750 fps]

Decided to move up and see if I could find a good node with more speed. At 74 grains, I had 2860, but dismal
accuracy. [1.5 - 1.6 moa]

At 75 grains, the accuracy came back just as good as the 73 grain load, but with much better velocity [2980 fps]
Pays to play a bit. No pressure signs, no case head expansion, but a great load.

My 257 Weatherby, using the 100 grain TTSX, makes ½ moa groups at 3575 fps, using 69 grains of Reloder 23
So it is ready for whatever game I decide to hunt with it. Should be a nice flat shooting load. Dave.
 
I am learning lots the more i reload. I am suprised at 1 grain increments equalling approx 100 fps. Congrats at finding the sweet spot Eagleye.
 
I had some great loads for my 300wm loaded up. Could remember entire velocity sets and powder weights. Fast forward 2 years i cant even remember what powder i used. This time im going to wright it all down. I do have a pic of my chrono reading 3688fps about 20' infront ofthe muzzle with 110gr gmx. Ill play again when i source more bullets. Thats the fun of loading
 
It seems like only yesterday when people who had finally got their mitts on a chronograph discovered that they weren’t getting speed and would solemnly announce that nobody ever “made the book” and others would nod sagely like a bunch of bobble-heads going down on a billy-goat and chanting that nobody ever got within 200 of what the manual said.

Fortunately some of those people reached a stage where they’d finally spent more money on gunpowder than gun magazines, and learned that a couple extra inches of a quality barrel would leave their welfare barrels and their grampas load in the dust. ;)
 
A chronograph is a very valuable tool when developing loads for one's rifle.
Very seldom is a load from any manual going to be close to stated velocity.

I remember, about 4 decades ago, I used a load listed in a manual for my
7x57, using [now obsolete] H205 powder with the Hornady 154 spire point. The
manual stated that a certain amount of powder should make 2700 and pennies.

I used that load a bit, and shot a couple of moose with it, but when I recovered
a bullet from a moose shot at 60 feet, I just knew that it was not as fast as they
said. Bullet expansion was much less than it should have been.

Well, when I finally acquired a chronograph, I discovered that this load was barely
making 2300 fps. Switching to IMR 4831 solved that problem.

I have seen a lot of those cases over the years, plus some barrels are "faster"
than others due to chamber and groove dimensions plus other obscure factors.

In any case, I will not use any load that marks the head of the brass case, or
that displays any additional expansion of the solid head of the case.

Some of the new powders have helped to extract decent velocities as well.
Handloading is a hobby in which one NEVER stops learning. :) Dave.
 
My 7mm Mag was a fire breathing dragon, until I got a chronograph. Nosler's max load from their manual with RL22/160gr Partition did 2700 fps from my 26" Shilen barrel

I'm guessing long throat was the culprit
 
todbartell said:
My 7mm Mag was a fire breathing dragon, until I got a chronograph. Nosler's max load from their manual with RL22/160gr Partition did 2700 fps from my 26" Shilen barrel

I'm guessing long throat was the culprit
Click to expand...

A little disappointing when 3050 is usually attainable with the 160 and the 26" tube. I get 3030ish in my 7 Mag with 67 grains of MRP. Dave
 
My 300wm savage cant best 2950 fps with 180s without pressure signs. Barely 2900fps with factory loads. Hence why im trying to turn it into a fatter 257 wby by launching 110gr gmx bullets at throat melting velocities until i need a new barrel. The only gun i own that seems fast is my 458wm. Starting loads net me max velocities but it is a 26.5" barrel. Its also one of my most accurate guns
 
Eagleye said:
A little disappointing when 3050 is usually attainable with the 160 and the 26" tube. I get 3030ish in my 7 Mag with 67 grains of MRP. Dave
Click to expand...

I ended up getting it up in the 2900's with a bunch of RL25. That was almost a couple decades ago now , bartell is getting old! haha

Like all cartridges, the 7mm Mag can perform with the right fuel. 68.8grs RL26 does 3040 fps from a friend's 24.4" Tikka with the 160gr Accubond, very accurate too
 
I just got some RL26 from TB, I ordered it with my 270win in mind. I'll have to try some in my 308norma to see what it will do. Sounds like you got a super load for the up coming season Eagleye.
 
Pete, RL26 works great in the 308NM. I have used it with bullets from 180 to 212gr with great accuracy and speeds
 
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