Shot the 300 wm yesterday!!

[tontotom]

Took the long range piece yesterday with some reloads I've been working on. A couple of weeks ago it shot 1-1/8" 3 shot group at 100 yards. My 1st 2 shots were touching but the velocity was a little low, 165 grain bullets at 3200 fps. I was feeling like I might make 1/2" group when I chambered the 3rd round.

 

The shot felt good and my hopes went to sh!t when the scope settled back on target. 2-1/2" high from the other 2. Velocity pushed to 3285, what the heck? The only difference I could find was a federal brass snuck in the mix, the other 2 were remington.

 

I've mixed brass on .243 and .270 before without a bobble but this was crazy. The powder is IMR 4831, 74 grains. Primer is CCI magnum.

 

Maybe I'm offbase and just jerked? Any thoughts from others who have more expirence-

 

Thanks,

[elkman]

i have had weatherby brasss shoot 300fps better than remington brass. Brass definatly makes a difference

[COOSEFAN]

I'm by no means an expert but I know that my custom .300 will shoot best with once fired Winchester brass. I can shoot with new brass and it'll hit considerably different than the once fired brass that it was sighted in with and not as consistent. It's weird but it is what it is. JIM>

[pwrguy]

you have to have consistent brass for consistent groups. Once fired is usually the best bet, although a lot of guys full length size and swear by it. I would start with 100 pieces of quality brass and fire form them. Also, you might try some of the other powders out there, although I have used 4831 extensively in 7mm and .300 and had pretty good luck with it. Another thing that could be an issue is the scope and the mounting system for the scope. Maybe 308 nut can give you some idea's if you have any suspicions about that.

 

I don't know what your personal experiences are, there are so many pieces that need to fit together for a good system. There might be other bullets that would fly better with your particular twist etc. Velocity is over rated when it comes to accuracy. I had a custom 300WM for a while and it seemed to like 180-200 grain bullets.

 

Good luck!!

[308Nut]

As far as the 'flyer' it could have easily been the fact that it was 85 FPS faster than the other two. 85 FPS in and of itself wouldnt make for 2+" of difference at 100 yards but if the load isnt in the right harmonic node with your barrel then whatever made the bullet run 85 FPS faster manifested a vibration that your barrel did not like. Once you find your 'node' velocity discrepencies wont affect your groups. At least not out to 600 yards. Once you get past that, the simple fact is that you will start to see higher and lower impacts due to higher or lower velocities. It really shows up at 1K.

 

As far as what caused the 85 FPS difference, it could have easily been your brass. Different wall thicknesses will have an impact on your burn area and subsequently the pressure, in turn affects your velocity. Inconsistent neck tensions can also affect extreeme spreads as well as cheap primers, seating depth consistency, and many other factors. IMHO, the brass manufacturer AND lot# needs to be the same and the necks need to be anealed after a few firings to soften them a wee bit to get them consistent again. Firing and resizing will work harden the brass. The molecular structure of the brass (in the necks) needs to be changed back to normal to get them right.

 

Hope that helps!

 

M

 

[tontotom]

Thanks for all the input. I'm not sure what was happening but I'll give it another go this weekend.

 

One thought on brass, if the necks work harden would that mean one should stay away from nickle plated brass? I ordered 100 pieces of RP nickle plated before thinking about this variable.

[jeffro]

I will never shoot nickel brass in a precision rife again. I did it once, and the ES, and SD were all over the place. Same load diferent brass great results. The nickel on the insides of the necks is very rough. This causes unequal neck tension. The nickel brass also doesnt last as long due to the plating process, that causes the brass to be brittle. You can feel the nickel in the necks when you seat the bullets. The nickel is also hard on dies, as it is much harder than steel.