Help with .300wm Load

[Greyfox]

I would look to the mechanical factors, bedding, mounts, and scope. If you have bore scope check your throat, and for an excessive carbon ring. Also inspect your barrel crown and muzzle break clearance if so equipped. Large groups and random flyers are tIp-offs that your issue may be beyond the finer reloading factors.

 

[Longtine88]

I expanded the neck out with the mandrel to get all deformities out and just expand the necks. Then I ran them through my bushing die so all neck tensions would be the same.

Your doing that backwards like they have said

 

[Kendoist4162]

How many rounds are down the tube in total so far? If it's still only double digits, barrel might not be broken in yet. My CA Mesa took just over 60 to just settle down a bit.

 

[Jeffrey Van Zandt]

I am trying to develop a load for a .300wm Christensen Arms Mesa Rifle and can't get it to shoot with a sub 2moa.

This is my current proponents:
205 Berger elite hunters
H4831
ADG brass never fired
Expander mandrel, the pressed for consistent neck tension
Seating depth .080 off the lands (tried right off the lands and same result)
Federal 215M primers

Powder charges:
71.8
72.0
72.2
72.4
72.6

All of them are garbage with random fliers. I've never had this big of an issue with a lid development. We have checked the scope mount and rings. I'm going to try a load I made for another rifle later to see if it does any better.

215 Berger and H-1000 start around 74grs but have you taken the rifle down looked at the bedding and all other things and torque the action back down if everything is good

 

[Dmagna]

I have had too many issues with Christensen to be worth my time again. I own 3 of them and I won't buy another. On my traverse I had the same issues. Ended up being my base coming loose. I used blue lock tight and jb weld to bed the base. Get 100 rounds through the gun and fire form your brass then try and develop a load. Most belted mags need fire formed brass.

 

[Dmagna]

215 Berger's and H1000 are a dream load, I would stay away from the 215s unless you can get ahold of 1000 of them. Same thing with H1000.

 

[LRHNTR]

Is your twist rate adequate? Too slow of a twist can cause inconsistent results.

 

[Dmagna]

Is your twist rate adequate? Too slow of a twist can cause inconsistent results.

It's a 1:10 should be fine

 

[Dmagna]

If you plan on sending the gun back to CA do not tell them you shot reloads. They will void your warranty and you are screwed. You would think a company would stand by their products no matter what.

 

[Rosebud]

How many rounds are down the tube in total so far? If it's still only double digits, barrel might not be broken in yet. My CA Mesa took just over 60 to just settle down a bit.

This!! Own a mesa took over75 rounds for it to shoot sub moa. Was about to box it up and back to CA. But now it's a shooter.

 

[Mike Matteson]

I expanded the neck out with the mandrel to get all deformities out and just expand the necks. Then I ran them through my bushing die so all neck tensions would be the same.

You kind of have that backwards. Size down and expand for neck tension. placing the deformities to the outside. I don't know what your barrel length is. I would also change to different primers. I would also use Fed 210M or just 210. Is your barrel free floating? Action bedded? Are you deburring your flash holes. Have you fireformed the cases? It was mention above that you can step up at 1/2gr at a time. The powder you are using H4831 is temp stable. There was a person the other day that place pictures here where he changes out his primers. Reduced the grouping by about 1-1/2" if I remember correctly. I wish I had down loaded the picture. I is and was a great example of how primers can effect the groups.

 

[skipglo]

Try some other bullets at different weights. I've had good luck with H-4831 and IMR 4350.

This for sure^^^. ALSO H4350 67.5 gr. 208 eldx.

 

[hawk-i]

The guarantee is Sub MOA out of the box, not after 100 rounds.
I think with CA rifles its hit and miss on what you get, quality control isn't what it should be for the premium price you pay.
Only my experience though, my Traverse is back at warranty repair for the 3rd time now.
Hopefully third time is the charm!

 

[Longtine88]

I agree with hawk. I've never found a rifle that rarely got much better. Rifles that shoot, will shoot accurately first several shots. If any of mine don't or didn't they were gone asap