Rifle load preferences

[critter]

I need help from experienced riflemen.

I have a Winchester model 70 in 300 Win Mag. It has a 26" barrel and synthetic stock. I have recently put a new scope on it and was zeroing the new scope. The gun reminded me quite strongly that it has STRONG preferences for certain loads.

All my ammo was reloaded. Shooting IMR 4350 and 150 gr Nosler ballistic tips, the gun will shoot well under 1 moa. Change over to 180 gr RN's and it shoots 1.5-2" or so. Try 165 gr Nosler BT's and it will shoot 4-6" groups regularly!

I know it is normal for certain guns to prefer certain loads. Is this much variance something normal? Might altering the bedding or some other alterations cause it to shoot all bullet weights into smaller groups? Should I work with different OAL's, different powder charges?

OR should I just stick to what it likes?

 

[dakotasin]

i would re-do load development from scratch. 150 grain bullets don't let the 300 win mag shine.

start w/ a different brand of bullet than what you had that shot so bad, some rl-22 or h-4831, and get a good load screwed together.

in 165 grain bullets, i've had great luck w/ barnes xlc, hornady btsp, and sierra gk's. the gk's really are pressed to their performance limit, so be careful on close shots.

in 180's, you can probably start and stop your load development w/ sierra 180 btsp and rl-22.

 

[Selfdfenz]

Before you give up on what you have you might want to evaluate bullet runout. I ran into an issue that sounds like yours and by playing with the distance the bullet had to travel to engage the rifling I got the results I was looking for. YMMV
Disclaimer:
All advice on reloading should be tempered with a recommendation to do a complete review of the reloading literature and cartridge specifications etc to stay w/i safety limits as improper procedure can lead to damaged equipment, injury or death.

S-

 

[Kingcreek]

That 165gr Sierra GK can fail at full .300 Win Mag velocities. Its a great bullet for .308 and I got great groups on paper with a .300 mag but even Sierra cautions against it, or atleast they used to. I found that out myself after exploding one in a big whitetail buck.
I've had good luck with the 165s and 180s from Hornady, Speer, Nosler partitions.

 

[rockstar.esq]

When I'm thinking about this I have to think that the overall length of the bullet has more to do with it than the weight. I can't see the twist rate being set up on a 300 win mag for shorter than average bullets. Generally folks will relate twist rate to bullet weight because weight does correspond to length within the same bullet design. What you may need is a bullet with the ogive farther back from the tip. When speaking of ogives, I have to concur with Selfdfenz in that the seating depth is critical for precision. I reduced my group size by 10% just by seating my bulllets .005" from the lands.