Re: Help On Understanding Neck Dimensions?
Your numbers are running right with what you will find in most factory rifles these days. So for a factory rifle they are certainly within specs.
I would say that your .314" bushing marked wrong. As Varmint Hunter points out, using a .314" bushing will generally result in case neck diameters in the .3145" to .315" range. I would say your bushing is undersized for its markings.
That said, if you are loading in a factory chamber, which you are, this will not effect your accuracy at all compared to the other variables in the factory chamber such as the loose neck and loose throat I am sure.
Just to give youan idea about the difference with a custom chamber and a factory chamber, if you came to me and asked me to build youa rifle in 7mm WSM, the first thing I would ask what you would be doing with the rifle.
If you were big game hunting, I would sit down with either a dummy round or a sample of factory ammo and take dimensions off these rounds.
I would have the reamer neck cut to 0.003" over loaded round diameter which would leave 0.0015" of bullet release when fired. This is about as tight as I like for a big game rifleyet it still offers greatly increased case life and accuracy.
In this chamber your necks would expand 0.003" total in diameter compared to 0.008" in your rifle.
To be honest, a factory rifle that hsa a neck diameter of only 0.008" over loaded round diameter is a pretty good one.
The only thing wrong and its not really anything wrong, is that you have more neck tension then is really needed from your bushing necking your brass to .312".
This will have no effect on accuracy or consistancy if your case mouths are square and properly deburred. Also, using the 162 gr A-Max with its long boat tail helps ease the bullet into the case neck.
With a bullet of this design, a decent rule of thumd is that any load that will group 3/4 moa or under at 100 yards will look very good as you range increases.
I have seen several loads with this A-Max and most other heavy A-Max bullets that shoot in this range at 100 yards and will group inside 1/2 moa at 200 yards and 1/3 moa at 500 yards.
Try the load out at longer ranges and this will tell you everything you need to know about the load.
It is vastly easier to tell a good load from a great load at 300 yards and out.
Sounds like your on the right track. Your using good loading tools and and getting fine accuracy for a factory rig.
As long as your bullet run-outs are low, I would not worry about getting another bushing.
You may want to tweak the OAL of your ammo to see if this effects group size at all but to be honest, just step back to 300 yards at least and see how this load shoots as it, may suprise you!
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