Neck tension for .308Win (again ...)

[Racalman]

I hope you all had a good Christmas holiday.

Santa turned up on time with a concentricity gauge, expander die and PGS mandrels for me

The concentricity of my existing handloads, made using the despised expander ball, varied between 1 and 3 thou (measured on the bullet).

Removing the ball and using the expander mandrels gave a steady 2 thou on each round, so that's a step in the right direction.

I seated bullets with three mandrel sizes: .306, .307 and .308. I measured the COL then applied 1kg to the tip of each bullet using a spring tension gauge. The COL didn't alter at all on any of the rounds.

Bearing mind that these rounds will be magazine fed, I'm planning to play safe and go with the .307 thou mandrel.

Any thoughts from the experts?

[The Gun Pimp]

Don't over think it. If you are looking for accuracy, never feed from a mag. Why? Because you are slamming the most delicate bit of the bullet (the meplat) against the rifle's feed-ramp. This can damage the meplat and misalign the bullet. Not good.

OK - forum keyboard jockeys will come on here telling you they get stunning accuracy loading from a mag. Fine - I've seen it as well but why go to all that trouble messing with neck-tension etc then risk ruining it?

Very few comps requiring ultimate accuracy require you to load from a mag. Even for McQueen, there's plenty of time to single-load.

[Racalman]

I understand what you're saying, but this is for snap shooting where there isn't time to load single rounds (well I could get a buddy to do it for me but not on a regular basis).

[WelshShooter]

What you've done is created consistency and have found that mandrel size has no significant effect on concentricity. You've now created more uniform neck tension without over working the brass, and if that doesn't give you more accurate handloads, then it should at least give you longer case life by working the case necks less.

[Racalman]

What you've done is created consistency and have found that mandrel size has no significant effect on concentricity. You've now created more uniform neck tension without over working the brass, and if that doesn't give you more accurate handloads, then it should at least give you longer case life by working the case necks less.

Thank you. I will certainly be testing these rounds to see if my groups improve (I last measured 0.7MOA at 1,000 yards - magazine fed ).

I'm glad to be rid of the expander ball, especially as I can see the rod is not straight as I rotate the die.

[Alpha1]

If you are re loading to fit your magazine you are not going to get any benefit. Or very little.

[Racalman]

If you are re loading to fit your magazine you are not going to get any benefit. Or very little.

You may well be right but as I am shooting at 1,000 yards against guys with 6.5mm rigs I need to get the best out of my ammunition. I posted top score in the last two outings but I need to do better.

Anyway, the question was about neck tension ...

[Alpha1]

Yes I know it is about neck tension. I have not used an expander ball in a long time all my fullbore reloading is done with L.E.Wilson bushing dies. Micrometer seating dies L.E.Wilson seating dies Body Dies and competition shell holders. I reload for two to 6.5 rifles one of them will not feed factory ammo from the magazine. So I reload to chamber dimensions and single load. The other one will feed anything. I make my own mandrels/expanders and have made one or two L.E.Wilson type neck and seating dies for my own use. Good luck with the neck tension thing sounds like you are doing Ok any way.

[The Gun Pimp]

I understand what you're saying, but this is for snap shooting where there isn't time to load single rounds (well I could get a buddy to do it for me but not on a regular basis).

It's 'horses for courses' - snap shooting won't demand the same level of accuracy as say benchrest. Rapid target-acquisition and trigger-release will probably out-weigh the 'nth' degree of ammo accuracy. Having said that, loading accurate ammo requires more or less the same process as any other ammo reloading so you might as well do it.

[Racalman]

It's 'horses for courses' - snap shooting won't demand the same level of accuracy as say benchrest. Rapid target-acquisition and trigger-release will probably out-weigh the 'nth' degree of ammo accuracy.

Yes, and wind reading skills. As for accuracy though, the A ring on a Fig. 11 is only 3 inches across and putting four shots into that off a bipod in 20 seconds at 1,000 yards is no picnic ...