What die for best accuracy?

[shawn68]

I read that a lot of benchrest guys full length size because when you only neck size, the cases volume changes after every fire forming. This is the first time I have heard this. Do you full length size in bench rest because bench rest chambers are so much tighter than factory chambers? I can see how fire forming in your factory rifle would increase its potential.
Could some of you benchrest guys shed a little light on this subject?

 

[Chawlston]

[ QUOTE ]
I read that a lot of benchrest guys full length size because when you only neck size, the cases volume changes after every fire forming. This is the first time I have heard this. Do you full length size in bench rest because bench rest chambers are so much tighter than factory chambers? I can see how fire forming in your factory rifle would increase its potential.
Could some of you benchrest guys shed a little light on this subject?

[/ QUOTE ]

Hello,

What you say is true, but the reason we full length size and bump the shoulder is so that we can shoot and reload very fast. Specifically, you need to be able to "dump" a round on target when your shooting conditions satisfy you. Typically one shot every four to five seconds. So, if you get sticky cases, the gun will get upset on the bags and actually prevent you from being competitive. Hope this helps.

One more point...... I shoot free recoil and when the rifle slaps my shoulder, I pull out the case and reload. Next you return to battery and make any sighting corrections that you desire. This whole process is usually shot to shot about 4-5 seconds. When you are in a match, that is really a lot of time to get your business done. I have shot on benches adjacent to Tony Boyer and have seen him wait until the last 10-15 seconds prior to beginning his record string of five shots. He is the fastest benchrest shooter I have ever seen.

James

 

[CatShooter]

When you ask "What die for best accuracy?", are you using a benchrest rifle/chamber, or a factory rifle with a field chamber?

There is a world of difference.

When a bench shooter FL sizes his case, it is just a tweak, because the die and chamber are just about the same size, so there is little change in the case - the shoulder is set back 1 or 2 thou just enough to make sure that there is no resistance in closing the bolt.

But when a case that is fired in a factory (or custom rifle with a field chamber) is sized, the case is reduced in size quite a lot.

The shoulder can be set back as much as 14 thou (or more), and the body can be reduced 6 to 8 thou. That's a LOT of rattle!!

In "non-benchrest" chambers, neck sizing is better for case life, and more accurate.

This is an "Apples and Oranges" thing.

If you are not shooting a bench gun, don't assume that bench techniques are best for you.

.

 

[davewilson]

68, i would say you have a 99% chance of better accuracy using a full length resizing die.

 

[shawn68]

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68, i would say you have a 99% chance of better accuracy using a full length resizing die.

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Is that because of the case volume? It does not change after fire forming? Isnt the ideah to make every round the same every time?