crimp questions

Bcwitt said:

I think if you research the subject, every single credible source says you always crimp for semi auto rifle. .001 is the normal interference fit for most rifle die sets. Military ammo is always crimped. Factory hunting ammo is always crimped. There is good reason for it. Crimping a non cannulured bullet causes no accuracy issues. Crimping will absolutely make more durable cartridges. If it was not necessary, why would the die have that feature? Have you ever seen a non crimped factory round?

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You can say that crimping has no effect on accuracy, but my real world tests have shown that my varmint load(even with a cannelure) that consistently under 0.75 moa(generally closer to 0.5-0.6 moa) does not do nearly as well when crimped, and struggles to stay sub-moa on a 100 yard target when crimped. With my plain jane fmj/soft point rounds, the difference has not been noticeable. As for the neck tension only being 0.001, none of my dies have been that sloppy. My Lyman dies came out at 0.003, and the three sets of Lee dies I have came out at 0.004, 0.003, and 0.003. in fact, I just remeasured a case. Neck outer diameter is 0.2455, and the neck thickness is 0.0125 inches. Double the neck thickness to account for the other side, and that gives us 0.025 inches. Subtract 0.025 from 0.2455, and we get 0.2205 inner diameter. The bullets are 0.224 inch(just measured three of them). Subtract .224 from 0.2205, and we get -0.0035 inches, or a neck tension of 0.0035 inches.

If your dies are only giving you 0.001 of neck tension, I would be contacting the manufacturer or verifying they are set up properly, as that is far below what most people consider acceptable.

That is part of the great thing about reloading, though. You can do what works best for you, and I can do what works best for me.