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<blockquote data-quote="Norske" data-source="post: 65114" data-attributes="member: 409">I've used my Pact chronograph for years as well.&nbsp; Generally I find that pursuing that last 100 fps velocity hinders accuracy in my over-the-counter production rifles.&nbsp; But a chronograph is the only consumer tool that can be used to even estimate pressures because pressure is proportional to velocity.&nbsp; Primer appearance isn't reliable, and by the time the case head shows an imprint of the ejector, you are dangerously near the pressure where metal fatigue will eventually cause the steel in the locking lugs to fail (70,000psi).Accuracy first, velocity second.&nbsp; I usually only chronograph my accurate loads.&nbsp; With my chronograph I've found no advantage to magnum primers (three brands) in my 338 WinMag.&nbsp; I also have found wide velocity and some accuracy variation between powder lots.&nbsp; Since my reloads use the best (for accuracy) overall length, I've learned some interesting things about the effect of seating bullets further out than &quot;normal&quot; on velocity as well.&nbsp; Seating bullets further out adds little % to the case capacity but subtracts a much larger % of the freebore.&nbsp; When my velocity reaches what's published, I quit adding powder.&nbsp; In the 338 mentioned earlier, my longer overall length got me the published velocity of a 225gr bullet with 3 grains less powder than published by the powder maker.Does everyone need to own a chronograph?&nbsp; No, but every group of friends should have one.</blockquote>

[QUOTE="Norske, post: 65114, member: 409"] I've used my Pact chronograph for years as well. Generally I find that pursuing that last 100 fps velocity hinders accuracy in my over-the-counter production rifles. But a chronograph is the only consumer tool that can be used to even estimate pressures because pressure is proportional to velocity. Primer appearance isn't reliable, and by the time the case head shows an imprint of the ejector, you are dangerously near the pressure where metal fatigue will eventually cause the steel in the locking lugs to fail (70,000psi). Accuracy first, velocity second. I usually only chronograph my accurate loads. With my chronograph I've found no advantage to magnum primers (three brands) in my 338 WinMag. I also have found wide velocity and some accuracy variation between powder lots. Since my reloads use the best (for accuracy) overall length, I've learned some interesting things about the effect of seating bullets further out than "normal" on velocity as well. Seating bullets further out adds little % to the case capacity but subtracts a much larger % of the freebore. When my velocity reaches what's published, I quit adding powder. In the 338 mentioned earlier, my longer overall length got me the published velocity of a 225gr bullet with 3 grains less powder than published by the powder maker. Does everyone need to own a chronograph? No, but every group of friends should have one. [/QUOTE]

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