Been reloading for my .308 for a while now. Use 44.5 gr of IMR4064 with a Rem 9-1/2 primer. Rifle has a 22" barrel. Nosler book says this is a compressed load and should yield 2700fsp out of a 24" test barrel. Finally got around to running this through a chrono today and had a 10 round average of 2775.7fps. What is most likely the reason to get higher than projected fps with a shorter barrel. If anything I would have expected to lose velocity. Would the temp and altitude have a major effect? Just trying to wrap my head around it as I was shocked to get these results as I was expecting 50-80fps less than 2700 not over.
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I feel I was denied, critical, need to know Information!
Variations in exact bore diameter , rifling style , chamber dimensions , brass dimensions , primer variation , powder variation , temperature control etc can make variations in velocity.
Does any one ever check their chronograph against a couple different ones?? Shoot through 2 at the same time??
When I first got my Magnetospeed, I shot with the Magnetospeed mounted, and using my Chrony to compare. The Magnetospeed always read a few fps higher, which makes sense, being that it measures velocity at the muzzle, not 15-20 feet away, like the Chrony.
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Only accurate guns are interesting.
velocity question when reloading
Linear Mode
