Quote:
Originally Posted by Blacktail1
After talking to Garry he asked about speeds and mentioned I’m way over . Took chrono and gun out again yesterday at 69 grn of r22 it’s going 3640fps and getting extractor marks on brass. Looking at my results I’m getting nosler max load speeds at min published load .... I’m going to try this over again and start below minimum published data and see what happens.. head scratcher for sure. I was thinking the r22 was hot but even my 4831 loads were well above published speeds . What would cause this ??
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The only thing that causes high speed is high pressure. For your pressures to be so much over published loads means either you have a REALLY tight chamber, too tight a neck which doesn't allow good bullet release or a very short freebore. It could also be a combination of all of those things. A quite remote though possible other explanation that accounts for heavy Coppering and way over speed loads is if the Bore isn't actually .257. If the bore is tighter/smaller than spec it can cause this same issue. Personally I would not be shooting this gun any more until I had checked it 12 ways to Sunday or had a really good smith go over it in detail.