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Old February 14, 2009, 12:20 PM   #1
Quadra
Junior Member
 
Join Date: December 28, 2008
Posts: 7
go no-go gauges in 6.5x55

I've been having trouble chambering once fired Lapua brass that have been both neck sized and fl resized in a new to me Krico 600 match rifle. I thought that it might be a tight chamber so I purchased clymer gauges for this caliber. The go gauge passed as did the no-go gauge. The no-go gauge is .004" bigger than SAAMI minimum chamber dimension for this caliber. The SAAMI website acknowledges that there is a difference between their min/max chamber dimensions and those of the European standard as dictated by CIP. From what I understand about the manufacturing process armsmakers must chamber their products to fall somewhere in between the mandated dimension to conform, not to a specified exact dimension. If my rifle as delivered from the factory had a chamber dimension that was not of minimum length and yet still conformed to the tolerance specification set out by CIP the only thing that the no-go gauge is telling me is that the bolt is closing on a gauge of that particular dimension. If it were a field gauge (I'm purchasing one)then obviously I know what I would need to do. The 6.5x55 cartidge case is manufactured by Lapua and Norma to the correct maximum dimension of .480 while North American brass is held to a maximum dimension of a nominal .473. The dimension of the gauge at the base is approx .473 and yields a sloppy fit in the bolt face as compared to the fit of my lapua brass measuring .478. I realize that these gauges are not measuring that dimension but shouldn't they more closely resemble all of the chambers profile and not just the point from the face of a closed bolt to the datum line on the chambers shoulder? When I close the bolt on a fl resized case it sometimes but not always refuses to go. I repeatedly cycled the action on a snug fitting case and saw a circular pattern lightly inscribed and there a small traces of brass shavings sitting in front of the breechface where the lugs engage. My dies are set a quarter of a turn beyond touching the shellholder and these cases fit two other rifles that I own with no problems. Does anyone familiar with this problem or caliber have any sage advice?
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