hounddawg said:I don't believe bolt lugs will give enough mechanical advantage to move a shoulder. I have no way to test that, just basing that on experience and common sense
0.003" over saami may be possible to chamber as the chamber is slightly longer. But 0.003" longer than the actual chamber, or -0.003" negative head clearance, is not. The OP is referencing brass fire formed in the chamber.The brass can't expand excessively unless the steel around it has first also expanded excessively. Steel is more elastic than brass, so it can spring back more, clamping down on the expanded brass. But the steel expansion is why this is generally considered a pressure sign. Another cause of difficult bolt lift is case head brass flowing into bolt face features (around the extractor if it is not flush with bolt face or isn't a close fit, or flow into the ejector tunnel) so that the bolt is having to scrape or smear the brass flowed into those features to open. This can feel sticky and examining the brass reveals it pretty clearly.
Usually, you can. This is why, looking at the SAAMI drawings for many rounds, the maximum head-to-shoulder datum on the case is longer than the minimum chamber headspace. In the case of the 243 Win, the cartridge maximum is +0.004" over chamber minimum and is still considered compatible by SAAMI. The idea is the chamber can absorb some extra brass by virtue of being a little wider than the cartridge, so the brass between the head and shoulder can be squeezed out fatter into that gap by the bolt lugs closing.
tangolima said:0.003" over saami may be possible to chamber as the chamber is slightly longer. But 0.003" longer than the actual chamber, or -0.003" negative head clearance, is not.
I hear you unclenick. I don't think it has anything to do with saami here. OP believed his brass was 0.003" too long in that particular chamber. I don't think he could close the action, at least not so without feeling anything unusual. One has to use a press to size down a brass by 0.003". With mechanical advantage of a press, it is easily over 1000 lb of force. No way by just casually pushing bolt forward. The only possibility is his brass is not too long.Again, look at the SAAMI drawings. They are intended to allow the manufacture of cross-compatible guns and ammunition. That means all ammunition within spec should operate in all chambers within spec. The maximum for rimless cartridge cases is most commonly 0.004" over the minimum for their chambers, so this is meant to be compatible. Remember that to gauge a chamber accurately you have to strip your bolt and use a delicate feel because you can close the bolt on an oversized gauge. That is stretching the whole chamber just with the leverage of the bolt handle and the pitch of the bolt lug engagement. Then remind yourself how much more malleable brass is than either gauge or chamber steel.