Re: 300 grain Berger velocity results!
+1...not only that, i was present at load development with TYLER...we were very careful, and between the 2 of us we have forgotten more about interior and exterior ballistics than most men. that load is safe....AND FAST!!!
Ok again I think people are fealing a bit attacked. No need to prove how much you know about ballistics. "most men" on here know far most than "most men" on other sights so you may not want to go throwing that around. I am not talking ballistics anyways. I am talking metalurgy. That mark is not where the shoulder was. Period. I have done a few ackleys and none of them have that mark. When brass is formed at say 50,000 cup it takes the form of the chamber. That is why you can even see marks left in the chamber from scotch bright if you dont do it correctly. That mark means one of two things. The first is a burr ring. VERY common on ackleys if you are not carefull in chambering, because of the sharp shoulder and very low taper of the case. The second can be case head separation. Either too generous on the head spacing or bolt setback from overpreasure loads.
Now on to the preasure issue. I am sure if you are guaranteeing that is "safe" you hooked up a strand guage to it and you can tell us what preasure you were running. I can tell you that ackleys are much harder to get the brass to "flow" into the ejector. The ackley is built around the idea of little to no brass flow or bolt thrust. If you are getting brass to flow on lapua 338 in paticular you are around 68,000-72,000. Now I am not sure on the improved because my experience with the preasure guages was before I improved one. But with the other ackleys it will jump you flow preasure up quite a bit. Around 70-75,000. I am not trying to get into a knowledge based pissing match. Just informing you that what you have is some extremely high preasures. What is safe to you at your current temperature may blow the next guy up. Or at least ruin his barrel.(most common in extreme over preasure cases) Just not a good idea to go telling others its "safe". They shoot your load at an outside temp 20+ degrees higher or even with a different primer and things could go very wrong. With retumbo it is so temperature sensitive I will have loads broken down to 10 degree spreads if I am running full tilt loads. I have spent alot of time in a ballistics room with the propper equiptment and even more time building the machines that make bullets for some of you. I have even spent time trying to purposefully blow up an action to test it before it was made available to the public. I am not saying I havent run my 338 lapua imp up to 3050. I am saying I would never tell anyone its safe. It also didnt take that much powder.
This is what a formed case should look like
Oh yeah when we were testing said action..... The cases got a mark similar to yours quite a while before the barrel blew off of it. For the record we were using a hammer to open the bolt around 20grns of blue dot and if I remember corectly the barrel didnt blow off until around 23.5? Did I mention we were testing a 300WSM?