I just completed a .460 Rowland conversion on a High Standard 1911. I test fired the gun first with a mag of .45 ACP to check for proper lower lug contact on the VIS. I got a good looking bowtie contact area so that was good.
The I fired 5 full power .460 R loads and gun functioned fine and all seemed good. Later looking over the .460 cases I noticed a problem. As you can see in the pic below ( far left is one of the .45ACP and then 3 .460R)
The .45 shows a rather deep FP indent ( all the .45's were like this) the next is an obvious pierced primer and the other two the indent is filled with what appears to be brass from the case.
The .460 case, when plunked, sits .003" lower than the back edge of the hood. The hood to breech face clearance is also about .003", so .006" headspace play.
when pushed through from the striker of the slide the FP protrudes .325", this is the same on my RIA 1911 for comparison.
Upper recoil lugs engage .055" so that is more than good.
I fitted the slide stop by hand until the thumb safety would engage nice but snug.
I'm guessing that all the .460's I fired had their primers pierced and that the indent were filled with vaporized brass from the escaping gasses.
The primers really don't shows signs of over pressure.
So what's happening here and how do I fix it. Both the .45 and .460 were commercial loads.