For what it’s worth my gunsmith wondered why it would be longer than Sami spec.
A little insight as to what may have happened. When I first learned how to chamber barrels by a very highly respected smith & BR shooter, I learned a few things. He had several wildcats of ether his own design or wildcats that were not mainstream. When he would chamber a barrel, there were no go gauges or no-go gauges. The procedure for chambering was to take a fired piece of brass from another rifle of the same cartridge, run it through some modified dies to get it back to "spec". Then that piece of brass was used to closely fit the chamber head space for a GO gauge. A piece of tape or two on the back and it became a NO-Go if you wanted. Keeping in mind you have a crush as well. This would produce a nice tight chamber without the use of go, no-go's, but it was specific to that brass and that chamber. You could then do one of two things to fit your brass to the chamber. Ether slightly jam the bullets keeping the case head against the bolt when firing, or if necking down, size the neck for a snug fit in the chamber. This gave you nice fire formed brass, but you would not really be able to swap that brass out with another rifle unless the same piece of brass was used to set the head space. Over the years he used a couple wildcats on regular occasion and they varied in chamber size. I've seen some vary by 0.050" or so over the years. Still didn't really matter. The guys that had them built were educated on how to form the brass, or the gunsmith did it for them. Not sure when they started using go, no-go's, but the guy I learned from started building rifles in the late 50's.
I have several rifles that were done this way and they usually work just fine with FL or Neck dies. You just need to get them correctly fire formed first. After that, with the proper dies, it's no different than any other sizing procedure.
I still use the intended brass as a guide. I just chambered up a 6br barrel with a new piece of Lapua brass. Nice snug fit and double checked with a G0, snug fit, No-go, was a No-go. Turned out very nice and it's a shooter!
Funny story, I later worked in another gun shop and one of these wildcat rifles from the guy I learned from came in for inspection. I knew exactly what it was, but before I found out about it, the owner of the shop took the rifle, used an incorrect head space gauge and told the customer that it had out of spec head space. Continued to "set" the head space with the wrong reamer, and wrecked a perfectly good wildcat barrel. The guy ended up with a double shoulder angle because he didn't check to see what cartridge it was. Simple chamber cast, or he could have asked me because I knew what reamer the original guy always used. Solution was a simple education of sizing of wildcat brass. No work needed to be done. Wish I had one of those pieces of brass after it got fired!
