Hi all, has anyone tried forming 7.7 x 58 mm cases from military 30-06 brass. I have checked several sources, and some suggest that the Jap case is sufficiently larger in the head such that a 30-06 case and when fired will bulge excessively. I have gone to the effort of hand trimming some 230 thou off the 30-06 case and FL sized it thru RCBS dies and it looks OK and dimensionslly seems similar to some Norma 7.7 cases I have. I do not have my rifle yet (still dealing with the border stuff) and have not fired any yet. Interesting enough, I have had some experience with incidents of this nature with the 6.5 x 55 with Winchester brass. Winchester (in at least the cases I have) chose to use a standard case head instead of the larger .479 case head and they do infact bulge quite distinctly. I have however fired these cases up to 7 times with no appreciable increase in bulge or any other issues you might expect. I have since switched to Lapua brass but really, asside from the appearance of the Winchester brass, I have not experienced any problems with it. Incidentally, my 6.5 is a Sako 75 and I have been loading the 6.5 for the more modern action. I ask this because it is a lot of work to trim the 30-06 brass but the Norma stuff is $120 USD for 100 ct. If it works great and do not mind the work but if not I guess I will have to cowboy up and pay the bucks.
Forming 7.7 x 58 mm Cases
- Thread starter rwn390
- Start date
Thanks zuke, turns out Ellwood has lots, also turns out to be considerably cheaper then Midway $55/50 ct. I sucked it up and bought 200. that should last me a life time. In any event I'm curious enough to try the 60 rds of '06 brass I formed and annealed. Let you know how it turns out. Just as an aside, I hear the Jap chambers were made oversized deliberately due to experiences in the tropics. That maybe what others were alluding to when they warned about '06 case head bulging.
