There is one thing that owners of the .308 Norma might not know.
Back in the late 50s and early 60s, many .30-06s were rechambered to the .308 Norma, along with some .308 Win. being re-chambered.
Some of the reamers used were made without provision to ream a throat, and rifles chambered with these reamers would give indications of high pressures with both factory loads and also the minimum loads listed in loading manuals.
Working as a gunsmith during this time, I came across several of these rifles so chambered.
The no-throat chamber is okay, as long as you know you have it, and know to have a throat, also called a bullet seat cut, so the bullet has some jump on leaving the case and before it engages the rifling. The problem comes in when you do not know it, and try to either handloads or factory loads.
Another problem is that many of the gunsmiths re-chambering rifles for the .308 Norma were not aware of this, either.
When I first begin to run into the problem, I spent considerable time running down the whats and whys of this. Finally, I was told by a reamer manufacturer that the reason some reamers were made this way was so the gunsmith could cut a throat suitable for the bullet being used.
As mentioned above, a lot of gunsmiths did not know about this and used the reamer as is.
There are probably many .308 Normas around from this time period that have been traded and changed hands because the owner tried the minimum load listed in loading manuals, or else factory loads, and discovered that he had to hammer the bolt open when using otherwise mild appearing loads.
The fix is simple--just buy a .30 cal. throating reamer and ream out about a 1/4 to 5/16 inch throat. It has been so long since I did it that I can't remember the actual throat depth, but I remember how I came up with the measurement I used.
I had an 03 Springfield in .30-06 that gave exceptional accuracy, even with the military barrel. I measured the throat in this barrel, and cut the .308 Norma throats the same length.
Some readers might know about this, and others might wonder why they have to hammer the bolt open on their .308 Normas, and why the primers fall out when the bolt is opened and the casing removed. The above is the reason.
I just wanted to post this in the event that it benefits other .308 Norma rifle owners. Maybe the information can be useful to someone.
That's good to know.
Thanks for writing about it.
Don
