Shooters seeking small groups have known for decades neck sizing cartridges gives both an accuracy advantage and increased case life. Unfortunately revolver shooters have been mostly unable to benefit from this knowledge. Unless you restrict your loads to one revolver and that revolver has perfectly matched chambers which are perfectly round, neck sizing will not work. Usually you are forced to full length size in a standard die which both overworks the brass case and leaves it loose in the chamber compromising accuracy.
Redding has come up with a solution which they claim improves accuracy. It is a dual ring carbide sizing die, in which the lower ring sizes the whole case to maximum dimension and the upper ring sizes the upper case to hold the bullet. This is not quite the same as fire formed, but it does guarantee fit in all chambers and in different guns without excessively sizing the entire case.
I have not verified Redding’s claim of improved accuracy, but I see no reason why this should not be true. It may not be a perfect chamber fit, but it is certainly an improvement. Increased case life? Most of my revolver cases fail from mouth cracks, so maybe. The cost for this improvement is around a hundred dollars for the die alone, sets are more. If I were buying a new die set it would be tempting.
Unfortunately carbide dies last a looooong time, which at my age is a lifetime. Fortunately there may be a way available and I have it have on the shelf! I use the LEE Factory Crimp die without the crimper as a last step in loading. The Lee Factory Crimp die sizes the case to maximum SAMMI dimension. Can I use it to full length size the case before loadng?
The test:
I wanted a tough test so I went to the range and picked up some “free range” brass. I quickly had 25 assorted 38 Special cases which would not fit in my S&W M66. Some were swelled 0.012 oversize, and had a prominent bulge at the base. There are some very poorly made revolvers out there!
After sizing in the factory crimp die all of the cases chambered easily in the M66. Seating 0.358 wadcutters in the cases required minimal force, and 0.357 jacketed bullets were a slip fit in most cases. Several with thicker walls would have been OK with the jacketed bullets.
This may be the answer to interchangeable ammunition and extended case life Some cases are not sized enough to hold a 0.357 jacketed bullet, so mouth sizing is required if you size your bullets 0.357 or want to load jacketed bullets. The dimensions are close, so it depends on the make of cases. Another reason to use single head stamp cases. If you have enough places on your progressive loader you can put both the Lee die and a regular die in the tool.
Let us know how this works for you.
Steve Hurst