In the past, I've used the "no-bullet" approach: form the case & neck to fit the chamber, fill it with Unique, plug with wax or a tissue wad and fire. The case fills out and I proceed to neck turning etc. Lately, I've been struggling with a shortened .308 (going to 30x44). The case fills out "pretty well" but is not fully sharp, and there is considerable run-out on the necks...in the order of .006-.008" After neck turning and a subsequent firing with a bullet, the run-out is less, but not yet in the .001" or less area. After the 3rd firing, it seem to get there. I'm thinking my initial "no-bullet" approach is false economy. What's the best way to fire-form?
Fire forming brass
- Thread starter feffer
- Start date
David Halblom
Flying Fish Fundamentals
I have shot a 30x44
for about 17 years now. My method, not perfection but mine, is to push back from 308 Lapua, trim to .035-.050 long, expand, turn in 2 passes, trim to max length of chamber, expand to .338 and then push a false shoulder at .005 long. Fill it up, put a cheap 308 bullet on top and fireform. The reason for the false shoulder is to get a crush fit when you initially fire. Have not had separation 1 since doing this and brass does not shorten as much on initial firing. Case will be 99.9% formed on the second firing and ready to trim and go compete.
for about 17 years now. My method, not perfection but mine, is to push back from 308 Lapua, trim to .035-.050 long, expand, turn in 2 passes, trim to max length of chamber, expand to .338 and then push a false shoulder at .005 long. Fill it up, put a cheap 308 bullet on top and fireform. The reason for the false shoulder is to get a crush fit when you initially fire. Have not had separation 1 since doing this and brass does not shorten as much on initial firing. Case will be 99.9% formed on the second firing and ready to trim and go compete.
David, thx for the detailed info especially since you are forming 30 x 44 and have long experience with it. Just so I'm clear, you form the case first from the .308 Lapua brass, and THEN trim it to .035-.050 long? I have been doing those steps the other way around (but think that may be causing me a problem).
In any case, after these steps, we have an initially formed case with a new neck partially formed from the old .308 shoulder. So most of the neck is thick (about .017" or so) and the last 1/8th" or so is left over from the old .308 neck and is thinner. And between them is a line that WAS the old .308 shoulder-neck junction. I have had a terrible time getting the final turned necks uniformly thick. If I'm shooting for a .0108" neck, the back of the neck will be that way, but the very front (near the mouth) will be a bit less...maybe .0105" and right around the junction line it might be .0100 or even a little less...measuring carefully with a ball mic. The bottom line is that these variations almost surely are enough to affect neck tension on the bullet. And I can sometimes feel noticeable differences when seating bullets. I posted earlier asking about neck turning issues, but did not put these details in.
So David, if you see where I might be going wrong, I would really appreciate the help. Also, I'm curious about what sort of chamber neck and case neck dimensions you find work best with the 30 x 44. Thanks!
In any case, after these steps, we have an initially formed case with a new neck partially formed from the old .308 shoulder. So most of the neck is thick (about .017" or so) and the last 1/8th" or so is left over from the old .308 neck and is thinner. And between them is a line that WAS the old .308 shoulder-neck junction. I have had a terrible time getting the final turned necks uniformly thick. If I'm shooting for a .0108" neck, the back of the neck will be that way, but the very front (near the mouth) will be a bit less...maybe .0105" and right around the junction line it might be .0100 or even a little less...measuring carefully with a ball mic. The bottom line is that these variations almost surely are enough to affect neck tension on the bullet. And I can sometimes feel noticeable differences when seating bullets. I posted earlier asking about neck turning issues, but did not put these details in.
So David, if you see where I might be going wrong, I would really appreciate the help. Also, I'm curious about what sort of chamber neck and case neck dimensions you find work best with the 30 x 44. Thanks!
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Dusty Stevens
Hollow Point Dispenser
Have you thought of a hydraulic die? It may save some components
David Halblom
Flying Fish Fundamentals
Feffer
I have not experienced the taper issue you are describing. But one thing may be if you are trying to turn in 1 pass. I turn all my brass, 6PPC, 30PPC, 30x44, in 2 passes. I take about 75-80% off the first turn and then to size on the second. The second turn is quite light. I am turning for .262, .332 for 30PPC, and .331 for 30x44. .0015 -.002 clearance. Those are the things that come to mind so far.
David
I have not experienced the taper issue you are describing. But one thing may be if you are trying to turn in 1 pass. I turn all my brass, 6PPC, 30PPC, 30x44, in 2 passes. I take about 75-80% off the first turn and then to size on the second. The second turn is quite light. I am turning for .262, .332 for 30PPC, and .331 for 30x44. .0015 -.002 clearance. Those are the things that come to mind so far.
David