What have you tried for neck clearance, and how did it work?

Al,
Thanks for the info. It would be interesting to do the same test over a chronograph. Before I heard of the idea that tune is velocity specific, I would "test" things without reference to what velocity changes were being caused by the changes that I was "testing"...sort of tuning by accident. Heck, I still fall back into that from time to time.
 
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Boyd...I plead "guilty as charged" for no chronograph data today. :eek:

But quite honestly, given the limitations of chronograph accuracy, I don't really use mine other than to look for basic velocity. My thinking is that accuracy is not exactly velocity-specific but more vibrational-specific. That known velocity levels in a specific combination show great accuracy may be more a serendipitous effect of the rifles being tested having similar barrel profiles, etc.

Or not. ;)

But here's some data on my 'control' load for these two groups from another outing .
The top target went: 3108, 3085, 3092, 3108, 3103 Avg. 3099

The bot. target went: 3094, 3106, 3097, 3094, 3101 Avg. 3098

rfdtargets.jpg
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I don't have any idea whether these are accurate numbers ot not, given the 1% error factor of my chronograph. Heck...they could be 25-30 fps. either side of these numbers. :D
 
Due to an error in comunications a few years back I ordered a 6BR reamer with a .262 neck and made the brass. The reamer ended up with a .272 neck, found out after chamber was done. The brass works fine even though it blows out a bit and I have been happy with it even with the mistake shoots fine just looks odd.
 
As Promised

We had some unusually light conditions today at Tomball. I set up to shoot at 200 yards.
I used the re-turned cases that do indeed now have .002 case neck to chamber clearance.
If this hurts accuracy, I sure couldn't tell. I shot three staright groups with my Sporter, the biggest was about .300, the smallest about .180, with a mid "two" in between. This was with the same barrel that gave me the Two Gun win at this years Bluebonnet.
I then sat my Rail Gun on the bench, with a proven barrel, and shot a couple of 10-shot "threes", then some fours. On one group, I called every body over after the first five, because it looked like about like a 30 caliber bullet hole on that 200 yard target.
Had a good day of shooting, and the "re-turned" cases shot really well.
I know this is all anecdotal, but in all honesty, the way we are shooting these 00 bullets now, with the heavy jam and lots of 133, neck clearance just doesn't seem to be a big issue, as long as you have enough........jackie
 
On re-turning

I discovered a number of years ago that the 30 BR and HBR case necks grew both in length and thickness. I now run them into my Pumpkin before I anneal them. This sort of tells me that the brass is flowing forward each time the Big Bang occurs inside it. There is no issue except after the necks have been turned a couple of times, one must be careful not to over bump lest the necks break away from the shoulder and if the expansion wasn't done straight, the necks will break @ the weakest point.
 
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