I've been chasing a load for my 6.5 Creedmoor and shooting a Savage 110 Precision mounted in a MDT chassis. For a lot of years I've been just using the standard full length seating die (non bushing). I've experimented both ways of just full length resizing and collet neck sizing. Side note: I also anneal. While i've been getting descent numbers past my Labradar, i've just never got that fuzzy feeling of "That's the load!". I would get sub groups of about .8 and sometimes larger but never that consistent sub group bliss.
Fast forward, I've played with powder charges in .1 increments and found that node. Then play with OAL and BTO and got that tuned but knew it was still missing a final piece of the puzzle. Then i learned about mandrel dies and boy i'm glad I did. I purchased a full length bushing sizing die and removed the expander ball and stem. I size the brass and the bushing sizes the neck just undersize with a .003 smaller bushing. The magic happened when I skipped the collet die and just used the mandrel die to open the neck to the perfect diameter (.002 bullet tension) and rounding the neck at the same time. My neck tension is now perfectly where it should be. Who'da thunk that neck tension was this important? I mean, i always knew it was but didn't realize how good a mandrel die was to getting it and figured the FL die was good enough.
The chrono numbers drastically reduced and I was so amazed that i almost thought something was wrong with the Labradar.
10 shot group
Average
2748.48
Highest
2752.47
Lowest
2743.7
Ext. Spread
8.77
Std. Dev
3.25
I followed up these numbers with the next 4 groups and the results were also showing up on the target. Thrilled to say the least!
Theory is from some world class shooters is to remove the expanding ball and stem in a full length seating die because when the expander ball is pulled back out of the neck it can slightly mis-align the neck thus the reason to remove it completely and either use a collet die or a mandrel die. From my trips to the range I've opted now for the mandrel die.
This may be old hat to some but after reloading for almost 20 years I guess I'm late to the party but glad I've finally got there. Now i need to order a mandrel for my .308 RPR.
Fast forward, I've played with powder charges in .1 increments and found that node. Then play with OAL and BTO and got that tuned but knew it was still missing a final piece of the puzzle. Then i learned about mandrel dies and boy i'm glad I did. I purchased a full length bushing sizing die and removed the expander ball and stem. I size the brass and the bushing sizes the neck just undersize with a .003 smaller bushing. The magic happened when I skipped the collet die and just used the mandrel die to open the neck to the perfect diameter (.002 bullet tension) and rounding the neck at the same time. My neck tension is now perfectly where it should be. Who'da thunk that neck tension was this important? I mean, i always knew it was but didn't realize how good a mandrel die was to getting it and figured the FL die was good enough.
The chrono numbers drastically reduced and I was so amazed that i almost thought something was wrong with the Labradar.
10 shot group
Average
2748.48
Highest
2752.47
Lowest
2743.7
Ext. Spread
8.77
Std. Dev
3.25
I followed up these numbers with the next 4 groups and the results were also showing up on the target. Thrilled to say the least!
Theory is from some world class shooters is to remove the expanding ball and stem in a full length seating die because when the expander ball is pulled back out of the neck it can slightly mis-align the neck thus the reason to remove it completely and either use a collet die or a mandrel die. From my trips to the range I've opted now for the mandrel die.
This may be old hat to some but after reloading for almost 20 years I guess I'm late to the party but glad I've finally got there. Now i need to order a mandrel for my .308 RPR.
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