Bushing Style Neck/Full Sizing Dies...
I want to know if I understand how these work correctly. For the parameters of this discussion, let's assume we are using Lapua Brass which is high quality and VERY consistent.
It's my understanding that the best way to use these dies is to load a few rounds and measure the neck of the loaded ammo, then take the smallest measured case and subtract .001 from it to determine the bushing size you need to order. This bushing should work for that entire batch of brass (again, assuming you are using VERY consistent brass).
My question is this...will that bushing only work for the first firing of the cases in that batch of brass??? The reason I ask this is b/c I'm wondering...Won't the thickness of the case necks vary after each/repetitive firings?...and if so, won't that affect the size of the bushing you need?
If my assumptions above are correct, wouldn't you need to have one size bushing for your first firing of your cases and separate bushings for each subsequent firing.?.?
What I'm trying to figure out here is if it's worth getting the neck sizing bushing die...or to stick with the regular deluxe die sets...
Thank you for any feedback you can give me![8D]
It's my understanding that the best way to use these dies is to load a few rounds and measure the neck of the loaded ammo, then take the smallest measured case and subtract .001 from it to determine the bushing size you need to order. This bushing should work for that entire batch of brass (again, assuming you are using VERY consistent brass).
My question is this...will that bushing only work for the first firing of the cases in that batch of brass??? The reason I ask this is b/c I'm wondering...Won't the thickness of the case necks vary after each/repetitive firings?...and if so, won't that affect the size of the bushing you need?
If my assumptions above are correct, wouldn't you need to have one size bushing for your first firing of your cases and separate bushings for each subsequent firing.?.?
What I'm trying to figure out here is if it's worth getting the neck sizing bushing die...or to stick with the regular deluxe die sets...
Thank you for any feedback you can give me![8D]
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The Redding S die allows you to choose from many different bushings for neck sizing. Although the neck may grow in length from brass flow it seldom thickens much that I could tell. After the second firing, and the second neck thickness adjustment the brass seems to remain stable dimensionally, for several firings.
Bullet tension is a trial and error type operation. From what I found it is best to get at least three sizes so you can try additional or less bullet tension, seeing how it works for you. Both of my 6mmBR's seem to like .002 tension. The group sizes with the 8twist XP rifle that Mrbruce built me shows a marked preference for .002 tension with the 105 A-max.0 -
Hey Bruce...You don't find that your necks get thinner after a few firings???
On another note...do you find that it's really worth going to the effort of using the bushing dies for consistent neck tension? How much difference does it make in your groups?0 -
quote:Originally posted by ECC
Hey Bruce...You don't find that your necks get thinner after a few firings???
On another note...do you find that it's really worth going to the effort of using the bushing dies for consistent neck tension? How much difference does it make in your groups?
The cases never really change much after the third firing. I am running the 6BR real hot, no sticky extraction and almost unlimited case life, no neck issues.
The neck sizing die keeps the neck centered during sizing, the bushing is loose in the die so it does not tilt or form the neck off center, I saw a remarkable improvement in bullet and case neck runout with it. The reason Mrbruce suggested the S die was to improve consistency, it worked. Groups went from .750 down to the .400's with no other changes.0 -
quote:Originally posted by bpost1958
quote:Originally posted by ECC
Hey Bruce...You don't find that your necks get thinner after a few firings???
On another note...do you find that it's really worth going to the effort of using the bushing dies for consistent neck tension? How much difference does it make in your groups?
The cases never really change much after the third firing. I am running the 6BR real hot, no sticky extraction and almost unlimited case life, no neck issues.
The neck sizing die keeps the neck centered during sizing, the bushing is loose in the die so it does not tilt or form the neck off center, I saw a remarkable improvement in bullet and case neck runout with it. The reason Mrbruce suggested the S die was to improve consistency, it worked. Groups went from .750 down to the .400's with no other changes.
One last question...I'm assuming you will need to use a different bushing for each different batch of brass.?.?0 -
Not necessarily. Depends. 0 -
You buy several bushings for each batch size. Your load will prefer a certain neck tension and that is what you go with. It has an effect on ES and SD which equates to on target group size at extended ranges.
I measure my brass thickness
add in the diameter of the bullet you are using, and then you have a loaded neck dia. Now you subtract .001" and .002" and possibly even .003" and order the corresponding bushings
unless you are turning off the high spots, in which case you measure brass thickness after turning and add in the bullet diameter.
all of these steps really only show great improvements in tight chambers, and especially in tight neck chambers.0
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