Expander Mandrel's

Kmccord

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Joined
Nov 30, 2016
Messages
768
Location
Reilly Springs, TX
I have been looking for ways to shrink my groups with all my rifles and have started looking at expander mandrel as another part of my reloading process. I am not into bench rest or any competition shooting, but would like to shrink my groups and my ES/SD. I have shopped around and was set on getting a Sinclair Gen II, but they are not in stock, so looking at 21st Century now since they are in stock, plus they seem to have it broken down into .0005 increments. Since this will be for hunting rifles, how light of neck tension should be used, again I am new to using expanders. My current setup is using FL Sizing die with the expander button, it measures at .260 on the calipers for my 6.5 Creed, my groups range from 1.0 to .595 in size, should I use .263, .262 or .2625, will it set it to this or will spring back in the brass cause it to be smaller than size on expander? Again I am new to using expanders, just FL size with standard expander in die and seat bullet, using expanders, would it change anything for group's or ES/SD or am I just p#### my money away??
 

GLTaylor

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Oct 11, 2019
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1,183
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Cedar Bluff, Al
Lowering SD and ES is typically a result of adjusting either/all of 4 variables. Just changing neck tension may certainly affect it, but is not a single source cure. Primers and powder have the most effect in my experience. Brass annealing and neck tension have effect to a somewhat lesser degree, but certainly present.
 

Kmccord

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Nov 30, 2016
Messages
768
Location
Reilly Springs, TX
The 28 Nosler was one that had the most issues with ES/SD, the 6.5 Creed is good, but could be better, the powder is measured twice, once with Chargemaster and then to balance beam to verify to add or subtract. I have tested with two different primers and the CCI produced the best but the difference was not that much. The only thing that I have not done is neck tension with mandrels, what ****es me off is the one flyer out of a group of three or even group of five.
 

sedancowboy

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Nov 28, 2014
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691
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Wilsall, MT
Low numbers are a process (low ES, SD and Group Size). It starts with good Brass, good prep, good components and good loading technique. To benefit from using mandrels to set neck tension and lower run out you will need to neck turn your brass (once when new) and anneal (after every firing). Annealing is just as important as using a mandrel to getting good numbers. I personally use both .001 and .002 less bullet dia. based on my testing, you do have some spring back. This is where annealing is important because your spring back will be consistent. For a hunting rifle I would start with a .262 mandrel assuming a .264 bullet dia.
Henry
 

Kmccord

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Joined
Nov 30, 2016
Messages
768
Location
Reilly Springs, TX
Thanks for the info, the brass is Laupua for the Creed, the annealing part is from Laupua and is fired three times and put to the side until I have my own Annealer. The components are primer CCI LRP, powder is H4350, RL16 and RL26, Bullets are Berger 140 EOL. Loading technique with powder is measured twice once with the Chargemaster and second with balance beam until correct throw is shown.
 

Howland

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Joined
Nov 19, 2017
Messages
82
Location
Upstate SC
I worked up a .338LM load and the tightest 200 yard groups were one grain above start charge but velocity ES was horrible. I suspected inconsistent ignition due to the low powder charge and got a set of 21st Century mandrels to see if increasing interference fit would improve velocity ES.

It did nothing to improve ES at the lower charge weight, but now I know that and it did show me that 0.003" interference fit was most accurate in that rifle. I had to compromise between tightest absolute group size, consistent velocity and consistent points of impact at different velocities. I ended up about 150 fps faster, low velocity ES and SD, almost as small groups (which should hold up better at long distances) and very little point of impact change when velocity is slightly higher or lower.

As to your question of whether you would be wasting money, it depends. If you can consistently keep 1 MOA, that should give you confidence of an almost certain humane kill on a deer size kill zone a long way out. Certainly out to distances where your 6.5 Creedmoor becomes marginally underpowered if you can accurately range distance and correctly dope the wind.

I'm at the point where I won't be able to become a better reloader until my fundamentals improve and I learn to accurately read downrange wind. Only once I am better at both will buying more tools for the reloading bench make any difference. But don't let me talk you out of the 21st Century mandrel set. I consider my set to be well worth the money. It might make zero difference with your rifle but it made a measurable difference in mine.
 
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