Mandrel Neck Sizing Brass

hereinaz

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I started mandrel sizing the necks of my brass. I loaded some 6.5 creedmoor Hornady brass, and I gotta say running the mandrel in them, it sure seems there was a significant difference in neck tension. I am not sizing the factory brass first. Is that anyone else's experience?

I loaded some .243 for myself without mandrel neck sizing, and I seem to recall there was more difference when seating those bullets. Any how, I am going to mandrel neck size everything for my precision rifles now, and anneal. Hope to see some improvement in SD and ES.
 
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trob_205

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I use the expander mandrel in new brass. I was tempted to just load the new 6.5CM brass I had, but decided to run the mandrel in them and I was happy I did. There wasn’t a huge variance in tension but enough for me to feel a difference in some. It also might help straighten any necks that might not have been perfect from the factory.
 
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TX_Punisher

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What mandrel dies are you guys using? I'll probably start doing the same with 6.5cm and 6.5prc.
 

kansas

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I've been using a 21st Century TiN turning mandrel in a expander die body. I've taken the expander button out of my sizing die and just resize the body then run the case through the expander die with the turning mandrel. That gives me .002 neck tension and has worked very well.
 

redleg1013

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Ive started using a mandrel as well just from the standpoint that the stainless or carbide mandrel, in the case of 6.5, has an extra .08-ish on the diameter than the threaded decapping rod. Tool deflection is an unfortunate reality, and when I can deflect the decapping rod in the die with finger pressure... I decap with a Lee Universal before I clean, use my sizing die with the decapping/expanding rod removed, then expand the neck with the mandrel, prime, charge, seat, shoot. No, it isn't the most efficient but it's the OCD I learned from the benchrester that got me into handloading.
 

towerofpower93

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Ive started using a mandrel as well just from the standpoint that the stainless or carbide mandrel, in the case of 6.5, has an extra .08-ish on the diameter than the threaded decapping rod. Tool deflection is an unfortunate reality, and when I can deflect the decapping rod in the die with finger pressure... I decap with a Lee Universal before I clean, use my sizing die with the decapping/expanding rod removed, then expand the neck with the mandrel, prime, charge, seat, shoot. No, it isn't the most efficient but it's the OCD I learned from the benchrester that got me into handloading.
Just to clarify, you simply pulled the depriming rod/expanding ball from a standard, non bushing, full length resizing die and then use the neck mandrel afterwards?

I ask only because I’ve been planning to use a mandrel on my .338LM brass after sizing with a bushing die, but for other calibers I don’t have bushing dies for I was wondering if doing the regular FL resizing, sans decap/expand rod, would still allow the mandrel to work it’s magic of consistent neck tension and the wrinkles pushed to the outside of the neck.

I realize this is working the brass in the neck more than a bushing die would, but I’m thinking about this for .223 and .308 for gas guns where I only use the brass for a few firings while looking to increase the consistency of the neck tension. As I resize on a 650 it would still just be one trip through the press on the prep pass, just with two dies in the toolhead.
 

redleg1013

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Yes, and I apologize for not being more specific. I removed the stem with the expander ball and decapping pin from my full length sizing die, then I use the mandrel to expand the neck.
 

towerofpower93

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Not a problem. And thanks for confirming.

I've wondered if that would size the brass down too far and cause the mandrel to crush the neck vice entering and expanding, but it sounds like it's a non-issue.
 

redleg1013

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Not a problem. And thanks for confirming.

I've wondered if that would size the brass down too far and cause the mandrel to crush the neck vice entering and expanding, but it sounds like it's a non-issue.
Nah, all the the mandrels I've seen are all nice and tapered at the end.
 

winniedonkey

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I keep seeing this concept pop up. From my memory it seems like it's been working well for most. I think it is time to join the club. Good info.
 

mensajd

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If you buy Forster f/l dies, you can have then custom hone the neck diameter so you don’t overwork the brass using this methodology.
 
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JOE62

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Honing the die gives you consistent case neck OD. You want consistent ID is what the mandrel does.
 
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hereinaz

I have no idea why I get these new labels...
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Honing the die gives you consistent case neck OD. You want consistent ID is what the mandrel does.
I think what he was saying is you can have Forster hone the OD so that it doesn't make the neck smaller than necessary before running the mandrel to expand it. At least, that is what I got from saying it fixes overworking the brass.

@mensajd is that what you were saying?
 
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nexusfire

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Just take a loaded round and subtract 0.04 from the outside neck measurement. That is your bushing size. Then run thru the neck turning mandrel.
 

IHFarmer07

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Questions for you all.
I would like to purchase a mandrel setup and I have looked a several different types, K and M shooting makes custom sizes which is handy or Sinclair, would you all go for the Sinclair with either stainless or carbide? Or would you all go for the K and M shooting one with what I'm assuming to be stainless? What would work the best?
 

towerofpower93

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Working with an N of one, but I used my Sinclair steel mandrels for the first time the other week to open up some virgin Lapua 338LM that had .004" of neck tension out of the box.

I stood the cases up in a cardboard box to make sure my homemade lanolin case lube got into the neck of every case. After letting them sit for a few minutes to allow the alcohol to evaporate they sized up like butter, leaving me with my desired .002" of neck tension, based on measuring the OD of the neck before and after sizing. I wasn't able to bottom out or cam over the ram in a Lee Classic Cast press, due to the length of the 338LM case and my desire to keep at least 4-5 threads of the die body in the press, but I could feel when the case mouth would just contact the step on the upper part of the mandrel and then back the ram down to remove the case. Measuring the OD of the necks on 15-20 pieces of brass showed they all ended up at the proper/desired OD.

Plan going forward will be to lube the entire case body and inside the neck before FL bushing resizing. I'll then swap over the single stage press to the mandrel die and run them all through again before tumbling off the case lube.

ETA: I bought both the turning and expanding mandrels in .338, and used the expanding mandrel first which gave me my desired OD. Had the brass sprung back more, leaving me with .003" or more of neck tension, my plan was to then try the turning mandrel, but this wasn't needed.

From the Sinclair description: Turning mandrels are sized .002 inch under bullet diameter and expander mandrels are .001 inch under bullet diameter.
 
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DrainTheSwamp2017

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I can report that I’ve seen lower sd’s using the mandrel. My loads for 223 and 6.5 cm went from 20’s in my ar to the mid to low teens and my 6.5 went mid to high single digits. I also started annealing at the same time on my 6.5 brass though.
 
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DrainTheSwamp2017

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Redding type s full length sizer with the bushing to squeeze the neck down a bit and bump shoulders, then set the final neck tension with a 21st century mandrel.
 
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Baer45

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Ive started using a mandrel as well just from the standpoint that the stainless or carbide mandrel, in the case of 6.5, has an extra .08-ish on the diameter than the threaded decapping rod. Tool deflection is an unfortunate reality, and when I can deflect the decapping rod in the die with finger pressure... I decap with a Lee Universal before I clean, use my sizing die with the decapping/expanding rod removed, then expand the neck with the mandrel, prime, charge, seat, shoot. No, it isn't the most efficient but it's the OCD I learned from the benchrester that got me into handloading.
Do you weigh or throw powder...jut curious...I have an auto throw but also read a lot of guys are using a Harrels powder throw out to 600 yds....?
 
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eicas

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I started using a mandrel after a bad experiece with a lot of virgin Lapua .308 brass. It’s now part of my routine. It’s the final step before I prime and load. Combining this with crosschecking loads using both an electronic and beam scale has shown significant improvements for me in all calibers.
 
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hereinaz

I have no idea why I get these new labels...
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Do you weigh or throw powder...jut curious...I have an auto throw but also read a lot of guys are using a Harrels powder throw out to 600 yds....?
I weigh charges. But, I lent my Chargemaster to a buddy and went with an old Lyman powder thrower. I have to say that it was very consistent, and out to 600 yards, I wouldn't have much problem running it cause velocity differences are going to be minimal.

I set the thrower to throw low and then trickled up to my target weight onto my scale. I was going fast, and at least half were right on the same charge and the others were off by a few kernels at most. I could have been more precise with it I am sure. It was also my first time using it. I bought a bunch of reloading stuff second hand when I first started, and that was with it.
 

Milo 2.5

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Could you elaborate on the new set they are releasing ?
I use their TiN coated mandrels and they are excellent.
Come in sizes .0005", steel, not sure how far under call dia they will go. Holland Shooting also offers a steel set that goes quite a bit under caliber dia also. I have a 6mm set, .239, .240, and .241"
 
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