I've been using mandrels for a while now. I've been reloading some 300 RUM RP brass. After I've full length sized and then go to open up the necks with a .306 mandrel, I'll notice a few cases where there is definitely more resistance with the mandrel going inside the neck. Given this apparent stronger neck tension, is this something that will affect my ES. Do you guys pull these cases out. Any thoughts?
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Mandrels
- Thread starter Triple BB
- Start date
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Have you annealed your necks? This will even up your neck hardness.
Are you lubricating the necks? If not, try Redding dry neck lube.
extend your annealing time a hair, polish inside necks with nylon brush in cordless drill (3-4 secs) , Separate sized cases by length and resistance - shoot the "good" lot vs the "bad" lot and see if difference shows on target.
I'm reply #6 and totally agree with all those who replied ahead of me. My understanding of the use of the mandrel is to eliminate the "donut" on the inside of the case neck where the neck meets the shoulder caused from stretching and resizing. "If" there is a donut at this juncture it will cause the inside diameter of the case to be smaller, which will cause extra tension on the mandrel. With the use of the mandrel, when the donut is forced out that material has to go someplace, thus I turn the case necks.
Mikecr
Well-Known Member
Yes it could affect ES/tune.
If you're FL sizing necks, here is a tip: Stop FL sizing necks.
I should've added a bit more info. I dip the necks in a small jar of Imperial Dry Lube that is refilled regularly with Mica dust. All brass is annealed after each firing with an Annie. These cases have only been fired two times. Appreciate the replies.
tylerthorson95
Member
I'm trying to learn-up on mandrels. Can someone to explain to me what a "donut" is? What is the benefit to a mandrel over a neck-bushing? When using a neck-bushing die, should I leave in the expander ball, or remove it? I contacted RCBS and the man I spoke with said he leaves the expander ball in his neck-bushing die because he doesn't neck-turn his brass.
Check this recent thread out. It has some good info that will help a bit:
https://www.longrangehunting.com/threads/bushing-dies-and-expanding-mandrel.369694/
https://www.longrangehunting.com/threads/bushing-dies-and-expanding-mandrel.369694/
MagnumManiac
Well-Known Member
If you never load your bullets below the pressure ring (donut) you will never see an issue.
A mandrel provides expansion of the neck in a more controlled way.
I still use expanders, but mine are sized correctly to only be .0015" interference, then the mandrel is only .0005" more.
Some are less than this.
Lube your necks with dry lubes, it never causes issues but helps immensely.
Cheers.
A mandrel provides expansion of the neck in a more controlled way.
I still use expanders, but mine are sized correctly to only be .0015" interference, then the mandrel is only .0005" more.
Some are less than this.
Lube your necks with dry lubes, it never causes issues but helps immensely.
Cheers.
