Expanding mandrel

[Ucsdryder]

I’m reloading 6.5 creedmoor and went to a Wilson expanding mandrel because the lapua brass and the rcbs FL sizing die didn’t open up the neck enough and I was getting very tight seating (damaging the bullets).

my question is, the mandrel is .263 so I’m only getting .001 tension. On some of the necks I could force the bullet about 1/8” into the neck by hand. I ran a couple through the magazine into the chamber of the gun and it was increasing COAL (.060” off the lands). It doesn’t seem like .001” is enough neck tension. They don’t sell a .262-.2625 mandrel which seems like it would be ideal.
Has anybody else seen this issue and have a correction for it?

 

[Rob5589]

Maybe contact Wilson about a custom mandrel? Did you look at Sinclair's selection by chance?

Oh, did remove the expander ball off the sizing die?

 

[Ucsdryder]

Maybe contact Wilson about a custom mandrel? Did you look at Sinclair's selection by chance?

Oh, did remove the expander ball off the sizing die?

Yes I’ll give them a call tomorrow and see what they say. I removed the ball.

 

[tdot]

Look at Neck Turning Mandrels, they are .002 below caliber, and with the brass spring back, you should net .0015 neck tension.

Had to edit my original post for bad math.

 

[Vandy321]

won't find a better company for them than 21st century

Gotta account for springback...~.001

.001 of actual tension worked fine for me with a 300wm load...single digits SDs.

In my experience though, I found expanding out .003 then compression back with a neck bushing die to .001 gave the most repeatable results.

If you were expanding .001, now account for springback of about .001, you weren't really setting any tension at all

 

[wind gypsy]

There are a number of companies that make mandrels to whatever dimension you desire. I use K&M mandrels just because I already had their setup for neck turning. I know 21st century makes them as well and their die setup may be preferable to allow the mandrel to float and self center better.

 

[Vandy321]

If you're going to neck size, I'd consider getting into the bushing die for setting tension. You'll see what I mean, but it's not always an even tension when you open them up.

I'd fire form, trim, turn necks, expander, neck bushing sizing die (redding makes a great one) then load.

Assuming you're doing that for lower SDs, might as well do it all.

 

[Harvey_NW]

Usually the expander ball in factory dies is .002" under caliber, I run brass over it 2x just to try and keep consistency. I also pull the expander for FL sizing .002" shoulder bump, and then put it back in and expand in a separate step so it doesn't pull the shoulder out. Do that and chamfer the case mouth and I bet your issue will go away.

 

[drewturner]

Sinclair make a nice and reasonably priced expander mandrel die. You will want the neck turning mandrel like is mentioned above. .002 under bullet diameter. If you are going to the trouble to expand necks are you also annealing? I have found annealing seems to make a difference in consistent neck tension from loading to loading.

 

[Lawnboi]

Wilson sounded pretty adamant when they came out with their mandrels that they were designed for virgin brass.

I use sinclair mandrels, I have a set for each caliber of a turning and expanding mandrel. That way as the cases lose their elasticity I can adapt.

Next on my list are some pin gauges and maybe a .0015 under cal mandrel.

I run a wilson bushings FL sizing die, no expander in it and then run my brass through with the turning mandrel.

 

[T28w]

I just had the same issue. New to reloading, got Lapua brass 6.5 creed, K&m expander mandrel, and Redding type s dies. For the virgin brass I started using the expanding mandrel with lube and then clean inside of next prior to seating bullets as I had heard of the issues seating bullets in virgin Lapua. I had to run the virgin brass thru the dies with a .290 bushing to regain tension that I wanted. I did this with out the expander ball in the die

 

[rayporter]

get a collet type bullet puller and put this pin gauge in it [after grinding a point on it]

you can get this for under 5 bucks. i keep a selection for various calibers. such as .241,.2415,.242,2425, and .243 for 6mm. many cost under 3 dollars.

https://www.amazon.com/Vermont-Gage-Tolerance-0-2625-Diameter/dp/B0006JD9V2/ref=sr_1_7?dchild=1&keywords=.26