Need Advice on Using Expander Mandrels

[jraulsten]

Merry Christmas to all and thank you for the replies!

Jim

 

[QuietTexan]

Just to be clear on what you're thinking, it isn't that he's taking the neck .001" smaller than the mandrel size, and then moving it up .001". It is that he's taking the neck .003" smaller than the nominal neck size rather than only .002" under?

Correct, I move down .002" and back up .001 with my current Lapua 6.5 CM brass. His seating force, while appearing uniform, is higher than the lee FCD because I would suspect he's benefiting from some spring back with the collet versus the -.002 mandrel.

I anneal and target -.001", and I'm very much so looking forward to the AMP press to see what this versus other sizing practices looks like.

Case Neck Tension - A Stress Analysis

Neck Tension and Case Hardness

bisonballistics.com

 

[RWE]

Another question, hope OP doesn't mind - if using a carbide expander mandrel negates using lube as I see it, is that correct?

 

[30BR]

The carbides and titanium nitrides do not require lube. You can lube if you want, but doing so introduces another variable.

 

[SealT5]

A lot has changed since I started using mandrels. I just ordered a 21st century die with the black nitride mandrels. Cuz why not. I needed a 30 anyways

 

[RidgeTop]

I like the carbide button and get all the consistancy I need with the least amount of brass stretch. I don't full size except for semi auto but I do keep ammo reloads specific for a particular firearm if I have two different rifles in the same caliber.

 

[QuietTexan]

Another question, hope OP doesn't mind - if using a carbide expander mandrel negates using lube as I see it, is that correct?

Honestly not a super simple question to me because while the mandrel might not require lube just for sizing neck lubrication does impact bullet seating. So depending on your overall cleaning and loading process you might still want to use something.

If you ultrasonic or wet tumble you might be better off with adding dry graphite back and mandrel expanding is a chance to dip the case neck before you run it through the press so carbide vs steel doesn't necessarily matter. You could also dip the neck or bullet right before seating and expand with the mandrel without lube.

If you anneal, AMP states that dry graphite doesn't adhere as well after annealing so you might be better served by a wet lube. If you use a spray or wet lube you might have to clean or brush the neck anyway to get any out that got in there before trying to go back to a dry lube inside the neck, or you can mandrel the necks when they're wet before cleaning.

If you don't clean at all other than maybe rubbing the brass by hand you still need to brush the necks out. I get greenish-blue flecks inside necks if I don't clean them pretty fast after shooting (and especially if it's damp) which is probably copper oxide which should be less hard than brass or carbide, but still you'd want to clean them up before you size.

 

[RWE]

Thanks all!

 

[Adipose]

Tagging in as well with a question - do you all that live with dry materials tumble to remove the lube after?

I do. I neck size with the mandrel after sizing the body then toss in the tumbler to remove the die wax or any dry lube left on the necks