Seeking a good source for expanding mandrels

[Brians356]

You can get to +/- .0001" if you put in the effort. Turning by hand helps, as does a lot of patience and a willingness to scrap cases.

Ah. A light dawns.

If you are willing to scrap cases, it means even a monkey can produce +/- .0001". Of course, only 1% of the cases might meet the spec when he's finished. I'm pretty sure Joe R is not scrapping any cases along the way to his .0003" variance, but Joe will have to speak to that (I wouldn't presume to).

Incidentally, +/- .0001" is actually .0002" variance, which isn't far, really, from Joe R's .0003" variance. And I'll wager it's impossible to tell on paper which groups were shot with .0002" vs .0003" variance cases, in a blind test.
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[Joe R]

Ah. A light dawns.

If you are willing to scrap cases, it means even a monkey can produce +/- .0001". Of course, only 1% of the cases might meet the spec when he's finished. I'm pretty sure Joe R is not scrapping any cases along the way to his .0003" variance, but Joe will have to speak to that (I wouldn't presume to).

Incidentally, +/- .0001" is actually .0002" variance, which isn't far, really, from Joe R's .0003" variance. And I'll wager it's impossible to tell on paper which groups were shot with .0002" vs .0003" variance cases, in a blind test.
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Brian,
You are right as rain. I do not scrap cases unless I absolutely have to. I put too much work in them (flash hole uniforming, flash hole de-burring, primer pocket uniforming, etc..) and I give each case the opportunity to redeem itself. I have found that variance in neck thickness is not an issue at all as long one gets the ID right. I would challenge anyone to show me, how in the world .0002 variance in wall thickness is going to affect a bullet at at 100 or 1K yards. None of the guys I shoot with claim to turn necks as precisely as I do, most are far more tolerant.

The Holy Trinity of Precision Handloading (per Erik Cortina) are:

1. Powder (selection and measuring)
2. Seating depth
3. Neck tension.

Neck wall thickness is not mentioned as a critical factor. We anneal, turn necks, resize, etc... is all about neck tension. Wall thickness is a subset of neck tension. Anyone that considers neck turning a goal in of itself has lost perspective.

As a competitive shooter (F-Class) my objective is to spend as much time as possible on the range watching and learning to read the wind and mirage. IMO time in the reloading room is a necessity not a hobby in of itself, as some people seem to think.

If you want to learn how tolerant rifles can be of unproperly sized brass, you only need to look here: http://forum.accurateshooter.com/threads/my-new-260-ai-build.3909184/

Kindest regards,

Joe

 

[Brians356]

The bullet is assumed to be rigid.

It's not strictly rigid, of course, in order for the bullet to obturate as readily as we know our typical bullet does.

Brass, according to the on-line handbook I just consulted, can have yield strengths between 11 ksi and 65 ksi, depending on work hardening and annealing history.

Depends somewhat on the alloy, no doubt. I have a hunch the range of yield strengths we encounter is significantly narrower than 54 ksi, perhaps even much narrower.
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[highlife]

I'll try some! Travis

 

[X-Caveman]

I'll try some! Travis

Ok. You're on the list. About 9 weeks out. Will be a set from .238 to .243 in 1 thou increments. The tweeners on the 1/2 thou increments from .2385" to .2425" to be sold individually.

 

[Joe Salt]

https://www.hollandguns.com/
They may help!

Joe Salt

 

[Mulligan]

Ok. You're on the list. About 9 weeks out. Will be a set from .238 to .243 in 1 thou increments. The tweeners on the 1/2 thou increments from .2385" to .2425" to be sold individually.

Are you also planning on a set for 7mm?
CW

 

[X-Caveman]

Are you also planning on a set for 7mm?
CW

If the 6mm sets are successful, we'll do 7mm, 6.5mm & .30 cal.

These are going to be very nice. M3 toolsteel, finish ground after heat treat between centers. +/- .0001" diameter tolerance. Geared towards the guys on the very tip of the accuracy spear and guys like me that just think they make a lot of sense.

 

[Mulligan]

If the 6mm sets are successful, we'll do 7mm, 6.5mm & .30 cal.

These are going to be very nice. M3 toolsteel, finish ground after heat treat between centers. +/- .0001" diameter tolerance. Geared towards the guys on the very tip of the accuracy spear and guys like me that just think they make a lot of sense.

thank you
I'm in for a 6mm set and hopefully the 7mm comes around soon.
CW

 

[Alex Wheeler]

I'm in for the 7mm! These are excellent product. I have made sets of them for guys and they are the best way to control neck tension. Fact is a few of the best shooters in Br have been using these but dont talk about it.

 

[Mulligan]

I'm in for the 7mm! These are excellent product. I have made sets of them for guys and they are the best way to control neck tension. Fact is a few of the best shooters in Br have been using these but dont talk about it.

I knew I couldn't be the only one doing this!
CW

 

[X-Caveman]

I knew I couldn't be the only one doing this!
CW

You have a pm.

 

[X-Caveman]

I knew I couldn't be the only one doing this!
CW

You have a pm.

 

[Mulligan]

You have a pm.

Thanks Travis.
CW

 

[BoydAllen]

Neck tension is spring back against seated bullet bearing.
You don't adjust spring back to area with different size mandrels, different size bushings, or friction changes.
I just think you should consider & understand this before venturing into pure lost.

We know that changing bushing size changes tune. That is an established fact that does not to jibe with your statement. Also, some very good long range benchrest shooters including mandrel expanding in their brass sizing/prep routine. Sometimes we forget that our visualization of how something works comes a distant second to what takes place on targets. Certainly, the hardness of brass, and how much a neck can be expanded without yielding are important factors. Years ago a prominent long range shooter told me that the last step in his processing of brass before loading it was mandrel expansion, and that he had a set of mandrels that were graduated by very small differences that he used for that purpose. He felt that that method gave him more consistent results. For me, pure lost is when you stop looking at targets for answers.

 

[Mulligan]

@AlloyTargets
Thanks Travis, looking forward to trying the new mandrels.
CW