Sinclair Gen II expander, Mandrel question.

[Boxcar77]

For those using this die/mandrel setup for setting neck tension. What mandrel are you using? It seems to come in Oversize and neck turning. Am I too assume the Oversize mandrel is the one that is .001 smaller than bullet diameter?

Thanks for any responses.

 

['Freak]

Their expander mandrel is .001” under bullet diameter and is used to expand the neck for a proper fit on the .002” under turning mandrel.

 

[chkunz]

There is a Sinclair Expander mandrel and a Sinclair Turning mandrel. The sales catalog does a good job describing them and their dimensions and function. Your brass will spring back some when you use them and different brands of brass will spring back differently. Start with the catalog descriptions and then measure the ones you buy with a micrometer when you receive them to know exactly what the dimension is of the one that you have, there may be a slight difference between what you measure and the stated dimension since all dimensions have tolerances and the tighter the tolerance the greater the costs.

 

['Freak]

Mandrels will swap between several of the different makers’ expander dies and turning tools. Thinkin’ some, like PMA: http://www.pmatool.com/ amongst them, offer mandrels in different sizes and possibly made to your specs for doing such as playing around with neck tension.

 

[bigedp51]

Boxcar77

The Sinclair mandrel floats in the expander die and has no centering effect and can increase neck runout because the body and neck of the case is not supported. I would recommend a Forster die with the high mounted expander that supports the case neck.

I experimented using the mandrel method after reading "Expander Mandrels and Neck Tension" and was not satisfied with either unturned or turned necks results. The case floats in the shell holder and the mandrel floats in the die leaving the case to move in any direction without any centering effect.

http://www.accurateshooter.com/technical-articles/reloading/expander-mandrels-and-neck-tension/

 

[Boxcar77]

Thanks for the responses.

Biged, it was that article that led me to be want to try an expander die. I do have a forster die for the caliber I was considering an expander for. I have only used the Forster sizing die a few times though because it was giving me about .006 neck tension, so I purchased a Redding bushing die and used it with great success. Albeit concentriicity was great on a sized neck bullet runout has suffered, but not on every loaded round. I fear neck turning is in my future.

 

[bigedp51]

Forster will hone the necks of their dies to the diameter of your choice, read below. You can also just order the expander and spindle unit only if you have other make dies

FL Bushing Dies vs. Honed FL Dies
http://www.accurateshooter.com/technical-articles/reloading/fl-bushing-dies-vs-honed-fl-dies/

Also read below, if you have a standard factory chamber your runout will increase if you size in one operation with a single bushing. Plus if you do not turn the necks you are just pushing any neck defects to the inside of the neck.

Two-Step Sizing and Case Neck Concentricity
by: Germán A. Salazar
http://riflemansjournal.blogspot.com/2010/04/reloading-two-step-sizing-and.html

By just adding a Forster high mounted expander spindle unit to my RCBS .223 full length die I'm getting .001 or less runout after sizing. And the Forster spindle unit can be used in a full length die or a neck sizing die and give you minimal runout.

 

[chkunz]

Boxcar77

The Sinclair mandrel floats in the expander die and has no centering effect and can increase neck runout because the body and neck of the case is not supported. I would recommend a Forster die with the high mounted expander that supports the case neck.

I experimented using the mandrel method after reading "Expander Mandrels and Neck Tension" and was not satisfied with either unturned or turned necks results. The case floats in the shell holder and the mandrel floats in the die leaving the case to move in any direction without any centering effect.

http://www.accurateshooter.com/technical-articles/reloading/expander-mandrels-and-neck-tension/

bigedp51, I had the impression from reports on folks putting O rings under dies that floating was conducive to reducing run out. But it sounds like you are stating the opposite. Do you have any data that shows this? A lot of folks are using the Sinclair mandrels and it would be good to know if this is a problem. Thanks for your input on this.

 

[bigedp51]

bigedp51, I had the impression from reports on folks putting O rings under dies that floating was conducive to reducing run out. But it sounds like you are stating the opposite. Do you have any data that shows this? A lot of folks are using the Sinclair mandrels and it would be good to know if this is a problem. Thanks for your input on this.

I thought what i said was very clear, I get "LESS" runout using a RCBS full length die fitted with a Forster expander and spindle assembly than with a Sinclair expander die.

Below a RCBS .223 full length die equipped with a Forster expander and spindle unit and a Lee lock ring with built in o-ring. This die produced "LESS" neck runout than using the Sinclair expander die or a Forster neck bushing die.

A case neck in a standard off the shelf factory rifle expands too much to use a bushing die in one sizing operation. The bushing floats and when compressing the case neck it ends up off center and inducing neck runout.

Look at the video below the neck of the case is still inside the neck of the die when the expander enters the case neck. This centers the floating expander with the center of the die and prevents the expander from pulling the necks off center like standard dies can do with the low mounted expander.

Forster Full Length Sizing Die Cutaway
https://www.youtube.com/watch?v=RgIfzsH8N6k

And after reading other postings at different websites and a posting by CatShooter here I'm also testing the Lyman type M expander after the above resizing to see if it reduces runout during bullet seating. The "step" in the expander helps center the bullet during seating by allowing the bullet to start centered in the neck without stress or scraping the bullet.

 

[snakepit]

Boxcar77

The Sinclair mandrel floats in the expander die and has no centering effect

http://www.accurateshooter.com/technical-articles/reloading/expander-mandrels-and-neck-tension/

The link you gave us to read says in describing the Sinclair die body and mandrel that it has an O-ring in the die cap that allows the mandrel to self-center within the case neck. Also the Sinclair ad and the associated video with the ad states that the O-ring allows the mandrel to float and find its center in the case neck.

 

[bigedp51]

My runout gauge doesn't lie, after full length resizing and neck sizing without the expander and then using the Sinclair expander die the runout increased. Out of five different resizing dies and methods the Forster expander unit produced the least neck runout.

This was with a off the shelf factory Savage .223 and standard dies, a custom chambered rifle with a tighter neck and bushing dies that did not over resize the case neck may produce different results.

But again when using the Sinclair expander die the case is free to move in the shell holder and the mandrel floats. This leaves the case unsupported when the necks are expanded and induced runout. The Forster expander is supported and centered by the case neck while the neck of the case is still centered and held by the neck of the die.

 

[Scott Harris]

My runout gauge doesn't lie, after full length resizing and neck sizing without the expander and then using the Sinclair expander die the runout increased. Out of five different resizing dies and methods the Forster expander unit produced the least neck runout.
...

My results differ from yours. Loading six different cartridges, the Sinclair die and turning mandrel do not impact concentricity one bit. I load about 15K rounds per year for F-class and measure regularly. Now, this assumes you are reducing the neck during F/L resizing such that it is only .002-.003 less than bullet diameter. In this case, the mandrel is not doing a lot of work and does not impact concentricity adversely.

If you shrink the neck down way more than needed and then try to run a mandrel through it.....runout will be introduced. But, the same would occur whether you used an expander button, mandrel, or simply tried to seat a bullet directly....you'd get runout. Most conventional fixed F/L dies size the neck down much more than needed. Bushing or custom dies address this shortcoming.

Regarding the topic of floating dies, mandrels, etc, I've always found that procedure to improve concentricity. The only time locking things in place would be good is if you could ensure that everything was perfectly aligned. This is a very difficult task when so many components are involved: dies, bushings, presses, press die threads, shellholders, etc. It's virtually impossible to guarantee that all those components stacked together are perfectly aligned. This is why allowing components to float usually produces better measured results. An analogous discussion occurs with the tailstock on a lathe. If you can't ensure that the tailstock is perfectly aligned with the headstock axis of rotation, a floating reamer holder will produce better results. Fortunately, a lathe tailstock is easier to get aligned than most dies and presses. ;D

 

[amlevin]

My results differ from yours.

As do mine. If my neck wall thicknesses are uniform and cases annealed frequently the Sinclair expander dies adds NO runout to my cases.

My runout gauge doesn't lie either.

 

[bigedp51]

I clearly stated the rifle was a off the shelf factory rifle meaning it did not have a custom chamber. I also stated I did not get good results with a bushing die.

The biggest problem the average reloader has when he comes here is translating what some of you are saying because you have custom chambered rifles. Mr. Harris below was very clear, it depends on "HOW" much the expander mandrel enlarges the neck or "HOW" much a bushing reduces neck diameter.

My results differ from yours. Loading six different cartridges, the Sinclair die and turning mandrel do not impact concentricity one bit. I load about 15K rounds per year for F-class and measure regularly. Now, this assumes you are reducing the neck during F/L resizing such that it is only .002-.003 less than bullet diameter. In this case, the mandrel is not doing a lot of work and does not impact concentricity adversely.

If you shrink the neck down way more than needed and then try to run a mandrel through it.....runout will be introduced. But, the same would occur whether you used an expander button, mandrel, or simply tried to seat a bullet directly....you'd get runout. Most conventional fixed F/L dies size the neck down much more than needed. Bushing or custom dies address this shortcoming.

.

Now Mr. Harris read below about runout and two step sizing with bushing dies.

Two-Step Sizing and Case Neck Concentricity
by: Germán A. Salazar
http://riflemansjournal.blogspot.com/2010/04/reloading-two-step-sizing-and.html

I'm not knocking your methods or firearms, BUT everyone should be clear about their chamber and dies. As you can see below there is a .003 to .004 difference in chamber neck diameter. And I'm also trying to load more accurate ammunition for my AR15 A2 HBAR.

Bottom line for my rifles a Forster expander unit works better than a expander mandrel or bushing die. Many people read the posting here only to find out that your methods do not work with off the shelf rifles. And this is why I added my postings about the Forster dies that support the case neck.

 

[snakepit]

I clearly stated the rifle was a off the shelf factory rifle meaning it did not have a custom chamber. Many people read the posting here only to find out that your methods do not work with off the shelf rifles. And this is why I added my postings about the Forster dies that support the case neck.

I agree with the prior Scott Harris posting. I use pretty much the same procedures as he does, F/L bushing die to resize to .002 less than the bullet diameter and then open it up to .001 with the Sinclair Mandrell and Die. No concentricity issues as measured with my Sinclair Concentricity Gauge using a totally off the shelf Savage F/TR .308 and a Savage F Class 6BR. Like so many things in reloading what works good for one person may not work for someone else.

 

[Boxcar77]

All good info to take into consideration. The expander die and mandrel will arrive tomorrow. I have a Forster F/L die but seldom use it. Maybe I'll give it a try and compare both methods and report my findings. I don't have an off the shelf rifle, seems I can't keep anything to factory specs as I like to tinker and the Internet spends a lot of my money.

Rifle is a TVP built 6.5x47L w/ a no turn chamber. Fireformed brass measures .294 and I'm resizing to .288 in 2 steps with a .291 bushing as an intermediate sizing.

 

['Freak]

Is .288” the measured neck OD with projectile or bushing ID?

 

[Boxcar77]

Is .288” the measured neck OD with projectile or bushing ID?

That's the bushing ID. Loaded rounds measure .290, I'm sizing down for .002 neck tension which seems to work best in my rifle.

 

[amlevin]

the Internet spends a lot of my money.

I'm going to save this line for the next time my wife asks about a charge on our Credit Card Statement.

"Wasn't me hon, the Internet did it" 8) 8)

 

['Freak]

Have you measured neck wall thickness and if so, how consistent is it?

It don’t figger that expanding necks on a floating mandrel would cause increased bullet runout. It do figger that unequal neck wall thickness combined with sizing necks down but then not somehow expanding so not shoving the neck wall inconsistencies to the outside could be the source of the projectile runout.