Do you really need both

[Bottom Fodder]

Are they really a reason to use both a neck bushing die and a mandrel die looks likes to me like if your using a mandrel die you could use a regular full length sizing die and a mandrel die or a bushing sizing die and not use a mandrel die. What am I missing? Inquiring minds want to know!
thanks

 

[Straightshooter1]

Are they really a reason to use both a neck bushing die and a mandrel looks likes to me like if your using a mandrel you could use a regular full length sizing die and a mandrel or a bushing sizing die and not use a mandrel. What am I missing? Inquiring minds want to know!
thanks

I get my best results using a FL sizing die that's been reamed so that I'm minimally working the neck, then running an expander mandrel for my desired neck tension. This give me very low runout on my necks and I like that the mandrel moves neck interior thickness variation to the outside (for the most part).

Using just a bushing sizing die will do just the opposite which can result in uneven interference between the bullet and case neck (releasing the bullet unevenly and as the neck expands the blowby exits unevenly). Whether this is of any concern depends of what level of precision you want or need and the quality of brass you're using. The one advantage that's might be most attractive, as I see it, is that the bushing doesn't size all the way down to the neck-shoulder junction, which pretty much alleviates the issue with donuts where that may be important for those who seat their bullets deep enough for the barring surface to be in that area of the donut.

I've used neck bushing dies and just don't get the neck runout that I'm after and running a mandrel in the necks afterwards doesn't improve that. FYI, I use a Forster Co-Ax press for my sizing process.

 

[jimmymac]

You will get a variety of answers here and there is more than one way to get good results.

I shoot short range benchrest. I use custom and semi-custom bushing dies only without any trouble. They work fine and my runout is on the order of .001. For my application, I don’t have any need for a mandrel step in my process because I know my bushing die is working good with my chamber.

One piece of common advice you see on this forum is that a concentricity gauge is an unneeded tool and a waste of money. I have a different take. How does anyone know how good their sizing die works without one? Runout in and of itself doesn’t alarm me when I can easily verify if my sizing dies and bushings are working properly together. Once I’ve established that my bushing and die combo is working, the concentricity gauge goes back on the shelf until a new die or bushing comes into play.

 

[Rocketvapor]

I didn't even touch the Die ID with a HSS reamer.
Took a Carbide reamer and it came out smooth.

 

[cwood59]

You will get a variety of answers here and there is more than one way to get good results.

I shoot short range benchrest. I use custom and semi-custom bushing dies only without any trouble. They work fine and my runout is on the order of .001. For my application, I don’t have any need for a mandrel step in my process because I know my bushing die is working good with my chamber.

One piece of common advice you see on this forum is that a concentricity gauge is an unneeded tool and a waste of money. I have a different take. How does anyone know how good their sizing die works without one? Runout in and of itself doesn’t alarm me when I can easily verify if my sizing dies and bushings are working properly together. Once I’ve established that my bushing and die combo is working, the concentricity gauge goes back on the shelf until a new die or bushing comes into play.

I agree with you. If you have a FL/Bushing die set made for your chamber, is concentricity a real issue or deal breaker? We can split an atom, but do we need to.....????

 

[Bottom Fodder]

I get my best results using a FL sizing die that's been reamed so that I'm minimally working the neck, then running an expander mandrel for my desired neck tension. This give me very low runout on my necks and I like that the mandrel moves neck interior thickness variation to the outside (for the most part).

Using just a bushing sizing die will do just the opposite which can result in uneven interference between the bullet and case neck (releasing the bullet unevenly and as the neck expands the blowby exits unevenly). Whether this is of any concern depends of what level of precision you want or need and the quality of brass you're using. The one advantage that's might be most attractive, as I see it, is that the bushing doesn't size all the way down to the neck-shoulder junction, which pretty much alleviates the issue with donuts where that may be important for those who seat their bullets deep enough for the barring surface to be in that area of the donut.

I've used neck bushing dies and just don't get the neck runout that I'm after and running a mandrel in the necks afterwards doesn't improve that. FYI, I use a Forster Co-Ax press for my sizing process.

Thank you sir, you said basically what I was thinking

 

[BoydAllen]

Different types of shooting have different requirements. For long range benchrest and F class, velocity spread needs to be minimized to a degree that is not required in sports shot at shorter distances. One of the effects of the internet and YouTube is people mixing stuff from long range into shorter ranges when there are other considerations that are a lot more important, for those distances. I would put the use of mandrels in that category. If you get more uniform bullet seating force doing that, for long range that matters. The other place it comes in is if you happen to have an expander die and for reasons of economy are working with a one piece die. In that case not using an expander ball and expanding necks with a mandrel will definitely give straighter ammo, and in a factory chamber I think that really crooked ammo will show up on the target, even at relatively close range. On the other hand, in short range benchrest, I do not believe that it would make a significant difference, given the accuracy that is commonly produced with custom bushing dies. Shooters of that persuasion generally tune by looking at their targets, rather than being ruled by chronographs. This is not to say that they are not used, just they are a lot less important.

 

[NZ_Fclass]

I use bushing FL dies for some calibres, with the expander removed, then a mandrel to set neck tension. It gives me the size that I need and doesn't work the brass too far. I'm about to add a set of 308 dies from Redding with the hard coated bushings and a carbide mandrel. One rifle has a tight neck and brass has to be neck turned. My existing set up - Forster - will remain for the other 308, which has a no-turn chamber. Neck dies? - been there - I tried it with my 223, fairly unsuccessfully

 

[Bottom Fodder]

Let me state I was referring to a mandrel die not the mandrel/button that comes usually is on a stem with decapping pin

 

[209jones]

Would like to have a properly reamed FLS die, and a neck die, with an included mandrel set in .002-004 range, rather than expander ball, no decap pin. Mandrels make life simpler, and come in handy at times, for fixing things on necks.

 

[powderbrake]

By using a bushing die, you can adjust the amount of contraction of the neck, and by selecting the mandrel diameter, you can get any inside diameter you desire.

You may find that a smaller bushing (say .003 or .004 below diameter of loaded round) gives a better result with your chosen mandrel size vs the results with a .001 undersized bushing. The use of a bushing die gives you the ability to change things without a new sizing die.

 

[Coyotefurharvester]

I had standard fl dies, so I just gutted them and let the mandrel set the inside neck diameter. This was after I went to universal decapping. This works really well with 223 range brass I pickup after carbine classes, so I have migrated over to most of my rifle cartridges.

 

[dcali]

No. you don't. If you want to experiment at the extreme edge of accuracy, go for it and try it all out. But you can make a rifle shoot very very well with factory bushing dies if everything is right.

 

[chromatica]

You will get a variety of answers here and there is more than one way to get good results.

I shoot short range benchrest. I use custom and semi-custom bushing dies only without any trouble. They work fine and my runout is on the order of .001. For my application, I don’t have any need for a mandrel step in my process because I know my bushing die is working good with my chamber.

One piece of common advice you see on this forum is that a concentricity gauge is an unneeded tool and a waste of money. I have a different take. How does anyone know how good their sizing die works without one? Runout in and of itself doesn’t alarm me when I can easily verify if my sizing dies and bushings are working properly together. Once I’ve established that my bushing and die combo is working, the concentricity gauge goes back on the shelf until a new die or bushing comes into play.

Exactly!. My concentricity gauge is how I measured my progress in developing an accurate workflow. Even though it sits on the shelf most of the time, its benefit is seen in every round I load.

 

[nksmfamjp]

Are they really a reason to use both a neck bushing die and a mandrel die looks likes to me like if your using a mandrel die you could use a regular full length sizing die and a mandrel die or a bushing sizing die and not use a mandrel die. What am I missing? Inquiring minds want to know!

The reason to do both is to minimize case neck cold work. To prevent cracks.

Using just a bushing sizing die will do just the opposite which can result in uneven interference between the bullet and case neck (releasing the bullet unevenly and as the neck expands the blowby exits unevenly).

That unevenness is why I added expanders back in my process.

I've used neck bushing dies and just don't get the neck runout that I'm after and running a mandrel in the necks afterwards doesn't improve that.

Yep. Shhhh. You are letting secrets out. The marketing says….. blah, blah, blah My experience too is bushings need clamped to get concentricity back. Without clamping, I get like 0.003 or more TIR. With clamping, I can get to 0.0015” to 0.002”. With a std Forster die, I can get to 0.001” neck TIR.

 

[rebs]

The reason to do both is to minimize case neck cold work. To prevent cracks.


That unevenness is why I added expanders back in my process.


Yep. Shhhh. You are letting secrets out. The marketing says….. blah, blah, blah My experience too is bushings need clamped to get concentricity back. Without clamping, I get like 0.003 or more TIR. With clamping, I can get to 0.0015” to 0.002”. With a std Forster die, I can get to 0.001” neck TIR.

can you explain clamping a bushing ?