Bushing dies and using a expanding mandrel

[hollywood1981]

Have a question if I am using a bushing die to set neck tension on the brass, would you also need to run a expanding mandrel after you already did a FL sizing of the brass with a bushing pushing the neck to .002? Just a little confused with this extra process and if it is really needed? Thanks

 

[Lunchbox27]

The Bushing will do the work on the outside of the neck. The mandrel works from inside. I use to leave the expander in the die, but my neck tension was never consistent. Using a mandrel gives me consistent neck tension, and helped lower my ES.

I use a bushing that is 4 thousands under my desired neck tension, then use a 21st Century neck turning arbor to bring it back up 2 thousands.

 

[High Desert duck]

The Bushing will do the work on the outside of the neck. The mandrel works from inside. I use to leave the expander in the die, but my neck tension was never consistent. Using a mandrel gives me consistent neck tension, and helped lower my ES.

I use a bushing that is 4 thousands under my desired neck tension, then use a 21st Century neck turning arbor to bring it back up 2 thousands.

I use the same technique. replacing the expander with a mandrel has also reduced my run out.

 

[hollywood1981]

Do's this added step weaken the neck of the brass faster, by doing an extra step with the the mandrel? Also if you get the right sized bushing, wouldn't that help with bullet run out? Just asking all of these questions, because I am starting to venture further down the rabbit hole with reloading. I am not a compition shooter, I mainly hunt. I do want a sub MOA round/rifle. The thing is I am not to the point of neck turning any brass currently, so I am just trying to justify spending the extra cash on the mandrel. I have read that if you neck turn your brass, and new batches of brass it id good to run a mandrel to get things consistent with the brass. I just feel I am using a reading type s die, and have the bushing contricity should be very good on the neck of the brass. Just need help bridging the gap so to speak. Thanks guys

 

[Howland]

It will not weaken the brass any, but it does work harden the brass. No more so than using a non bushing full length sizing die with an expander and certainly less when you measure it very finely as described by @Lunchbox27 above.

It does work harden the brass more than using the precisely chosen bushing to get exact neck tension you want, but again as noted above, any variation in neck wall thickness is pushed to the inside and can add to lack of concentricity. If you're turning necks and using bushings, you are adding a step that work hardens the brass more and doesn't provide any concentricity or accuracy benefit.

Even if you don't turn necks, I've measured neck thickness variation and haven't come across any lots where the average variation exceeds 0.001" and the maximum variation more than 0.0015". I've only done that with premium brand brass, though. If your concentricity is less than that, you're doing OK. My concentricity is acceptable on the neck but when I measure halfway between the ogive and tip, I have some issues. The location pretty much narrowed the issue to the seating.

Full disclaimer, I don't turn necks and I do use a bushing then open it to the exact size using a mandrel. I bought several sizes of 21st Century mandrels so I have the expander ball that came with the die, plus four smaller mandrels in 0.0005" increments. In my .338LM I found that 0.003" interference fit gave the best accuracy across the powder charge range and particularly at the optimum charge. It was a measurable difference.

If you're only hunting and want sub MOA accuracy, that's fine. If you're only hunting woods and fields where your maximum shot will be 200 yards, even that might be overkill. If there is no practical limit on how far out the game might present itself, the difference between .6 MOA and .8 MOA just extended your reach by enough to offer more good shots provided you know your dope and can read the wind.

You get to decide how far down the rabbit hole you want to go unless you are just unable to control any inherant OCD traits. This is just a matter of the degree to which you are analytical. There is a shorter descriptive that applies to those unfortunate enough to be so afflicted.

 

[hollywood1981]

Thanks for the reply guys. So currently reloading loads for my 6.5 prc rifle. As said in the earlier post above I'm using a redding type s die with bushings. Current bushings I am using for the reading are .289, .290, and .291. My outside neck diameter with a loaded round is .292 this is why I chose these 3 bushing diameters, and am still playing with them to find the best SD and ES. If I were to use the 21st century mandrel expander what diameter would I use for the expander neck? I noticed on the 21st site with the custom 6.5mm sizes .261 to .265. So which size would I need if my bushing diameters are larger like above?

 

[High Desert duck]

I would start with the .262. You are looking for .001 to .0035 ish. The diameter of the mandrel will set your neck tension. So .264 - mandrel diameter = neck tension
your spring back May cause a small variance. That’s why you may want to experiment with different mandrels.

 

[Howland]

I picked up four. I have the expander ball that came with the dies for 0.002" interference fit. I then bought mandrels to test 2-1/2 to 4 thousanths. My rifle happens to be most accurate with 0.003". Who knows what will work best in your rifle. If you're going to pick up the die the mandrel goes in and one mandrel, pick up a few more and find out.

 

[hollywood1981]

So would it be better to just size the brass with the redding type s minus the bushings, and us the 21st century manderl for proper neck tension? I'm just confused with the sizing of the mandrel and using the bushings I have. Cannot wrap my head around it one bit. I'm thinking my bushing size is way bigger diameter than the mandrel, to me if I run a mandrel thru a sized neck of .290 say for example is the mandrel going to size the neck due to the larger diameter bushing? If someone has the same FL and bushings I'm using an also the mandrel I would like to know how they are using these together. Any other info you guys can give will be much appreciated!

 

[padom]

Precision Reloading for Extreme Accuracy (Bullet Seating)

I am putting together my reloading equipment for a .338 Lapua Mag. I am interested in the community's opinion and I am very open to suggestions. I want to have precision reloading equipment that will allow me to assemble ammunition that is incredibly precise. I enjoy the reloading process and I...

www.snipershide.com

Just answered these vary questions a few days ago. Read the above thread

 

[hollywood1981]

Thanks Padom, that was a good read, i guess I will have to just experiment with the diffrent 21st century mandrel sizings. Just want to know which 3 sizes I should get for 6.5 prc, instead of buying more than I need.

 

[padom]

Thanks Padom, that was a good read, i guess I will have to just experiment with the diffrent 21st century mandrel sizings. Just want to know which 3 sizes I should get for 6.5 prc, instead of buying more than I need.

You buy 1.

 

[hollywood1981]

Which on should I buy lol?

 

[Jordanwickham]

Which on should I buy lol?

If you are reloading 6.5 Sinclair comes in .263 mandrel o.d. 21st comes in multiple o.d.'s. I use a .263 mandrel. The size of bushings depends on your round and brass prep. The size of mandrel depends on what you are doing. I use .263 to get 1 thou neck tention but that rifle is a target rifle. If you were to be hunting and possibly banging your rifle with a mag loaded 1 thou is probably a little light. As far as bushings to use it's bullet diameter .264 + neck wall thickness x2 - desired neck tention. Typically new 6.5 brass is around .014 neck wall. So .264+.028-.001=.291 bushing. If you are running a bushing and a mandrel I would go with a .289 bushing and a .263 mandrel so you know for sure you are utilizing the mandrel on all parts of the neck. But all of that depends on the neck wall thickness of YOUR brass.

 

[hollywood1981]

Thanks for the great information Jordan, will use this as a starting point.

 

[padom]

Get a 21st TiN turning mandrel which will give you .002 neck tension. Bushings you will have to play with and take some measurements. I use bushings that give me neck diameter .004 under loaded neck diameter...that way the mandrel is only opening the neck back up .002....this works the brass the least.

 

[High Desert duck]

Get a 21st TiN turning mandrel which will give you .002 neck tension. Bushings you will have to play with and take some measurements. I use bushings that give me neck diameter .004 under loaded neck diameter...that way the mandrel is only opening the neck back up .002....this works the brass the least.

^^^^ This. Exactly.

 

[BCMulx]

Just want to clarify something. You don't NEED to use a mandrel. Especially if you're a newer reloader and just figuring stuff out. You can get very accurate ammo by just using a bushing die.

There are plenty of people who don't tumble or clean their brass, set neck tension using a bushing die, seat the bullet, and shoot 1/2 MOA groups. Very easy to go overboard with what you think you NEED.

Now, if you want to, by all means. I'm personally playing around with Sinclair Carbide Expander (-.001") and Carbide Turning (-.002") mandrels to start, but think I'm Interested in getting a better set of pin gages so I can really measure neck tension after springback.

 

[padom]

Just want to clarify something. You don't NEED to use a mandrel. Especially if you're a newer reloader and just figuring stuff out. You can get very accurate ammo by just using a bushing die.

There are plenty of people who don't tumble or clean their brass, set neck tension using a bushing die, seat the bullet, and shoot 1/2 MOA groups. Very easy to go overboard with what you think you NEED.

Now, if you want to, by all means. I'm personally playing around with Sinclair Carbide Expander (-.001") and Carbide Turning (-.002") mandrels to start, but think I'm Interested in getting a better set of pin gages so I can really measure neck tension after springback.

For new reloaders I wouldnt even be suggesting bushing dies. A good old Forster FL sizing die set to bump.the shoulder properly will produce excellent, accurate ammo from the jump.

Once you have done that long enough and understand exactly what your die is doing then venturing off into.bushing dies and mandrels makes sense IF you know why....working the brass the least is one very good reason.

Cleaning brass, especially with SS is overrated and a complete waste of time and CAN hurt you foe bolt gun brass. I wipe my brass off and size it...

I do tumble in corn cob every 2-3 firings depending on caliber before annealing but that's it. Leaving a little carbon in the necks helps.

For those of us that tested accuracy and SD's with dry vs SS vs ultrasonic cleaning Im here to tell you it doesn't matter to the target down range. It might matter to you to have all that bling brass but the target doesn't fucking care.

 

[Petrov]

For new reloaders I wouldnt even be suggesting bushing dies. A good old Forster FL sizing die set to bump.the shoulder properly will produce excellent, accurate ammo from the jump.

Once you have done that long enough and understand exactly what your die is doing then venturing off into.bushing dies and mandrels makes sense IF you know why....working the brass the least is one very good reason.

Cleaning brass, especially with SS is overrated and a complete waste of time and CAN hurt you foe bolt gun brass. I wipe my brass off and size it...

I do tumble in corn cob every 2-3 firings depending on caliber before annealing but that's it. Leaving a little carbon in the necks helps.

For those of us that tested accuracy and SD's with dry vs SS vs ultrasonic cleaning Im here to tell you it doesn't matter to the target down range. It might matter to you to have all that bling brass but the target doesn't fucking care.

Is there a difference in ES and SD beteen cases that have be just corn cob tumbled and SS pin tumbled with carbon in the neck removed?

 

[padom]

Is there a difference in ES and SD beteen cases that have be just corn cob tumbled and SS pin tumbled with carbon in the neck removed?

Yes I get my lowest SD's leaving carbon in the neck and not SS tumbling...either by not tumbling at all or corn cob... regularly in the 2-5 SD range after proper load development.

 

[Petrov]

VS SS tumbled necks? What about when you anneal your brass? Do you completley clean the carbon off the necks before doing the annealing?

 

[padom]

VS SS tumbled necks? What about when you anneal your brass? Do you completley clean the carbon off the necks before doing the annealing?

I tumble in cc for an hour before annealing.

 

[Petrov]

Thats my only concern when annealing "dirty" brass, the soot on the neck when brass gets heated to 750 degrees.
Do you clean your primer pockets at all?

 

[spife7980]

Yeah, it gets heated... and then you lube it, run it over the expander ball/mandrel which smears it out even, then you tumble it again to get the lube off and whatever else comes out. Then you run a brush in the neck to even the dust out again. I wouldnt sweat it.

I scrape pockets because I have the time and wouldnt use the time to do anything else while Im sitting in front of the tv so why not? Im already depriming them one at a time, 3 more seconds to spin it on a scraper isnt going to kill me.
If I had to do it in an unconditioned garage or shed I sure wouldnt, but on a couch in front of the tv in the air conditioning I dont see why not, wont hurt.

 

[padom]

Thats my only concern when annealing "dirty" brass, the soot on the neck when brass gets heated to 750 degrees.
Do you clean your primer pockets at all?

My bolt gun lapua brass is far from "dirty" especially after cc.....no.i don't touch primer pockets. Its all OCD vudoo. You can do it, but doesn't show any different results downrange.