Expander Mandrel

[FNG1001]

Been reading a lot about expander mandrels and, particularly, the use of 21st Century expander mandrel (0.001 below bullet diameter) and turning arbor (0.002 below bullet diameter) over the range of mandrels they offer, differing in 0.0005 in size. I current Forster FL resizing dies for all my reloading.

How many of you use the turning arbor, or expander mandrel, instead of going down the route of setting neck tension using the the caliber specific expander mandrel kits? I found some chatter about this in light discussions from thread a few years ago, but thought I would ask in a dedicated thread.

References:
0.002 Turning Arbor: https://21stcenturyinnovation.com/buy-online/ols/products/black-nitride-turning-arbor
Caliber Specific Mandrel Kit: https://21stcenturyinnovation.com/buy-online/ols/products/caliber-specific-expander-mandrel

 

[ACard]

PMA carbide expanding mandrels

 

[spife7980]

Turning arbors

 

[ma smith]

PMA carbide expanding mandrels

Just curious -- are these 1.0 or 2.0 under or a tweener size?

 

[CK1.0]

I like/use/can recommend the Sinclair TiNi turning arbors (bullet diameter -.002"). https://www.brownells.com/reloading...ng/tin-coated-turning-mandrels/?sku=749019014

The SInclair die body is solid too, the 21st Century die body with the hole in it feels flimsy/shitty (which is odd for 21st Century stuff). https://www.brownells.com/reloading...ase-neck-turning/generation-ii-expander-dies/

 

[ACard]

@ma smith 0.001 under so 0.243 is 0.242

Neck Expanding Equipment - Carbide Exp. & Neck-Up Mandrels - Page 1 - PMA Tool

www.pmatool.com

 

[OREGUN]

Sinclair mandrel die and whatever turning mandrel (-.002) I have (stainless, carbide, etc). If I’m playing with lighter neck tension, I’ll use an “expander mandrel” (-.001).

 

[ma smith]

@ma smith 0.001 under so 0.243 is 0.242

Neck Expanding Equipment - Carbide Exp. & Neck-Up Mandrels - Page 1 - PMA Tool

www.pmatool.com

Nice. I've used the sinclair -.001 carbides and I think they are very good. I do like the idea of 1.5 thou under bullet diameter, but AFAIK the 20th c. kit is just bare steel and they want you to moly lube it. Raw steel makes me scared of galling. I will keep eyes open if someone does a 1.5 or 2.5 under in carbide.

 

[R_A_W]

Porter's Precision Products – P3 Machining / Gunsmithing

www.portersprecisionproducts.com

 

[Franko]

Sinclair carbide mandrels. They aren't cheap but they are slippery and I expect them to last a long time.

 

[Herb Stoner]

Another vote for Porters Precision - excellent stuff!

 

[FNG1001]

Turning arbors
View attachment 8147797

Are those the black nitride or titanium nitride? How has your experience and results been? I have their GenX expander die, and black nitride turning arbor for 6.5 (to solve a difference problem). I am leaning toward getting the remaining turning arbors in the calibers I'm interested in, mostly due to my positive experiences with them so far and my preference for keeping things the same (not jumping around too many manufacturers) unless another product is greatly superior.

 

[spife7980]

Are those the black nitride or titanium nitride? How has your experience and results been? I have their GenX expander die, and black nitride turning arbor for 6.5 (to solve a difference problem). I am leaning toward getting the remaining turning arbors in the calibers I'm interested in, mostly due to my positive experiences with them so far and my preference for keeping things the same (not jumping around too many manufacturers) unless another product is greatly superior.

Steel and TiN

 

[CK1.0]

Maybe ask @OREGUN, since it sounds like he has all the different types... but I'm not sure what the arbors are made out of, or what they are coated in, matters that much.

I chamfer after the cases get run through the mandrel, so IDK if there would be any difference in the final product whether using carbide, TiNI, BlackNi, or plain steel ones...

 

[OREGUN]

Maybe ask @OREGUN, since it sounds like he has all the different types... but I'm not sure what the arbors are made out of, or what they are coated in, matters that much.

I chamfer after the cases get run through the mandrel, so IDK if there would be any difference in the final product whether using carbide, TiNI, BlackNi, or plain steel ones...

I have several regular old stainless and one that was sold as ”carbide”. I use a dab of imperial die wax on all of them prior to starting and a touch on a q-tip in the case mouth as well. Can’t tell the difference. The 6mm (.241”) one is stainless and got ~5000 cycles a year for 3 ish years prior to switching to a mandrelling sizer. It has visible wear but I’ve never measured it. The others, far fewer cycles, no wear. I decided to keep buying cheaper stainless ones for most calibers as I think they’d provide a lifetime of use at a few hundred cycles a year. Never had any galling or other issues.

I dry tumble, anneal, size/decap, mandrel, trim/chamfer. So my necks have carbon in them when I mandrel and all case mouth operations (trim, chamfer, deburr) happen last in the brass prep process.

I load for <1/2” groups and <10 SD. It’s more precise than is required for PRS but not as tedious as the benchrest guys get. My entire goal is to get there in the fewest number of touches as possible. I hate reloading.

 

[Snuby642]

Sinclair mandrell - 0.002 for each caliber.

I have set the expander buttons in each fls die to yield 0.004 - 0.006 under. I believe this way the brass is worked with less stress.

I have seen up to a 20% reduction in group size accross the board.
Also in the case of 223 range brass it seems that my loads transfer to different brass with less variance.

Everything including plinkers gets the extra step. You can just shove the targets farther out.

 

[Baron23]

Been reading a lot about expander mandrels and, particularly, the use of 21st Century expander mandrel (0.001 below bullet diameter) and turning arbor (0.002 below bullet diameter) over the range of mandrels they offer, differing in 0.0005 in size. I current Forster FL resizing dies for all my reloading.

How many of you use the turning arbor, or expander mandrel, instead of going down the route of setting neck tension using the the caliber specific expander mandrel kits? I found some chatter about this in light discussions from thread a few years ago, but thought I would ask in a dedicated thread.

References:
0.002 Turning Arbor: https://21stcenturyinnovation.com/buy-online/ols/products/black-nitride-turning-arbor
Caliber Specific Mandrel Kit: https://21stcenturyinnovation.com/buy-online/ols/products/caliber-specific-expander-mandrel

I went with the kit for 6.5 manbun and I'm glad I did. With spring back, just picking a mandrel that "should" have given me .002" interference fit actually did not and I was glad that I could step thru the kit to find one that did.

Just me and I just recently bought this kit and am using mandrels for the first time...so I don't know that I'll get superior performance from using it but it damn sure satisfied my OCD tendencies! hahaha

 

[R_A_W]

6.5 manbun

haha definitely calling it this going forward

 

[FNG1001]

I went with the kit for 6.5 manbun and I'm glad I did. With spring back, just picking a mandrel that "should" have given me .002" interference fit actually did not and I was glad that I could step thru the kit to find one that did.

Just me and I just recently bought this kit and am using mandrels for the first time...so I don't know that I'll get superior performance from using it but it damn sure satisfied my OCD tendencies! hahaha

Did you get the whole kit, or picked from it? Which of the sized mandrels do you use the most? They have a great range.

 

[Rathmatik]

I've mostly used the Sinclair steel expander mandrels, measured 0.001" under bullet diameter. However, I've recently started using SAC neck bushings in a Redding Type S die and the concentricity is incredible, so I started skipping the mandrel.

 

[FNG1001]

Steel and TiN
View attachment 8148055

Thanks! Have you noticed any measurable improvement in SD and/or grouping? Ive read threads about steering clear of steel mandrels. Any negative experience with these? I was considering the black (coated) nitride .

 

[Baron23]

Did you get the whole kit, or picked from it? Which of the sized mandrels do you use the most? They have a great range.

I just got the kit so as to not have to dick with ordering another as the neck brass gets a bit thinner with use. Ah....later I'll have to look and see if I still have the one I used last still in the die. I'm shooting Berger 140 hybrid targets and they are .2635 on the bearing surface. So, I do remember the first time I used them I immediately went to the .2615 mandrel and found the necks were still too tight (spring back, yeah? And, they all were annealed with an AMP). I just stepped up in the mandrel kit until I got the .2615 I wanted.

I know, not much help and I doubt I'll use most of the mandrels in the kit, but I'm covered for what I need. Did the same with Vermont Gage's pin gauges that I bought from Travers Tool. Every .0005 over a pretty good range. They are like $4 each. I'm just that way...prob why I'm broke! ;-) haha

 

[spife7980]

Thanks! Have you noticed any measurable improvement in SD and/or grouping? Ive read threads about steering clear of steel mandrels. Any negative experience with these? I was considering the black (coated) nitride .

No but I spray lube my brass inside the necks so it’s not ever going to be an issue.

 

[CK1.0]

6.5 manbun

Not to get sidetracked lol...

But personally, I hate hearing/reading "6.5 man bun". It's cringy, and to me, it seems like a kowtow to all the rifle goofballs who think they are somehow cooler than other guys because they shoot some wildcat (usually Dasher/BR or another case that requires mag kits that fuck up every match even though they continue to say/post "mine runs 100%").

The 6.5 Creedmoor changed the game, and probably more so than any other case, is responsible for the growth of the long-range shooting scene. Yeah, a lot of guys new to the sport shoot it... but so do guys like Morgun King, arguably the best guy out there.

IMO, it's still the best choice for a shit ton of guys out there, and I don't like it when wannabe rifle guru guys put it down just for being ubiquitous. I don't even have one, but I kind of want to get one due to all the shade that gets thrown at it since it's not cool enough.

Honestly, when someone says they shoot Dasher/BR/BRA/BRX or something like that, it's hard not to think "Here we go, another smarty-pants".

End tirade.

 

[OREGUN]

Not to get sidetracked lol...

But personally, I hate hearing/reading "6.5 man bun". It's cringy, and to me, it seems like a kowtow to all the rifle goofballs who think they are somehow cooler than other guys because they shoot some wildcat (usually Dasher/BR or another case that requires mag kits that fuck up every match even though they continue to say/post "mine runs 100%").

The 6.5 Creedmoor changed the game, and probably more so than any other case, is responsible for the growth of the long-range shooting scene. Yeah, a lot of guys new to the sport shoot it... but so do guys like Morgun King, arguably the best guy out there.

IMO, it's still the best choice for a shit ton of guys out there, and I don't like it when wannabe rifle guru guys put it down just for being ubiquitous. I don't even have one, but I kind of want to get one due to all the shade that gets thrown at it since it's not cool enough.

Honestly, when someone says they shoot Dasher/BR/BRA/BRX or something like that, it's hard not to think "Here we go, another smarty-pants".

End tirade.

TL;DR: CK1 says using the phrase man bun is small dick energy.

 

[Baron23]

"6.5 man bun"

Oh for fuck sake....when I got on this forum I was beat over the head with man bun, man bun, man bun ever time 6.5 CR comes up.

So not often, but sometimes in a whimsical mood I'll pop it out. Please don't triggered about it and take it up with your Iron Drum therapy group ;-) haha

wannabe rifle guru guys put it down just for being ubiquitous.

And I'm neither a wannabe anything and def don't try to pass myself off as a rifle guru. Its the caliber I shoot in my two precision rilfes.

See above about avoiding triggering! ;-) haha

 

[CK1.0]

Oh for fuck sake....when I got on this forum I was beat over the head with man bun, man bun, man bun ever time 6.5 CR comes up.

So not often, but sometimes in a whimsical mood I'll pop it out. Please don't triggered about it and take it up with your Iron Drum therapy group ;-) haha


And I'm neither a wannabe anything and def don't try to pass myself off as a rifle guru. Its the caliber I shoot in my two precision rilfes.

See above about avoiding triggering! ;-) haha

I wasn’t coming at you, sorry if it seemed as though I was…

And I’m not triggered lol, I just don’t think guys should have to make a joke or apologize for shooting a case that is honestly probably the right choice for a lot of guys.

I might have been over sharing something that has been bothering me is all.

 

[Baron23]

I wasn’t coming at you, sorry if it seemed as though I was…

And I’m not triggered lol, I just don’t think guys should have to make a joke or apologize for shooting a case that is honestly probably the right choice for a lot of guys.

I might have been over sharing something that has been bothering me is all.

Haha…no problem at all, my friend. All good

 

[OREGUN]

6.5 Creedmoor is an excellent, practical cartridge that actually has application to the real world outside of PRS. As gaming and gamers have taken over PRS, so have gaming cartridges.

Sorry for contributing to the thread drift, I've been here long enough to know most the guys that throw out the manbun moniker were sucking 6.5 Creedmoors dick 5-6 years ago when it was all the PRS hotness. Irks the shit out of me. The cartridges didn't change, the guys that shoot them have, and honestly I see more manbuns around the PRS scene now than ever before. That and Subarus.

If we are going to call 65CM a gamer cartridge, my question is, have you met the 6 dasher?


Honestly, I don’t feel like there is a “gamer” anything. The point is to make the plate go “ding” more than the other guy. Whatever gets there wins.

At least a 6.5 can kill an elk.

 

[Taylorbok]

I've had good luck with the stainless from 21st century. I skipped the kit and just ordered the individual mandrels .002" under bullet diameter for their respective cartridges, it's like $25 per caliber vs $175.

I'd like to try the nitride or carbide but I haven't had the need. I also spray lube in the necks

 

[Tokay444]

I eliminated the mandrel step from my process and haven’t looked back. I use a Redding Type-S die with no expander, and picked a S.A.C. bushing that gave me the same ID as I was getting with my mandrel, and my groups are just as tight as ever.
When I was using mandrels, the 21st Century black nitride we the slickest.

 

[OREGUN]

I eliminated the mandrel step from my process as haven’t looked back. I use a Redding Type-S die with no expander, and picked a S.A.C. bushing that gave me the same ID as I was getting with my mandrel, and my groups are just as tight as ever.

SD/es over 20+ rounds?

 

[CK1.0]

To get back on track a little, IMO the turning arbors (-.002" bullet OD) are probably a safe bet for most people, but if one wants to try some other sizes/ODs, no reason not to other than money.

That said, there's a lot of variation one can experiment with just by having one turning arbor/mandrel... as far as what neck tension/bullet grip they get... it will change by what size their FL die is honed to and/or depending on what size bushing one uses.

It's hard to quantify... just know that if you follow a .269" bushing with a .241" turning arbor/mandrel you'll get a different result than you would with a .266" bushing followed by the same .241" turning arbor/mandrel if that makes sense...

These days in 6mm I prefer what I get using a .266" honed die vs something larger, maybe over-squashing the case mouth/neck a bit (I anneal every firing so who cares) and I feel like the mandrel engages the cases a little more and I end up with a slightly more consistent result.

And besides, after noticing how much case mouths actually get fucked with when tumbling off the lube after sizing, I'll be sticking with the mandrel if only just for fixing that post-tumble.

 

[Tokay444]

 

[CK1.0]

IMO using a mandrel is better than not using one for a couple of big reasons, besides the obvious concentricity and neck tension reasons often cited.

First, using the mandrel to push any irregularities to the outside of the neck makes seating bullets more consistent/repeatable, it just does, and that may lead to a more consistent/repeatable BC (and with fancy bullets every little bit helps, BC is expensive these days).

Secondly, as I mentioned above, if one tumbles the lube off their cases after sizing, they're messing up their case mouths/necks probably way more than they know... and hitting the mandrel before seating bullets fixes the damage.

In the end, there are other reloading processes that I do that I loathe way more than the mandrel step, the mandrel step is quick and easy so there's almost no good reason to not do it IMO.

 

[OREGUN]

These days in 6mm I prefer what I get using a .266" honed die vs something larger, maybe over-squashing the case mouth/neck a bit (I anneal every firing so who cares) and I feel like the mandrel engages the cases a little more and I end up with a slightly more consistent result.

I one hundred percent agree with this. For a while now, I’ve been sizing the neck down smaller than most people. I want the mandrel to positively size the neck up…not to just barely kiss the neck walls because I’m not sizing down very much.

 

[CK1.0]

I one hundred percent agree with this. For a while now, I’ve been sizing the neck down smaller than most people. I want the mandrel to positively size the neck up…not to just barely kiss the neck walls because I’m not sizing down very much.

Yeah, in 6mm I used a .268" or .269" bushing for a long time before hitting the mandrel, and it was ok, the mandrel would just barely touch the cases, and to a certain extent I could maybe see why one might go back to a bushing-only because maybe they weren't seeing much difference with the mandrel.

But since going to a smaller bushing in order to get the amount of engagement I was looking for (so it didn't require too much effort, but I could definitely feel at the handle that the mandrel was really opening the necks back up), I have definitely noticed a difference for the better.

 

[Tokay444]

My TIR is less than .001” without a mandrel.

 

[Herb Stoner]

Yeah, in 6mm I used a .268" or .269" bushing for a long time before hitting the mandrel, and it was ok, the mandrel would just barely touch the cases, and to a certain extent I could maybe see why one might go back to a bushing-only because maybe they weren't seeing much difference with the mandrel.

But since going to a smaller bushing in order to get the amount of engagement I was looking for (so it didn't require too much effort, but I could definitely feel at the handle that the mandrel was really opening the necks back up), I have definitely noticed a difference for the better.

I made this move recently based on input I received here and, at least early on, its showing some improvement in concentricity and SD. I’m using SAC Modular dies and Porters Precision gage pins. Annealing is with an AMP so I’m not concerned about a little bit more working of the brass.

 

[Baron23]

So, for those who use mandrels and for those that don't.....how do you verify what you have in resulting neck I.D.?

I ask...and please understand that I'm really a novice metallic reloader....but for those who buy (for example) a .002 under bore diameter mandrel, after you run it how do you know what you have.

In my very limited experience, I was was quite surprised by the degree of spring back I encountered and I had to go to larger than anticipated mandrels to get the .002 interference fit I was aiming for. This was once fired Lapua 6.5 CM case from Berger ammo that was annealed with an AMP.

I used pin gauges to check. Hey, it occupies my retired time and keeps me off of the street! hahah

Of course there is always the true thought that if the ammo shoots well then who gives a fuck. LOL

 

[CK1.0]

So, for those who use mandrels and for those that don't.....how do you verify what you have in resulting neck I.D.?

I ask...and please understand that I'm really a novice metallic reloader....but for those who buy (for example) a .002 under bore diameter mandrel, after you run it how do you know what you have.

In my very limited experience, I was was quite surprised by the degree of spring back I encountered and I had to go to larger than anticipated mandrels to get the .002 interference fit I was aiming for. This was once fired Lapua 6.5 CM case from Berger ammo that was annealed with an AMP.

I used pin gauges to check. Hey, it occupies my retired time and keeps me off of the street! hahah

Of course there is always the true thought that if the ammo shoots well then who gives a fuck. LOL

I’ve always thought of the obligatory/ubiquitous “2 thou of neck tension” as an arbitrary thing… most seem to base their calculations on something like neck OD more so than actual measured interference fit.

For me, I don’t have any pin gauges to measure the actual ID of the necks post-mandrel… I’ve just been using a .241” mandrel for long enough where I can feel a difference between what a .268” vs a .266” bushing feels like both when the mandrel is going in and out of the cases and when seating bullets…. in my case, if I had to guess, the interference fit would probably be more than 2 thou measured with a .241” pin gauge. Feels right, shoots right though.

 

[straightshooter1]

So, for those who use mandrels and for those that don't.....how do you verify what you have in resulting neck I.D.?

To find my neck's ID, I measure the thickness of the neck with a ball micrometer, multiply that number by 2 and subtract that from my OD measurement. Otherwise, I measure the neck's OD before seating a bullet and then after seating and the difference tells me my "neck tension".

 

[Tokay444]

So, for those who use mandrels and for those that don't.....how do you verify what you have in resulting neck I.D.?

I ask...and please understand that I'm really a novice metallic reloader....but for those who buy (for example) a .002 under bore diameter mandrel, after you run it how do you know what you have.

In my very limited experience, I was was quite surprised by the degree of spring back I encountered and I had to go to larger than anticipated mandrels to get the .002 interference fit I was aiming for. This was once fired Lapua 6.5 CM case from Berger ammo that was annealed with an AMP.

I used pin gauges to check. Hey, it occupies my retired time and keeps me off of the street! hahah

Of course there is always the true thought that if the ammo shoots well then who gives a fuck. LOL

For me it’s less about the physical dimensions I’m left with, and what shows up on target. I use a .265” bushing and press a bullet in.

 

[Tokay444]

View attachment 8149152

This includes my first shot on a clean barrel, which I've logged as being up to 80fps slower than average. I could delete that 2798, but it is what it is.
I run my Magnetospeed on an MKM mount on my arca rail, so that it never touches my barrel. I have data on almost every shot that's left my barrel save for the ones in competition, and I quickly came to the realization that the mandrel was a waste of time at the bench for me.

 

[Trevor]

IF you are looking to get into neck mandrels, i would suggest pin gauges; sourced from any online tool company McMaster-Carr or SunCoast and a collet bullet puller, you can buy a set of pin gauges for $40.
You will need to grind the edge off of one end of the pin.
Conduct your testing to find which size shows the best results.
Once you find the desired next tension, (for that specific bullet) than consider getting a dedicated carbide mandrel.

In my case .30 cal i bought pins from 304 - 3075 in .0005 increments and conducted tests, some sizes were easy to eliminate others required additional testing. My best results where .002 under, and as luck would have it I had a carbide neck turning mandrels in the proper size.

Someone mentioned spring back, it is an important consideration, and is consistent across your (same lot) of brass. As a result we can eliminate it as a variable in testing.

The only additional consideration, I use an 8 sec count to expand each piece of brass.

Trevor

 

[CK1.0]

IDK, for me it’s what shows up on target too, except I’ve experienced the opposite thing. Since adding the mandrel I’ve noticed much more consistency/repeatability shot-to-shot than I got previously when I was sizing bushing-only (expander ball removed). My ammo comes out the same level of awesome every time now without having to think about it, so when I suck, it’s me, there’s no blaming the ammo.

I don’t shoot as many shots over the chrono, as most of my practice is off obstacles, but I haven’t seen an SD that wasn’t a single-digit in over 2 years every time I’ve checked.

This is off a cattle gate and Shmedium, 750 yards, 6CM practice barrel way past its prime with a no BS 3000rds on it:

 

[R_A_W]

Is that a 1/3 ipsc?

 

[CK1.0]

Is that a 1/3 ipsc?

Yeah, think so, 35% I think.

I suck at all sorts of stuff, but I make pretty good ammo these days.

 

[R_A_W]

Are you seeing any velocity variance now that you’re @ 3000rds? That’s a pretty high count on a 6CM

Call it 4.5” with that top impact… 0.5-0.6 MOA off a cattle gate is great

 

[CK1.0]

Are you seeing any velocity variance now that you’re @ 3000rds? That’s a pretty high count on a 6CM

Call it 4.5” with that top impact… 0.5-0.6 MOA off a cattle gate is great

I’ve never run it faster than 2900fps and have always jumped ~.100” off, more so than anything else, I think that’s why the barrel has lasted so long.

Also, I didn’t clean the barrel with anything more aggressive than Bore Tech Eliminator, nylon brushes, and cotton patches for its first ~2200rds and thought it was dead…. But I brought it back to life with bronze brushes and Iosso and have been shooting it, still hammers.

I really didn’t know how to properly clean a barrel for the first 2200rds and have been more aggressive every 200-250rds since, now I let the borescope guide me.

I must be pushing it at this point and should retire it, but it’s still shooting… so I’m on the fence as to either pull it after hitting the range tomorrow, or keep going until it dies for real this time, IDK… I still haven’t experienced a speed drop-off yet, so who knows…