Mandrel v bushing dies on case necks?

[gabe ledesma]

In some of my early experiments with case forming i did try sizing cases with a mandrel instead of just using a bushing. This is with turned necks. I turned 10 cases ( 6ppc ) to 263. And then after i fireformed the cases i used a 256 neck bushing to size the neck down again. Next step was getting the right mandrel to give me just the right feel when I seated my bulletts. Back then i was using my own bullets that where flat base and had a very small pressure ring 243.2. OK these are the problems i acquired using a mandrel. The first 3 fireings On the 10 cases worked out ok but after that I started getting very Unconsistent bolt closure. The reason the bolt did not have a smooth consistent feel anymore was beacuse of our little friend, yes you guessed it the dreaded donut. After a few firings that donut was moving up the case neck and by using a mandre I was pushing that donut out and by doing so I was getting very unconsistent bolt tension ,And as our friend speedy gonzales says, thats bad ju ju. So for that reason alone i was convinced not to use mandrels on turned necks. I guess on unturned brass it can work ok but for the type of shooting i do ( benchrest ) its not for me.
Gabe

[Chism G]

Ive never done a mandrel vs bushing test, but I suspect that you will get mixed results from such a test.

Why?…because so much of the test results hinge on shooter skills. If I had the time and the dies and the interest,I would call Gene Beggs and reserve a session in his tunnel. I would use my Rail Gun to conduct the experiment. Just for the fun of it.

I imagine that “Ole Beggs”,would be delighted to report the findings. (Thats why I like him.)



Glenn

[CCrider]

Just testing I have sized with a button and then opened the necks up with a mandrel. Compared to just using the button I was consistently getting single digit Es when using the mandrel with the button, where my Es runs in the teens. Made no different on the target.

[Mram10]

In some of my early experiments with case forming i did try sizing cases with a mandrel instead of just using a bushing. This is with turned necks. I turned 10 cases ( 6ppc ) to 263. And then after i fireformed the cases i used a 256 neck bushing to size the neck down again. Next step was getting the right mandrel to give me just the right feel when I seated my bulletts. Back then i was using my own bullets that where flat base and had a very small pressure ring 243.2. OK these are the problems i acquired using a mandrel. The first 3 fireings On the 10 cases worked out ok but after that I started getting very Unconsistent bolt closure. The reason the bolt did not have a smooth consistent feel anymore was beacuse of our little friend, yes you guessed it the dreaded donut. After a few firings that donut was moving up the case neck and by using a mandre I was pushing that donut out and by doing so I was getting very unconsistent bolt tension ,And as our friend speedy gonzales says, thats bad ju ju. So for that reason alone i was convinced not to use mandrels on turned necks. I guess on unturned brass it can work ok but for the type of shooting i do ( benchrest ) its not for me.
Gabe

Thank you Sir. Appreciate the explanation

[Mram10]

Just testing I have sized with a button and then opened the necks up with a mandrel. Compared to just using the button I was consistently getting single digit Es when using the mandrel with the button, where my Es runs in the teens. Made no different on the target.

I need to try that.

[Mram10]

Let me preface. I shoot F class, Target Rifle & British Match rifle so my distances are from 300-1200 yards.

Over that range of distances, I've concluded that it's desirable to get loads with uniform low velocities & tweak them with tuners or devices performing a similar function to optimize performance generally over the full range I'm shooting. Where I can use a Lee collet, the results work for me, but where I can't do that, I use Wilson dies with no neck turn chambering, like my 6MM BR.

For the same reason, I moly all my pills & always jump my loads.

Definitely the ranges I’m interested in. Thank you

[Mram10]

I've waited to see were the replies might go before my own reply.

My simple answer is yes I have. I neck size using a bushing that produces a neck of slightly smaller ID than desired (0.001 under) then an expander die to open the neck to the desired ID size. Testing over the 4 cartridges I load for shows slightly smaller groups for those mandrel sized than those just bushing neck sized. Note that the reduction in group size is very small but for me it is worth the added effort.

Great info. Thank you

[Mram10]

Al,
You’re such a sad creature. Always looking for a way to call someone out for asking a “why”. Still don’t care what you think. I haven’t been snotty with anyone. Get a life. Plenty of good guys on here that answer questions understanding that the “why” is important. Nobody has time to read your 20 minute rants. I’ve really tried to like you but you’re just miserable

[alinwa]

[QUOTE=Mram10;829711] Always looking for a way to call someone out for asking a “why”. ...../QUOTE]

"calling someone out??"

"calling you out?"

I'm trying to help you.....

IMO if you just ask "why do people do it this way" you'll learn about things you've yet to consider.

Gabe Ledesma explained very well one of the problems and I'll add that even when one has developed a turning/forming/sizing method that eliminates donuts up front, the act of dragging the expander back through a resized neck even without a donut will reset the shoulder angle such that headspacing, or at least headspace feel (the thing Gabe described as unconsistent bolt closure) is moved from a solid abutment of the entire case shoulder against the chamber shoulder, to headspacing against the neck/shoulder junction. In short, it forces you the reset the headspace upon bolt closure. Consequently it requires you resize the shoulder/body junction back too far which, in the end, will always result in the formation of more donuts......new donuts..... even when they've been eliminated from the first few firings.

Top accuracy, in fact all accuracy that falls under the umbrella of "tuning" is primarily about vibration control. About getting the entire system to flex consistently from shot-to-shot.

And to achieve vibration control over multiple firings of a set of cases, one must FIRST achieve consistent sizing for consistent bolt closure feel, then one must form a system which will maintain it over multiple firings.

You don't need to "answer" this post..... this isn't some sort of argument.......but please think about the questions

[Al Nyhus]

I experimented with the mandrel method when shooting the 30 WareWolf (basically a .165 short 308 Lapua) my HBR gun. And no...it was not with any sort of Lee collet die lash up.

Initially, it seemed to show some slight accuracy improvement.

What I was actually seeing was that the mandrel was a bandaid for how bad the necks I.D.'s were. They were round but also tapered. Like this, top to bottom (exaggerated, if only obviously ):



After finding that, I made the neck I.D.'s perfectly round the on my fired cases and tested that. The results on previously neck turned cases was a train wreck. But on new cases, where the neck I.D.'s were made perfectly round before outside turning....the accuracy was better than it had ever been especially at 200 yards. Beggar 10's @ 200 became solid 10's and the 'almost-a-10' 9's @ 200 became beggar 10's. Grand Aggs are won or lost @ 200 and the Grand wins came with more regularity after that.

Since that, inside case neck work became part of my BR case prep routine, carrying over to the 30BR cases and even to the 30 WolfPup with the .085 length neck.

Does every case need it? It depends. If necking up or down, I do it. I did it on my 6PPC with the 220R cases and found nothing with both barrels. But on my 22BR, there was an improvement. My 20 Practical (necked down Lapua 223 cases) shows the same characteristics. I haven't fixed them yet, but I will and will test them next Spring.

I don't compete any more in registered BR tournaments but still consider the case neck I.D.'s to be a critical part of case prep if you're looking for BR level accuracy.

Good shootin'. -Al

[vtmarmot]

So, should I be investing in inside case neck turning tools as well as outside? And if I do, how to keep the insides of the necks concentric with the outsides?

For my benchrest rifles, and some others, I size with Redding type-S bushing dies. I have not had donut issues. For most of my hunting rifles I size with conventional dies but am careful not to bump the shoulder too much.

There is a third category of rifle that I use in more casual competitions such as egg shoots. I have been planning on some of these to use body dies in conjunction with Lee collet dies. I am talking about unturned necks here. Is this a sustainable method of preparing cases or will I run into trouble after a few firings?

[jackie schmidt]

The way most shoot the popular Short Range Benchrest rounds, bullets never get any where near the donut that will, regardless of our best efforts, form at the neck/shoulder junction after several firings.

That is why I consider it a non factor.

However, in disciplines where longer bullets are used, especially in a shorter throated chamber, it can be a huge issue if the shank of the bullet gets into the donut.

The best solution is to throat your chamber for a specific bullet so this never occurs.

[Al Nyhus]

So, should I be investing in inside case neck turning tools as well as outside? And if I do, how to keep the insides of the necks concentric with the outsides?

Well, therein lies the problem for most. There's no commercially available inside neck tools that do an adequate job. In fact, with one exception, most of them will make things worse.

And you're right to be concerned about keeping the inside of the necks not only concentric, but parallel with the outside. That's why the inside needs to be done first on virgin, unfired cases. Once that's done, you need a perfect mandrel fit on the neck turner to guarantee results. I have mandrels in .0005 increments to fit the neck I.D.'s after they've been made round and straight. At times, you'll have to straighten the necks relative to the case body before doing the necks. But that's easy to do with a little thought, a few neck bushings around the O.D. of an untouched neck and the tools and ability to measure it.

One thing you'll find when doing necks this way....there's very little heat generated when turning the outside of the necks. That alone tells a lot....

Very few want to go down this road, though. It's a lot of time, some investment in gear and rethinking for minimal returns. But if don't want to leave anything on the table, it's worth looking into. -Al

[alinwa]

Well, therein lies the problem for most. There's no commercially available inside neck tools that do an adequate job. In fact, with one exception, most of them will make things worse.


Very few want to go down this road, though. It's a lot of time, some investment in gear and rethinking for minimal returns. But if don't want to leave anything on the table, it's worth looking into. -Al

BOOM!!!

.............Very few want to go down this road, though. It's a lot of time, some investment in gear and rethinking for minimal returns. But if don't want to leave anything on the table, it's worth looking into. -Al

Well said Al, thank you


AND..... there's more.


But before "more" can possibly be discussed it must be said that this isn't an easy problem...... it's in fact one of the bitterest conundrums in the shooting games.

#1-"how do you MAKE good cases?"
#2-"how do you KEEP these cases good?"


Ya' wanna' ANNEAL?
Ya wanna' just MAKE NEW CASES EVERY MATCH?
Or do you wanna' completely rethink everything you ever knew about reloading?
Ya wanna' own 6 reamers and spend more on reloading dies than you did on the barrel(s)????


Welll, the answer is...... how good you wanna' be?

Most folks stop long before Big Al The Nyhus...... LOOOONG before.

But then most folks aren't swapping out a crappy ol' Roush motor for a Ferrea'd up Bischoff neiyther now.......


are they

[michaeljp65]

There is a new machine out called the IDOD. Turns the inside at same time as outside. https://www.youtube.com/watch?v=Qx6MNdIijxg