Expander mandrel as an option

JCSC · Oct 22, 2020

If I want to attempt I have more consistent neck tension, vs FL sizing, can I remove my expander ball and use the FL die to bump the shoulder the appropriate amount and then run a mandrel thru to hold a consistent diameter?

I notice that I get slightly different feels when seating bullets and my calipers showed some variations from case to case.

how much neck tension is recommended for a bolt gun vs gas gun and should i use a lubricant of some sort prior to seating? I generally do not crimp, even with the gas gun.

I’m really trying to take my loads for the 6.5 to a slightly higher level of precision and I have done nothing more than FL size thus far.

iShoot17 · Oct 22, 2020

You should be using the expanding mandrel after completing the sizing step. You are correct in removing the decapping stem and expander ball from the die prior to sizing.

As for lubricating the necks, I will dip certain rifle cartridges in Imperial Neck Lube media prior to running through the mandrel. It isn’t a consistent practice though and I can’t say I can shoot the difference when I do.

As for crimp - I don’t crimp rifle cartridges, even 223 out of a semi. The only time I use crimp dies is on magnum revolvers.

Something that you can learn to “feel” to help your game is seating pressure. As you continue to seat rounds, and have a consistent hand pressure, you’ll feel ones that are easier or more difficult to seat. I can say that I’ve seen differences in these while on the range.

Demi-human · Oct 23, 2020

How many firing cycles on the brass?
Are they all of one lot?
How long do you dwell the brass in the die?
When were they last annealed?
Did you lube each neck the same? I lube necks.

Yes.

The expanding mandrel will help keep straighter necks and a smoother seating, but there is much more to neck tension than the mandrel size.
And once we’re talking neck tension by mandrel size, it is often so light it doesn’t coincide with a Gas Gun.

My target rifle brass has one thousandth interference.
My AR I size to four thousandths under, -.004. This required a honing of the sizing ball, as I do not mandrel these.
I anneal every cycle, because the brass will harden differently upon firing.
This varying hardness gives it different spring back when sized down, and then back up with the mandrel. That causes different seating pressures you are feeling in the press.

What is the end use of this ammunition? That has a lot to do with how far one looks into the dark.

(I stopped before I bought the K&M hydraulic seating pressure gauge.)

JCSC · Oct 23, 2020

Demi

one firing on this 65 CM brass and it is hornady, not of the same lot.

it has never been annealed, although I do anneal my Grendel brass occasionally by hand.

I have never tried to dwell when sizing. Usually just the normal up down. Hadn’t ever thought of that.

I lube consistently when sizing with hornady one shot. My lubricant comment was me wondering I you lube the bullets to help them seat smoother.

I have a pretty good feel on the press with a good amount of loaded rounds under my belt, but I I have always noticed some pressure inconsistencies when loading. I threw a mic on these to verify they were the sized batch and I got .259/.260, so .004”.005” tension. That sounds good for the gas gun and excessive for the bolt.

I planned on Ill advice for mandrel sizing gas gun brass, but figured I would ask, because if I can use the same process on both these 65’s I would have.

end use is ultimately the most accurate creedmoor match ammo I can load within reason. I have dialed in a sub MOA spire point hunting load and I have a batch of 140 bthp a I am going to load and see what the guns capability is.

I appreciate your time and comments. Thanks!

Demi-human · Oct 23, 2020

There is no reason you can’t use the same load process with both guns. The auto may not see the full extent of the benefits of the process, but it will stream line the loading process and keep things less complicated.
Though, the joy of seating after mandrel expanding is worth the double sizing strokes on my shoulder.

I have two die sets for the same cartridge because my target rifle gets Filet Mingon, and while they fit and shoot well, the time expenditure is too great for the mass the AR requires.
On occasion, even I would sometimes rather be shooting.

(Single Dad Priority Planning Powers... Activate!)

243winxb · Oct 23, 2020

JCSC said:
consistent neck tension,

Outside neck turn brass. I can neck turn 223 brass & still use my standard RCBS fl die/ with expander, for bolt action. Turning removes the factory donut & allowes the expand easy exit from the case. The factory donut is different from brand to brand. Some more then others.

JCSC said:
how much neck tension is recommended for a bolt gun vs gas gun and should i use a lubricant of some sort prior to seating?

Bolt- .0015" to .002" Auto .002" minimum , MORE if there is bullet movement from chambering. Test change in col , before, after chambering. The .002" neck tension will provide the 35 pounds bullet pull minimum, military standard. (5.56)
I lube & brush inside all necks. Even brass that is neck turned & no expander is used.

243winxb · Oct 23, 2020

JCSC said:
not of the same lot.

Buy 100 new brass , minimum. All of the same lot. Uniform flash holes. Trim all to same length. Uniform primer pockets (i dont). Neck turn.
Sort brass by 3/10 gr weight.

After all this, you may shave 1/4" off your 100 yard average group size. Or not.

jmorris · Oct 23, 2020

I notice that I get slightly different feels when seating bullets and my calipers showed some variations from case to case

What variations and how much? Using brass all from the same lot?

I’m really trying to take my loads for the 6.5 to a slightly higher level of precision and I have done nothing more than FL size thus far.

What are you getting now, what have you gotten with premium factory ammunition and what level is your goal?

Blue68f100 · Oct 23, 2020

Your opening a can of worms where these is no end. We all have been down this route that want to shoot the best we can get. I would start with annealing the brass, before sizing, after cleaning so it's easy to see the thermal oxidation bands. I turn all my necks so there all the same, no thick or thin walls. Then you have a couple of options. You can use your same sizing die, and just move the shoulder back the bare min 0.001". Or you can use a bushing die to set how much neck tension you want, or go custom honed neck. This way nothing touches the inside of the neck. Or size the necks just a tad under then expand it back out, separate step using a Mandrel die with the correct size to yield what you want.

Personally I would not use the OS for sizing. I would switch over to Imperial Sizing wax since it will give you a more consistent feel.

Like said buy good quality brass all the same lot, makes things easier in the long run.

JCSC · Oct 27, 2020

Just wanted to thank everyone for the responses.

I had the opportunity to shoot some handloads ladders with the ruger this weekend and I can’t say that I need to do much in regards to additional brass prep. I had some 140 hobby and 123 eldm blems.

140 shot .8 - 1 1/4 groups in 4 strings
123 shot .6 4 shot groups in the first two strings I ran. I had to cut it short and could finish the other 3 strings.
This gun shows some real promise in the accuracy department.

I need to try some heavier 143’s once I find them available locally.

Expander mandrel as an option

JCSC

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