can i lap a 44mg FL size die for less neck tension?

[bmortell]

for me in 44 mag with fatter rifle diameter boolits in brass I get a lot of neck tension and it causes soft lead to get slightly boat tailed by a couple thousandths. so I think that might be the only reason I need hard lead to get accuracy because the case is changing them and not because there too soft. I have a carbide sizer that I normally use but I also have the steel one I had first. is there any reason im not thinking of why I cant just lap the old one bigger? I have made a few push through sizers bigger to and exact size I wanted and a good finish. just using sandpaper wrapped on a drill rod and the switch to paper with 3 micron diamond paste and slugged as I went. im assuming the die the only thing id need to do different is making sure I increase size evenly from front to back? or is there something about the design or shape of the die that makes it more complicated. and is there a good way to quantify how much neck tension I want or need in 44 mag rifle. like have the brass expand "x" thousandths when seated, what might that number be? thanks

[44magLeo]

On my Marlin it likes cast at .432 or .433. I use an NOE M style expander button in a Lee universal expander die. I bought two sizes, one is .434x.430, the other one is .436x.432. My die set has a .429 expander.
With these three sizes I can set the neck tension where I want it.
If you want to try adjusting your steel sizer I can't see why it wouldn't work. Most cast bullets need about .001 or .002 neck tension. You can open the sizer enough to give you an inside diameter of the case mouth .001 to .002 smaller than your bullet diameter.
This will work fine for the lot of brass you used to adjust the die. If you change the brass the ID of the case mouth might change. A thinner walled case neck will have less tension than a thick walled cases neck.
You might adjust the neck size of your die to give you, say a .429 or .430 ID then use an expander to go up to the size you want. This way the die will work on thin or thick walled cases.
Will it increase case life? I'm not inclined to think so. Straight walled pistol cases tend to fail from the crimping than sizing.
I would suggest you try the NOE expanders in the Lee universal expander die.
I use this same set up to expand other rifle cases to shoot cast bullets.
Leo

[DougGuy]

What powder drop do you use? If you use a powder thru expander it might be easier to get a custom expander made, everything would be concentric.

Also, if boolits are soft enough that the brass swages them down, it would seem that they would be soft enough to obturate to fit the throat upon firing and that would in turn fix the problem, IF in fact a problem exists.. You're only measuring boolits that haven't been fired.

[dkf]

The carbide will take a very very long time to open up with emery or lapping paste. Much longer than hardened steel push thru dies. I use a regular .44spec/mag Lee sizer for cast (followed by the right sized NOE plug for the bullet size) and a Lee .44mag "U" carbide sizer for jacketed along with the regular Lee expander that came with the die set. The regular Lee carbide sizer that came with my .44spec/mag die set sized too large for jacketed, both .429" and .430" jacketed bullets did not have nearly enough neck tension. I primarily use .432" cast bullets.

[country gent]

You can lap the die out a steel die would be best. The issue will be most of the sizing in a pistol die is done at the base, this is why the short carbide rings work so well. Lappping the die bigger may cause issues with chambering of the sized cases do to them not being sized enough. Also the slightly larger case may cause problems with other dies in the set. A new expander of the desired dia and length might be the way to go. Opening the case up a few thousandths will affect how it enters the belling expander die seating die and the crimp.

[GBertolet]

In my 1894 Marlin 45 Colt, I just set up the carbide die to size about 3/8" of the case, just enough to grip the bullet well, leaving the rest of the case unsized. Most Marlin's have generous chambers, so you can go quite a while, (depending on your load ), before full length resizing is necessary. I just load to traditional ballistics ( 255 gr @1050 fps from the rifle).

I have the original steel die also, which I did lap, to size the cases less, when FL sizing becomes necessary. All my dies are RCBS, and the steel sizer, is tapered from the factory, which turns out to be great.

Depending on what make of dies you have, RCBS makes a Cowboy expander ball, in 44 cal, which opens up the case a little more, handling cast bullets better, without having them swaged upon seating.

[bmortell]

Also, if boolits are soft enough that the brass swages them down, it would seem that they would be soft enough to obturate to fit the throat upon firing and that would in turn fix the problem, IF in fact a problem exists.. You're only measuring boolits that haven't been fired.

I do see signs of base gas cutting on air cooled coww but not on heat treated 50-50 or HT WW.

or maybe I should stop being stubborn and order a mold for my marlin that actually has a gas check. feel like that would make it easier to get consistent accuracy as people tend to say with the gun

[1hole]

Well, you certainly could lap the steel die with common materials but steel "straight line" cartridge dies are made with a bit of taper anyway. So, before you do anything else, try sizing your cases only halfway (or less) down and see if you can't get the inside where you want it without bothering with an expander at all.

I started loading 240 gr. SWC for my then new S&W M-29 in '67. In my long experience loading cast for .44 mag I'm puzzled over the obsession some experts have for oversize cast bullets. I've learned it's difficult to the point of impossible have a lead alloy that's too hard for the ignition and start pressure of a full power .44 mag load to fail to swell and fully obturate the bore before the bullet enters the forcing cone. Meaning the precise start diameter of medium to heavy cast bullets in a .44 mag load is almost irrelivant. IMHO.

Silicon carbide "sand" paper (black) will work fine to lap case hardened steel sizer dies but the ONLY thing that will cut tungstun carbide sizers is diamond and few of us have any tubes of fine diamond paste lying around.

[mdi]

I'm reading the OP wants less neck tension, not a sized base. I think the easiest way to remedy the situation would be a Lyman M die. I'd try that before modifying a die, easier. The larger case mouth may not swage the softer bullets down...

[bmortell]

I thought about the noe expanders but they only have .434x.430 which I measured the expanders in my 2 sets of rcbs dies and they are .4298, so upon careful consideration I decided I will hit one with a hammer. I don't need 2, so if I clamp one in a vice and convince the end to peen a bit wider I can just make my own. I have the ability to increase size that way either cold or hot and mic and polish back down if needed, plus I have a v block concentricity gauge to check straightness relative to the threads. what could go wrong !

[Taterhead]

Yeah, the ticket is an expander plug that is about 1-2 thou smaller than bullet diameter. The sizing die undersizes the neck ID (as the OP has stated). The expander of appropriate size and length will open it back out to the needed ID and depth of the neck ID.

[bmortell]

I tried my fix it with a hammer method, but first I want to correct that the stock expander was .425 diameter not .430 I was off by a whole 5 line in the mic so I want to correct that false info.
but I took the stock expander beller and touched it with a file above the bell spot to make sure its not too hard to hammer. then I set the knurled end on a anvil and hit the opposite end around evenly with a hammer and got it swelled trumpet shaped to about .434 diameter. it did develop tiny vertical cracks on the round chamfer but I think its still plenty strong enough for its job. of course it didn't swell perfectly round so I lowered the high spots then put it in the drill press and stoned and sanded till its .431, I made a dummy round to test measure and after my new expander seating my .4325 boolits expand the brass by .002 which is much better than stock.
so I guess you can modify your regular expander. or atleast if you have a spare one.

[44magLeo]

bmortell, NOE makes a .436x.432 expander plug. I know because I have one. I also have the .434x .430 plug. The o0ne is listed as a pistol plug the other a rifle plug.
The expander in my Lee die set is .427 then tapers up to .436 where it stops at a shoulder. My RCBS set has an expander that is .424 then tapers up to .465, the size of the threaded section. Both of these would probably be ok for a 44/40 that is a .427 diameter .
As a matter of fact I do Have an older Lee 44-40 set. The expander in that set is the same as the one in the 44 mag set. .427x.436.
I have a 310 set, the M die has an expander marked 429, it measures .4325x .428.
I have 5 sizes of expander plugs to use.
If you want to try honing out your steel die , go for it. Just don't go to far.
Leo

[gloob]

Also, if boolits are soft enough that the brass swages them down, it would seem that they would be soft enough to obturate to fit the throat upon firing.

Can't say for 44 mag revolvers. But, IME in reloading soft cast for Glocks, "case-swaging" of the base of the bullet can definitely ruin your day, even if the bullet is full diameter further up. Who'd a thunk it? I wouldn't have until I saw it for myself.

Yeah, the ticket is an expander plug that is about 1-2 thou smaller than bullet diameter.

That's fine for hard or jacketed bullets. Or when it doesn't otherwise matter. But sometimes it does matter. Going 1 thous smaller might give you a bit of a margin in case your bullets are not consistent, but this can still deform a soft boolit (especially if the case mouth is thick or of a hard alloy.)

If the expander is the same diameter as the bullet (provided the size die is tight nuff to begin with, as OP has described), the case mouth will contract back 1-2 thous after the plug is withdrawn, and you will basically retain full neck tension while minimizing "case-swaging." You can also make a plug smaller much easier than making it larger.

[Taterhead]

Can't say for 44 mag revolvers. But, IME in reloading soft cast for Glocks, "case-swaging" of the base of the bullet can definitely ruin your day, even if the bullet is full diameter further up. Who'd a thunk it? I wouldn't have until I saw it for myself.


That's fine for hard or jacketed bullets. Or when it doesn't otherwise matter. But sometimes it does matter. Going 1 thous smaller might give you a bit of a margin in case your bullets are not consistent, but this can still deform a soft boolit (especially if the case mouth is thick or of a hard alloy.)

If the expander is the same diameter as the bullet (provided the size die is tight nuff to begin with, as OP has described), the case mouth will contract back 1-2 thous after the plug is withdrawn, and you will basically retain full neck tension while minimizing "case-swaging." You can also make a plug smaller much easier than making it larger.

I agree wholeheartedly that Glocks don't tolerate undersized bullets. Stock Glocks consume the majority of my cast bullet reloads.

YMMV, but I have found less than acceptable neck tension when expanders are the same diameter as bullet diameter. Most of what I load and shoot are auto-loaders and some revolvers, so we might have different experiences.

1-2 thou and my PCed alloy (3% Sb, 1% Sn) gives proper neck tension and no swaging -- for my ammo. I don't load anything that requires soft lead.

[bmortell]

I finally did test shooting with 10 shots of each stock expander and my modified .431 expander. before either I stole my leupold vx3 from another gun and mounted it with good rings to proper inch pounds cleaned the bore and re fouled it during sight in, used sorted boolits ect. trying to make everything perfect. and how life normally goes I got no helpful data. both shot average of 1.2" at 25 yds which isn't great since my aperature sight groups were only 10-20% bigger and I don't think im someone who can aim irons that great so I thought it was mostly my eyes making that size. then I grabbed a few jacketed factory loads I have left and they shot 2.5" so idk. guess ill just try different powders and charges for my cast

[gloob]

I read the post where you thought about it, but I missed the part where you actually pulled it off. So I had to go back and find/read your post #12, lol. That was a slick trick with the hammer!

Taterhead, yeah, we have a different experience. I have used a 356/360 NOE expander with 356 MBC Smallball 9mm with no problems with neck tension. This worked out so well, I decided to make my own expander for 10mm/40. I couldn't find one a full 401 thous, and I had problems with cast in my Glock. These both worked so well, I went ahead and I bought a 452 expander for 45 ACP, even though I never had a problem in that caliber, before. You see, even manufacturers like NOE don't normally make expanders that big. The fact I could buy the 9mm and 45ACP in full cast bullet diameters of jacketed +1 thou is only because of the existence of .357 and .45 Colt, or something like that. So you're definitely in good company with your thoughts, here.

But I later jumped on Zero's jacketed bullet deals, and I tried leaving these oversized expanders in there. And the neck tension was still fine, to my testing and satisfaction. So I have loaded and shot many hundreds that way with no problem, using an expander that was a thous larger than the bullets. In all 3 of these calibers.

I am also no stranger to the occasional experience of poor neck tension in two different calibers. In both my cases, this was due to a combination of bad pickup brass with thin walls and the fact my size dies in those two calibers are rather generous/loose, right at the bare minimum sizing to begin with. In both of those cases, I threw out the offending headstamps, and I was right as rain. Oh, that was before I ever loaded cast or used oversized expanders, too, so the expander had nothing to do with it.

[bobthenailer]

A+ on turning down the expander size a few thousands , use a drill press if yo have one or a regular drill and polish the expander to desired dia using fine sand paper 500 to 800 will do.

[1hole]

My experience with cast in Glocks is limited to one. I load medium hard 200 gr./.452" SWC in range brass and using common dies for my 1911; my friend's .45 ACP Glock swallows my ammo like M&Ms and accuracy is very good for both of us. What am I doing wrong?

[44magLeo]

The 45ACP is a straight walled case with no taper. The 9mm case has a taper. Fat bullets in a 9mm causes a bulge in the case, or is just too big to chamber. On the 45 ACP the chamber is a bit more generous.
Leo