M die question
- Thread starter zeek
- Start date
Ian
Notorious member
The rifles really need a specialized neck expander/bellmouth sort of die. I prefer the RCBS cast bullet dies and spuds myself, but there are lots of options.
You can get a Lee "Universal Expander" die (which is just a belling die) and get proper inserts for it from NOE Bullet Molds, or try and use it like it is just to make flares.
The problem is rifle brass necks are hard and factory sizing dies make the necks too small for cast bullets. A better solution for cast bullets is use Lee collet neck sizing dies and adjust them so they only squeeze the neck down enough to hold the bullet (.002-3" interference fit), or use the more expensive bushing neck dies with selectable bushings, then bellmouth or use the M dies or others to uniformly expand the necks and also bell or make a "start" at the mouth for your cast bullets so they don't get scraped when seated.
If you buy an M-die for .30-caliber, get the "31" size because the 30 is for jacketed .308" bullets.
You can get a Lee "Universal Expander" die (which is just a belling die) and get proper inserts for it from NOE Bullet Molds, or try and use it like it is just to make flares.
The problem is rifle brass necks are hard and factory sizing dies make the necks too small for cast bullets. A better solution for cast bullets is use Lee collet neck sizing dies and adjust them so they only squeeze the neck down enough to hold the bullet (.002-3" interference fit), or use the more expensive bushing neck dies with selectable bushings, then bellmouth or use the M dies or others to uniformly expand the necks and also bell or make a "start" at the mouth for your cast bullets so they don't get scraped when seated.
If you buy an M-die for .30-caliber, get the "31" size because the 30 is for jacketed .308" bullets.
I use the K&M expander die since it is the easiest to change. Also, it is the easiest for which to make custom expander plugs.
I have the RCBS setup, but changing the expander plug is not easy.
When I began, I would take the next larger expander plug and worked it down to be the size I wanted plus .001. This .001 extra was to allow for brass springback after pulling it through the resizing die.
I have the RCBS setup, but changing the expander plug is not easy.
When I began, I would take the next larger expander plug and worked it down to be the size I wanted plus .001. This .001 extra was to allow for brass springback after pulling it through the resizing die.
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Spindrift
Well-Known Member
I mostly use the Lee «universal» flare die, with the appropriate expander plug from NOE. The plugs from NOE are available in many sizes, giving you many options regarding neck tension. I also have the RCBS expander die. Both systems work well.
The powder-through expanders commercially available (that I’ve seen) seem a bit short for rifle bullets.
The powder-through expanders commercially available (that I’ve seen) seem a bit short for rifle bullets.
CWLONGSHOT
Well-Known Member
Agreed not REQUIRED, but darn helpful!!!!
Same said for the LEE die using NOE expanders.
As a rule I dont load cast without them.
I made a video on the M-Die some time back. Hope you enjoy
rumble.com
Same said for the LEE die using NOE expanders.
As a rule I dont load cast without them.
I made a video on the M-Die some time back. Hope you enjoy
The Lyman M-Die
Short introduction into a die that I've used for many years. Its not new, it's really tailored to the cast bullet and it helps immensely with proper an squarely seating of your bullets. It stops shavi
rumble.com
Petrol & Powder
Well-Known Member
Lots of good comments but I think dannyd was the most succinct.
Spindrift also introduces a good option. The Lee universal expander die coupled with the appropriate expander plug from NOE is a good option. With that setup, you don't use the plugs that come with the Lee die, you're just obtaining the Lee die for the die body that the NOE plugs are designed to work with. Not only does NOE offer a lot of options for expander plugs (you have very good odds of finding the one you need) but they are also inexpensive. This allows you to buy one die body and plugs for all of the cartridge/bullet combinations you want expanders for.
The "M" die profile is a simple concept. It is a good expander in general, but I think it is particularly well suited for loading cast bullets. It allows you to expand the case neck to the desired diameter AND depth, something many flare type expanders do not permit. In addition to better control over the expanding process, the "step" at the top of the expander plug produces a much better case mouth to receive cast bullets. The standard expanders that "flare" the case mouth like a funnel can work but too often they end up being a compromise between the necessary amount of flare and the correct depth that the expander enters the case.
As for powder through expanders, either with or without the "M" die profile, they can save you some case handling during the loading operation, but I would rather have the appropriate expander profile than the convenience of a powder through die. So, if the choice was the convenience of a powder through expander OR the correct expander - the correct expander will win every time.
Spindrift also introduces a good option. The Lee universal expander die coupled with the appropriate expander plug from NOE is a good option. With that setup, you don't use the plugs that come with the Lee die, you're just obtaining the Lee die for the die body that the NOE plugs are designed to work with. Not only does NOE offer a lot of options for expander plugs (you have very good odds of finding the one you need) but they are also inexpensive. This allows you to buy one die body and plugs for all of the cartridge/bullet combinations you want expanders for.
The "M" die profile is a simple concept. It is a good expander in general, but I think it is particularly well suited for loading cast bullets. It allows you to expand the case neck to the desired diameter AND depth, something many flare type expanders do not permit. In addition to better control over the expanding process, the "step" at the top of the expander plug produces a much better case mouth to receive cast bullets. The standard expanders that "flare" the case mouth like a funnel can work but too often they end up being a compromise between the necessary amount of flare and the correct depth that the expander enters the case.
As for powder through expanders, either with or without the "M" die profile, they can save you some case handling during the loading operation, but I would rather have the appropriate expander profile than the convenience of a powder through die. So, if the choice was the convenience of a powder through expander OR the correct expander - the correct expander will win every time.
JonB
Halcyon member
zeek,
welcome to the forum.
"necessary"...IMHO, it's only necessary when it's necessary.
Ian, spells it out in his complete post above, I just quoted the one sentence as that's what I use for expanding rifle caliber case necks...and yes, I do this on all that I reload...but I imagine there is some instances where it isn't necessary.
Snakeoil
Well-Known Member
Here is my reasons for why the M-die is a key part of cast bullet reloading.
1. It makes a short socket into which you can place the bullet before placing into the shell holder.
2. Keeps the bullet straight when being seated into the case
3. Prevents the case from shaving lead or lube as the bullet enters the case.
4. Provides a proper lead for the bullet without overworking the brass like a flaring type tool does.
I make M-die plugs specific to the cartridge/bullet being loaded. I just made one today for one of the guys I shoot with. I've made them from various types of dies. The guys at the club keep a looking for dies at garage sales for cheap money or free at gun shows and give them to me as cores to make M-dies.
If you have access to a lathe, making the plug is easy. Make the longer guide portion of the plug the ID of your sized case neck. Them make the step 0.002 bigger than the size of the bullet to allow for spring back of the brass. Make the step no more than 0.100 long. I polish, harden and repolish mine. But I've also made them unhardened and they work fine as well. I normally adjust the die so that when I put a gas-checked bullet in the case, it goes in about the dept of the gas check.
1. It makes a short socket into which you can place the bullet before placing into the shell holder.
2. Keeps the bullet straight when being seated into the case
3. Prevents the case from shaving lead or lube as the bullet enters the case.
4. Provides a proper lead for the bullet without overworking the brass like a flaring type tool does.
I make M-die plugs specific to the cartridge/bullet being loaded. I just made one today for one of the guys I shoot with. I've made them from various types of dies. The guys at the club keep a looking for dies at garage sales for cheap money or free at gun shows and give them to me as cores to make M-dies.
If you have access to a lathe, making the plug is easy. Make the longer guide portion of the plug the ID of your sized case neck. Them make the step 0.002 bigger than the size of the bullet to allow for spring back of the brass. Make the step no more than 0.100 long. I polish, harden and repolish mine. But I've also made them unhardened and they work fine as well. I normally adjust the die so that when I put a gas-checked bullet in the case, it goes in about the dept of the gas check.
Snakeoil
Well-Known Member
You gotta work with the tools you got. I have to admit that I don't think of doing things that way since I have the machine tools at my disposal. But I have suggested the drill press "technique" to others in the past when they needed to trim a thou or so off something round.
When you get gray hair, "pretty" is open to interpretation.
When you get gray hair, "pretty" is open to interpretation.
Petrol & Powder
Well-Known Member
/\ Spot On /\
That "socket" that Snakeoil speaks of is also useful when using a progressive press. The "socket" feature holds the bullet in the proper alignment when the shell plate is rotated. This may seem like a small thing, but it matters.
I also agree that the "step" works the brass less. While on a flare type expander that makes a funnel shaped case mouth you can adjust the depth of the expander to get the desired amount of flare BUT you are then stuck with whatever depth the main portion of the expander ends up reaching. Again, this may seem like a small feature but it matters.
I've also found that for handgun ammunition and cast bullets the proper diameter for the main portion of the expander (not the step), you generally want the diameter of the expander to match the diameter of your bullet. After the expander is removed, the brass will spring back a little and you will get the proper amount of neck tension without the brass sizing the bullet down farther.
For example: If you're using a cast bullet that is .358" you want the expander to also be .358" in diameter. When the expander is withdrawn the brass will spring back a little and you'll end up with an expanded case diameter of roughly .3570" -.3575" and the correct neck tension.
This isn't a hard rule but it's a good place to start.
I have M die and Lee expander but recently finding (for 30/30) my needle nose does a better job. I don't trim brass much. Pin tumbling and M die leave a small sharpish edge that the pliers smoothes out so shaving happens less often. Pistol brass gets the Lee tool as does 308. BO gets the pliers. M or NOE used just to expand the neck. I have a chamfering tool that gets used on recently trimmed only, inside and out. Still trying to figure out why I sometimes don't get shaving on the base band but on the drive band of the PCd rifle bullets. Happens just above the 'lube' groove. Somehow the neck curls back. Could be mis-aligned bullet seating but I don't see any 'runout' looking at loaded ammo. Snake swallowed egg problem?
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Snakeoil
Well-Known Member
I really cannot envision how the step on an M-die leaves a "small, sharpish corner". The step on the M-die should be a taper from the guide portion to the step portion just by nature if having a slight radius on the cutting tool. So, it should smooth the corner just like your pliers method.
Ian
Notorious member
I think he meant at the case mouth because Lyman spuds don't have a proper bellmouthing portion above the second step.
This is where I get into disagreements with just about everyone on the M-dies. I had ONE and sold it, no good IMO. I used RCBS for years and now make my own neck expanding spuds. So far, the ONLY time I've needed a second guide step was for (of all things) .45 ACP. Even with nose-matching seating punches I was still getting crooked bullets until I made a spud that had a .002" larger by .120" long parallel section before the belling part to help the bullet get perfectly straight. Lyman's second step is at least .004" larger which is too much for something like .30-caliber and doesn't bell the mouth sufficiently to prevent scraping. If you're using a belling type die and over-belling, well, that's user error. Just bell barely enough to prevent scraping, it doesn't take much.
This is where I get into disagreements with just about everyone on the M-dies. I had ONE and sold it, no good IMO. I used RCBS for years and now make my own neck expanding spuds. So far, the ONLY time I've needed a second guide step was for (of all things) .45 ACP. Even with nose-matching seating punches I was still getting crooked bullets until I made a spud that had a .002" larger by .120" long parallel section before the belling part to help the bullet get perfectly straight. Lyman's second step is at least .004" larger which is too much for something like .30-caliber and doesn't bell the mouth sufficiently to prevent scraping. If you're using a belling type die and over-belling, well, that's user error. Just bell barely enough to prevent scraping, it doesn't take much.