chamfering vs lyman M die

[lurcher]

I watched a video a while back (Richards precision) where the presenter stated he felt that inside chamfering necks was a risk, and that the case mouth should be treated as a second crown. he advocated merely polishing the end of the case with steel wool. Is this a real concern? could a VLD chamfering tool actually have any affect on accuracy?

I pulled some 7mm 162 amax from some rounds a while back and noticed scoring on some projectiles which led me to think about the lyman M die as an option as opposed to chamfering, what are peoples opinions on the pro's and cons of the M die. I see sinclairs sells a .280 die are these things calibre specific or will this die work on all 7mm cases? they are cheap enough so thought about giving one a try

 

[CatShooter]

I watched a video a while back (Richards precision) where the presenter stated he felt that inside chamfering necks was a risk, and that the case mouth should be treated as a second crown. he advocated merely polishing the end of the case with steel wool. Is this a real concern? could a VLD chamfering tool actually have any affect on accuracy?

I pulled some 7mm 162 amax from some rounds a while back and noticed scoring on some projectiles which led me to think about the lyman M die as an option as opposed to chamfering, what are peoples opinions on the pro's and cons of the M die. I see sinclairs sells a .280 die are these things calibre specific or will this die work on all 7mm cases? they are cheap enough so thought about giving one a try

I use "M" dies on everything when possible - I can't remember the last time I chamfered the mouth of a case.

Along time ago, I had to pull some bullets from chamfered cases and they were torn up pretty bad - and it was a 14 degree tool, too.

 

[rox]

what are peoples opinions on the pro's and cons of the M die.

I've used them extensively, both for neck expanding and as an alternative to chamfering. I no longer expand with them, since they seem to lead to more runout than alternatives like the Sinclair floating carbide mandrel or the 21C TiN one. I still use M dies as an alternative to chamfering, but with a custom mandrel where the narrow section is undersize so it doesn't expand the neck. My motivation is automation, rather than any dissatisfaction with chamfering

..

 

[memilanuk]

Along time ago, I had to pull some bullets from chamfered cases and they were torn up pretty bad - and it was a 14 degree tool, too.

Was that with a kinetic puller, by chance?

 

[CatShooter]

Along time ago, I had to pull some bullets from chamfered cases and they were torn up pretty bad - and it was a 14 degree tool, too.

Was that with a kinetic puller, by chance?

No...

 

[memilanuk]

Interesting.

I've seen some raggedy looking chamfered case mouths after using a kinetic puller - almost like the thin edge extruded a little. Doesn't seem like the forces involved would be enough, but thats what I've seen.

Never noticed any ragged case mouths on the occasions I've used a press-mounted puller.

 

[lurcher]

so will the .280 die do all 7mm calibres? guess I'd better buy one of these things.....

 

[Juma]

M Die is worth its weight in gold.My uncomplicated view is chamfering must create unevenness in support for the projectile.Use them for Barnes[55gr and 62gr] and Sierra 65gr when loading the 223.Great piece of kit.

 

[Baddog0302]

If you look at the profile of a Lyman "M" die expander it is step l while the RCBS puts a tapered flair \ / to the case mouth. OR custom expander's can be ordered to expand the neck to your desired neck tension and put a slight flair to the case's mouth.
l
l

 

[lurcher]

did some searching on M dies and it seems they can introduce a major source of runout? people modify them or make copies where by the first "step" matches the inside diameter of a sized case so that it only acts as a pilot and does not size (expand) the case neck other than the final flair at the mouth
http://www.beartoothbullets.com/tech_notes/archive_tech_notes.htm/39

in practice is introduced run out a pain with these dies?

 

[CatShooter]

did some searching on M dies and it seems they can introduce a major source of runout? people modify them or make copies where by the first "step" matches the inside diameter of a sized case so that it only acts as a pilot and does not size (expand) the case neck other than the final flair at the mouth
http://www.beartoothbullets.com/tech_notes/archive_tech_notes.htm/39

in practice is introduced run out a pain with these dies?

I have not found it to be a problem... not many match grade sizing dies bring a neck down as far that the die in the article did.. that was for cast lead bullets.

 

[Joe R]

I use a Lyman M die to expand the necks so that they will fit properly with my neck turner, and for that it works great.

I recently bought a 8mm Mauser M die so I could have a friend on mine shave the mandrel down to .310. Well, in the process he discovered that the mandrel did not fit exactly 90 degree perpendicular to the die top, because when he put it in the lathe it wobbled. He fix it for me and it is now straight. So, yes they can be angled and still be straight.

Regarding the inside chamfer of the case neck, I do it with a VLD tool, but I also polish the necks with steel wool so that there are no sharp edges and the inside of the necks is uniformly smooth for proper bullet release.

Kindest regards,

Joe

 

[bigedp51]

I have read in other forums about reloaders using the M type die in rifle calibers for reducing neck runout during seating. The only type M dies I have are in pistol calibers and since the Lyman patent expired even Redding dies are using the type M expander. But these pistol dies use a roll or taper crimp after the case mouth has been expanded.

The center die below is a Redding type M die.

So CatShooter how is the case mouth pressed back and straightened again after bullet seating on a rifle cartridge. My AR15 RCBS .223/5.56 dies use a taper crimp but how do you straighten the belling at the case mouth on a normal rifle die set and keep a perfectly straight neck?
(I gots to know)

 

[CatShooter]

I have read in other forums about reloaders using the M type die in rifle calibers for reducing neck runout during seating. The only type M dies I have are in pistol calibers and since the Lyman patent expired even Redding dies are using the type M expander. But these pistol dies use a roll or taper crimp after the case mouth has been expanded.

The center die below is a Redding type M die.

So CatShooter how is the case mouth pressed back and straightened again after bullet seating on a rifle cartridge. My AR15 RCBS .223/5.56 dies use a taper crimp but how do you straighten the belling at the case mouth on a normal rifle die set and keep a perfectly straight neck?
(I gots to know)

I can't tell you, cuz I'd have to kill you

OK OK... I'll cut you some slack.

If you refer to your picture:

... I adjust the die so the neck/mouth goes just a tiny smallest amount higher than the position shown in "A", so it just kisses the base of the first "ramp"... the amount of flair that I have actually measured on cases I have done is about 3 or 4 thou, but because of the design, that 3 or 4 thou does NOT go deeper into the neck than a few thou... if you draw your fingers across the neck, you can almost feel the flair - it is just enough to keep a flat based bullet from falling over, before it goes into the seating die... in fact, I use a flat based bullet to adjust the die.

The flair is so little, that the case will chamber in a tight neck chamber without interference.

 

[bigedp51]

Thank you CatShooter, that explains a great deal about "NOT" having to touch the case mouth after seating. And why the case mouth is more uniform when seating the bullets.

Now CatShooter what do you do about cats that don't like RC helicopters.

(I'm spending more time repairing cat damaged helicopters than reloading) :'(

 

[JohnKielly]

I too noticed issues with necks hand chamfered with either old RCBS style or an older K & M VLD tool (before it had the centering guide).

Anyway, I changed to a Wilson VLD chamfering cutter & no more issues. I'd figured that the problem was that I wasn't addressing the case neck square with freehand tools & the result I got with the Wilson seems to have proved me right. There's the extra plus too, that once the cases are trimmed, all chamfers are identical.

 

[CatShooter]

Thank you CatShooter, that explains a great deal about "NOT" having to touch the case mouth after seating. And why the case mouth is more uniform when seating the bullets.

Now CatShooter what do you do about cats that don't like RC helicopters.

(I'm spending more time repairing cat damaged helicopters than reloading) :'(

Why, I shoot them, of course, you silly person

 

[masterblaster1]

interesting, am I to understand the M die will take care of the reaming of the case when sizing? I normally trim after neck sizing, does this mean I have to size twice before trim and after?

 

[CatShooter]

interesting, am I to understand the M die will take care of the reaming of the case when sizing? I normally trim after neck sizing, does this mean I have to size twice before trim and after?

The "M" die does not ream the case neck - it is an expander that is capable of putting a tiny flair to the mouth, instead of cutting a chamfer.

 

[bigedp51]

masterblaster1

The "type M die" is just a method used to expand the case neck and open up/flare the case mouth. I first read about it in a forum where the poster was reloading for the M14 rifle for use in competition. If you Google the type M die expander and look under images you will see custom expanders are being made using this principle to reduce neck runout during seating. I'm guessing but this method may have been written about by Zediker or other military competitors and not bench rest shooters.

As a side note the person posting about the M type die was shooting .309 rebated Lapua bullets and he may have had a custom "type M expander" made for seating with his M14.

Below is what I was researching for expanding my .223/5.56 case necks, and everything I was reading dealt with reloading for semi-autos.

http://www.mrbulletfeeder.com/rifle-calibers/