Do all 9mm Sizing Dies Hourglass the case?

Mikul · September 13, 2002, 10:29 AM

I would prefer that my 9mm cases didn't have the hourglass shape that I get from the Dillon resizing dies. Do the resizing dies from any other manufacturer leave a straight taper?

Jim Watson · September 13, 2002, 02:22 PM

Only the ones that will blow up your gun.

The hourglass shape is a sign that your brass is being sized small enough that there is a tight interference fit to the bullet. In used brass this is the best way to avoid setback of the bullet against the feed ramp. Speer reported that .060" of setback of a 9mm bullet could double chamber pressure.

I had some failures to extract in .45 ACP that I traced to setback of jacketed and plated bullets, which raised chamber pressure enough to swell the brass tight in the chamber. And that with a round that operates at little more than half the 9mm's pressure.

I now cannelure .45 brass under a jacketed bullet like Federal factory loads.

Be glad of your 9mm hourglass.

Mikul · September 13, 2002, 02:55 PM

If the hourglassed shape is so great, why doesn't factory ammo come with the same shape? Also, doesn't bulging the case out and pushing it back in with every reloading stress the brass unneccesarily?

Isn't the crimp there to prevent bullet setback?

cheygriz · September 13, 2002, 03:04 PM

I can't speak to Dillon dies, since I don't use them. However, I have two sets of 9MM carbide dies, Lyman and Redding Pro. Both of these resizing dies leave a noticable reduction in the case.

This is as it should be. I want cases that will hold the bullet tightly, and I don't want the hassle of canneluring cases.

Remember also that the 9MM is a TAPERED case. If a sizing die sized it straight, it would be unuseable.

The first 10 years or so that I reloaded, I was very concerned with the appearance of my ammo. The last 25 years, I couldn't care less what it looks like. I care how reliable, safe and accurate it is. I'd rather have an ugly round that is safe, reliable and accurate, than a pretty one that isn't.

Jim Watson · September 13, 2002, 04:11 PM

Factory ammo DOES have an hourglass appearance; at least the Wunchester USA, S&B, and Olympic in the next room do... although you have to look close at the Oly. Can't tell about the Federal and Corbon, they are cannelured at the base of the bullet, which is an even better retainer.

True, the contour is less on the factory loads. They have the advantage of working with new, springy, clean brass that gives a better grip. They also have control of brass thickness, mouth diameter, and bullet diameter.

Good reloads have more hourglass shape because the die maker knows you will likely be running through brass of different makes, thicknesses, brass temper, and different numbers of reuses. And then loading it with bullets of diameter and length not known to them. They have to figure on sizing it down to work safely with about anything on the market.

Yes, sizing and expanding works the brass, but I usually lose empties out of an automatic before they wear out. I occasionally split a .45 because they are more expensive and I look for them harder. I seldom see a cracked 9mm, they are cheaper and usually go for use on a range where brass pickup is difficult. I worry about it only on same lot number rifle brass for use in an accurate gun.

Even a hard crimp is not enough to prevent bullet setback. The bullet has to be tight in the caseneck to start with. Military and some premium defensive ammo has a case mouth sealant which not only keeps out water, it glues the bullet in place. Even so, I have seen it said that even factory loads are required to stand up to only three trips from the magazine to the chamber, as for use as the top round in a carry gun.

bfoster · September 14, 2002, 11:48 AM

I have a series of three inserted carbide sizing dies that I made myself to address this "problem" (it helps to own a tool & die shop). The inserts are tapered, and long enough to size the full length of the case, unlike the short, straight cut inserts used in all commercial dies I've seen. A special shell holder is also used. Only a very small radius (~0.005") is ground onto the "mouth" end of the insert so care has to be taken to insure that each case is positioned correctly before raising the ram of the press. The trouble is that you need a different die using a slightly different taper for different bullet seating depths. Commercial production of such dies just isn't feasable due to the cost of this approach in a very, very competitive market.

Bob

KP95DAO · September 14, 2002, 04:21 PM

I laugh every time I see people bemoan "bullet setback." If your bullets are supported by the powder column, as my "hot" rounds are, there can be no "bullet setback." This applies to my 9mm, 40 S&W, 357 Sig, and 45 ACP rounds. Try it, you'll like it!

cheygriz · September 14, 2002, 05:48 PM

KP95DAO,

you make an excellent point, my friend! That is one of the reasons that I use Hodgdon's HS-6 in all of my 9MM loads. Power Pistol, AAC#7 and Herco work well for fulling the case as well.

Still, I like a good tight fit of bullet into case.

BTW, does anyone know of a good quick way of applying asphaltic varnish to bullet/case that doesn't take forever to accomplish? Ortho tree sealant is a good product to use, but I can't find a good procedure to apply it that doesn't take much care and much time.

Chris McDermott · September 17, 2002, 07:28 PM

The old-style steel resizing dies should be tapered, but you will have to lubricate your cases.

September 13, 2002, 10:29 AM	#1
Mikul Senior Member Join Date: March 21, 2000 Posts: 1,396	Do all 9mm Sizing Dies Hourglass the case? I would prefer that my 9mm cases didn't have the hourglass shape that I get from the Dillon resizing dies. Do the resizing dies from any other manufacturer leave a straight taper? __________________ There are two types of men: those with guns, and those at their mercy.

September 13, 2002, 02:55 PM	#3
Mikul Senior Member Join Date: March 21, 2000 Posts: 1,396	If the hourglassed shape is so great, why doesn't factory ammo come with the same shape? Also, doesn't bulging the case out and pushing it back in with every reloading stress the brass unneccesarily? Isn't the crimp there to prevent bullet setback? __________________ There are two types of men: those with guns, and those at their mercy.

September 13, 2002, 03:04 PM	#4
cheygriz Senior Member Join Date: May 11, 2002 Location: high up in the rockies Posts: 2,289	I can't speak to Dillon dies, since I don't use them. However, I have two sets of 9MM carbide dies, Lyman and Redding Pro. Both of these resizing dies leave a noticable reduction in the case. This is as it should be. I want cases that will hold the bullet tightly, and I don't want the hassle of canneluring cases. Remember also that the 9MM is a TAPERED case. If a sizing die sized it straight, it would be unuseable. The first 10 years or so that I reloaded, I was very concerned with the appearance of my ammo. The last 25 years, I couldn't care less what it looks like. I care how reliable, safe and accurate it is. I'd rather have an ugly round that is safe, reliable and accurate, than a pretty one that isn't. __________________ If you think a mighty military force is expensive, wait 'til you see what a weak one costs.

September 14, 2002, 05:48 PM	#8
cheygriz Senior Member Join Date: May 11, 2002 Location: high up in the rockies Posts: 2,289	KP95DAO, you make an excellent point, my friend! That is one of the reasons that I use Hodgdon's HS-6 in all of my 9MM loads. Power Pistol, AAC#7 and Herco work well for fulling the case as well. Still, I like a good tight fit of bullet into case. BTW, does anyone know of a good quick way of applying asphaltic varnish to bullet/case that doesn't take forever to accomplish? Ortho tree sealant is a good product to use, but I can't find a good procedure to apply it that doesn't take much care and much time. __________________ If you think a mighty military force is expensive, wait 'til you see what a weak one costs.

September 13, 2002, 02:22 PM	#2
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,539	Only the ones that will blow up your gun. The hourglass shape is a sign that your brass is being sized small enough that there is a tight interference fit to the bullet. In used brass this is the best way to avoid setback of the bullet against the feed ramp. Speer reported that .060" of setback of a 9mm bullet could double chamber pressure. I had some failures to extract in .45 ACP that I traced to setback of jacketed and plated bullets, which raised chamber pressure enough to swell the brass tight in the chamber. And that with a round that operates at little more than half the 9mm's pressure. I now cannelure .45 brass under a jacketed bullet like Federal factory loads. Be glad of your 9mm hourglass.

September 13, 2002, 04:11 PM	#5
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,539	Factory ammo DOES have an hourglass appearance; at least the Wunchester USA, S&B, and Olympic in the next room do... although you have to look close at the Oly. Can't tell about the Federal and Corbon, they are cannelured at the base of the bullet, which is an even better retainer. True, the contour is less on the factory loads. They have the advantage of working with new, springy, clean brass that gives a better grip. They also have control of brass thickness, mouth diameter, and bullet diameter. Good reloads have more hourglass shape because the die maker knows you will likely be running through brass of different makes, thicknesses, brass temper, and different numbers of reuses. And then loading it with bullets of diameter and length not known to them. They have to figure on sizing it down to work safely with about anything on the market. Yes, sizing and expanding works the brass, but I usually lose empties out of an automatic before they wear out. I occasionally split a .45 because they are more expensive and I look for them harder. I seldom see a cracked 9mm, they are cheaper and usually go for use on a range where brass pickup is difficult. I worry about it only on same lot number rifle brass for use in an accurate gun. Even a hard crimp is not enough to prevent bullet setback. The bullet has to be tight in the caseneck to start with. Military and some premium defensive ammo has a case mouth sealant which not only keeps out water, it glues the bullet in place. Even so, I have seen it said that even factory loads are required to stand up to only three trips from the magazine to the chamber, as for use as the top round in a carry gun.

September 14, 2002, 11:48 AM	#6
bfoster Senior Member Join Date: October 13, 1998 Location: N. of Fords Switch, OK, USA Posts: 297	I have a series of three inserted carbide sizing dies that I made myself to address this "problem" (it helps to own a tool & die shop). The inserts are tapered, and long enough to size the full length of the case, unlike the short, straight cut inserts used in all commercial dies I've seen. A special shell holder is also used. Only a very small radius (~0.005") is ground onto the "mouth" end of the insert so care has to be taken to insure that each case is positioned correctly before raising the ram of the press. The trouble is that you need a different die using a slightly different taper for different bullet seating depths. Commercial production of such dies just isn't feasable due to the cost of this approach in a very, very competitive market. Bob

September 14, 2002, 04:21 PM	#7
KP95DAO Senior Member Join Date: December 30, 2000 Posts: 699	Bullet setback. I laugh every time I see people bemoan "bullet setback." If your bullets are supported by the powder column, as my "hot" rounds are, there can be no "bullet setback." This applies to my 9mm, 40 S&W, 357 Sig, and 45 ACP rounds. Try it, you'll like it!

September 17, 2002, 07:28 PM	#9
Chris McDermott Senior Member Join Date: March 30, 2000 Posts: 245	The old-style steel resizing dies should be tapered, but you will have to lubricate your cases.