Too much hourglass...

[fireboltxl]

I need some help. I have been reloading 9mm for a couple years now on a Dillon 650xl with all Dillon parts (just as is came from the factory). Up until recently my 9mm was all for Production minor loads shot out of a Glock, so if it could fit in the mag and case gage the Glock would shoot it. However I have moved to Open shooting 9 Major.

After a significant amount of testing and experimenting I have found that the hourglass shape of the 9mm from reloading is causing me feeding issues with my 170mm mags. Is there any way to eliminate, or reduce the amount of hourglass shape I am getting from my reloads?

A fellow local shooter has as Hornady sizing die and when the two rounds are compared side by side the visual difference is amazing. Both rounds are loaded at OAL 1.165 with MG 124gr CMJ bullets, with mixed range brass.

Edited April 1, 2013 by fireboltxl

[sd624]

I had the same problem. Only fix I found was to use a non Dillon size die.

[Jaxshooter]

I use a Lee Undersize die foe sizing my 9 mm brass for Open. Never had a problem since changing.

[Steve RA]

Perhaps not a good thing in this particular instance, but, in general, the "wasp waist" effect is desireable in preventing bullet setback.

[fireboltxl]

Perhaps not a good thing in this particular instance, but, in general, the "wasp waist" effect is desireable in preventing bullet setback.

Interesting enough, when the bullet slams nose first into the bottom of the feed ramp it will set back about .020...

[Retread1911]

If you want to try some roll sized brass send me a PM and I will get you a sample. That is assuming you do not want to order a U-die which may correct the problem as well if it really is the brass.

What kind of internals are you running in your mag? I wonder if the spring isn't strong enough to feed rounds reliably?

I run a stock 170 in my STI factory open gun. The lower end one for the life of me I cannot remember the name tonight. Never had any feeding issues but then again I roll size all my brass before loading.

Retread

[superdude]

Is it the hourglass shape or just the fact that the 9mm Luger case is tapered and this is a problem for some magazines, such as 1911 and 2011 designs? This combination increases nosedive.

Edited April 2, 2013 by superdude

[fireboltxl]

Conducted many experiments with mags, springs, etc, the ammo is the one constant that keeps nose diving. When I use factory ammo that does not have the hourglass it runs like a champ, when I use my buddies ammo that does not have the same amount of hourglass it runs like a champ, so it is my ammo. The only difference is the shape of the brass since we have the same bullet and OAL.

As I mention ones in the OP he uses a Hornady sizing die, his brass has the same taper as factory brass.

I was thinking about the shape of the brass. If you take your hands and hold them up so you can see the back of your hands, then put your thumbs together at the knuckles, there is likely a tiny little gap you can see daylight through, now slide one hand up long the knuckle. See how they interlock and then force must overcome that locking. I think this is exactly what is happening in the mag.

[fireboltxl]

If you want to try some roll sized brass send me a PM and I will get you a sample. That is assuming you do not want to order a U-die which may correct the problem as well if it really is the brass.

Retread

So my question on that, would I just skip the sizing die? How does the brass get deprimmed, can I back the die out far enough to deprime but not change the shape of the brass?

Have looked around, quite difficult to find reloading parts right now.... Surprise, surprise... I will ultimately want to purchase a sizing die, I have good access to once fired 9mm...

[superdude]

The difference might be how much taper the rounds have. The amount of taper varies between 9mm brass. See the article below for more information, and how taper contributes to nosedive.

http://38super.net/Pages/9mm%20Automatic.html

[Retread1911]

If you want to try some roll sized brass send me a PM and I will get you a sample. That is assuming you do not want to order a U-die which may correct the problem as well if it really is the brass.

Retread

So my question on that, would I just skip the sizing die? How does the brass get deprimmed, can I back the die out far enough to deprime but not change the shape of the brass?

Have looked around, quite difficult to find reloading parts right now.... Surprise, surprise... I will ultimately want to purchase a sizing die, I have good access to once fired 9mm...

I am using the http://www.casepro100.com/ to roll size my 9mm. It sizes the base of the case as well as sizing the rim of the case. It does not replace the sizing die or the swage.

If you are interested to see the result toss me a PM and we can work out a sample for shipping cost unless you happened to be in the Twin Cities in which case we can just meet and I can hand you some. The case pro is an impressive machine.

If you decide to get completely processed brass then you would either run a universal decapping die or back off your sizing I'd just a bit to ensure a clear flash hole but not size the brass.

[fireboltxl]

The difference might be how much taper the rounds have. The amount of taper varies between 9mm brass. See the article below for more information, and how taper contributes to nosedive.

http://38super.net/Pages/9mm%20Automatic.html

Great info, thanks for the link...