Hornady 300 Blackout Die Problem (maybe)


December 8, 2013, 10:56 PM
This is my first time reloading for 300 Blackout but not my time reloading. I'm using Hornady's New Dimension Custom Grade dies in a L-N-L progressive to convert .223 cases. The problem I'm having that a newly sized case will fall right in to case gauge, but it stops short of seating flush with the case gauge face. It's as if the shoulder is too high on the case. As you can see, the die is seated so that it's barely touching the shell plate.

At this point, I'm not sure if the sizing die is defective or if the case gauge is defective. I don't have any factory ammo to completely rule out that it's the case gauge. I'm thinking it might be a die issue because I can't twist the bolt when the case is chambered (the barrel isn't in the upper yet - AR build).

Is there anything else I can do to rule out a die problem? I want to make sure I'm thorough in my troubleshooting before calling Hornady.

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December 8, 2013, 11:18 PM
Someone with experience in this will chime in here shortly, but I think the .223 case is too long, it must be cut. The .300 blackout is a necked up .221 Remington Fireball case.

December 8, 2013, 11:52 PM
I resize 223 Remington into 300 BLK on a single stage press. Yes, the 223 Remington case has to be shortened before reforming.

In your picture of the die on the shell plate, is there a case in the die? If not, even though your die is touching the L-N-L, with a case in the die, there may be enough flex in the system that does not permit the shoulder to be moved enough.

I have purchased a set of Hornady's 300 BLK but I have replaced the sizer die with a Redding. Frankly, I do not remember the reason, I've slept a bit since then.

I do still use the Hornady seater die but I also use the Redding seater as well. Each is set for different bullets since I ended up with two seater dies.

Hope this helps.

December 9, 2013, 12:13 AM
I use the Hornady 300 BLK dies and find It has no problems sizing the shoulder back far enough. Make sure the expander button on the decapping rod isn't hitting the inside bottom of the case. Might try turning your sizing die in for more positive contact with the shell plate. I'd recommend the Hornady Headspace gauge set that works with your calipers to check headspace. The 350 insert works for 300 BLK. For my rifles I have to back my sizing die away from the shellholder or my Hornady sizing die pushes the shoulder back too far for my rifles chambers. Use adequate case lube.

December 9, 2013, 08:06 AM
1. First make sure the the sizing die is adjusted so that the shell holder contacts the base of the die when the ram is at the top of its stroke when resizing a case. This ensures that the sizing die is bumping the shoulder back as well as reducing the diameter of the case. If the shell holder does not contact the base of the die, the diameter of the case is squeezed down, making the case (and distance to the shoulder) longer. 2. Flex in the platform, requiring shims. 3. Slop in the bushings, requiring shims. 4. Shell plate is not tight enough to the platform, adjust it. 5. The deck height of the shell plate is larger than .125" Each station may be different. 6. A full length sizing die is not technically a case forming die. There is a certain amount of spring back in the brass case, and this spring back has to be taken into consideration when designing the die and its intended purpose Case forming dies usually need to be made to smaller internal dimensions to compensate for more spring back, because the case dimensions are being altered to a greater degree. Sometimes a full length sizing die will work as a case forming die, but it depends on a large number of variables, and is impossible to predict with any accuracy.

December 9, 2013, 10:42 AM
Folks have mentioned flex in the press. Adjust the die so that it barely kisses the shell plate when actually sizing a case. Then if it still won't size it correctly, call Hornady.

I have both a Hornady and a Forster 300 BLK sizer, and both work fine. One is a hair tighter, but that is not unusual, considering manufacturing tolerances.

December 9, 2013, 11:07 AM
I just checked for flex with the case in the die. In fact, I just tried it on both the L-N-L and a Lee turret press. The Lee has more flex, but the Hornady's was minimal. I'm going to give Hornady a call.

December 9, 2013, 12:10 PM
I just did some more testing. This time I used the Lee Turret press:

Size the case
Check the case
Turn the die down 1/16 turn
Recheck the case....

It finally worked! I'm surprised such small increments would mean the difference between an in spec versus out of spec case. I suppose the rules are a little different when converting cases to different calibers. Lesson learned here!

December 9, 2013, 12:30 PM
This sounds like what I experienced when I first started reloading (.223). I had no idea that there would be enough flex to matter, with all that metal involved. But, on my dies I had to touch the shell holder to the ram and then turn some more to get the shoulder datum to where it should be. I took measurements along the way to see just how much difference it made and was surprised by the results.

I have the Hornady 300 BLK set, too. I have only tried a few .223 cases that had become rejects. I followed the die set instructions and the cases go right in a Wilson case gage as they should. (I don't have the gun built yet to really start loading for it.)

December 9, 2013, 03:41 PM
It finally worked! On both press? If only on the Lee, maybe a deck height problem with the Hornady? http://i338.photobucket.com/albums/n420/joe1944usa/Firearms%20%20and%20%20Reloading/th_ShellHolder1.jpg (http://s338.photobucket.com/user/joe1944usa/media/Firearms%20%20and%20%20Reloading/ShellHolder1.jpg.html) This Dillion plate is undersize, your Hornady may be oversize??http://i338.photobucket.com/albums/n420/joe1944usa/Firearms%20%20and%20%20Reloading/th_DillonShellPlate.jpg (http://s338.photobucket.com/user/joe1944usa/media/Firearms%20%20and%20%20Reloading/DillonShellPlate.jpg.html) Click photo for larger view.

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