Hornady Seating Die Deforming Boolets

[Capt Mike]

Please don't jump on me if this is an old topic, but I have been working on this problem all day and Hornady tech support was no help. I finally received my Lee 7.62x39 155 gr mold and cast a few boolets to try in my 300 Blk. I powder coated the boolets and sized them to .309 with no problems. I then loaded a couple of rounds and when I seated the boolets in the cases and the Hornady seating die deformed the top of the boolet badly; so badly that I cannot get the round to chamber. I have seated the boolet progressivly deeper and it still hits the throat. I took a boolet and put it in a case using another die (308 seating die and it barely seated it deep enough) and I did get the round to chamber. Am I going to have to get another make of seating die to seat cast boolets? (this die also deforms boolets cast from my Lee 150 grn FN)

http://i181.photobucket.com/albums/x46/captmike01/DSC_0385_zps85324c04.jpg (http://s181.photobucket.com/user/captmike01/media/DSC_0385_zps85324c04.jpg.html)

http://i181.photobucket.com/albums/x46/captmike01/DSC_0386_zpsa4f5eaa0.jpg (http://s181.photobucket.com/user/captmike01/media/DSC_0386_zpsa4f5eaa0.jpg.html)

I know the boolet needs to be seated a little deeper, but in this case no matter how deep you seat it it hits the throat (boolet deformed from .308 to .313) The backlit shot show how the die shaped the boolet. Suggestions?

[blikseme300]

Looks like way too much resistance seating and not a seater problem. I had a similar problem when I started loading for the 300blk. The solution was to anneal the brass and the use of an expander die before seating. The expander opens up the neck to 1 thou under boolit diameter.

[Capt Mike]

That must be why some do a crimp; makes sense. I'll go look for an expander die.

Just found this at Midway: http://www.midwayusa.com/Product/680890/redding-3-die-set-300-aac-blackout-762x35mm

I don't have any Redding products, but hear they are good.

[blikseme300]

Capt Mike,

What I did not add to my post is that I use a Hornady 300blk/Whisper set and make use of a custom expander that works the same as the Lyman M-die. I use. Lee universal expander body with a self made custom insert that mimics the functioning of the Lyman product. The expander opens up the case neck ID to .309 to accommodate the .310 boolit. I use the Lee boolit you mentioned as well and it is a great combination in my rifles.

I use a Hornady LnL AP for loading the 300blk and my die stations are populated thus: 1. Resize and decap 2. Lee Pro Auto-disk powder dispenser 3. Lee Universal Expander die with custom insert 4. Boolit Seater 5. Lee FCD for light crimp

[Capt Mike]

Will the expander that comes with the Lee work well enough on the 300 to use? I have an RCBS single stage press. After doing a little research I think I understand what is required. The neck needs to be opened up to close the the diameter of the boolet and the top slightly flared....right? And the "custom" expander is made to open up the neck.

Update: I ordered a Lyman M die and a Lee Universal Expander. I will see what I have to modify/build to get the correct neck diameter when they get here.

[milprileb]

M die will solve the problem. Lee die is not going to do it. Own both, been thru this .

[Capt Mike]

Both dies came today and I loaded a few rounds and went to the range. The Lyman "M" die expander measured out to exactly .308 and I am loading boolets cast, PC and sized to .309. The Hornady boolet seating die still leaves a ring around the top of the boolet, but no major distortion. I can now seat the boolets deep enough to chamber, but I am still having feeding problems and the last round will not lock the bolt back on my 300 AAC BLK. The rounds are: boolets from Lee C312-155-2R, powder coated w/GC and weigh 166.7 grns. Loading 15 grns H110 & CCI 400 primers. COL is 1.987 and CL is 1.360. Formed case fits easily in my Wilson Check die.

This is the target using my standard 125 grn SMKHP load. Group on the top right (edge of black circle) are the first 3 shots at 35 yards. All others were fired as quickly as I could acquire the bull.

http://i181.photobucket.com/albums/x46/captmike01/Untitled-1_zpsdc55e0b5.jpg (http://s181.photobucket.com/user/captmike01/media/Untitled-[URL=http://s181.photobucket.com/user/captmike01/media/Untitled-1_zpsdc55e0b5.jpg.html)

The second target is using the load as described above. There were multiple feed problems and the bolt did not lock back.

http://i181.photobucket.com/albums/x46/captmike01/tgt_zpsc7442613.jpg (http://s181.photobucket.com/user/captmike01/media/tgt_zpsc7442613.jpg.html)