I have recorded my 300 blackout loading journey
here. As a matter of fact it is time for me to update the site with additional load data and tools I use to enjoy reloading 300 blackout. I had no idea it was going to turn into what I have today and get so many visitors.
http://www.dayattherange.com/?page_id=3460
I get a lot of questions via email, which proves interesting as I do not consider my self to be an expert on the 300 Blackout round far from it but I do not mind helping if I can.
The one thing I will say is learn from my experiences and save some money
Meaning if you are going to load lead bullets forget the larger size expanding balls etc, this is not meant to poopoo on anyone's suggestions I just found they do not work as well with lead. The main reason is lead bullets from different manufacturers are sized differently, for this reason I have found the Lyman M die to work best. But please get the right one I got mine from Midway, and there are two different dies for 30 caliber rounds.
Product #: 153391
Lyman #: 7349004 UPC #: 011516790040
You can get it a few cent to 1 buck cheaper from other places but I found Midway was in stock.
Please read the instructions for using the M Die it is a two step expander and this die with the exact same powder charge with Missouri Bullet Company 245gr lead bullets went from 4inch shot gun like pattern groups very unpredictable. To under 1inch at 50 yards and 1.275 at 100 yards. As a matter of fact I shot my 300 blackout very little at 100 yards because of the frustration from very large 4 to 6 inch groups if you can all it that. I thought it was my scope at first, come to find out it was just lead bullets that were the problem. My jacketed supersonic loads grouped great. The MBC bullets are sized to .309 and are great quality. I have tried Palmetto Projectiles also. I found with lead the problem with accuracy was due to the case not being expanded enough and shaving the base of the bullets as well as squeezing the bullets down from .309 and .310 all the way down to .307 even when utilizing the lee rifle expander. It was the Lyman M Die that solved this issue.
The other tool to get is a Sheridan case guage
http://www.sheridanengineering.com/index-1.htm I had finished rounds that would fit in the Wilson guage but not chamber in 3 different rifles. Once you understand what the Wilson case guage is -- a guage for checking cone to head for overall length then you realize why. Cone to head are Wilson's words not mine as I called them about my problem, and the gentleman on the phone explained it that way. This guage is only to make sure you have trimmed your brass to the right length. The Sheridan guage is a chamber guage built to saami spec to mimic the 300 blackout chamber, and will also tell you if your length is right. This was an invaluable tool to me.
One last thing, mindset. Do not think the 300 blackout is some magical round that will shoot lights out without following all the steps you do with normal rifle rounds. Most important I have found is case separation. This is another thing that tightened up my groups, I separate 308 and 223 brass by headstamp and understanding case volume to get the best accuracy, but with 300 I was just blasting away and disappointed at my results. Well if you are using cut down 223 brass it needs to be separated the same way due to case thickness. I say case separation is even more important if you are using cut/trimmed back 223 brass, that far down the brass thickness varies a lot from brand to brand affecting case volume which most definitely affects accuracy.
Sorry for such a long post, 300 blackout has become one of my favorites and I just want to share my endeavors and pitfalls to help others.
Mr. Revolverguy