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Question about converting .223 to 300 blackout

7K views 47 replies 8 participants last post by  gdmoody 
#1 ·
Does anybody have any experience with converting .223 to 300 blackout? I am going to convert about 3,000 .223 cases to 300 blackout and have a question about procedures. After cutting the case to length, but before forming do you need to de-burr and champer the brass or can you do that after the brass is formed? Maybe another option would be to de-burr the outside before forming. I would like to eliminate any steps not needed. I have been studying the process and have all the tools I need on order, but would like to hear about first hand experience.
 
#2 ·
I have not done it, but I have been doing a little studying on it myself. My personal feeling are that you would not need to chamfer and de-burr before forming. I see that the brass is going to "stretch" a little as it is formed. My thoughts are that if would be a waste of time because you are going to have to trim them to the proper length after forming anyway!

I went ahead and traded for some 300 brass, instead of forming them myself, but no where as near as many as you are talking about!!
 
#3 ·
I haven't myself but have done some studying and watching you-tube videos. It seems like a 50-50 split on whether or not to deburr. The ones that have did it to help eliminate debri in the dies.
 
#4 ·
Guess the thing I need to do is try it both ways. I've watched several videos and some trim & de-burr before forming and some don't mention it one way or the other.

Another thing I've wondered about is annealing before forming. I haven't seen anyone doing that, but the brass is going to be stressed a lot during forming and it seems to me annealing might help prevent premature spiting or cracking.
 
#6 ·
Steve,
I have processed many hundreds - probably closer to 1000- and can answer any questions.
Either PM me or reply here.
You might find that the Harbor Freight mini metal chop saw a good piece to have, esp. at the price.
As to annealing, I have not seen a real need to anneal prior to forming. I use a Hornady 3 die 300 Whisper set that has an expander die that nicely opens the 223 mouth and then run it into the chop saw using a form to limit my cut. Then into the 300 whisper decap/form die- trim to length using WFT with the 300 BLK insert.
Fast and accurate.
I usually anneal when finished.
My loss is well under 2% and most times none are lost to split necks.

Gary
 
#8 · (Edited)
I bought the Harbor Freight 2" chop saw for $29.95 and had a 20% off coupon so it cost me $23.95. Also got six extra blades and hope that is enough. I have ordered a cutting jig, 30 caliber pilot for the 3-way trimmer, and a Hornady 300 whisper die set that should be here next week.

Do you de-burr and/or champer after you cut the brass but before forming?
 
#9 ·
Tend to do that before just before loading unless there is an obvious piece of something hanging on the cut edge.
Sequence is as follows:
Assuming clean brass( I usually SS pin tumble deprimed cases -Lee universal decapper)
Run it into the expander die, cut off excess, run it into form die, trim to length, de-burr and chamfer case mouth, prime-usually 50 to 100 at a time, then reload them.
Has worked for me though I am sure others have a good system that works for them.

Gary
 
#14 ·
Hmmm, I thought the first thing that is done when converting .223 to 300 blk is to cut the neck off just behind the shoulder. That leaves an opening that is about .338" dia. The case is then formed to 300 blk dimensions which reduces the mouth size to hold a .308 bullet. So just how, exactly, does expanding the .223 neck fit in with this process?
 
#15 ·
I'm not understanding the need for the expander die either. Unless you don't cut the brass down first. There is a you-tube video of a guy with a Dillon 650 with case feeder and power trimmer. He was just pulling the handle on 223 brass from the feeder and it was spitting out 300 bo brass.
 
#16 ·
I just came across a video that looked like the guy had expanded the case mouth before he cut it down. The subject of the video was a cutting jig and he didn't explain how or why he had formed the case before cutting it down to size. I've looked at several videos and that is the first time I've seen the case being formed before it was cut.



Do you have link to that video? I would be interested in seeing how he is doing that.
 
#18 ·
I have done it both ways but have found that running it into the expander makes my life easier.
Get very little to no case loss doing it this way. I probably stems from the times when I did not have a HF metal chop saw and I cut the cases down with a mini tube cutter and it was easy to cut too short if I did not expand first as the cutter would/could slip down a bit.
There are many ways to skin this cat and just find one that works for you and go for it.
Gary
 
#22 ·
Thanks for the links. I watched both and like the first one better (don't have a Dillon). Taking the decapping rod out of the sizing die is the thing I had not thought about. I'll have to try both ways (cutting before sizing and sizing after cutting it down).

In both videos they had to champer and de-burr after trimming to length. Using the RCBS 3-way cutter head you don't have to do that. I bought one of the 3-ways for trimming .223 and thought you had to buy a new $50 3-way head for each caliber, but found out you only need different pilots for each caliber. The body with the de-burr cutter works with all calibers.
 
#24 ·
That is some good information howln, thanks for putting it up. The first one was more helpful to me since I don't have one of those super Dillon trimming gizmos! I am guessing that the process would work with any kind of dies?

I bought a3 die set of Lee dies but I will probably never use the Factory Crimp Die that came with it. I bought that single shot H&R .300 so I will never crimp any of them, but crimping is another thing altogether!
 
#25 ·
Taking the decapping rod out of the sizing die and and sizing before cutting the neck is definitely the better option. After sawing the cut is badly burred inside and out. If they were formed before cutting the neck the burrs are removed when trimming to length. If the neck is cut off before forming I believe you would have to de-burr and champer before they could be sized. That is just an extra step that can be avoided.

I'm going to convert 50 pieces today and see how it goes. If I don't have any problems I'll start doing batches of 200 at a time.
 
#27 ·
Wow! That seems like quite a leap to go from .30-06 to .243. I'd expect to form .243 from its parent, .308, but if there's a reliable way to make them from .30-06, I'd like to see instructions. I shoot both, and currently can't find any reasonably priced .243, but .30-06 brass seems to be plentiful.
 
#31 ·
Here’s a report on my first attempt at doing the conversion. The first observation is that it is a messy operation. The cutting and trimming results in brass dust everywhere. The dust from cutting is very fine and hard to clean up.

I don’t think my first idea about removing the decapping rod and forming the brass before cutting is the best way. That results in having to size the brass twice. When the brass is sized without the expander bulb the ID is too small to allow the trimmer pilot to enter the mouth. So I had to reinstall the decapping pin and size the brass a second time before it could be trimmed.

I also learned that the brass is going to have to be manually de-burred and champered after cutting. Cutting leaves a large amount of burrs on the inside and outside of the mouth. It those are not removed before sizing it will plug up the sizing die. I crushed two cases that way.

Tomorrow I will cut, de-burr, champer, form, then trim in that order to compare with what I did today. I ruined 10 pieces of brass today mainly trying to set up the 3-way trimmer. It works really well once it is set up properly but it’s a PITA to set up when you change calibers. Most of the problems are my lack of experience so maybe it will get easier next time.
 
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