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9/22/2017 12:11:25 AM
Posted: 7/18/2012 7:40:45 AM EDT
My last 300 BLK reloading question was pretty stupid, maybe I can go 2 for 2.

On a whim, I bought a L.E. Wilson headspace gauge in 300 BLK. I took 50 rounds I loaded up with fresh Hornady brass on a set of Lee dies and checked them. All of them sit slightly below the lower step in the gauge (i.e. sitting too far into the chamber). So I tried the new, unsized Hornady brass. Same thing. Then I took one piece of the new brass, resized it (one half turn after the die bottoms out on the shell holder) and checked that. Same thing. I took an old piece of once fired Remington brass and it read properly (between the steps of the gauge). After resizing it, I was back to where I started with the brass sitting below the deck of the gauge.

I dont know of any way to adjust the full length resizing Lee dies other than the 1/4 to 1/2 turn method. Is there a problem with my Lee dies? Am I worrying about something I shouldnt be? Ive never had this problem with a Wilson gauge before on anything else I reload?

In case it matters, Im loading on a Lee turret press. Im only loading 220 SMK's w/1680 for use in my Wilson Combat 16 inch barrel. Shooting it through a MultiMount. I have yet to fire any of these reloaded rounds.


Link Posted: 7/18/2012 7:52:57 AM EDT
I had the exact same results. If you follow the directions with the Lee die, it will over re-size your brass (at least it did mine). I now have the die set up to just barely touch the shell holder at the end of the press stroke. The resized brass now measures correctly on the case guage.
Link Posted: 7/18/2012 8:04:21 AM EDT
(BRASS) Trim to Length Range (min-1.348 to max-1.368)

I trim 1.358"
Whats your mic say. (caliper measurement)
Link Posted: 7/18/2012 9:44:05 AM EDT
Lower the die to within an 1/8 of an inch or so of the shell holder. Size a case. Check it in the case gauge. Keep screwing the die in until it bumps the shoulder back so it just barely fits in the gauge. Then check it in your chamber. Just because it goes in the gauge does not mean it will fit in the chamber.
Link Posted: 7/18/2012 9:57:42 AM EDT
[Last Edit: 7/18/2012 10:05:26 AM EDT by 243winxb]
The Lee dies were a special order by Midwayusa to there specs. Lee does not stock the 300 blk the last i looked. Maybe now they do?? When forming brass from a different caliber, the shoulder may need to be pushed back more than what a standard FL die would. Brass springs back. Your Lee/Midwayusa die will work both as a forming die & FL die. But you must control/measure the shoulder bump.
Posted by on 19 October 2011 12:55 PM
Currently we do not stock this die set as a standard item. Our distributor MidwayUSA has done a special run of this cartridge.


In 2012, we will be adding this cartridge as a standard item. It will be a Very Limited Production PaceSetter 2-Die Set.

Link Posted: 7/18/2012 10:09:33 AM EDT
[Last Edit: 7/18/2012 10:10:52 AM EDT by 243winxb]
From Lee > Forming 300 AAC Blackout Cases
Posted by Steph @ Lee Precision on 15 June 2012 11:29 AM
Should you choose to make 300 AAC Blackout cases from 223 Remington or 5.56 cases, you may have to ream the case necks to obtain a maximum loaded case neck outside diameter of .3340". The reason for this is that the case wall thickness of a rifle case is tapered, being thinnest at the case neck and thicker towards the case head. When you trim the longer case to the shorter dimension, you are getting into a thicker case wall. The maximum allowable case neck wall thickness is .013" when seating a .308" bullet. Because of the taper of the case, wall thickness at the case neck mouth may be .013" but could be thicker just above the shoulder. The thicker wall in this area will cause the loaded case neck outside diameter to be in excess of .3340". This will cause the bullet to be pinched by the case when the round is chambered, which may result in dangerously high chamber pressures.
Link Posted: 7/18/2012 12:57:50 PM EDT
Link Posted: 7/18/2012 2:53:13 PM EDT
[Last Edit: 7/18/2012 3:01:14 PM EDT by bigedp51]
I have seen new unfired brass that was .009 shorter than minimum headspace, so this means the rear of the case would be below and inside the case gauge.

The main use of the case gauge is to check your "fired" cases (cartridge headspace) and only push the shoulder back .002 to .004 on semi-autoto rifle and .001 to .002 on a bolt action.

Helpers for die setup adjustments.

I'm 62 and have a hard time seeing my Wilson gauges so I switched to the Hornady cartridge case headspace gauge adapter for a vernier caliper.

And don't ever buy a Wilson case gauge for the .303 British because they will just drive you crazy.

New brass

And a fired case

Link Posted: 7/18/2012 4:35:19 PM EDT
I just use the Lee FL die for the initial forming on the case from 223 set with the Wilson gauge. Once fire formed, I size them in the Hornady FL die and use another method that works for me to getum sized right. The Hornady seater works better than the Lee IMHO.

I wanted the Hornady set first, but were BO'd, had to settle for the Lee to get going. The Lee set works, I just like the Hornady set better YMMV.

This post is worth what you paid for it.

Link Posted: 7/19/2012 12:26:01 PM EDT
Wow, I never knew that there were any Lee full length resizing dies out there that you didnt bottom out on the shell holder. Ill try tinkering with the sizing depth and see what I come up with.

Since these are subsonic, low pressure rounds, how deep into the chamber would you guys say is too deep? I dont think its too deep for the firing pin to light off the primer right now.

I guess the question is, should I tear them down and start over or not? They will probably be a bitch to pull, Im using the Lee Factory Crimp Die with these.
Link Posted: 7/19/2012 3:52:33 PM EDT
If they are more than .005 below I would use them, but toss the brass after the first firing. You created excessive headspace and the inside of the case is the one that pays the price.

Less than .005 and shoot them and reload them as if nothing happened.
Link Posted: 7/19/2012 4:15:49 PM EDT
Shoot them, i think you will be ok because of this >
I took an old piece of once fired Remington brass and it read properly (between the steps of the gauge).
If the Rem. brass was at or above the high mark of the gage, then you may have a problem with your reloads. I see no problem with fire forming what you loaded. Make adjustments on the FL die when you size the brass next time. The head clearance has to be more than .010" to get a case head seperation.
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