223/556 to 300BLK case conversion

[Caveman Jim]

This is my first attempt at converting 223/556 into 300BLK. I used my newly concocted lanolin & Heet case lube & let me tell you it is SLICK!!!
I ended up with over 150+ cases that passed the case guage test & 21 that didn't so they got thrown into the recycle bucket. I used different headstamps for this operation & it seemed that the 223 cases formed a bit easier than the 556 (slightly thicker case is my guess).
I used different headstamp case's that were shorter than 1.748" (I have thousands trimmed at 1.750 to reload my freedom bullets)...

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[KeepnitReel]

What's your load data going to look like? I just finished my first 300 blackout build and going for more supersonic then subsonic in the 135 to 180 grain projectiles. From what I've been reading Lil' gun powder seems to be the best results then others. What you thinking ?

 

[Caveman Jim]

I'm going to try working up loads with W296 powder (same as H110) (since I already have a tin (jug) of it).
I'm going with the 110g for plinking & the 140g for hunting deer.

300 AAC Blackout Load Data - Nosler

 

[drstrangelove]

I'm in the midst of doing this very thing. Knocked out my first 25 rounds of subsonic 220gr Leatherhead bullet 300blk last night. It is a tedious process. I used a cutoff saw and jig I got off amazon, then formed and deprimed the cases with the FL die. Then had to trim (lee case trimmer) to length and remove the military crimp on the 556's (I use the cone end of a deburring tool). Then comes deburring and case mouth expansion (extra die you have to get when using hitek coated bullets on the cheap). Then hand priming. Then drop 10gr of 4227 and use bullet seating die to 2.065" (seems short but this is recommended by the leatherhead guys due to the ogive shape. Many reports on blogs that it works fine.) Then factory crimp die. It's enough work that you really don't want to lose your fired brass. I don't like the fact that the new cartridges are so much heavier than 223 cartridges; it makes back-slapping the mags before shooting a necessity because they slip around in the P-mag a lot.

 

[Twodogs]

I'm loading for both a 16" bolt action and a 8.5" AR , took the easy route and just bought 2000 rds of brass, loading everything from 90 gr to 240 gr.

 

[Caveman Jim]

Converting IS a lot of work...
I used a HF miniature chop saw & a cutoff jig from ebay. I did a test cut then measure (1.385) with a ruff edge. I cut 50 then I debured inside & out.


I then lubed them with a lanolin & Heet concoction and resized them & it stretched the case to 1.396.



I then took them to the Lyman trimmer & proceeded to get a workout & hand cramps to achieve 1.366-1.368 end result. I decided to take the resized cases back to the chop saw and cut em down to 1.372 (no pic) then trimmed to final length, debured, case gauge check then into the tumbler for 2 hours & done.... it was a workout until I figured out the best path.

 

[ageingstudent]

I'm in the midst of doing this very thing. Knocked out my first 25 rounds of subsonic 220gr Leatherhead bullet 300blk last night. It is a tedious process. I used a cutoff saw and jig I got off amazon, then formed and deprimed the cases with the FL die. Then had to trim (lee case trimmer) to length and remove the military crimp on the 556's (I use the cone end of a deburring tool). Then comes deburring and case mouth expansion (extra die you have to get when using hitek coated bullets on the cheap). Then hand priming. Then drop 10gr of 4227 and use bullet seating die to 2.065" (seems short but this is recommended by the leatherhead guys due to the ogive shape. Many reports on blogs that it works fine.) Then factory crimp die. It's enough work that you really don't want to lose your fired brass. I don't like the fact that the new cartridges are so much heavier than 223 cartridges; it makes back-slapping the mags before shooting a necessity because they slip around in the P-mag a lot.

Forming your own brass gives a new meaning and purpose to "policing" your brass. It's like losing a child in a supermarket if you can't find one.

 

[Caveman Jim]

I'm in the midst of doing this very thing. Knocked out my first 25 rounds of subsonic 220gr Leatherhead bullet 300blk last night. It is a tedious process. I used a cutoff saw and jig I got off amazon, then formed and deprimed the cases with the FL die. Then had to trim (lee case trimmer) to length and remove the military crimp on the 556's (I use the cone end of a deburring tool). Then comes deburring and case mouth expansion (extra die you have to get when using hitek coated bullets on the cheap). Then hand priming. Then drop 10gr of 4227 and use bullet seating die to 2.065" (seems short but this is recommended by the leatherhead guys due to the ogive shape. Many reports on blogs that it works fine.) Then factory crimp die. It's enough work that you really don't want to lose your fired brass. I don't like the fact that the new cartridges are so much heavier than 223 cartridges; it makes back-slapping the mags before shooting a necessity because they slip around in the P-mag a lot.

For conversion, the final case length is supposed to be 1.368 max which I've read that bolt actions like em long & AR's like em shorter 1.350-1.355. This data is from the Internet so it must be true...
The first 40 rounds I fired through my new build were flawless. They measured 1.353 after firing, in the next few days I'll process them without a resize then case gauge them to see if they need it.

 

[Caveman Jim]

Well I couldn't wait to find out if they needed resizing or not so they indeed needed resizing....

 

[Member 5605]

They areally are easy to make.

Annealing will help them last a little longer.

 

[Caveman Jim]

Forming your own brass gives a new meaning and purpose to "policing" your brass. It's like losing a child in a supermarket if you can't find one.

Ohmygod ohmygod ohmygod, I know it's here somewheres, it's gotta be here an I ain't a leavin here till I find it, honey can you get the flashlights!!!

 

[Caveman Jim]

They areally are easy to make.

Annealing will help them last a little longer.

Well then good buddy I guess I'm gonna have to drag out the torch and get jiggity with it.... Caveman like fire!!!!! UGHHHH

 

[Member 5605]

Well then good buddy I guess I'm gonna have to drag out the torch and get jiggity with it.... Caveman like fire!!!!! UGHHHH

Considering the area that's now the mouth, used to be the body... will easily work harden quickly. It's also a thickener mouth so.. yup.

Fire away!

 

[KeepnitReel]

@Caveman Jim

DIY CASE ANNEALER

 

[v0lcom13sn0w]

good job! i make my own 300blk brass too. i do the harbor freight mini chop saw,squirrel daddy jig, rcbs trimmer with 3 way trimmer head and a cordless drill attached (saves SOOOO much time) hornady one shot case lube, and hornady dies. i never case headspace gauge them...i just roll with'm.

ive had good luck with the 125gr speer TNT bullets for super sonic loads. i use 208gr hornady BTHP match bullets for subs.

ive played around with h110 but i prefer 1680 for all of it now...its finally abundant in my area.

i have a thread on my subsonic 300blk load somewhere in the reloading section here

 

[Caveman Jim]

@Caveman Jim

DIY CASE ANNEALER

Thanks man, I'm going to download & print this for later on this year since I'm super busy right now.

 

[v0lcom13sn0w]

BTW im on some of my 300blk 3rd and 4th reloadings and havent had ANY stretch. maybe due to me loading them subsonic?

 

[Caveman Jim]

good job! i make my own 300blk brass too. i do the harbor freight mini chop saw,squirrel daddy jig, rcbs trimmer with 3 way trimmer head and a cordless drill attached (saves SOOOO much time) hornady one shot case lube, and hornady dies. i never case headspace gauge them...i just roll with'm.

ive had good luck with the 125gr speer TNT bullets for super sonic loads. i use 208gr hornady BTHP match bullets for subs.

ive played around with h110 but i prefer 1680 for all of it now...its finally abundant in my area.

i have a thread on my subsonic 300blk load somewhere in the reloading section here

I'm still considered a n00b in the reloading world. Last year I was all giddy competing my first batch of 223/556 cases & my friend (reloading mentor) came by to check them out. He asked if I used a case guage on them? I had not & was scolded & told to do the job right...so i ordered one and tested all 400 cases & found 80+ did not make the cut. I even tried them in my chamber & they would not chamber.
From that moment on I case guage EVERYTHING....
Remember these (from another email thread) that I could not get to resize?

The bag of brass totaling about 200 sat for months & I decided to try & assimulate them into 300. I sprayed them with my new case lube concoction & resized the first one in the 223 die & checked it & low & behold it passes!!!! I believe the problem I was having with this batch was it was a used Hornady die God knows how old the thing was but I got rid of all the used die sets and bought all new Lee dies (223, 300 & 40S&W) with a Lee turret press kit.
I'll continue to use a case gauge checker on every round I reload since it is incorporated into my routine.

 

[v0lcom13sn0w]

thats a good thing you have good habits! i do not condemn what you do at all! its easier to learn new habits than break bad ones! keep on keepin on!

 

[Caveman Jim]

BTW im on some of my 300blk 3rd and 4th reloadings and havent had ANY stretch. maybe due to me loading them subsonic?

Could very well be the case here, all mine are supers for now... Praying the bill to get suppressors off the list....