300 Blackout


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Trent
June 10, 2012, 02:50 PM
Ok.. I had a bunch of AR lowers leftover from when I had my gunshop. So on a whim, I decided to build a dedicated 300 AAC blackout... (getting tired of 5.56 and want to experiment some.)

But ... I have no ammo, and I flat out refuse to pay the high entry fee of factory ammo / cases. :-)

Before I get started, does anyone got experience (good or bad) or useful tidbits of info on converting 223 casings?

In particular, I'm looking for an .. expedient (fast) way of chunking out about 500 cases from 223 parents.

Also, not really relevant to the question above, but for some background info on WHY I chose this caliber. I already have a ton of 220 grain Sierra Matchkings on hand from 300 Win Mag shooting - I planned on this being a subsonic only gun, so it's built with a pistol length gas tube. This was an overriding factor in this caliber selection; commonality with stuff I already have; in this case, 220 grain bullets, a surplus of AR parts, AR magazines, and 223 parent cases.

That, and the novelty. :)

Thanks in advance for any help/advice!

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MarkA
June 10, 2012, 03:25 PM
http://www.youtube.com/watch?v=5rpx5XbqAgM

Looks pretty expeditious.

Walkalong
June 10, 2012, 03:39 PM
Another variation.

http://www.youtube.com/watch?v=5ukuy8CRfko&feature=related

Trent
June 10, 2012, 04:09 PM
Thanks guys!

cfullgraf
June 10, 2012, 04:42 PM
I use a Dremel and cut at the shoulder of the 223 Remington. A jig as shown in the videos wold be more precise and maybe a bit quicker over all reforming time.

I also got a 300/221 Fireball (or is it 221/300 Fireball) trim die to do the preliminary forming and to be able to trim the case to the proper length.

Clean up the mouth and do final forming in the full length die then final trim.

Not difficult to do, a bit time consumiong.

As a side note, I am finding re-formed 223 cases have less internal volume than 300 Blk cases so adjust you loads accordingly if you switch between the two cases.

Trent
June 10, 2012, 05:04 PM
Chuck,

With the cost of factory ammo, I'm only going to shoot hand loads, and plan on working up the load starting 10% under what they list for the subsonic 220gr load. Thanks for the tip about the volume being different than factory, that thought hadn't crossed my mind. That would become relevant if I ever bought factory brass (likely, as sometimes I'm known to go the path of least resistance... and I'm a sucker for bags of brand new shiney things...)

Trent
June 10, 2012, 05:05 PM
Also, if 223 cases have less internal volume, then I would have to assume that the 5.56 MILITARY cases I plan on using will have even LESS than that. So that becomes even more relevant!

cfullgraf
June 10, 2012, 06:14 PM
Also, if 223 cases have less internal volume, then I would have to assume that the 5.56 MILITARY cases I plan on using will have even LESS than that. So that becomes even more relevant!

Not necessarily. LC 5.56 military cases typically run significantly lighter than WW 223 Remington commercial cases indicating that the internal volume of the LC cases is probably more than the WW cases.

EMC45
June 11, 2012, 10:54 AM
I chuck the .223 case into my cordless drill and then clamp it in a pipe cutter and let the drill spin the case and the neck portion falls off on the bench. I did a bunch like that. Worked fine.

highlander 5
June 11, 2012, 03:12 PM
I've made a couple of thousand cases using a 300/221 form die,sawzall and a file.
Run the 223 case thru the die use sawzall to cut off the excess and file to clean up,deburr inside and out and your off and running. I could make 75 cases an hour with the above method. There are folks on sites such as Gun Broker who sell formed brass for short money.

M.Weier
June 11, 2012, 08:55 PM
I reload 300 blackout but I go supersonic.....From what I understand about reloading sub's you start a little over the load data then work down to just under supersonic velocitys. Starting 10% under a subsonic load data could lead to a squib and then to a "big problem"......just food for thought and i am by no means experienced loading subsonic.

Swampman
June 11, 2012, 10:14 PM
M.Weier is correct, when working with subsonics it's better to work down than up, this is particularly important when working with jacketed bullets, they are not easy to remove when stuck in the bore.

Trent
June 12, 2012, 08:50 AM
Interesting, never thought about there being a difference with the approach to loading subsonic. Never done it before!

The thought of extracting a jacketed 220 gr 30 cal from a 16" barrel makes me cringe a little inside.

rsilvers
June 12, 2012, 09:13 AM
But ... I have no ammo, and I flat out refuse to pay the high entry fee of factory ammo / cases. :-)

Cases and ammo are pretty cheap. Cheaper than 30-30.

http://www.midwayusa.com/product/2923270375/advanced-armament-co-aac-reloading-brass-300-aac-blackout-762x35mm-primed

http://www.cheaperthandirt.com/2AACO102860-1.html

rsilvers
June 12, 2012, 09:15 AM
Chuck,

With the cost of factory ammo, I'm only going to shoot hand loads, and plan on working up the load starting 10% under what they list for the subsonic 220gr load.

http://www.300aacblackout.com/

It says to adjust powder "down as needed."

Suggested subsonic load:

R-P 300 AAC BLACKOUT brass
Remington 7.5 primers
11.2 grains of A1680 powder (Adjust powder charge down as needed. Factory ammo is 1010 fps for 16" barrel)
Case length is 1.368 +0.000 -0.020
Sierra 220 MK loaded to 2.120 OAL (this length is optimal for reliable feeding from USGI magazines)
Chamber pressure 21,100 psi.

Trent
June 12, 2012, 09:18 AM
Cost is relative. :)

This is a subsonic only gun, can't shoot supersonic out of it due to the short gas tube. Would do nasty things to my bolt.

I have 40K+ 223 cases, around 3,500 220 Gr. Sierra Matchkings (made a bulk order of 5K for my 300 win mag a few years back, still working though them). Also have powder / primers.

So cost to make my own is $0.

Subsonic is more costly; 220 gr bullets cost more.



A buck a piece is a bit much to swallow, when I have all the components sitting here. :)

Trent
June 12, 2012, 09:19 AM
It stripped the midway USA link out.

http://www.midwayusa.com/product/856618/remington-ammunition-300-aac-blackout-762x35mm-220-grain-subsonic-open-tip-match-otm-box-of-20

rsilvers
June 12, 2012, 09:29 AM
This is a subsonic only gun, can't shoot supersonic out of it due to the short gas tube. Would do nasty things to my bolt.

If your gas port is too large to shoot normal ammunition, you can get an adjustable gas block. I know you know this, but just saying it for others to hear. The gas port in my rifles shoots subsonic and supersonic with no adjustments.

Trent
June 12, 2012, 10:03 AM
No, I didn't know that. :)

You got a link to where I can get one?

rsilvers
June 12, 2012, 10:06 AM
This is a two position and it may need modification to be gased correctly:

http://dsgarms.com/ProductInfo/NVSB255616C.aspx

Probably you should get this one as it is variable - but won't be quick to jump between two positions:

http://www.syracordnance.com/

Trent
June 12, 2012, 11:12 AM
Pricey, but looks like they'd fit the bill. Think I like the second one a better, ability to fine tune is always a good thing.. :)

One last item to order before I make a run at it; sizing dies. Any recommendations there? I've been partial to Redding and Forster over the years, but with this being a relatively new cartridge, I'm open to suggestions.

cfullgraf
June 12, 2012, 01:01 PM
I currently use a Redding resize die with the 300 Blk.

I bought a Hornady set first. At the time, it was all that I could find. Then bought the Redding second. I forget whey I did not like the Hornady resize die but it has been retired after a short life.

I still am using the Hornady seater with 300 Blk.

I like Redding dies. I have been having issues with several different Hornady dies of late and will probably swear off them for a while.

rsilvers
June 12, 2012, 02:19 PM
Just note that the older Hornady Whisper(R) dies resize a few thou smaller than desired for 300 BLK brass. They fixed it on the Blackout marked dies.

The Lee seem fine. Crimp die is optional but only $10.
The Forster seem fine - best choice for bolt action ammo as they do the least resizing.
The Redding seem fine and crimp.
The RCBS seem fine. Not sure if it crimps.

cfullgraf
June 12, 2012, 09:16 PM
Just note that the older Hornady Whisper(R) dies resize a few thou smaller than desired for 300 BLK brass. They fixed it on the Blackout marked dies.



My Hornady sizer die is marked 300 AAC/Whisper so I guess it is one of the new ones. I still do not remember exactly why I retired the Hornady sizer die. Maybe just because i found a Redding set.

M.Weier
June 12, 2012, 09:50 PM
The thought of extracting a jacketed 220 gr 30 cal from a 16" barrel makes me cringe a little inside.

The thought of missing a squib and sending another one down the pipe REALLY makes me cringe!:what:

jglenn
June 12, 2012, 10:00 PM
I have the RCBS dies and like them alot


the seater die taper crimps the case... no need for a 3rd die.



typicial RCBS quality.

I form the case 1st from stock 5.56 LC cases then cut them close to length using a Harbor freight small cut off saw.

then final length on my Lyman

with a bit more work I believe I can use just the saw

ChrisK
June 13, 2012, 01:12 AM
As the others are saying, chop it off at the neck and size (221 fireball sizing die or 300 BO) and then trim. I then use a Lyman 30 cal M die and drop it into a Case Gauge. If it doesn't fit, it's usually because the neck thickness is too thick. I use a LE Wilson 30 cal neck reamer then resize and try the gauge again and repeat until it fits. Lee is now making a 230gr 30 Cal Mold if you cast and it's only around $20 (if you want to shoot cheap). I'm shooting subsonic, home cast bullets in my AR and haven't had an issue with leading. I'm also having better luck with my subsonic H110/W296 loads over the A1680 loads.

Swampman
June 14, 2012, 12:05 AM
M.Weier - Of course caution is always advised where the possible loss of your face is concerned, but the sound of those 220 grain bullets hitting the target board/backstop a hundred yards away is pretty hard to miss. It seems louder than the sound of my weapon firing and I'm just running a slightly modified Yugo SKS with a "cheap" Yankee Hill 7.62 Stainless Phantom suppressor.

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