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Old 03-28-2011, 9:33 PM
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joelogic joelogic is offline
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Default Reloading 300 AAC Blackout

It seems every other forum has a thread on reloading 300 AAC Blackout so I am pleased to start one on Calguns. The information out there is spread across the internet but its out there. Here is just some info that I have learned along the way. The Gun.

First off the prices people are charging for processing 300BLK brass or processed 300BLK brass is outrageous. I understand capitalism and this is still new but come on it doesnt take more work than processing .223 brass. It just takes some know how and some modified tools.

I am not interested in making 300BLK cases 1 at a time. Why did I buy a XL650? You can process 300BLK cases quickly on a single stage press but I want to use my progressive. What you need to form a .223 case into a 300BLK case on a progressive press with the Dillon 1200 trimmer. 1, You need a sizing/trimming die from CH4D. http://www.ch4d.com/ The owner is super cool. His webpage is hard to navigate but just give him a call. I asked for a 300BLK size/trim die and he assured me that he has reviewed the chamber specs for 221/300 fireball, 300 whisper, and 300BLK and they are all the same. So he sold me a 300 whisper size/trim die and he told me he would roll mark it 300BLK if it made me feel better. 2, A spare toolhead that you can modify. Respecting the marketplace for 300BLK brass I wont go into too many details but basically you need to modify the toolhead so that you can use this die and still use the vacuum attachment. Dillon says you need to use a specfic trimmer to trim 7.62x39 because the brass is so short so same would apply with 300BLK. BS, my friend, mod your toolhead and trim any short brass you want. 3, you will need a set of dies. I bought the Forster benchrest set, expensive, yes, but they are really nice. 4, you will need the 7.62x39 powder funnel. Everything else on the dillon would be the same as if you are processing .223 brass except you will be using the large pistol casefeeder plate with the washer installed (Just like 7.62x39).

Station 1, universal decapping die or a .223 sizing die.
Station 3, the CH4D 300BLK size/trim die.

When trimming almost 10mm of brass you must use care. The speed you work the handle has to be just right. Too fast or too slow and the blade can get caught in the brass and burn your motor out. I would describe it as a quickly continous stroke. That is it for forming a 300BLK case out of a .223 case. Swage as usual. I use the Dillon Super Swage with the .308 arm and small primer ram. On the load cycle just use the dies as you were loading any other round. The sizing die just expands the neck and seat to mag length 2.2ish". Congrats you have just loaded a new and exciting round.

So far I have worked up two supersonic rounds. Not interested in subsonic since I do not live in a free state.
Left round, is a 108gr Frangible bullet ($40 per 1k, awesome) sitting on 19grs of H110.
Right round, is a 150gr FMJ sitting on 18grs of H110.
I havent chrono'd the rounds but they should be around 2000fps. I also havent tried to push for a small grouping but they look good so far. More testing to come.



As a note you do need to shave the ribs on the inside of pmags to get the rounds to chamber right. It not so much the angle but the friction of the bullet dragging on the rib. 10rd mags shouldnt be much of a problem but stuffing 30rds of 150gr bullets in a pmag with a spring meant for 55gr bullets is asking for trouble. Shave the rib and the bullets chamber fine.


Update 7/1/11:
During the testing phase I went with 18 grains of H110 because that is what it took to cycle the action and lock the bolt on an empty mag. Well during slow fire testing that was ok but under heavy use testing I started to see signs of over pressure, mostly blown primers. I drilled the gas port hole one drill bit larger (I failed to write down what bit, next time I pull the gas block off I will check) and worked up a new load starting from a lower starting point. I settled at 16 grains of H110 with the best grouping. Gun runs smooth and fully functionally.

Chrono Data: 150gr FMJ BT with 16 grains of H110.
1st run: 1776,1780,1810,1778,1791
Average, 1787
Standard Deviation: 14.1

2nd run: 1778,1812,1824,1763,1797
Average, 1794
SD: 24.73

Drop Data:
100yds -1.6"
150yds -6.8"
200yds -16.1"

Last edited by joelogic; 07-05-2011 at 1:59 PM..
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