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Troubleshooting a 300 AAC load


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Trying to figure out some 300 AAC reloads for a buddy. He got these guys from another of his friends. They shoot but don't cycle properly. I've taken apart and reverse engineered my fair share of bullets and haven't seen anything like this being done on a 300 AAC. Probably explains why those rounds don't shoot for poop.


What I've got so far:


Load #1

- Federal 180gr Trophy Bonded Tip bullet (who even sells these? Never seen them available)

- 5.56 converted case

- 9.5 gr of a super coarse extruded powder. The load was so compressed I had to "dig" it out with a sharp tool.


Load #2

- 147gr FMJ-BT bullet

- 5.56 converted case

- 18.5 gr of the same powder. Again the load was super compressed and had to be dug out.


Here's a pic of that crap. Anyone have any clue what powder the guy's using? IMR4227? Doesn't look like it.... thoughts?



Edited by shibiwan
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Some kind of heavy stick powder, that's for sure. 


What was the loaded COAL on these two rounds?  Do you have any more you can measure? 


On that 147 load, that seems HEAVY, at 18.5 grains.  My 150s are running 16.1 grains of H110 (not compressed) - that charge weight he's using is really gonna depend on the powder, too. 


If you have some chrono velocities and the COAL, it would be alot easier to narrow down the powder. 

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52.84mm (2.080") for the 180 gr 


53.21mm (2.095") for the 147gr 


Heavy definitely on the 18.5 gr with the 147 FMJ's. Still, 300 AAC's have issues with powder selection when you hit the 150gr mark. Choose the wrong powder and it no likey.


Underpowered is how I felt about the 9.5gr in the 180gr.


I think it's the wrong powder too. No chrono though. Not until my bd :D ... then again I'm too lazy for it.


Buddy is hooked on my 220gr subs. Gave him a small handful to play with a coupe weeks ago and today he brings me this crap that doesn't cycle (I've test fired them previously) and wants me to "do these like you do yours".  <laughs>  <lmao>



forgot to add.....the following link is handy/useful for reloaders: http://www.precisionreloading.net/


The smokeless powder database is handy. 

Edited by shibiwan
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I've been running the Hornady 150gr FMJ BTs at 2.090", and the 150gr SMKs at 2.125" - same charge weight of 16.1gr H110.  I quit using the SMKs and only load the Hornady 150s now, and every batch I bring them out another 0.010", and check 10 from the batch on a target grouping.  They're getting better thus far.  They started at 2.060", cannelure all the way down to the case mouth (cases originally cut and prepped to 1.363").

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Shib, you had two different pics of that stuff up yesterday - from both loads - can you repost those two?


With all those pics in this thread, Gibbs should be able to scratch-n-sniff his monitor and tell you what the powder is.  I'm just sayin'...

Edited by 98Z5V
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Shib, I'd tell the guy just to go pop all those off - unless they're WAY overpressured.  That compressed 147gr load with 18.5 grs in it - I'd watch that one.  I'd shoot one, once, and really check that brass close.  If it's safe, just cap them off and reload the brass after that. 

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