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Posted: 4/8/2017 9:33:03 PM EDT
| 13 grains of 8208 in Hornady brass, CCI 450 Primer and 160 grain RN Hornady bullets. It's too windy to get my chronograph out but definitely sub. Kinda fun. |
| The 160 grain Round Nose bullet looks really long, I bet it protrudes really deep into the 6.5 Grendel case. This has got to reduce the case capacity of the available case volume and hopefully limits the chance of a flash over (explosion where all powder is ignited to quickly). |
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Which last I read had never been able to be replicated, and is very likely an excuse used when people improperly reload ammo.
That said, Trail Boss is an extremely good choice when trying to create lighter than normal loadings (which is what is was made for), to include subsonics. 9-10grs in .308 is perfectly acceptable and generates ~1000FPS with just about any bullet you like. It takes up a massive amount of volume but weighs next to nothing. http://www.imrpowder.com/PDF/Trail-Boss-data.pdf |
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Secondary explosion effect caused by use of heavily-reduced charges in rifle cartridges. It seems to cause a pressure wave or something, and often causes kabooms. What I've read and heard about the risks of really light loads is that rather than a column of powder burning in a controlled manner, you get a lot of the powder burning all at once in the case and causing what is more or less an explosion vs. a burn, which is what generates the big pressure wave you are taking about. I don't have a Grendel so don't know the case dimensions off hand. But if you think about a .308 that is probably close, at the base of the case you have essentially a ID of around .40" and a column of powder maybe 1.5" tall. The .40" at the bottom is the exposed surface area that is going to ignite and burn its way up the column (grossly over simplified since the column starts travelling down the barrel). If you filled the case to where when on its side it was say 1/2 full of powder, you now have a 1.5" x .4" surface of powder that could start burning all at once. Like was said above, I don't know if it has or can be replicated in test conditions, but the theory does make sense. |
 6.5 Grendel Subsonic Suppressed |
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| LRRPF52 what powder and bullet were you using? |
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LRRPF52 what powder and bullet were you using? Quoted:
LRRPF52 what powder and bullet were you using? Description in the video. Finally got my suppressor in and took it out to try with the subsonic loads I made up. Not sure what is up with the audio and my second camera died but you can still tell that the bullet impacting an old propane tank 75 yards downrange is louder then the rifle.
PPU 7.62x39 Brass, non-fireformed Hornady 160gr RN CCI Magnum Large Rifle Primers IMR8208 powder, I will not share exact load data but when working with Subsonics start on the high side and work down so you don't stick a bullet in the barrel. |
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Cool, but why? I suppose if you're into 6.5 but don't have .300, and you have suppressors... |
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