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July 28, 2017, 09:29 AM | #1 |
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Join Date: June 23, 2011
Location: asheville north carolina
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Help me out with some inch by inch questions
I've looked and looked but can't find any inch by inch velocity readings for 300blk or 6.8spc (either the original or spc II). I know the 300blk is pretty near topped out at ~9 inches but I'd still like to see some numbers corroborating that. I'd also like to see how short you can go with the 6.8 before you start to lose a bunch of velocity. Any help or data would be appreciated, so if you have either caliber please post your caliber, barrel length, velocity and load if you can. Again, thank you in advanced.
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July 28, 2017, 10:59 AM | #2 |
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Join Date: February 13, 2002
Location: Canada
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"...at ~9 inches..." Nine inches of what? Barrel? Depending on who you ask/believe velocity loss per inch can be 25 FPS to 100 FPS per inch. There was an article in one of the gun rags, years ago, where the guy(forget who and the cartridge used) cut 1" off at a time with velocity tests at each length. Results were 100 FPS loss per inch. Others are saying, now, with no documentation, it's 25 to 50.
Doubt you'll find anything like that for a specific cartridge though. The only rifle cartridge Ballistics by the Inch tested is .223 using 45, 50 and 55 grain bullets.
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July 28, 2017, 11:54 AM | #3 |
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I was going to say, 'go to BallisticsByTheInch.com but they don't seem to have .300Blk on there yet.
AR15.com has an article on it. Edit: Make that two, at least. As does 300BlkTlk.com. |
July 28, 2017, 03:07 PM | #4 |
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Location: Texas and Oklahoma area
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110gr VMAX and TAC-TX are both right at 2200fps even out of my 9" barrel measured with a Magnetospeed. Both rounds are marketed as being 2375-2400fps from a 16" barrel. So, a 9" barrel will get you about 92% of a 16".
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July 28, 2017, 04:25 PM | #5 | |
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Join Date: June 15, 2008
Location: Georgia
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Several things here. I haven't looked at any of these so I don't know if they are any good or not.
https://video.search.yahoo.com/searc...fr=tightropetb Quote:
Test results from 6.5 Creedmoor. It only lost 54 fps from 27" down to 20" with 142 gr bullets. https://rifleshooter.com/2016/02/6-5...p-a-creedmoor/ Some 308 data http://www.thetruthaboutguns.com/201...-and-accuracy/ This should keep anyone busy for a while that actually wants to learn. https://search.yahoo.com/search?ei=u...e=23207_101916
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July 29, 2017, 10:10 PM | #6 |
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Join Date: November 5, 2016
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I've heard this from a barrel manufacturer that knows a thing or two about cartridges and barrels:
The 6.8 has quite a bit more power than a 300BO, 110s at 2550, 120s at 2460 out of a 16" barrel. The 300 is apx 100-150fps slower than a 7.62x39, 200fps slower than a 30-30 with the same weight bullets out of the same length barrel. |
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