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.223 Keyholing
updated 11 months, 1 week ago
2 Members
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7
Posts
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Shot some 55gn Lightning bullets out of my AR today, and about 20% of them keyholed at 25 yards. The last time I shot these they didn’t keyhole, and other loads (77gn SMK, factory M193) were fine today. Could it be my load?
Data:
Lightning 55gn FMJ-BT
Powder: 26.0gn CFE223 (223 starting load)
Primer: CCI 400
Seating depth: 2.23”
Trim length: 1.75”
Gun: Aero Precision upper
Ballistic Advantage 5.56 1-7” 16” barrel.
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Apparently they are just crap bullets.
Looking at their products, that’s the only jacketed bullet, all the rest are cast.
Your keyholing is due to jacket failure at high rotational speed. The bullets are coming apart as soon as they leave the muzzle. Almost makes me think they are plated rather than a true jacketed bullet.
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Unless the bullets are really low quality and have visual defects, I doubt being overstabilised is the issue. It’s like a car wheel – providing it is balanced, you can go as fast as you like and there will be no juddering.
The amount of whatever powder you are using is not the issue. 26gr is fine and the comment saying it’s too much is rather dumb. I use 25gr of a faster powder under a heavier bullet.
Do you have a muzzle device on the rifle?
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[deleted]
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Wow there’s some junk comments on here. That’s what you get for asking advice in the internet lol.
I have shot PLENTY of 55gr through my colt 1 in 7 barrel and been fine. Also listen to your reloading manual on starting charges not these people lol. That’s a crazy problem you got. Maybe it is the muzzle brake?
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Your barrel might be toast.
Several years back I had this FN 1-7″ 16″ CHF/CL barrel that started keyholing on paper at immediate close range (15 yards and less) after only about 2500 rounds or so. My 77gr handloads didn’t keyhole when I shot some sample strings. The 55 and 62 gr factory ammo would keyhole 1 every 10 rounds or so after I got the barrel warmed up.
I tried diagnosing (even removed all muzzle attachments) with no effect.
I ended up just getting another barrel (BCM 16″ 1-7 CHF/CL which is probably a FN barrel anyway) and it’s got 5000+ rounds on it without issue.
I had the problem barrel in my garage since then and recently got around to handing it over to my gunsmith after I was cleaning out some cabinets in my garage. I asked him if he could take a look at the barrel before I junked it. He bore scoped it and he said the lands were missing chunks near the chamber. Very abnormal for throat wear. Could be a combination of a bad barrel to begin with and my running it hard (lots of fast shooting in SoCal summer weather).
I’m guessing the lighter weight / shorter 55 and 62 gr bullets were being affected by my barrel wear / damage, but the 77gr had more bearing surface to deal with the destroyed lands.
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26grains is alot of powder for a 223. Thats probably your issue.. start at 20.0 and work up to 23.0
