doc540 Posted February 28, 2013 Share Posted February 28, 2013 (edited) Savage M12 1/9 twist .223 55gr Varmit Nightmare X-Treme HP (Midsouth bulk Hornady's) 24.5gr IMR 3031 Out of 65 rounds today, I had 5 tumblers. All other shots were tight and accurate. Four of the tumblers were tight in their groups. I left this one alone to show how accurate it was. Crown's good, barrel's good, rounds weigh 55gr However, I did not check diameter or symmetry of every round. How could a tumbling bullet still be right on the money? Edited March 1, 2013 by doc540 Link to comment Share on other sites More sharing options...
Amerflyer48 Posted February 28, 2013 Share Posted February 28, 2013 (edited) Varmint bullets tend to have thinner jackets, could it be possible you had a few casings longer than the others and got a bit more crimp possibly damaging the jacket destabilizing the round and causing a downrange tumbling to begin at say 85-90 yds. which would still be mostly accurate vs. a bullet that starts tumbling at say 45-50 yds. which would be all over the landscape. I remember a shooter once(1993 or so) that had a problem with some varmint bullets spinning too fast and coming apart due to too fast a twist don't remember the bullet or the twist rate but they never made it to 200 yds. he went from 9s and 10s to misses and finally figured he grabbed the wrong box of ammo for his .222 silhouette rifle ( he aslo shot prairie dogs with a .222 ) Natchez shows in the notes a 1-12" to 1-10" twist for this bullet maybe you are on the edge of shattering due to centrifugal force (?) and only destabilizing.. Hope not I have 200 of those bullets about to be loaded into my BHW 1-8 AR-15 John P.S. using your load data (IMR site posts 24.6c @ 3200 fps. +/-) and info provided your bullet is spinning at about 258,600 RPM A post over at shootersforum.com shows Hornady saying 260,000 RPM is the ceiling so having said that you are in the realm of bullet distortion which could cause serious yawing and/or coming unglued. given variances between published data and your individual rifle you could be overspinning easily. MV * 720 / twist = RPM fun with math http://www.shootersforum.com/ballistics-internal-external/78073-f-y-i-varmint-bullet-rpm-limits.html Edited February 28, 2013 by Amerflyer48 Link to comment Share on other sites More sharing options...
lee blackman Posted February 28, 2013 Share Posted February 28, 2013 (edited) Wow, that is amazing for sure. This is probably a stupid question, but do you think its actually tumbling or maybe just extreme, and I do mean extreme nutation around a stable axis? PS: I think amerflyer48 hit the nail on the head. I'd be willing to assume that the 5 of 65 rounds fired were at the higher velocity end of your SD. I would also be willing to bet if you brought your powder charge weight down by a few tenths of a grain it would eliminate the problem. Edited February 28, 2013 by lee blackman Link to comment Share on other sites More sharing options...
Dan Sierpina Posted February 28, 2013 Share Posted February 28, 2013 Do you crimp the ammo? If so, did you trim the cases for consitency? Link to comment Share on other sites More sharing options...
doc540 Posted February 28, 2013 Author Share Posted February 28, 2013 (edited) measured every single case for consistency hand-measured every single powder load neck-sized the cases (only shooting the same brass from the same gun) seated with an RCBS Rock Chucker and RCBS die remeasured every round for OAL bullets are Hornady and repackaged a Midsouth bulk 5 out of 60 tumbled but remained accurate Edited March 1, 2013 by doc540 Link to comment Share on other sites More sharing options...
perrysho Posted March 1, 2013 Share Posted March 1, 2013 This comes under the heading of a "LOT OF THINGS I DON'T KNOW". Couple of guys post in here that are ballistic/technicians gurus. When a bullet traveling above the sound barrier drops under same will sometimes tumble. Check this out, post your findings please. Maybe one of em old gents at SIERRA will talk to you, they know a lot. www.sierrabullets.com Have FUN, be SAFE, Perry Link to comment Share on other sites More sharing options...
doc540 Posted March 1, 2013 Author Share Posted March 1, 2013 Someone on another forum posted the problem had happened before with the same bullets due to quality control glitches and some bullets not having the proper core. makes sense to me Link to comment Share on other sites More sharing options...
Amerflyer48 Posted March 1, 2013 Share Posted March 1, 2013 the physics screams a tumbling bullet can't be accurate, like a tumbling football cant be as accurate as a spiraled ball.. proper core ? as in weight or seated funny or not seated in the base (nose heavy) Guess I will weigh all 200 of mine and see if it is a weight issue any of this ammo left you could shoot at say 200 and see if the tumblers are still anywhere near the POA ? it is an interesting phenomena to say the least I'd like to see more groups at different distances to get a picture of the path of these tumblers or more info as to the defect that causes this to happen John Link to comment Share on other sites More sharing options...
doc540 Posted March 1, 2013 Author Share Posted March 1, 2013 (edited) Will load some more and shoot at 200yd, then report back. Today is soft points only, but if I have a tumbler I'll note it. thnx btw: here's a tumbling softpoint in a 5 shot group at 100yds Edited March 1, 2013 by doc540 Link to comment Share on other sites More sharing options...
Dan Sierpina Posted March 1, 2013 Share Posted March 1, 2013 You never said whether or not you crimped the ammo. If you are, don't, then try again. Link to comment Share on other sites More sharing options...
doc540 Posted March 2, 2013 Author Share Posted March 2, 2013 (edited) Yes, I guess I'm very slightly crimping (nothing like handgun ammo) and seating with an RCBS die. Today I shot 50, 50 sp's and 50, 55gr hp's at 200yds. Not one tumbler out of the 100. Very windy, but 200 is a lot more fun than 100, that's for sure. Edited March 2, 2013 by doc540 Link to comment Share on other sites More sharing options...
Dan Sierpina Posted March 2, 2013 Share Posted March 2, 2013 In a bolt gun, you don't need to crimp. I don't crimp even in an AR, or M1A. Link to comment Share on other sites More sharing options...
doc540 Posted March 2, 2013 Author Share Posted March 2, 2013 In a bolt gun, you don't need to crimp. I don't crimp even in an AR, or M1A. I didn't think so. Since I'm new to reloading, I just followed the Dillon directions and got them seated well. thnx Link to comment Share on other sites More sharing options...
ZombieHunter Posted March 4, 2013 Share Posted March 4, 2013 I've had terrible issues with those Varmint Nightmare bullets (in multiple rifles); they are VERY thin jacketed. I've even blown them apart in a mid-range load going down range. I will not use them anymore. I would suggest getting a better projectile. You get what you pay for, and those are CHEAP. Link to comment Share on other sites More sharing options...
doc540 Posted March 4, 2013 Author Share Posted March 4, 2013 (edited) I've had terrible issues with those Varmint Nightmare bullets (in multiple rifles); they are VERY thin jacketed. I've even blown them apart in a mid-range load going down range. I will not use them anymore. I would suggest getting a better projectile. You get what you pay for, and those are CHEAP. Thanks, but I don't hunt with them or shoot matches, so I got my money's worth. Out of about 500 of them downrange so far, I've only had 5 or 6 tumblers. Last 100 have been tumbler-less. I do have some quality Sierra's, but I'm reserving them for when I learn to shoot this thing. Edited March 4, 2013 by doc540 Link to comment Share on other sites More sharing options...
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