Hard cast 55 grn gc oolits in 223

I have an old ruger #3 in 223 that I bought nearly 1000 Barnes varmint grenades for, going thru my oddment box I found a part box of hardcast 223 bullets, with copper gcs fitted and lubed with that blue lube. Sized at 0.225"
At some stage I'd tumbled them in alox and, as there were only about 65 left and I had a 100 cases primed and ready I looked up my 4th edition lyman cast bullet handbook and could see I could use 2400.
I loaded them up with 10.5 grns 2400 and headed for the 25 yard range to sight them in.
I spent the first half dozen chasing round the target trying to get the darn things to hit where I could see and eventually found they shot 8 inches low and 5 + inches to the right.
Group sze for the next 5 rounds was under an inch at 25 yards.
I thought the scope must be off so put 3 of my varmint grenades downrange, 3 overlapping holes, 1/2" low and central ( it's sighted for 3" high at 100 yards and point blank range is around 280 yards.
WTH is going on here.
Velocity of the cast bullets 1860 +/- 23 fps, velocity of the VGs 3340 fps.
Cast loads were very quiet and recoil free.

WAG- the cast is exiting the barrel at a different node of barrel vibration.

Still gives a somewhat decent group; but at a wildly different point of impact, because the barrel is pointing differently.

Robert

Many thanks for that info. I never cease to be amazed at how little I know. I just never would have believed that sort of poi change was possible even though the evidence is staring me in the face.
I pulled all those bullets and put them in the melting pot and saved the 2400.

The number three I had was chambered in .223 and wouldn't hold the same point of impact from day to day . No matter the load you could sight it in on Monday and Tuesday the group would be somewhere else .

Jack

Jack, I think your #3 must of read the internet stories about what they do and don't do, but the two I have had (the other was a #1 in 308) were consistent enough but I never tried the 308 with cast boolits just speers BTSP of 165 grns or 150 fmjs which more or less shot within an inch of each other.

I have a T/C Venture bolt gun in 223 with a twist of 1/12. It absolutely adores a 58 gr. RFGC from an NOE mold with 6.3 gr of Red Dot. with an MV of about 1850. At 100 yards, it has out-shot every jacketed bullet I have tried at normal JSP velocities (2600 and up) except Sierra match 22's using a 4x scope. It took a while to get things just right, however.

Think it's a 2016? R700 ADL sporter(skinny) brrl 223. PTG single shot plate and a Bushnell Elite 4500 4-16X50....

19g of IMR4198 behind a Lee 225-55RF with a medium jam. I'll put it up against any JB shooting sporter for 5 shot groups @100 yds.
Oh,I won't win every round but you'd better bring your A game and a set of dial calipers. Anything less,you're gonna be buying lunch,haha.

I'm not a Lee fanboy by any stretch,but this particular mould is EASILY in my top 3 for as cast roundness out of a whole bunch of moulds. Just one of those perfect matches. Good luck with your project.