Several years ago I got wrapped up in making these, lots of 22 lr shells turned into 48, 50, 52, 55 and 60 grainer's.  I did use some turned teflon for noses that took my pills to 36 and 40 grain.  Experimented with a punch making both concave bases and a serious rebated boat-tail along with some powdered tungsten, lime, flour, etc. measured and dumped in before the lead, like you, to move the CG forward. Somewhere I have a book with pages of notes, some ideas worked, some failed. 
   
I shot more than a few prairie dogs with all kinds of combinations.  The "Ear Splittin Louden Boomer" I made for this activity, (22-284) pushed  these with enough snot I did see some come undone.  Coating the brass case internals with flux before swaging the cores in, then heating in an oven just over 600° help keep them together until impact.
Terminal performance with this thin jacket was generally spectaular at most velocities over 1200fps.
I made dies that I used 22 mag shells for extra long/heavies, used some very fast twist barrels and experienced some pressure issues.
Sorry I drifted a little, an answer for target accuracy?  I'd tried these in a few matches back then, maybe it was more the shooter than the bullet but when I tried them in a match it was always a struggle.
---more than a nickle's worth of info that really doesn't matter.
Greg