I recall that people shooting M29s in metallic silhouette competition 30 years ago had a lot of trouble with them "shooting loose". They ended up with too much cylinder play, the guns would spit like mad, became hard to cock and accuracy nosedived.
Back then I used a Dan Wesson .44 mag. They would stand up to anything.
I have a 4" M29 from that era and I don't shoot hot loads in it.