I have a mod 29 44 mag. Its very accurate besides one cylinder. Looks a little over bore compared to the others. I get 1" groups at 25 yards with the other 5 but this one drops the shot from 1" to 3" consistently.

If I have it reamed, it could cause inconsistent results. Is the cylinder screwed? I haven't had a chance to chrono the differet cylinders, cause it really doesn't matter if it's inconsistent.

Have you measured the cylinder or the cases from this cylinder and compared it to the others?

Is the timing off on this one cylinder at all causing the bullet to impact the side of the barrel as it enters the barrel?

I have the same problem with one of my revolvers what i ended up just doing is keeping a spent case with X drawn on the head in the bad chamber to remind me which chamber is bad and just use the other chambers. The other option is contacting the manufacturer and seeing about getting a new cylinder or sell it and get ya something better.

Yea BB its little more open than the others.Didn't measure brass but did the cylinder which was clumsy.By .003" which is alot I think. Out of time? I don't know. Good question. How can I tell? Bet you got a neat little trick for it.

BC, you just apply light pressure with your finger against the cylinder when you cock it so that momentum won't keep the cylinder rotating. If it is out of time the cylinder stop won't pop into its recess on the cylinder.

If it is only slightly out of time it isn't going to cause any problems. It the bullets are impacting the side fo the barrel then you should be seeing evidence of lead splattering or an excessive ammount of copper build up where the bullet is impacting.

If the one cylinder is definetly larger than the others then this is most likely your problem. No real way to fix it that I know of other than purchasing a new cylinder. You can't make them smaller.

wow!! this thread has been a major help!!! great trick there to check cyclinder lock up timing. I tryed it and consistantly that bad chamber was off time, my earlier thought that maybe my chamber was out of size with the other cylinders was totally wrong I checked all my cylinders for dimension the rear of the chambers all measured .380 dia. and the front end of each chamber measured .358 dia. My conclusion is the bad chamber is deffinately due to lock up timing. I closely examined the recess on the bad cylinder, guess what?? theres grime and dirt build up in the recess that went totally unnoticed.... All I have left to do is try firing it and see what kind of results I get. wish me luck!!