M29 with .433" throats

[Northern Flatlander]

So I gots this M29 pinned and recessed, with .433"+ throats twenty or so years ago. I be damned if it can shoot under 3" at 25m with cast bullets. Ive tried everything from the food-trough commercial BB SWC's @.430"(which sometimes get into the 2" range) to soft cast Keith's @432" with loads ranging across the alloys yield strength with no avail..
I worked out the variable of my ability every damn time Im at the range with one or another Ruger SA, which always shoots 1.5" +- with their favorite loads.
Frustrating.
So my question is; should I do the whole LBT process or send the unit to Bowen for a re-cyl or rechamber the little bugger to .45 Colt.

Thanks for reading.

Dwayner

[Mikey]

Did you ever mic the barrel?  If the throats are .433 you can do a couple of things without kicking over the gun for something else or having another cylinder installed:  mic the barrel and then bore lap/fire lap the barrel to .432 or .433 using either the LBT (Veral Smith's) process or the process used by Beartooth Bullets and then shoot bullets that are .433 in diameter. 

Or, you can call Smith and Wesson directly after you have mic-ed the barrel and tell them of the discrepancy between the throat size and the bore diameter and ask if they could install a new cylinder with smaller throats - the custom shop at S&W should be able to do this for you.  HTH and good luck.  Let us know how it goes. 

[Northern Flatlander]

Thanks Mikey
I like the Idea of a re-cyl. Ill check that route for sure.
Dwayner

[Bigeasy]

Assuming your barrel is not way out of spec, you should be able to get good accuracy with .433 throats.  Unless the bullet is cast super hard, or driven at slow velocities it should "slug up" slightly in diameter to fill the throats upon firing, then back down slightly for the bore, which should be about .429 / .430.  Three thousandth is not a big difference, especially since you have tried bullets sized to .432 with no real improvement.  Do jacketed slugs shoot appreciably better?  You may have excess leading in your bore, or possibly a flaw that is hard to see.  Groups in the two inch range at 25 yards are not really that bad with cast bullets.  A lot more iron sighted big bore revolvers shoot one hole groups on the Internet then they do at the range..

Larry

[Northern Flatlander]

Hia Larry
The internet groups point, I agree.
Like I mentioned, I can get quite a few sub-2" groups with my various Blackhawks.
Oh, yes. Jacketed loads shoot the hot damn in that 29. Under 2" regularily with the loads it likes, on my good shooting days. Too bad Im not a fan of jacketed type.

[Mikey]

Dwayner:  if your 29 shoots jacketed slugs well but not cast, it sounds like a Marlin microgroove barrel trying to shoot cast slugs before it is fire lapped/bore lapped.  I believe that you think about lapping it to shoot cast bullets.  This is a pretty easy process and a fun one and will smooth out a rough barrel, properly.  HTH.