Model 27 top strap flame cutting?

[Pantera Mike]

All,

I have a 1967 Model 27 that came to me with seemingly little use. I had it fitted with a second cylinder in 357/44 Bain and Davis. I noticed today what seems to be some rather extreme flame cutting of the top strap. This is after perhaps 1000 rounds with revolver-spec loads (22.0gr of WW296 with a 158gr JHP)

See attached pic. More to follow….

 

[Pantera Mike]

By way of contrast, I have tens of thousands of full power rounds through my Model 29 in 44 magnum, using 23-24gr of WW296 with various 240gr lead and JHP bullets. It also exhibits a bit of flame cutting but not nearly as extreme, for probably 20x the use:

 

[Pantera Mike]

So my question is, should I be concerned about the top strap wear on my Model 27? I would hate to saw the top strap in half just having fun at the range….

 

[Pantera Mike]

I should also mention that the cylinder to barrel gap is .006” on the Model 27 and .009” on the Model 29.

 

[6string]

Flame cutting of the top strap tends to go only so far, then stops.
However, both of your revolvers exhibit considerable forcing cone erosion, particularly at the edge.
That's a bigger issue. It'll only get worse. In extreme cases, such as with extensive use of magnum loads in a K-frame model 19, it can potentially precede a cracked forcing cone. Probably not a big worry with the M27. With the M29, though, I've seen thus myself and been concerned.
The remedy is to have the barrel set back one turn and then have the forcing cone recut and the B/C gap reset. That'll fix things up.

WW296 is one of the worst offenders for this type of erosion.

 

[diecidecimi]

I would be worried about that forcing cone erosion, more than the flame cutting.....

 

[stansdds]

That model 27 has seen a lot of full power loads, likely handloads using slow burning ball propellants H-110/W-296, but could also be from full power factory ammo using 110 or 125 grain bullets. The flame cutting of the top strap is usually self-limiting, the erosion of the forcing cone only gets worse with more of the aforementioned ammo.

 

[raljr1]

that 357 load made me go back to the books. I load 15 gr 296 behind a 158 gr sjhp. That 22 grains seems way hot for me.

 

[Hair Trigger]

that 357 load made me go back to the books. I load 15 gr 296 behind a 158 gr sjhp. That 22 grains seems way hot for me.

.357/44B&D is a .44 Magnum case necked to .357, so the case capacity is significantly greater than the .357M case. You get a big jump in MV, even better performance than .357 Maximum. My guess is the flame cutting and FC erosion is due to all that powder still burning after the bullet is past the FC. I bet it makes one helluva bang.

 

[raljr1]

.357/44B&D is a .44 Magnum case necked to .357, so the case capacity is significantly greater than the .357M case. .

I missed that when reading the OP. Thx



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[Retired W4]

I was wondering if a shield, as the 310 Night Guard has, might help. I have no idea how that thing is installed but it does protect the scandium frame.