Forcing cone/top strap erosion on 629

elrotundamundo · June 20, 2014, 10:34 AM

My son has a fairly new S&W 629. He shot maybe 500 rounds of American Eagle 240 grain factory loads, then we bought a Dillon 550B, A bunch of Starline brass and Berry's 240 grain FP plated bullets. Due to powder availability we used Herco, 800X, and now CFE pistol and loaded them to around 1250 FPS. Primers are CCI large pistol. He has a membership to a local indoor range and shoots a lot. Recently we noticed easily visible erosion of the lip of the forcing cone and the top strap. The gun has maybe 3500 total rounds through it. Is this normal for this many rounds or is something else going on here?

madmo44mag · June 20, 2014, 10:44 AM

Pictures would be real helpful here.

chiefr · June 20, 2014, 10:44 AM

I would make sure your timing and BC gap is within specs.

NoSecondBest · June 20, 2014, 10:46 AM

They all get some of that but it usually progresses to a set point and stops. Must be where the heat no longer cuts in that area. All mine have always had some but never got worse after a while shooting.

rg1 · June 20, 2014, 11:08 AM

My Ruger Super Blackhawk has some erosion on the top strap but it seemed to happen rather quickly and then slow down or stop. With that many rounds through the pistol I'd say it's common. Like mentioned I'd check the cylinder to barrel gap. I've only shot Win 296 powder with 240 grain bullets in mine. It's supposed to be worse when shooting light weight 44 cal bullets with slow powders. A couple powders I've read are bad about flame cutting has been with old now discontinued 630 and the new Lil'Gun. Mine has far less rounds fired than yours and is mostly a hunting pistol and not a range plinking pistol. Shouldn't be an issue with your powders and load levels causing excess cutting.

mikld · June 20, 2014, 11:55 AM

Gas cutting. All my revolvers have it to some extent. I keep my 629 reloads mild so I don't see much there. I believe some powders will cause more gas cutting because of a higher "flame temperature". I read some time ago about powder's flame temperature, pressure, and barrel erosion. A 22-250 is a good example; some powders will "shoot out" a barrel quicker than others...

totaldla · June 20, 2014, 12:00 PM

Does it look like the following? Then I suspect the cylinder isn't in-line with the bore. S&W will fix it free of charge.

madmo44mag · June 20, 2014, 12:31 PM

Quote:

They all get some of that but it usually progresses to a set point and stops. Must be where the heat no longer cuts in that area. All mine have always had some but never got worse after a while shooting.

This is why I said pictures would help.
There is always some erosion to a new revolver barrel and top strap.
Without a picture it is hard to say if it is normal or not.

elrotundamundo · June 20, 2014, 06:56 PM

The erosion of the forcing cone is uniform around the circumference and not quite as bad in the above post. Will try to get pictures and post them. Thanks, all.

June 20, 2014, 10:34 AM	#1
elrotundamundo Member Join Date: August 14, 2011 Location: North Idaho Posts: 56	Forcing cone/top strap erosion on 629 My son has a fairly new S&W 629. He shot maybe 500 rounds of American Eagle 240 grain factory loads, then we bought a Dillon 550B, A bunch of Starline brass and Berry's 240 grain FP plated bullets. Due to powder availability we used Herco, 800X, and now CFE pistol and loaded them to around 1250 FPS. Primers are CCI large pistol. He has a membership to a local indoor range and shoots a lot. Recently we noticed easily visible erosion of the lip of the forcing cone and the top strap. The gun has maybe 3500 total rounds through it. Is this normal for this many rounds or is something else going on here?

June 20, 2014, 12:00 PM	#7
totaldla Senior Member Join Date: August 11, 2009 Location: SW Idaho Posts: 1,499	Does it look like the following? Then I suspect the cylinder isn't in-line with the bore. S&W will fix it free of charge. __________________ Keltec P15 at 1200 rounds

June 20, 2014, 06:56 PM	#9
elrotundamundo Member Join Date: August 14, 2011 Location: North Idaho Posts: 56	forcing cone erosion uniform The erosion of the forcing cone is uniform around the circumference and not quite as bad in the above post. Will try to get pictures and post them. Thanks, all.

June 20, 2014, 10:44 AM	#2
madmo44mag Senior Member Join Date: December 29, 2008 Location: Ft.Worth, Texas Posts: 1,522	Pictures would be real helpful here.

June 20, 2014, 10:44 AM	#3
chiefr Senior Member Join Date: January 27, 2010 Location: AR Posts: 1,401	I would make sure your timing and BC gap is within specs.

June 20, 2014, 10:46 AM	#4
NoSecondBest Senior Member Join Date: December 7, 2009 Location: Western New York Posts: 2,736	They all get some of that but it usually progresses to a set point and stops. Must be where the heat no longer cuts in that area. All mine have always had some but never got worse after a while shooting.

June 20, 2014, 11:08 AM	#5
rg1 Senior Member Join Date: November 6, 2001 Posts: 1,131	My Ruger Super Blackhawk has some erosion on the top strap but it seemed to happen rather quickly and then slow down or stop. With that many rounds through the pistol I'd say it's common. Like mentioned I'd check the cylinder to barrel gap. I've only shot Win 296 powder with 240 grain bullets in mine. It's supposed to be worse when shooting light weight 44 cal bullets with slow powders. A couple powders I've read are bad about flame cutting has been with old now discontinued 630 and the new Lil'Gun. Mine has far less rounds fired than yours and is mostly a hunting pistol and not a range plinking pistol. Shouldn't be an issue with your powders and load levels causing excess cutting.

June 20, 2014, 11:55 AM	#6
mikld Senior Member Join Date: February 7, 2009 Location: Southern Oregon! Posts: 2,891	Gas cutting. All my revolvers have it to some extent. I keep my 629 reloads mild so I don't see much there. I believe some powders will cause more gas cutting because of a higher "flame temperature". I read some time ago about powder's flame temperature, pressure, and barrel erosion. A 22-250 is a good example; some powders will "shoot out" a barrel quicker than others...