Mod 29 throat condition question.

[Petander]

When a 44 mag cone looks like this,what would you do?

A friend asked whether to buy or not. I have a similar looking 357 that has lost some velocity and blows by a bit already.

Buy,shoot,don't worry? Do not touch? Buy cheap,get re-coned?


https://i.postimg.cc/KvdjGc5n/Screenshot-20191227-131016.png

[DougGuy]

That's not a throat that's a forcing cone. Rifles and autopistols have throats revolver barrels have forcing cones. That one needs recut.

This photo is immediately after the 11 degree cutter was used, before de-burring and final polishing:

253723

[Petander]

That's not a throat that's a forcing cone. Rifles and autopistols have throats revolver barrels have forcing cones. That one needs recut.

This photo is immediately after the 11 degree cutter was used, before de-burring and final polishing:

253723

Yeah I fixed my post language throat/cone,my bad I don't know why it sometimes slips that way. Language barrier...

Thank you.

Did you only re-cut 11 deg or did you also set the barrel back?

[Outpost75]

Looking at how the face of the barrel and forcing cone entrance are eroded, that barrel has been shot alot with hot loads and needs to be set back a full thread, refitted to bring barrel-cylinder gap within specs and the forcing cone re-cut and lapped. Very likely the gun has also developed some end-shake, needing the crane stretched and possibly realigned, and may also need timing adjustment, likely a hand replacement and possibly also an oversized cylinder stop/bolt if the cylinder locking notches show peening from cylinder backspin, which happens in Model 29s shot with too many hot loads. All that needs to be fixed before setting back the barrel or you are wasting your money.

If the gun is under factory warranty I would return to S&W to be adjusted and possibly rebarrelled.
Otherwise you may have a $250-350 gunsmithing bill plus any replacement parts to put it back right.

[lefty o]

maybe buy if its dirt cheap. that looks to me like someone who liked to scrape that out with a knife or tip of a screw driver, and did it many times. its going to need some tlc.

[Outpost75]

maybe buy if its dirt cheap. that looks to me like someone who liked to scrape that out with a knife or tip of a screw driver, and did it many times. its going to need some tlc.

Nope, thats what throat erosion from thousands of hot rounds with #2400, W296 or H110 powder looks like.

The unburned powder granules at high pressure function in the same manner as sand blasting.

[Petander]

Thanks everyone,

it's a 29-3 10 5/8" with silhouette sights. Most probably VV N110 full house loads for a long time.

Here in Finland ,we don't have much of a revolver culture anymore,it's all Glocks - which are ok,just not for me. But that means it's very hard to find a gunsmith who understands revolvers.

[Moleman-]

I have a 29-3 that has similar gas erosion that took many rounds to look like that. How is the end shake & cylinder gap and timing?

[osteodoc08]

Nope, thats what throat erosion from thousands of hot rounds with #2400, W296 or H110 powder looks like.

The unburned powder granules at high pressure function in the same manner as sand blasting.

Not to mention Lil Gun.

Confession time:

I loaded some 170gr bullets with Lil Gun in a 41 mag and turned a throat from
normal to looking like that in about 50 rounds. Basically nitro sand blasted the darn thing. Live and learn.

[Petander]

50 rounds!

Wow.

Anyway,that gun wouldn't be for me but a friend. We haven't seen it live,it's a full day drive away. We don't see those long barreled every day but trying to find a good smith first.. I think I better concentrate on my similarly eroded 357 and advise my friend to forget about this one.

For laughs: the seller said "forcing cone is just fine,those are factory tool marks from a jumping cutter."

[Moleman-]

Got the 29-3 with a 8-3/8" barrel used and have had the hand replaced 2x, and the cylinder stop replaced one time in 30 years. The bluing has been worn away on the front window of the frame from gas as well. This gun has been shot heavily. Going to set the barrel back and fit a new cylinder. The 629-2 has a replacement 8-3/8" barrel (original was 6"). The forcing cone on that barrel is still nice and sharp and hasn't been shot remotely as much as the 29 has. The gas cutting of the forcing cone wouldn't be as big of an issue for me as would the timing, lockup and cylinder gap/endshake. One of my favorite guns to shoot

[LAH]

Simple thing to recut the cone. If that's the only problem I'd take the deal.

[Outpost75]

Simple thing to recut the cone. If that's the only problem I'd take the deal.

As badly as that barrel face is eroded a simple re-cut isn't going to do it. At minimum set the barrel back a thread and refit, but very likely if the gun has been shot that much with heavy loads it is going to have multiple other issues... And if the OP is in Europe, he is going to have trouble finding a competent gunsmith who knows revolvers.

[onelight]

Do full power light bullet loads do more damage to the forcing cone than full power standard weight bullets ?
Like 180 compared to 240-250 in 44
My 44 developed end shake but my forcing cone is nowhere near that bad it's a mod 29 from the 1970s.

[Petander]

Do full power light bullet loads do more damage to the forcing cone than full power standard weight bullets ?
Like 180 compared to 240-250 in 44
My 44 developed end shake but my forcing cone is nowhere near that bad it's a mod 29 from the 1970s.

I'd like to be educated about this matter,too. We all remember mod 66 cracking forcing cone reputation. Theory was light bullets cause the worst sandblasting effect because they are short,the high pressure peak happens when the bullet base enters forcing cone. Short bullet = longer time to blast hi pressure by.

Or something like that. I do have a 66 which is just fine,I never shot light bullets much but it's well used.

[osteodoc08]

In reference to my mishap, the lighter bullets, from my understanding, have a minute amount of time less in cylinder allowing more of the unburned powder to sandblast the forcing cone as opposed to the heavier ones. This is more prominent with ball powders like 296/LG. I think it was Linebaugh that advised AGAINST Lil Gun years ago when it first came out. Not sure of the current thinking. I strictly use LG in rifles now.

[LAH]

As badly as that barrel face is eroded a simple re-cut isn't going to do it. At minimum set the barrel back a thread and refit, but very likely if the gun has been shot that much with heavy loads it is going to have multiple other issues... And if the OP is in Europe, he is going to have trouble finding a competent gunsmith who knows revolvers.

Guess I'm not seeing the barrel face correctly. Maybe my computer. If it requires a set back it will take a good hand to make everything correct.

[Petander]

Got a new pic to see the frame and possible cutting. I also asked for some measurements,shake & gap for example. That gun looks good on the outside.

My 357 has similar cone erosion but much more cutting up there in the strap,it surprised me because that gun looks clean too, and is tight,within normal measurements all over. Shouldn't buy guns without eyeglasses on.

Anyway,we didn't completely pass on this yet:

https://i.postimg.cc/gkLfvJLk/IMG-20191230-151355-416.jpg