How can I stop top strap erosion?

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totaldla

New member
I have a 329pd. The blast shield is a steel insert directly above the barrel/cylinder gap, protecting the alloy frame. I recently decided to try some magnum loads using W296 powder. Within 20 rounds I began to get erosion of the blast shield.

I'm wondering if there a magic metal coating that would slow down or prevent erosion. Is there such a thing? Thanks in advance.
 
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w_houle

New member
No. Some is just going to happen, but it shouldn't go far. Aside from that... don't shoot hot fancy ammunition through it for range practice.
You mentioned using a powder but not a bullet weight, what weight are you using?
Oh, and you might want to consider a faster burning powder
 
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totaldla

New member
240gr XTP for 1200fps.

I can do the same velocity without erosion with Ramshot Enforcer. Others have told me that a flake powder such as 2400 won't cause erosion either.

W296/H110 have been around for a long time and folks have been shooting some pretty high-end loads with them. I was thinking that someone had figured out how to stop erosion using some special something - perhaps not.
 
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Doodlebugger45

New member
I am really only familiar with top strap erosion on the 357 Maximum, but there might be some parallels with other cartridges. There are 2 things to learn from the early 357 max shooters. First of all, the erosion only went so far and then it stopped for some reason. Secondly, the ones that got the erosion were the ones that tried to shoot light bullets at very high velocities. I would suggest the same for your 329. Go ahead and use 296 but don't try to use light bullets in hopes for rifle velocities. Go and make some hot loads but stick with heavy bullets. But chances are the erosion will stop soon enough with no real damage done. Keep your eye on it though.
 
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41mag10mm

New member
It may not be too practical but you could get parts ceramic coated. This process has been around for awhile being used on engine exhaust. I have had my Harley exhaust headers coated inside and out with it to reduce the radiant heat. It works extremely well at that application withstanding constant temps in the 500 degree range. When researching this last year I seem to remember there were coatings that withstood temps in the 2500 degree range. Like I said this might not be practical but I thought I'd throw it out there.
 
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18DAI

New member
In steel framed revolvers top strap erosion is self limiting, in my experience.

On my duty 66's it would get to a point, and cease.

On those unobtanium frames with the mickey mouse "blast shields", you just need to keep replacing the blast shields. Sort of protecting the revolver from.......doing what it is designed to do. A guy at my range has one of those 329's and shoots it a lot. He's on blast shield number two.......as of last time I saw him. The way he knew it was time for a new blast shield is the original one fell out :confused: . Innovative. ;)

At least S&W will pay your shipping both ways. :)

An old mossback I use to work with took a #2 pencil with him on qualification days. He would run it back and forth over the flame cut in the topstrap of his 66. He claimed it prevented further cutting. Dunno if he was onto something there.

I wonder how many blast shields are needed during the service life of those revolvers? I also wonder how many rounds before the topstrap stretches and the revolver is permanently out of time?

Good luck! Regards 18DAI.
 
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stevieboy

New member
I've assumed that flame cutting is pretty much a fact of life. I've only experienced it with a single round -- 125 gr. .357 magnum. Firing that round has left a noticeable cut mark in the top strap of my 686 (stainless) and my Model 27 (blued). Firing 158 grain magnums does not seem to produce the same effect.
 
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old bear

New member
Stop top strap erosion

To stop or really slow down top strap erosion, using a number 2 pensile fill in the area on the top strap above the forcing cone. Apparently the graphite stops the flame cutting. I have been doing this to all my revolvers for 30+ years and I never had problems with flame cutting.
 
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Jim Watson

New member
Friend of mine did the same, considered the graphite was acting as a heat shield.

A pencil in the shooting box to take to the range seems not a huge burden.
Here's hoping you don't get in enough gunfights to need a time out to apply anti-erosion treatment.
 
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.284

New member
I like the pencil idea. Does the graphite help the cleaning process around the forcing cone? That seems to be one of the harder areas to clean.
 
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old bear

New member
First, you don’t need to apply graphite every time you shoot, from my experience one application holds up well. The graphite does not come off with cleaning; at least when using #9 and a brass brush. My guess is that the graphite acts as a heat barrier and helps prevent some of the fowling around the forcing cone, so that area does not get as dirty as it would without the graphite, but the area we are referring to is still a bear to clean. Give it a try if you don’t like it well you don’t have to use it again and it didn’t cost anything.
 
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GeauxTide

New member
Get a heavier frame piece for shooting reloads, like a Redhawk. I've owned several 19s, 66s, 29s, 27s, and 28s that suffered frame cutting with heavy loads and slow powders. My 57s and 657s did not, which I found interesting. A Ruger Single Six and several Blackhawks in 41 and 44 did not suffer, either.
 
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totaldla

New member
old_bear said:
First, you don’t need to apply graphite every time you shoot, from my experience one application holds up well. The graphite does not come off with cleaning; at least when using #9 and a brass brush. My guess is that the graphite acts as a heat barrier and helps prevent some of the fowling around the forcing cone, so that area does not get as dirty as it would without the graphite, but the area we are referring to is still a bear to clean. Give it a try if you don’t like it well you don’t have to use it again and it didn’t cost anything.
Click to expand...

That's exactly what I was looking for. I knew there had to be something in common industrial use that would increase the life of the 329pd blast shield. I figured someone who welds for living would pipe up with a solution. But a #2 pencil certainly is something easy to try. Thanks.
 
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James K

Member In Memoriam
I guess for owners of .44 Magnum revolvers a suggestion like "cut the load to something reasonable" is not acceptable.

Jim
 
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orionengnr

New member
If the blast shield is replaceable (and someone previously stated that it is) then it is really not a big deal. This is entirely different than the top strap itself eroding, which would be a cause for concern.

What I am really wondering about (given my experience with Scandium revolvers, especially of the Magnum breed) is this:

How in the Hell do you shoot heavy Magnum loads through a 329 without permanent wrist damage? I know the 329 weighs a good bit more than the 340/360, but those things are downright brutal, at least to my 50+ year old, carpal-tunnel-syndrome affected wrists. And even the 396 (.44 Spl) and the 325 (.45 acp) were somewhat unpleasant with full power loads.
 
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