Gas Cutting in a 44Mag

[Sam06]

Anyone ever have a 44Mag Gas cut before?

First off I have had 44 Mags since 1977 and have reloaded for them almost as long. I just had the 1st instance of Gas cutting in my 629. I think it is due to Bullets a little small. The cast bullets I used are .429 and I usually use .430 bullets. The Gas cut line is very small now, not much more than a scratch. Like you took a very sharp nail and scored the topstrap.

Here are my questions:

1. Will this stop if I use larger bullets?

2. Is the gun wrecked?

3. What if anything can I do to stop this from happening.


Thanks in advance...........Sam06

 

[laytonj1]

All magnum revolvers will flame cut. How much depends on cylinder barrel gap, bullet weight and velocities (pressure). The lighter the bullet and higher the velocity then the faster the flame cutting. The good thing is it will only go so far and stop. It will not weaken the gun.

Jim

 

[Sam06]

Thanks jim. This is the 1st time I have seen this happen in a 44Mag. I checked the end shake of the gun and it is not excessive the gap is with in specs and I have shot the gun a long time. Then this weekend I shoot it and see the cut line. I know it will stop but I am worried that I did something wrong. I shoot handloads:

20gr 2400 under a 240 SWC so I know its not the load. I figured it was the bullet as they were a little undersize from what I normally shoot.

 

[IdahoG36]

I just took my new Ruger SP101 out today and fired 60 rounds through it. There is a small line in the top strap that wasn't there when it was new. I assume it is flame cutting. It's pretty shallow, but it is noticeable.

Here is a pic with the flame cut line circled.

 

[roklok]

That line in the pic is not flame cutting, it is not in line with the cylinder gap. 60 rounds would not flame cut a steel revolver with any sane load.

 

[IdahoG36]

I wasn't sure what it was. I didn't see it there before.

 

[Smaug]

Don't worry about it

But do go back to the 0.430" bullets and a decent crimp.

 

[Gun 4 Fun]

As laytonj1 said, all magnums do this. This may seem like a dumb question, but are you sure it's even cutting? I've seen what looked like flame cutting and it turned out to be a tiny strip of lead deposited there from shooting lead bullets of poor quality or that were a little too soft. It was hard to tell at first, but when really cleaning the gun, I was able to scratch it. Then I realized what it was and scrubbed it right off with a bronze brush.
If it is flame cutting, don't worry about it.
Your load is actually pretty close to top end with 2400 and a 240 bullet. They usually recommend 21 gr. as top with the "new" 2400 powder. A number of years ago they [Alliant] changed the formula slightly for 2400 and now it is slightly faster than it used to be, so 21 gr. will do just about exactly the same as 22 gr. used to, with a 240 gr. bullet.
With all due respect to smaug- switching from a .429 to a .430 dia. bullet won't start flame cutting, and may not give you your best accuracy. You need to check the diameter of your chamber throats in your cylinder. Plug gauges are best, but a decent caliper will work almost as well. The diameter of the throats should determine the size bullet you use. If you have throats measuring say .428 you'll probably have best luck with bullets of .429 dia. But if you have throats that measure .430 or larger you'll get your best results with.430 dia. bullets.
Throats are a more important number than even bore dia. The reason is, your bullet has to go through the throat before it goes through the barrel. Any bullet that either exactly matches or is within .001 of your throat size will usually give your best accuracy. If a bullet is too small, it may not obturate [slug up] and fill the throat, allowing it to enter the forcing cone ever so slightly tipped, ruining accuracy. If it's over throat diameter, when it's fired it'll be squeezed down to throat size anyway. You just don't want to be squeezing down to much upon firing.
Bullets that closely match throat size, will usually give best accuracy, with minimum leading, provided that the bullet is the right alloy and hardness, as well as properly lubed.

 

[batmann]

I'm not a gunsmith, but I believe flame cutting just above the forcing cone is normal on magnum handguns and will be noticable but should only go so deep and then will stop or not not go deeper. It should not weaken the frame.
The only firearm that had a serious flame cutting problem, in my memory, was those produced for the .357 Maximum. The older K frames S&W had a forcing cone problem when everybody went to the 125 gr and lighter .357's.