.38 fouling in a .357 and pressure with .357

[ArmedBear]

I picked up a used 686 and shot some .357 handloads in it.

I had thought the gun was clean, but I may have missed some .38 fouling in the chambers.

There were obvious signs of overpressure when I ejected and looked at my spent brass.

However, I had also switched primers for this box of rounds (you take what you can find, these days).

For the purposes of working up a new load, would you think the .38 fouling could have caused the excess pressure, or should I assume that the primers were the cause?

(These were Winchester small pistol magnum primers, whereas I'd been using CCI small pistol standard primers. So I would expect that the new primers are hotter.)

 

[pps]

Clean out the fouling and run a few more rounds. If the pressure signs go away, you'll have your answer.

 

[Steve C]

Fouling should make no difference as to the pressure of the cartridge. It may cause the case to stick a bit in the cylinder and if fouling is present and causing that stickiness it would not be pressure related.

Other signs like flattened, pierced or cratered primers would not be caused by .38 fouling that doesn't block the bullet in its path out of the cylinder chamber and down the bore.

 

[ArmedBear]

Thanks.

I did get the "stickiness" on ejection, but I originally thought that was related to the pressure (since the flatterned and cratered primers were present). I just found the fouling, as well.

So I cleaned the revolver, of course. Took a few rotations of CLP and wire brush. It was pretty thick -- so thick and consistent that I'd looked down the charge holes and thought I just saw the normal step in diameter.

Now I will also back off on the powder charge...

 

[rcmodel]

Fouling should make not difference as to the pressure of the cartridge

I disagree.

It (hard packed .38 Spl ring) can most certainly raise pressure if it is severe enough to prevent the case mouth or crimp from expanding fully to release the bullet.

Clean it with a .40 cal bronze bore brush, solvent, and a cordless drill.
Then try it again.

rc

 

[rmuzz]

What I've heard about .38spc/.357 mag is congruent with what rcmodels says as far as yes it can cause case mouth to not fully expand... but speaking only for myself the idea of taking power tools to my shooting tools give my spine shivers. Whats your suggestion for an alternate method? I think I used a small, fairly stiff, plastic brush and did it by hand when I first got my 19-5... was really not all that dirty to be honest though.

 

[Walkalong]

the idea of taking power tools to my shooting tools give my spine shivers

Your not drilling your gun, just running a bronze brush into the chambers. Works like a champ.

 

[KyJim]

Yes, fouling in the cylinders of a .357 by using .38 special can cause pressure problems when shooting .357s. As Walkalong noted, all you need to do is clean each chamber with a bronze brush.

 

[Jim K]

Hi, rmuzz,

A bronze (brass) brush will NOT harm a steel barrel. Period.

Your kind and gentle plastic bristle brush will NOT do the job. Period.

Jim

 

[ArmedBear]

This was probably lead, not just powder fouling.

A good manual scrubbing with a bronze brush, and a few soakings of CLP in between, took care of it.

.357 cartridges now drop in and stay loose, like they should.

I shouldn't have missed that, but the gun looked so utterly clean otherwise, that I forgot that some people shoot nothing but .38s in their .357s.

 

[Walkalong]

How did she shoot?

 

[Virginian]

In my experience, fouling from 38s may inhibit loading of 357 length cartridges, but if you don't feel any resistance there, it will not cause any problems. It shouldn't, the projectiles are exactly the same diameter.

 

[jfh]

Use the bronze-brush and power driver routine; it's painless and quick.

I routinely shoot 38s from my 357s--typically, 2-3" carry guns. I clean the chambers after every range visit--and I have found the HD nylon rifle brushes (Brownells) to do a satisfactory cleaning job. If not, use the .40 cal bronze brush.

As for the recipe--if you are getting flattened primers and cratering, you are too hot.

Jim H.