I have heard you should not shoot semi jacketed 357 out of the 19-3 does this include FMJ? and should you never shoot semi jacketed or just not a steady diet of them?

IMO, nothing wrong with a semi-jacketed or full jacket bullet in a model 19. But I would stay away from the 125 grain and lighter bullets. They are the ones that seem to be responsible for forcing cone issues in K frame .357 revolvers.

There is nothing wrong with shooting jacketed (partial or full) bullets in a Model 19-3 as long as they are 158 grains. Problems can arise (so I have read) if you mainly shoot lighter weight bullets (125 grains for example) in your .357 Combat Magnum.

I only shoot JSP or JHP 158 grain bullets in my .357 Magnums, including several Model 19s, and I have never experienced any problems.

Bill

You’ll do just fine shooting 158 gr bullets, lead, semi jacketed, or full jacket.

Where did you get this idea?

Lots of garbled nonsense going around about the old K frames with the flat-bottomed forcing cones.
The cracked forcing cones are only a problem with hot loaded .357 cartridges with light bullets. as Mike C2 points out above.
You can load any bullet you want in .38 Spl.
And if you want to shoot .357 loaded to max all the time, a model 686 L frame is designed for that.

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Having nothing to do with 19’s and K-frame specifically… but still on the subject… it is a REALLY bad idea to shoot a whole slew of lead bullets and then move to shooting jacketed without first scrubbing your bore clean and free of any built up lead inside.

Lead buildup will make your bore incrementally SMALLER, and sending a jacketed magnum round through that is an instant method of raising pressure much higher than you’d otherwise have with that ammo.

Thanks everyone I was told by a gunsmith that this is the only flaw in the older 19's but he did not say why. I will heed your advice and steer clear of light bullets.

I shot a lot of the Speer semi-jacketed bullets in 19's and 28/27's when they were available from Speer. I always shot them in magnum velocity loads; the Speer reloading manual had a caution notice to load them only to magnum velocities. Reportedly, the jacket and core could potentially separate when loaded to 38 Spl velocities.

AFAIK, the issue isn't as much one of jacketed (vs non-jacketed) bullets.
It is more related to light bullets (125gr and lighter) and hot powders.

Shooting a LOT of these kinds of rounds has been known to erode the forcing cone of a K-frame barrel, which can eventually lead to a crack in the forcing cone at the "yoke cut" on the bottom of the barrel.

While there are some documented cases of this issue, it seems to still be a relatively uncommon problem.

So, jacketed vs un-jacketed bullets isn't really the question. The real problem is using light bullets and hot powders to try to achieve maximum velocities - and shooting a LOT of ammo loaded that way.

JMO and YMMV.

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What K Frame Magnums don't play well with are the light bullets such as 110 grain and 125 grain. The 158 grain ammo is OK, jacketed included. That said, I'd still shoot mostly 38 special which will keep your K frame from loosing up over time. I have seen a few M66 2.5" bbl. guns need their headspace addressed after much shooting with 125 grain jacketed ammo.