My J-frame Journey

[EODFXSTI]

Still may send the gun in since one chamber is about 0.97 mm (~0.38") and the others are about 10.0 mm (~0.394"). My Taurus .357 Magnum has all chambers around 0.97.

So it appears that the 340 PD has four slightly larger chambers and that would explain the expanded brass that then does not fit in the smaller chamber.

Frankly, I don't know if it matters as one normally does not shove empty brass back into a gun. If they continue to eject fine, and do not affect accuracy, it seems like a non-issue. Maybe more of a problem for a reloader with the expanded brass.

I agree, if it functions fine for its intended purpose 100% of the time, then it is good. If it hangs up occasionally, then I would say the problem still exists in which case, sending it in is your best option.

Sending it in for peace of mind may be worth it to you anyhow. What's the worst that would happen?

 

[45sRfun]

I wish I had some of those cylindrical go no-go gauges so i could measure the chamber diameters out of curiosity. I wonder if there is a company that sells them individually. Would not want to buy an entire set as they likely are very costly.

Only problem I can see is if the extra chamber diameter (about 3.6% of diameter, so 1.8 percent effectively around the case) would cause the case to hammer the cylinder and potentially damage it over time. But even so, can send it to S&W now, next month, next year, or years from now.

 

[EODFXSTI]

I wish I had some of those cylindrical go no-go gauges so i could measure the chamber diameters out of curiosity. I wonder if there is a company that sells them individually. Would not want to buy an entire set as they likely are very costly.

Only problem I can see is if the extra chamber diameter (about 3.6% of diameter, so 1.8 percent effectively around the case) would cause the case to hammer the cylinder and potentially damage it over time. But even so, can send it to S&W now, next month, next year, or years from now.

Bet your local gunsmith has them.... Local!

 

[45sRfun]

Bet your local gunsmith has them.... Local!

Yep. Had a good gunsmith at my favorite gun shop and they moved about 150 miles away from the big city. He had been broken into several times and once slept in the back room and caught a thief in the act. The local police gave him an award for catching the crook and they show the scene inside the gunshop when it happened in this short video. Pretty cool. He had to turn all his records over to the ATF when he closed, but said it is many file cabinets with decades of records, all paper no digital. He now runs a small gun shop out of a pole barn on is rural property, basically semi retired.

My current two favorite gun shops have no gunsmiths. The one sends guns out to a gunsmith. The other one has two guys who are not gunsmiths but think they can do gunsmithing anyway. When they could not even change out the factory mag well for the included glock mag well on a new Ruger PC9 carbine, I realized they are a couple of hack gunsmiths.

 

[45sRfun]

SAAMI spec for the .357 Magnum chamber is 0.3809 (9.675 mm) (page 45). My one "tight" chamber measures with my basic caliper 9.7 mm and the expanded cases from the other "larger" chambers measure 10mm (~0.39"). So S&W owes me a new cylinder and I would be a fool not to claim it. So, sometime in November I will send in the gun.

 

[EODFXSTI]

Yep. Had a good gunsmith at my favorite gun shop and they moved about 150 miles away from the big city. He had been broken into several times and once slept in the back room and caught a thief in the act. The local police gave him an award for catching the crook and they show the scene inside the gunshop when it happened in this short video. Pretty cool. He had to turn all his records over to the ATF when he closed, but said it is many file cabinets with decades of records, all paper no digital. He now runs a small gun shop out of a pole barn on is rural property, basically semi retired.

My current two favorite gun shops have no gunsmiths. The one sends guns out to a gunsmith. The other one has two guys who are not gunsmiths but think they can do gunsmithing anyway. When they could not even change out the factory mag well for the included glock mag well on a new Ruger PC9 carbine, I realized they are a couple of hack gunsmiths.

That is a super cool video. I love "instant-justice" stories.

I hope all his paper records were illegible....

"I'm no gunsmith, but I'll give it a shot on your gun" Those are the best aren't they?

After reading through all this, you have your mind made up and it is a sound decision. And you still have a useable shooter in the meantime

 

[45sRfun]

Some interesting observations in comparing the 340PD with two 442s and a Taurus .357 Magnum.

A .38 S&W cartridge case is 0.3863 near the base, 0.3856 near the bullet end, and 0.3855 at the bullet end. The .38 Special/.357 Magnum chamber is 0.3809 near the opening.

I have two brands of .38 S&W, Federal and PPU. The Federal round fits in all chambers of all three J frames and fits the chambers of the Taurus, but that with the Taurus the last few mm have to be pushed in. The PPU must be slightly larger because it fits partway into all chambers of the three J-frames, but will not fit into any chambers of the Taurus.

The only chamber I had trouble with was PPU on the smaller chamber of the 340PD, the one that is tighter than the others. Curiously, I pushed the extractor star out and laid the cartridge into it and it went into that supposed tighter chamber farther and easier.

Conclusions:
1. The 340PD is no worse than the two 442s
2. The Taurus has tigher tolerances than the S&Ws.
3. The tighter chamber on the 340PD may not be tighter, but may seem tighter because the extractor star may ever-so-slightly overlap the chamber bore.

A slight bit of filing on the star at that chamber might help, but that may not be a good idea, especially in light of what is on GunAnalyst:

"Sometimes there is not enough pressure applied to the center extractor pin, which results in this. . . . Check if the extractor’s central pin is in the proper position."