Blown primer, stuck cylinder

A few days ago I went to a nearby indoor range to test some hand loads. I warmed up with a box of PMC 38 special, then shot a box of 158grain lswc reloads (25 rounds of Unique in five shot groups ranging from 6.0 to 6.8 grains, then 25 rounds of #9 in five shot groups ranging from 11.4 to 12.2 grains) to see what my 4" model 66-2 prefers. I got the best accuracy overall with 6.8 grains of Unique, followed very closely by 11.4 grains and 12.2 grains of #9. But it was a small test group. I'll be going out soon to do some more testing. But I digress...

After my hand loads, I decided to try some 158 grain XTPs from Underwood Ammo that I've had since this spring. This stuff clocks in at about 1400 fps out of a 4" barrel, so it was pretty hot – noticeably hotter than my reloads – but I still thought the recoil was manageable. After the fifth round, the cylinder locked up completely with one live bullet left in the cylinder. Wouldn't budge one bit, nor could I pull the trigger or pull the hammer back. Fortunately, this gun shop/range also has a smith on the premises. Turns out the ejector rod had backed out. And coincidentally (or not), one of the last rounds had a blown primer. Underwood Ammo is sending me a return label to return the suspicious box for testing and has agreed to send me another box in exchange. I've heard nothing but praise for Underwood, so it's probably just my luck that the first rounds I've ever shot from this company blew a primer.

What I'm really wondering is:

1) would the blown primer have been enough all by itself, or
2) more likely those last five hot rounds as a whole (presumably all loaded to excessive pressure)
to loosen the ejector rod sufficiently to cause a jam, or
3) has the ejector rod most likely been loosening up over time without my noticing it and the hot rounds were just the final straw?

It's just a WAG but I'd say number 3. However, any .357 ammo that starts a 158-gr jacketed bullet at 1400 FPS from a 4-inch Model 66 is nothing I want to shoot in my 66.

M29since14 said:

any .357 ammo that starts a 158-gr jacketed bullet at 1400 FPS from a 4-inch Model 66 is nothing I want to shoot in my 66.

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Are you thinking in terms of wear and tear on your hand or the gun? The blast/flame ball wasn't excessive from my perspective, and the recoil didn't bother me a bit, even with wooden grips. But it was only a few rounds. A whole 50 round box might be another story! I also have a box of 180gr hard cast WFN that I haven't shot yet, which is probably loaded to around 1300 fps out of a 4" barrel. At any rate, I have no plans to make such hot ammo a habit, but I do plan to keep the 180 grainers for hiking. I'm no expert, but I would expect a hot 158/180 grain bullet to be gentler on the gun than a hot 125 grain bullet.

You don't say, but were you shooting a .38 Spl. or .357 Magnum gun? If you are shooting nearly 7 gr/Unique behind a 158 gr. bullet in a .38 you are way past pushing your luck!

Where are you getting the velocity figures of 1400 FPS for the Underwood ammunition and the 1300 for the 180 gr. bullet loads? Are these your chronograph figures, or manufacturers claimed velocities? What I can tell you is to get these velocities, with the bullets you cite, out of a 4" barrel, that pressures are way beyond SAAMI standards of 35,000 PSIG or 46,000 CUP for .357 Magnum. You will be hard pressed to get more than 1250 with a 158 gr. jacketed bullet in a 4" gun. You will rarely see 1400 with that bullet even in an 8 3/8" barrel. I have hundreds of rounds of chronograph data to support this!

To answer the original question though, most likely the extractor rod loosened gradually as M29since14 said.

Alk8944 said:

You don't say, but were you shooting a .38 Spl. or .357 Magnum gun?

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The revolver in question is a 357 (model 66-2).

Alk8944 said:

Where are you getting the velocity figures of 1400 FPS for the Underwood ammunition and the 1300 for the 180 gr. bullet loads?

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The manufacturer claims 1500 fps for the 158gr XTP and 1400 fps for the 180 gr WFN with no reference to barrel length. Two reviewers claim average velocities close to 1500 fps with the XTP bullet out of 6" barrel and one of them also quotes an avg. 1450 fps out of a 4" M28. One reviewer on the manufacturer's website claims an avg. 1406 fps with the 180 gr bullet out of 6" barrel. I recall seeing a separate claim of 1300 fps out of a 4" barrel somewhere else. I don't own a chrono and though I have no reason to doubt such claims, I have no personal data to refer to, thus my qualifier of "about" such and such velocity. For what it's worth, I didn't think the recoil or blast was out of the ordinary, so maybe the bullets weren't moving that fast after all. I have no idea what powder Underwood is using, but wouldn't that impact the amount and timing of peak pressure?

Alk8944 said:

To answer the original question though, most likely the extractor rod loosened gradually as M29since14 said.

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I suppose I'll have to be more vigilant then. The rod screws into the cylinder counterclockwise, correct?

The cylinder tightens in a counterclockwise direction on ALL stainless models. The changeover from right hand to left hand threads was in the early 60's, well before the production of any of the stainless models.

I expect that your ejector rod had been loosening over an extended period. There really isn't an "driving force" to work them loose and the theory behind the change from right hand to left hand was that the direction of cylinder rotation would act to tighten the ejector rod. As you have seen that particular theory doesn't hold water, something rather predictable when you consider the microscopic amount of torque that the forward lock is able to impart on the center locking pin.

You can't go by reviews or other folks data. Without a chronograph for YOUR gun the velocity is just a guess.

Be careful tightening the rod. Do not BUBBA it with a pair of pliers

Rule3 said:

You can't go by reviews or other folks data. Without a chronograph for YOUR gun the velocity is just a guess.

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It hasn't been a high priority, but one of these days, I'll get a chronograph so I can rely on my own data.

Rule3 said:

Be careful tightening the rod. Do not BUBBA it with a pair of pliers

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It should be good to go for a while at least. The gun smith tightened it (and warned against putting loc-tite on it if it ever came loose again). If using pliers would run the risk of applying too much torque, should the need ever arise, I presume hand tight is good enough.

SeamasterSig said:

It hasn't been a high priority, but one of these days, I'll get a chronograph so I can rely on my own data.



It should be good to go for a while at least. The gun smith tightened it (and warned against putting loc-tite on it if it ever came loose again). If using pliers would run the risk of applying too much torque, should the need ever arise, I presume hand tight is good enough.

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There is a tool but a padded vise (with wood or "plastic" jaws) works well. No loc tite ever needed

FWIW, if I need to tighten an ejector rod, I use a piece of 1/8" thin lead, wrap it around the knurling, then use just enough force with a pair of pliers to gain grip. It doesn't take much, and the lead grips the knurling well, as do the serrations in the pliers. The lead also protects the knurling.

Rule3 said:

There is a tool but a padded vise (with wood or "plastic" jaws) works well. No loc tite ever needed

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Doubless said:

FWIW, if I need to tighten an ejector rod, I use a piece of 1/8" thin lead, wrap it around the knurling, then use just enough force with a pair of pliers to gain grip. It doesn't take much, and the lead grips the knurling well, as do the serrations in the pliers. The lead also protects the knurling.

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Thanks for the tips!

When I shoot ammo that I am unfamiliar with or it is supposed to be hot stuff I will use an L-frame or N-frame pistol until I can see just how big and bad the ammo is.
For me, K-frames are not strong enough that I would feel safe running hot hot loads.

I know this is a topic that has been kicked around, flame cuts, cracked barrel at the forcing cone, so forth. I like the way an L-frame just sorta kicks a bit and settles back down.

chasmatic said:

When I shoot ammo that I am unfamiliar with or it is supposed to be hot stuff I will use an L-frame or N-frame pistol until I can see just how big and bad the ammo is.
For me, K-frames are not strong enough that I would feel safe running hot hot loads.

I know this is a topic that has been kicked around, flame cuts, cracked barrel at the forcing cone, so forth. I like the way an L-frame just sorta kicks a bit and settles back down.

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That's an interesting policy, and if I had an L-frame, I would probably do the same. But I haven't shot anything out of my K-frame so far that made me wish it weighed more overall or had more weight forward.

My K frame snubby is my favorite gun, but I follow the advise of other more experienced shooters and consider firing magnum ammo something that's there if I need it, but not for practice.