Over pressure rounds

[gssp]

Picked a nice minty 625-9 Mountain Gun in 45 Colt. Mounted a Trijicon RMR on it. Love it. Was out on Saturday testing some loads with a cast 282 gr LBT boolit. In 130 rounds, 2x, a load, one with HS-6 and the other with Power Pistol, had fierce recoil. Enough recoil the gun/shooting hand, came out of my support hand's grip and the muzzle came back enough to hit me in the head.

Those two chambers, when fired with subsequent loads (all under 20,000 psi per Brian Pearce's article which differentiates between 14,000/20,000/32,000 psi loads) are hard to eject. I need to take a plastic faced mallet and tap on the ejector rod end to get the fired cases to eject; just those two cylinders. Otherwise, the gun, cylinders, ejectors, etc, look and fire fine. I mic'd the two cases which had fierce recoil and just ahead of the extractor rim the diameters were as follows.

Normal dia = .475-6"

Heavy recoil = .483-4"

The two cases I can see maring (for a lack of a better word) all the way around the case where it "adhered" to the chamber walls. If I reinsert an empty case into any of the cylinders, no problem. The two heavily expanded cases would take some effort to reinsert them.

Opinions please? I'm pretty confident some extra powder must have ended up in the 2 cases. Loaded on a Dillon 550, using the auto powder thrower. I kept the loading area clear of interruptions and stayed focused but I somehow must have screwed the pooch.

The gun itself, kept shooting fine,and I was able to finish my testing. When I got home, I cleaned it well and took a good look at it. Nothing seemed out of place, visually or mechanically.

Suggestions please?

 

[Bearbait in NM]

GSSP,

I'll start the ball rolling. I have limited experience with an N Frame in 45acp and 45 Super, but a ton of experience with heavy Colts, 454 Casulls etc,, as well as higher than "book" pressures with 1911's.

In my testing so far with 45 Supers in my new 625PC with loads that are probably close to 30K, and certainly at or above 20, in no testing has my gun become uncontrollable as you describe. My 45acp is going to behave a little differently than yours in 45 Colt, due to the length of the cases etc., but they should behave similarly. You are correct, something in your reloading is certainly suspect.

I could see perhaps different brands of brass, especially differences in OAL and crimping adding to variations in pressure, but probably not what you describe. I have worked with Power Pistol and HS6 very extensively in 45acps, Supers, Rowlands and 454 Casulls, and both powders behave very consistently. meaning that small charge increases yeild very uniform increases in velocity, have not seen spikes or "cliffs" in my velocities, which is my only way to guess at pressure (against published sources). Both of those powders are slower than the typical fast handgun powders where you can really hit the ceiling fast and suddenly.

I am not versed well enough to diagnose chamber problems as they might relate to velocity spikes, but perhaps others here can advise you on those matters. But, if you are doing this testing without a chrony I would highly recommend picking one up. Besides wondering if you snafu'd with your Dillon, without velocity to help you diagnose you are really skating on very thin ice.

As to the Dillon, it is possible to bridge powder yielding some pretty erratic dispenses. They need to be kept clean, and in all honesty, it would be pretty hard to visually see a difference in a grain or two even if looking into the case before seating the bullet. perhaps you need a powder check die? I kinda gave up on my Dillon for any rounds that are close to the ragged edge for any cartridge.

Craig

 

[gssp]

Craig,

Thanks for getting back to me on this. I now realize I did leave a few details out.

I was shooting over my Oehler 35p and on both occasions, where I did not write down exact velocities, they were over 1500 fps where as the rounds fired in the same string/powder charge were in the 800 fps (HS-6) and 900 fps range (Power Pistol).

I'm actually considering moving away from my Dillon, as you descried for carts on the "ragged edge" where a double charge is possible.

For the record, these were fired in brand new, unfired, Starline 45 Colt cases with new CCI 300 primers.

Alan

 

[427mach1]

There is only one way your velocities could have jumped from 800/900 to 1500 and that is a much larger powder charge. I wouldn't care if it was double, 1.5x, 1.2x, or whatever, it was too high. You might want to have your cylinder NDI (non-destructive inspection) since this appears to be WELL above maximum velocity (and therefore max charge).

 

[chipking]

I suspect that you have swelled (swollen) those two chambers with overloads. That is why subsequent rounds even at standard pressure are hard to eject. It is purely your choice but were it me I would have the cylinder replaced before shooting the revolver any more.
AND I would stop trying to make my S&W 45 Colt a magnum revolver.
Chip King

 

[tomcatt51]

Opinions please? I'm pretty confident some extra powder must have ended up in the 2 cases...
The gun itself, kept shooting fine,and I was able to finish my testing. When I got home, I cleaned it well and took a good look at it. Nothing seemed out of place, visually or mechanically.

Suggestions please?

Measure the chambers. I normally use a telescoping gauge and a 0-1 vernier mic. Do the usual out of round check at several depths.
Or shoot some more rds and see if ALL the empties from one cylinder full will re-chamber in ALL the chambers. See if two are tight re-chambering. That would not be good.

You may have got lucky and got away with this or you may have two swelled chambers. N frame 45s don't have very thick chamber walls and won't tolerate the loads Rugers will.

The 550 Dillon doesn't auto-index, so lapses in attention (like stopping to get another beer) can result in double charges.

 

[jepp2]

I don't know your load specifics. I have seen comments in various forums that some people think a double charge is just a "proof load". Let me share some numbers with you that might help.

Using QuickLoad and the closest bullet listed (260 gr.) I ran some cases using Power Pistol. Quickload lists the SAAMI max pressure at 14,000 PSI, just for basis. 8 gr. of Power Pistol gave 10.6K PSI peak pressure and 816 fps which was close to what you observed. If I double the charge to 16 gr. the pressure goes up to 41.4K PSI and the velocity is 1445 fps. So the pressure increased 3.9X for less than a double of the velocity.

Since the velocity was in the range of your observed velocity, it appears you may have double charged the 2 cartridges fired in your cylinder. Feel lucky your cylinder didn't split. But you have probably ruined your handgun.

 

[tputto]

The brass on a cartridge case is somewhat elastic and will return to near original dimension after firing, except near the rim where the metal is thick and does not normally expand. S&W chambers are thinnest at the locking notch. You might want to take another look at the chambers with a very bright light, to see if the steel has dimpled outward at the location of the notch. If there is a noticeable dimple, I'd show it to a gunsmith.

I would not bang on the ejector too hard to remove a stuck case. One could put a cleaning rod into the chamber and hit the case directly, with no risk of bending the ejector. I have had some handloading mishaps too

 

[Bearbait in NM]

Alan,

As the others have noted, YIKES. 1500 FPS with a 280 grain bullet is way into Ruger only 45 Colt loads. More like 5 shot cylinder Ruger only loads. Given that those velocities are obtained safely with slower powders, as Jepp calc'd for you, I bet you were WAY beyond 40K.

Good luck with getting the gun checked out.

Craig

 

[flintsghost]

Check the cylinder throats on all chambers. S&W doesn't always get them cut to dimensions that it is supposed to. I've seen cylinders on new guns without any throating at all and some that were insufficiently cut. This will drive pressures through the roof, even to include case head separation. Measure all 6 with calipers. Those two may be smaller than the rest. That may also account for chamber roughness as the final chambers are cut with the same reamer that cuts the throat at the front of the cylinder.

 

[scooter123]

IMO you haven't ruined your handgun but you have ruined the cylinder. As Chipking suggest I don't think it would be wise to shoot this revolver any more until you have a new cylinder fitted to it. Unfortunately, that may be a problem, because S&W may not have a spare in stock.

Step one is to contact S&W and own up to your mistake. Then ask them if they have any 625 Long Colt cylinders in inventory and how much it will cost to have a new cylinder fitted to your gun. Finally, I suspect that you can expect this repair to take anywhere from 4 months to a full year. Because repairs go to the back of the line with any warranty work going ahead of you.

Option to is to look on the Brownell's and Numrich's web sites and see if by chance they have to correct replacement cylinder in stock. If they do, you could then look for an independent gunsmith qualified to fit a new cylinder to your gun. Then you get into another line and wait for however long it takes for that repair.

 

[gssp]

Talked to S&W today. They are emailing me prepaid and insured FedEx label. Best case scenario; 3 weeks. Worst case; 10 month.s

I've been shooting 45 Colt for years. I've never tried to magnumize the old guy Chip King, especially in the S&W. As I stated before 20,000 psi was my top intended pressure. I also don't drink alcohol, TomCatt51.

I appreciate everyone's input.

Alan

 

[tomcatt51]

I also don't drink alcohol, TomCatt51.
Alan

Didn't mean it to sound like an accusation, just meant that it's easy to get out of sync if you stop for something or get distracted. The auto index Square Deal B's are harder to get "out of sync" on.

 

[Bearbait in NM]

Alan,

Thanks for the follow-up, and I hope things work out with S&W. I do appreciate you posting this story up, as I am currently working with 45 Supers in my 625PC. I too am not looking to turn mine into a magnum, just up the performance a tad.

In my case, there have been in the past places that will convert the 625 in 45acp to 460 Rowland. Based on what I have read about the 625, I strongly feel that 40k might be a bit too much. Well, more than a bit. Albiet yours is a 45 Colt, your experience has helped confirm to me that no way I would rechamber mine.

I noted earlier that I am not fond of my Dillon for rounds that are on the edge for one reason or another. What I have done in the past is use my dillon to deprime, prime and flare by the batch. I then use a benchrest dispenser to charge the cases on a block. I have seated and crimped these cases in the last two Dillon stations, or on my single stage. In this way I can get a little additional benefit from the Dillon.

Craig