DA timing question

[dmize]

Can someone explain to me how a DA gets out of time?
I delt with 2 S&W's in the past that did this and now my 480 Raging Bull.
When trying to cock SA the cylinder was trying to turn before the cylinder bolt dropped. Would work smoothly DA but had slightly off center firing pin strikes.
We have a 3rd party gunsmith,as in he only deals thru the lgs. He called and said he had it fixed but wont tell me what was wrong. Kind pissed me off.

[bradshaw]

TIMING is co-ordination of mechanical movements necessary to rotate the cylinder and index the next chamber when the revolver is hammer-cocked or trigger-cocked. The cylinder must unlock, rotate, and stop without binding, and the cylinder must be locked before the firing pin strikes the primer of the cartridge just rotated into battery.

Beginning with properly timed double action revolvers, it may generally be said that a Smith & Wesson will go "out of time" before a Ruger, and a Colt Python will go out of time before an S&W.

As for parts wearing out, hard double action shooting will degrade a Dan Wesson hammer and trigger faster than the Ruger, S&W, or Python. DWA used nickel plated powdered metal for hammer and trigger. On the S&W, I speak only for the forged, case-hardened hammer and trigger. Of Ruger, I refer only to all steel revolvers.

CARRY-UP is another term for timing, although less inclusive.

THROW-BY is the term used to describe failure of the "stop" or "bolt" to stop cylinder rotation at the next chamber.

Retarded timing or carry-up permits the firing pin to strike the primer before the chamber is indexed (locked). A bullet fired before or after top-dead-center likely will index the chamber. An exception is when the bullet shaves a wedge between cylinder and frame, seizing the cylinder in place.

SPITTING is the ejection of bullet and propellant particles at the moment of fire, and has at its source a multitude of deficiencies, including timing, chamber-to-bore misalignment, eroded forcing cone, excessive cylinder gap, rough chamber exits or forcing cone, along with dimensional irregularities, all exacerbated by high chamber pressure

Rapid hammer or trigger-cocking causes a cylinder "out of time" to index via the flywheel effect (centrifugal force).

Worn parts can cause the bolt to drop and rise in the stop notch before the cylinder starts to rotate. Wear may also prevent the bolt from unlocking at all. These are just a few of the conditions which may be brought on by poor fitting, wear, abuse, and breakage.

While proper cleaning and lubrication prolong service life, it also prolongs the shooter's sanity to start with a quality revolver.
David Bradshaw

[dmize]

Well David I do sincerely thank you for the well thought out and exellently worded explanation.
Right up to everything after the last comma.
Please do describe a quality revolver to me.
Is it the 480 SRH I have that doesnt group as well as the Raging Bull?
Or is it one of the numerous S&W's documented on here that have severe issues right out of the box instead of my 8 year old revolver that has literally digested at least 2,000 rounds of full throttle H110 and 400 grain loads with nary a hiccup other than the one that the smith spent enough time with a stone to fix that he charged me a whole $20?

[bradshaw]

dmize.... these past few weeks I've been wearing either an M-29 8-3/8" or M-29 4-inch, sometimes both. These guns have put a lot of venison on the table, are wonderfully reliable and accurate. Years ago, a Smith & Wesson factory guru set back the barrel of the 4" to take up forcing cone erosion and tuned the revolver, as he did numerous of my .357's and .44's. Neither of these well seasoned revolvers is available for trade for a brand new one.

Each fine revolver design has its strengths and weaknesses. Within that, the respective manufacturers have turned out great and lousy examples. Nowhere was this so thoroughly proven than in IHMSA handgun silhouette competition. As in other fields of competitive marksmanship, the shooter tends to keep what works, and drop what doesn't. To work in that environment a revolver must be accurate, and it must endure.

While the S&W held the accuracy, many examples faltered on the endurance end. I have an 8-3/8" M-29 that held up through a ferociously active period. The above-mentioned S&W master smith set back the barrel to eliminate forcing cone erosion, set gap at .004", and tuned the revolver so that it locks up wiggle-free as a Freedom Arms.

Against that, I've seen some sad failures, and was on the line when a yoke pin kicked out of a brand new M-29 in less than twenty shots. The owner, an IHMSA silhouetter, was not happy.

I suspect that the accuracy deficit of your SRH .480 may be due to alignment or forcing cone issues, a possible compression ring in the bore, or some dimensional irregularity----such as chamber-to-bore misalignment----but not to "carry-up." While I do not want to offend the owner of a SRH .480, I disagree with a 6-shot .480 Ruger. I said so to the manufacturer; reckon I can say it now. I think the 6-shot cylinder on a BIG BORE is a mistake.

Simple timing check for carry-up: apply light drag to the cylinder with a finger, then slowly trigger-cock and dry fire revolver. Cylinder should be locked up at hammer fall.

Repeat process while thumb-cocking. Cylinder should lockup before or at full cock.

I haven't the experience to remark BFR revolvers. Owners speak positively of BFR strength and accuracy, which has arouses my interest. Taurus revolvers I have shot could not push aside my Rugers and Smith & Wessons.

Sanity:
The proof of a revolver is in the shooting, just as the proof of accuracy is on the target. The more one wants from a revolver, the better it must perform. I consider the firearm an instrument: When you have a good one, Play it.
David Bradshaw

[bradshaw]

dmize.... Curious, for a moment I thought your S&W----2,000 rounds of 400 grain bullets fueled by H110----was a Model 29. I kept seeing bullets strolling out the muzzle, dropping like an anchor, followed by a few parts floating out of the sky. Now, I think you have an X-Frame .500 S&W, and that it treats you very well.

In considering a course of action for your .480 Ruger, I'd call Ruger Custom Service and find out if they'll fix. Or, will Ruger impound it and offer you an exchange.

If Ruger will fix it, find out before shipping whether they can and will replace a bad barrel or bad cylinder or bad frame. If not, and you're deeply attached to it, have a known smith look at it----with an eye to fitting a 5-shot cylinder.

Some years ago a guy called me to report that he'd blown up his Super Redhawk .480 with factory Hornady ammo. Said he was a long time big bore shooter with beau coups guns, including custom and Dan Wesson Super Mags. Said Ruger would flat-rate a replacement, but not replace it free, as his load was a factory round. Hence, responsibility of ammo manufacturer. Ruger told him that they would replace the gun free, he said, if he'd blown it up with a handload.

He was not happy, but he paid the flat rate for an exchange.

It makes me dizzy to contemplate giant holes with hardly any meat around 'em.

At the risk of being cursed by loving afficiandos, nor do I approve a Super Redhawk six-shot .454 Casull. Althgough a slice more meat around the boiler room, Casull's baby howitzer was bred for greater pressure than the .480 Ruger.

I consider a six-shot 155mm field piece a vanity, and advise the audience to stand back.

As your Taurus provides big bore power with reliability, I cannot criticize. I remember reports of many .454 Raging Bulls locking up when it hit the stands, with factory repair miles behind Ruger and Smith & Wesson. I did not care for the SA and DA trigger of Taurus samples I've been exposed to.

It is difficult for my fingers to wander past Ruger and Smith & Wesson and Freedom Arms, and fine custom artisans, with my hands now filled and satisfied.
David Bradshaw

[bradshaw]

dmize.... there may be another explanation for inaccuracy out of your SRH .480. Author of BIG BORE REVOLVERS informs me that very sloppy chamber reaming----unsupported reamer----was done on some .480 Rugers.

Result: uneven chamber walls and reverse-taper chambers----which make extraction difficult. A wallowing chamber can give a bullet a bad start to its short life.

My take: unless you have very difficult extraction, bad chambers may not be the cause of your inaccuracy. Whether I mentioned it or not before, GROOVE DIAMETER should not exceed bullet diameter. That, and slug the bore to check for a COMPRESSION RING at the frame.

Off-center primer indent in DA fire sounds like retarded CARRY-UP (cylinder not locked at hammer fall).

I smell a gun that is not right. TIMING and CARRY-UP issues sound like bad assembly, not wear.
David Bradshaw