Fine tuning a gem - and it worked

[keithherrington]

Lucky enough to get this gun a while ago and was super happy to have done so.



Came with the original JM grips, but since I hate the shape I installed my one and only set of Nill Classics, then VERY carefully blended them to the frame.


But the accuracy was not what I expected or wanted. Not bad, but I knew it could do better. So I gave everything a MUCH closer look. Come to find out there were two issues that should have impacted its ability to group: a bad crown and a wonky (technical term) B/C gap.
a. The crown had been cut poorly when finishing the barrel so I sent it back to the Performance Center and in a quick fashion they recut the muzzle.



b. But the B/C gap was plain weird. It went from .008" on the left to effectively zero on the right. The soot rings on the cylinder face also told me something was not quite right. You can see how the soot ring on the right side of each charge hole is dramatically narrower than the on the left.


Using a jeweler's loop, I found a burr kicked up when the forcing cone was cut. I removed that with a black Arkansas stone, then remeasured with feeler gauges. The right side now measured .004". I continued to work with the black Arkansas stone taking care to remove no material from the left side. I monitored how square I was by the soot markings on the face of the barrel. I finally got it to .008" on the left with light drag and .007" on the right with light drag. I think that a .001" difference is now well within factory specifications, if not custom specifications.


Taking the gun to the range tomorrow with my normal selection of match grade 45ACP ammo to see if my efforts have born any fruit. I'll post pics of the groups to show results.

Keith

 

[H Richard]

With that being a Performance Center gun I would have been very very disappointed. I would have probably sent it straight back to them to correct. What you had to pay for that quality of handgun you should expect it ready to go out of the box.

 

[keithherrington]

With that being a Performance Center gun I would have been very very disappointed. I would have probably sent it straight back to them to correct. What you had to pay for that quality of handgun you should expect it ready to go out of the box.

I've been sending guns to the PC for work since 1994 and that is exactly what I did in this case. In the letter I asked them to address both issues. WRT the B/C gap, I'd already removed the burr when they received it so the B/C gap was .008"/.004". Since they never send comments back with the gun regarding what they did, I can only assume they found .008"/.004" to be within their standards.

In my experience S&W and especially the PC handles used guns in a significantly different manner than they do new guns. And this is by no means the only time I've had PC guns come up short of my expectations. In each case of me sending them a used gun to work on (I've never bought a PC gun new from S&W) I've had to pay for the PC to correct issues that in my opinion should never have left the factory. These issues run the gamut: from crooked barrels on three other JM Specials (all with 5" barrels), to choked barrels at the forcing cone due to over tightening them in the frame, to bad crowns and poorly cut forcing cones.

I keep buying them because when all these issues are finally corrected, they have all proven to be superb shooters, that when sold always make me a profit. Bottom line: they have proven to be very good investments.

Keith

 

[keithherrington]

Took it to the range today...

and in my opinion, my efforts have paid off. Five shot group at 25 yards.

178 grain Meister SWC over 4.2 of Vit N310, the load I traditionally use at 25 yards for Bullseye in my 5" Model 625.


All loads tried today showed improved accuracy.

The burn rings are now much more concentric and even as well.


Keith

 

[Dale53]

Keith;
It looks like your efforts paid off, big time!

I guess I got lucky. My 625-6 with 5" barrel had properly sized throats, barrel cylinder gap is close and even and it shoots extremely well (well under 1" at 25 yards off a rest). Here is a target shot standing at 25 yards:



My 625-8 JM Special, again, had proper throat size (you can feel the bullets having ever so slight contact when you chamber them, for a perfect fit), tight but not too tight barrel cylinder gap, and it too shoots extremely well. Here is a standing target shot at 25 yards:



A couple of my friends liked the performance of my JM Special so much that they went out and each bought one. I checked each of them and shot them and they both met my standards of excellence.

It appears that every revolver is a law unto itself. We got lucky. You weren't quite so lucky, but you prevailed and are NOW "lucky" ("The harder I work, the "luckier" I get <)) That certainly applies to you.

The only thing I did to my two revolvers was I installed a set of matched springs from Jerry Miculek (Bang, Inc.). I set the trigger to my preference (9.0 lbs. double action and 3.0 lbs. single action).

Kudos!

Dale53