Rain, rain, come and stay...

Tom,

We're gonna have to meet sometime so you can try my Springfield Champion. I'm in San Jose, so driving "over the hill" shouldn't be much of a problem. Or you could come to the slums in Silicon Gulch if it ever stops raining!

Here's what the Springfield did at about 10 yards with Federal Hydrashoks on my second range session.

CHAMP02-2.jpg
 
Hello Folks,

> "Query: Does this .40 S&W revolver require some kind of moon clips
> or is the extractor modified for a rimless cartridge?"

The 646 can shoot .40 S&W cartridges with moon rings or without, although you increase the chances of a light strike by not using moon rings. The extractor only engages with the moon rings, however, so unless you like picking the hot brass out with your fingernails, I'd shoot with the moon rings. (Saturday, for example, I finished off the 50 rounds I bought with a two-shot round without moon-rings and the brass came out fine.)

> "As for chamber problems... the cartridge heads shouldn't bind up on any
> part of the recoil plate (breech face) when the cylinder rotates. There may
> be a high spot or something else at play here."
>
The spent cases can back out enough that after three or four shots, the first spent case hits the frame as the cylinder tries to rotate the fifth cylinder into position and the whole cylinder jams up. Seemed to happen mostly with reloads and hotter factory cartridges.

> "For sticking brass... "
>
This as well as the "backing out" problems has been attributed to the physical qualities of the titanium cylinder. That it is a "dry" metal with a high frictional coefficient, but also fairly elastic. So it can allow the brass to expand slightly larger than the cylinder, then when the cylinder contracts the brass may stick. Or it may back out, then stick.

These same problems are occurring on all the Ti cylindered guns, from what I can see. It's worst with reloaded ammo, the brass seems softer and expands easier, or with "hot" factory loads.

But when I stay with "middle of the road" factory fresh ammo, I don't have any disasters. You can still feel the brass sticking to the cylinder when I stroke the rod to push the shells back, but I no longer have to put a piece of wood on the extractor rod and hit it with a hammer.

- Thomas
 
I was reading other posts about the 646 and one owner said that loads needed a full crimp instead of the taper-crimp. His theory was that the taper crimp allowed the bullet to exit the case at lower pressures and this forced the case mouths to expand tightly to the chamber walls. With a roll crimp the bullet is held longer until sufficient pressure builds up to force the bullet out and the case relaxes more after the pressure eases. I dunno about this theory, but he says it's working for him.

Come to think of it... I had a 1955 target .45 ACP who's extraction was "sticky" with light loads like Win 185gr FMJSWC target. But when loading new .45 AutoRim cases with a 255gr LSWC at 1000fps the cases almost fell out of the cylinder. Hmmm. I used a roll crimp on the .45AR cases to retain that big whomper too. Maybe there's something non-intuitive here.

See also: http://thefiringline.com/forums/showthread.php?p=1453954#post1453954
 
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