So fun update, after about 1300 rounds and double that in dry fire, my MR73 went out of time. After speaking directly with Chapuis, and exchanging some videos and emails, they're sending me new parts to fix it.
What's the story on what is wearing out?Originally Posted by jetfire
Did they say anything about it being out of spec?
Keep us updated.
By my count that's 3900 trigger presses? That's not a lot.
According to the french, "According to their expertise, the Cylinder Latch or Cylinder Latch Spring (parts 140 and 141 ) and have been damaged or weakened or the spring moved a little bit from its location"
This was determined from sending a video of me showing the failure mode and how it occurs when firing the gun rapidly double action. The funny thing is I never got around to modifying it in any way, this gun was stock as it came from the factory, all I did was run it like I'd run a GP100 or 686.
By comparison, my 10mm GP100 match champion has more than double that number of live rounds and triple the trigger presses, and it's fine. My 586 L-Comp has like 100 fewer rounds but a gojillion more trigger presses - also fine. I'm waiting until the parts get here from Froglandia and I do the fix before I offer a more informed opinion on what specifically caused the failure. It's a shame there aren't any qualified MR73 armorers in the states though.
If it's just a spring that's not a big deal. Hopefully it's an easy drop in fix. At this point you're guinea pigging this thing to find out if it will hold up to the rigors of hard, fast, shooting.
Frustrating though. Did the French give you any lip about "not shooting it that way"?
Maybe that's not a good thing. Awaiting further info after repairs.
"Gunfighting is a thinking man's game. So we might want to bring thinking back into it."-MDFA
Beware of my temper, and the dog that I've found...
They did not, although context is pretty difficult to infer via translated emails. I got the sense they were like “c’est la vie, shit happens when you party naked”
Is the out of time exhibited with it skipping chambers in rapid DA (dry-hopefully) fire? Any peening of the cylinder notches? Will be curious to see photos of the parts you replace.
One interesting detail I've noticed is that the ramps leading into the cylinder notches on the MR73 are kinda oval-shaped rather than straight as they are on S&W and Ruger revolvers, as if they were made with an olive-shaped cutter rather than a straight end mill. The MR73 ramps actually curve back downward as the cylinder stop approaches the notch. (A note on nomenclature: I am saying "downward" as the notch is oriented relative to the frame when the stop is moving "up" to engage the notch, but it would be "upward" if you think of "down" as into the notch, oriented the way you typically view a notch.) At speed, this could be expected to have the effect of dynamically reducing the engagement of the stop with the approaching far edge of the notch. I've worried about that and thought about reworking the notch ramps.
On my GP MC, there was a burr or raised lump at the end of each ramp where the ramp met the notch. As the stop rode the ramp up into the notch, at speed, the burr/lump would kick the hand back downward, reducing the engagement of the stop with the approaching far edge of the notch. Initially, I had some moderate peening from dry fire. When I noticed the peening and the raised burrs, I stoned the burrs out of the ramps so the ramps go smoothly all the way to the end and have a clean drop into the notch. I also stoned off the peening (love brushed stainless here) so the far side of the notches was flat/flush with the OD of the cylinder and looked new. Immediately on reassembly, I noticed the sound of the notch hitting the stop was just a little cleaner and more solid without that micro-tick when the stop hit the lump. Since then, I've done a ton of DA dry fire and there is zero additional peening.
Pleased with that result, I did the same thing on my M&P 340. You can see a sliver of silver on the blackened stainless cylinder at the end of each notch ramp, but I'm OK with that.
Essentially, I've put "deburr cylinder notch ramps" on my general revolver pre-use prep checklist. It's a high level of commitment to act on a belief that I know how to design the cylinder notch lead-in ramps better than Manurhin/Chapuis. I'm also kind of waiting for someone to come along and explain what I don't understand that makes the MR73's notches actually correctly designed.
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Not another dime.
Well, I mean they aren't wrong?
Good to hear.
I'm sort of - of the mind - springs are maintenance items. It's when you have to replace hard fitted parts after a short period of time that I get antsy.
Though I mean my GP100 is about like yours ~4000 rounds through it and probably another 4000 dryfire presses.
I was just about to start selling some guns. Guess I’ll stick with my beautiful Smith&Wesson revolvers. 😁
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