American Mech Quandary

:confused1: Weird

looks like a screw up at the riffe factory . personally i wouldnt use that in a big gun ,it will engage in the mech but will cause a lot of up force on the housing ,and down force on the sear ,in addition to the pulling force that the sear is designed for .
phi

btw many euro shafts will work in american mechs ,and many euros will work with "riffe" shaftsl

It didn't damage your mech.

Mech sears will catch and hold different notches than what they were designed to hold. Just because it seems to hold doesn't mean you should use a shaft not designed for that mech, it's not ideal and possible that the mech will release when it's not supposed to. That said there are euro shafts with notches that are more different to another euro shaft and have more potential for failure, than to a US shaft, and people use them interchangeably without giving it a second thought. In general though you will see a rounded sear for euro shafts, and a square sear for US shafts, it's visible through the forward part of the housing once you take it out of the gun. Fit also has to do with how long the small piece of shaft past the notch/at the rear end of the shaft is.

In the end there's no substitute to inspecting closely how a particular shaft functions with your mech. I've made US shafts into euro shafts on a few occasions by cutting off the the back piece which includes the notch, and grinding/filing a new notch. When you do it little by little until it finally fits, you get ideal holding power IMO because you can make the tolerance very small. Basically you want to achieve a hair of distance between the flat part of the back of the shaft and the roof of the housing. If the shaft can't go up then it can't skip over the sear and you're safe.

That looks like an accident waiting to happen.

Quote from ddonnell

Just was told by a Riffe team member that the sear is made to accept both, so no problems.

Had me worried. Especially since I remembered we kept the guns live in the ponga..:@

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they can say whatever they want, that is not safe , especially in a riffe mech , a round notch shaft puts upward pressure on the top of the housing ,you said it as loaded with 5 bands ? that means you had 400# to 500# of pressure acting on the top of that thin sheet metal housing,that is desgined to have 0# presure with a square notch shaft :@
phil

Dude that is sketchy as ~`~`~`~`, and I do some really sketchy stuff.

weird, other 3/8'' riffe shafts ive seen, as well as, those by mori, kitto, etc. have a step cut into them so they can fit in mechs but all had the square notch. call riffe and talk to jay or julie and don't forget to tell us what they say.

Make sure you have adequate dental insurance.