617 and mass driver questions

[Guitarmageddon]

Hello everyone, Im feeling emboldened after the general success of the trigger work on my r8, and setting my sights onto my 617. The trigger pull on it is ungodly, has to be over 12lbs easy because it trips the max weight beep on my scale every time I've tried it.

 

Its also been back to smith twice for light strikes last year, and I suspect they just cranked the strain screw even more. Only specific note from the repair order was "side plate repair" and it fires reliably as it sits ever since. But damn is that trigger heavy, now that I have 7lbs on the other gun and another comparison. 

 

Id like to recap/sanity check some of the stuff I've read on various other forums/threads and get your thoughts.

 

1)don't go with the extended firing pin, keep it stock. not needed

2)use the mass driver hammer from apex
3)not sure on going with reduced main/rebound, couldn't find conclusive info on what worked.

4)8lb DA pull should be realistic to light off most ammo, if not definitely on federal auto match (i coincidentally arrived on auto match with the stock gun because it was the least sticky to eject from the gun, so i have a lot of that)

Any other nuggets of knowledge on doing lightening with a rimfire. I definitely feel like its more of a mixed bag and less of a sure thing than messing with centerfire. 

[mchapman]

For what it's worth, I tried the mass driver and could not get it to work for me.Along with stoning and polishing, I am using the stock hammer, an .500 long firing pin, a 13 lb rebound spring, and a wolf reduced main spring. I also use an 8 by 32 by 1/2 inch long set screw with blue loctite, in place of the factory strain screw. My trigger pull weight is 7 1/2 to 7 3/4 pounds, and I can live with that. AZ Shooter is using the mass driver with good success in his 617 I believe. I would expect Steve to answer here shortly about his set up.

Edited August 19, 2021 by mchapman

[AzShooter]

I really like my Mass Drive Hammer.  It's been working for me with the stock firing pin as Randy suggests.

 

I use an 11 pound rebound spring with mine.  I primarily shoot Federal BYOB ammo out of it but have no problems with Mini Mags and Blazers.

 

You can probably manage below 8 pounds with most ammo.

 

[Guitarmageddon]

5 minutes ago, AzShooter said:

I really like my Mass Drive Hammer.  It's been working for me with the stock firing pin as Randy suggests.

 

I use an 11 pound rebound spring with mine.  I primarily shoot Federal BYOB ammo out of it but have no problems with Mini Mags and Blazers.

 

You can probably manage below 8 pounds with most ammo.

 

oh very interesting. ok.  do you use a different main spring? @mchapman i also do the set screw in my r8 I just did. are the rebounds interchangeable between the different frame sizes? i have a bunch and Im pretty sure they were labeled k/l/n frame but I have to dig them out i cant remember. 11lbs to 14lbs in my toolbox.

[AzShooter]

1 minute ago, Guitarmageddon said:

oh very interesting. ok.  do you use a different main spring? @mchapman i also do the set screw in my r8 I just did. are the rebounds interchangeable between the different frame sizes? i have a bunch and Im pretty sure they were labeled k/l/n frame but I have to dig them out i cant remember. 11lbs to 14lbs in my toolbox.

I use the stock mainspring.  Play with rebound springs until you find the one you can shoot without out running the trigger.  Resetting the trigger is key.

 

[mchapman]

The rebound springs you have will work ok in the 617. The main spring I am using is just the standard wolf reduced spring. I believe that the rebound, and main springs will work across the board for k,l and n frames.

[Toolguy]

Everything across the bottom (horizontal) - rebound slide and spring, trigger, cylinder stop, is the same for KLN. Forged and MIM parts don't always play well together, though. I don't mix forged and MIM.

The vertical parts - hammer and hammer block are the same for K and L and bigger for N on the new style (MIM), and all 3 are different on the old style (forged).

The main springs work in all old and new style guns, KLN. 

Edited August 19, 2021 by Toolguy