686-6 FTF (and it isn't the hammer spring tensioning screw)

[Bench]

The setup: 200-300 rounds through this new 686-6 357. 13# rebound spring and extended firing pin from TK has been installed. Factory hammer spring and the screw is tightened all the way. That's all there is to the set up other than factory.

Issue: Initially I was getting FTF with CCI BR4 primers and that was the reason for ext FP though now even on my reloads (38 spl +p) I'm getting good solid primer strikes on some but then very light dimples on all others that are reloaded with CCI SPP. I gave up on the BR4's.  It seems that it's not the usual 'tighten the screw' solution. If it was my reloads the primer strikes would look similar not some deep and others shallow in the same cylinder load. The ext FP appears to be free in the frame. I've done nothing else to the pistol.

Is this some kind of 'interference' in the firing process of DA? Where should I be looking? I'm not sure if the issue presents in SA.

 

Thanks.

[Joe4d]

get a sharpie,,, blacken both sides of hammer,,, dry fire it a bunch, see if its rubbing on the sides, basically look it over repeat somewhere else.. its catching somewhere.

[gargoil66]

9 hours ago, Bench said:

The setup: 200-300 rounds through this new 686-6 357. 13# rebound spring and extended firing pin from TK has been installed. Factory hammer spring and the screw is tightened all the way. That's all there is to the set up other than factory.

Issue: Initially I was getting FTF with CCI BR4 primers and that was the reason for ext FP though now even on my reloads (38 spl +p) I'm getting good solid primer strikes on some but then very light dimples on all others that are reloaded with CCI SPP. I gave up on the BR4's.  It seems that it's not the usual 'tighten the screw' solution. If it was my reloads the primer strikes would look similar not some deep and others shallow in the same cylinder load. The ext FP appears to be free in the frame. I've done nothing else to the pistol.

Is this some kind of 'interference' in the firing process of DA? Where should I be looking? I'm not sure if the issue presents in SA.

 

Thanks.

BE:

 

Does it work with factory loads? 

 

Also, did you install a after market 'competitive' main spring?  If so, you may find the only primers that work reliably are Fed 100's.  

 

By all means, check that the hammer isn't scraping on the side of the frame as JFD recommended.

 

Go to Fed 100 primers since they are the most sensitive on the market.   Ensure that what ever device is seating the primers is seating them firmly to the base of the primer pocket.  .005" below the rim is the amount I believe.  It is easy to measure with calipers but visually the primer will be far enough below the rim that you can easily see it.

 

Guys here have other suggestions but the primer and seating depth seem to be the two big issues with handloading for revolvers.  Particularly if a guy dropped in a competitive mainspring.  

 

GG

 

 

 

[Ice36]

Check head spacing, might need to add a shim

[Toolguy]

I would look for a broken firing pin or hammer stud. We're all just guessing here.

[Bench]

Thanks All, late last night I started working backwards...pulled the hammer and ext FP out, the FP is new and the hole is free and clear. Working up from the bottom of the hammer there looked to be nothing out of sorts. Then I saw a shiny rub mark just below the top radius on the right side of the hammer. I reassembled everything and could see that the hammer/frame gap on the right side was a lot smaller than the left side. As the gun heated up during a good session yesterday the issue came up later on and with this small of a gap I can see hammer travel impingement being an issue here.

 

Is the solution as simple as removing small amounts from the hammer or is it a hammer shim kind of a thing? This is a new factory gun so there's no wear/slop that should be taken up by a shim. There doesn't seem to be any burrs on the frame so I'm not going to touch that.

[pskys2]

1 hour ago, Bench said:

Thanks All, late last night I started working backwards...pulled the hammer and ext FP out, the FP is new and the hole is free and clear. Working up from the bottom of the hammer there looked to be nothing out of sorts. Then I saw a shiny rub mark just below the top radius on the right side of the hammer. I reassembled everything and could see that the hammer/frame gap on the right side was a lot smaller than the left side. As the gun heated up during a good session yesterday the issue came up later on and with this small of a gap I can see hammer travel impingement being an issue here.

 

Is the solution as simple as removing small amounts from the hammer or is it a hammer shim kind of a thing? This is a new factory gun so there's no wear/slop that should be taken up by a shim. There doesn't seem to be any burrs on the frame so I'm not going to touch that.

NO, Ron Power sells shims for just that issue.  Go to his website or Midway and get a pack.

[practical_man]

Bench

 

i had a similar issue. In my case the hammer stud was not completely square with the frame. That angle caused the hammer to rub on the right side of frame. Being feint of heart I had to consult a pro to make the adjustment. It runs fine now and hammer looks centered in the frame. YMMV. 

 

 

[Bench]

Thank you  practical man. Do you happen to recall what the adjustment was?

[practical_man]

Bench

 

The hammer pin had to be squared to the frame. That level maintenance is above my comfort level so I sent it out to a pro

 

 

[Bench]

10 hours ago, practical_man said:

Bench

 

The hammer pin had to be squared to the frame. That level maintenance is above my comfort level so I sent it out to a pro

 

 

Thanks, I've been leaning a bit closer to having the gun get a trip through S&W.

[Toolguy]

You can make a tool for that out of a 4" long, 1/4" diameter piece of steel rod with a hole in each end. Drill the holes in the lathe. Center drill, then drill about .010 to .015 under size for a pilot hole. Finish drill one end 9/64" (.141) for the hammer stud, one end #38 (.1015) for the trigger stud. Make the holes about 1/2" deep.

 

Then you can slip the tool over the stud and check for square and gently adjust as needed, by pushing on the top of the rod in the desired direction. Make the holes as close a slip fit as possible so the tool is an extension of the stud. Then you can use a small square against the side of the rod.

Edited March 30 by Toolguy

[Bench]

58 minutes ago, Toolguy said:

You can make a tool for that out of a 4" long, 1/4" diameter piece of steel rod with a hole in each end. Drill the holes in the lathe. Center drill, then drill about .010 to .015 under size for a pilot hole. Finish drill one end 9/64" (.141) for the hammer stud, one end #38 (.1015) for the trigger stud. Make the holes about 1/2" deep.

 

Then you can slip the tool over the stud and check for square and gently adjust as needed, by pushing on the top of the rod in the desired direction. Make the holes as close a slip fit as possible so the tool is an extension of the stud. Then you can use a small square against the side of the rod.

Toolguy, thanks, looks like I'll at least make the tool for checking square but it goes back to S&W if it's out of square.

[Toolguy]

Once you have the tool on there, you may as well tweak it a tiny bit and be done. It seems silly to go through all the hassle and expense of sending it back at that point. Besides, they won't fix that anyway. They'll say it's in spec and send it back.

Edited March 30 by Toolguy

[Bench]

5 hours ago, Toolguy said:

Once you have the tool on there, you may as well tweak it a tiny bit and be done. It seems silly to go through all the hassle and expense of sending it back at that point. Besides, they won't do that anyway. They'll say it's in spec and send it back.

Thanks, it's a good weekend for tool making.