Does anyone here have data on hole spacing vs. breechblock travel? My firing pin strike is .025” low right now. Looking at the sectioned view in SSR&A, the link has gone about 30deg past top dead center at the firing position.

Bob,
I appreciate the info. Shame on me for making an assumption that the firing pin would be centered after having CPA install a new breechblock, loop lever and dbl. set triggers a couple years ago. This 35/30 Maynard barrel is the first of (5) barrels that has given me firing issues. It is also the first with a large rifle primer. In thousands of shots with the other barrels and small primers, I have not had a single misfire even though the pin strike was visibly low. 3 or 4 out of 10 are misfires now. Since I’m breechseating this barrel, facing a few thou off the barrel face and deepening the rim recess to suit is a non issue. In looking at the assembly drawing, my gut feel is .001” in link hole spacing will raise the breechblock several thousandths. I am hoping someone here has been down this path.

I sent a 44.5 to cpa that was originally a 32-40 and wanted a 22lr
Barrel and rim fire breach block . Got it back and firing pin was putting a hole in the back of the case , hitting to high.
Sent it back , Gail told me that had to make a new link due to the fact that cpa and Stevens actions are a little different in geometry.
Not sure about the center fire blocks but I would assume it’s the same problem.

3rd hand information can’t guarantee it’s true . Setting up CPA actions, they have links with different hole spacing. Switch them out until the correct block height is achieved. 

44 1/2 not exactly the same as a CPA however. It’s possible Stevens did it the same way switching out until correct. 

Boats

When I started my project to make stronger links for the Model 44s, I found that my inventory of links showed a variance in hole spacing of .012.  So now when I set about a link replacement I have to measure the existing link first.  The hole spacing in the 44 link is crucial, because any variation changes the lockup.

For a 44-12, the spacing only varies the alignment of the firing pin, but I could believe that they had a selective-fit-at-assembly procedure.  I think they were already doing it for the 44.  

That 30 degrees is the angle of the toggle with respect to the plane of the breech face.  I failed to realize that's what you were talking about.  Has nothing to do with the final position of the breechblock.  Draw two lines, one between the link pin centers, and another between the lower link pin and the lever pivot center. The angle between those two lines is the critical one. Should be only a couple of degrees beyond 180 degrees when the lever is fully closed, and it probably is.  

Bottom line: if the pin strike is low, you need a link with wider spacing.  Since the angle of the toggle linkage is about 30 degrees from the plane of the breech block motion, the change in link spacing will be the amount of change you want for the firing pin x .866 (cosine 30).  (To move the pin up .010, lengthen the link spacing by .00866. )

Thank you all for the good info! Measurement shows I need to raise the breechblock .025” to get a center hit on a LR primer. Since SR primers have never been an issue, I think Ill go .013-.015” and see what the results are with both.