Ithaca M37 Deer Slayer Police Special Slug Consistency

[roo_ster]

Howdy:

Trying to discover the secret sauce to maximize accuracy by minimizing slop / maximizing consistency in re-assembly. Especially in the area of the yoke, yoke screw, and magazine cap.

FTR, my M37 is a DSPS from way back with the removable barrel, so it comes all the way apart. New ones are, IIRC, soldered in place. Smooth bore, 20" bbl, extended magazine. Light & handy.

Was shooting slugs and doinking with the rear sight when I noticed the bbl (with quarter matted rib-like dealy the rear sight is dovetailed into) was not aligned top dead center. Was getting some great slug groups out at 50 yards(1), but when I adjusted the rear sight, I would get diagonal movement, not just lateral movement of POI. Took a closer look and the bbl was not TDC.

So, what's the secret sauce to get the bbl assembled consistently? Witness marks? Torque wrenches? A pilgrimage to Ithaca, NY?



(1) With Federal Truball foster slugs and Brenneke short mag slugs. Both 2 3/4" Once I get this sorted, I will have confidence to take deer or hog out to 100 yards, given the 50 yard performance of these two monster hunks of lead.

 

[desidog]

What do you mean by "extended magazine tube"? You can't extend the M37's tube since the lug is in the way. Do you mean you have a DSPS gun with an eight round capacity?

The barrel should be true when you unscrew the retaining nut into the recess on the lug (which is soldered to the barrel). When that the nut is tight, if your rear sight is not TDC, you need to either file or mill out the high side of the dovetail, or just live with it...

Incidentally, a lot of them are really tightly choked. (Mine has a bore diameter of .706") Which you may want to consider since Foster slugs can safely be swaged down much more than Brenneke slugs, when fired through a choke since they are hollow.

 

[roo_ster]

What do you mean by "extended magazine tube"? You can't extend the M37's tube since the lug is in the way. Do you mean you have a DSPS gun with an eight round capacity?

The barrel should be true when you unscrew the retaining nut into the recess on the lug (which is soldered to the barrel). When that the nut is tight, if your rear sight is not TDC, you need to either file or mill out the high side of the dovetail, or just live with it...

Incidentally, a lot of them are really tightly choked. (Mine has a bore diameter of .706") Which you may want to consider since Foster slugs can safely be swaged down much more than Brenneke slugs, when fired through a choke since they are hollow.

Yep 8 rnd capacity with a 20in bbl. Might have to just put it 8n a gun vise, level the receiver, level the bbl by way of the flat top of the matted rib, and make witness marks to ensure repeatabilty.

Maybe so on the fisters. The benneke slugs i have fired have the ribs that are supposed to swage down when passing through chokes.

 

[Noz]

My father in law left me a Deer Slayer in his will. It is scary accurate with "punkin ball" slugs.