Miroku Winchester 1886 Reassembling Issue – Can’t Get Hammer Screw To Thread In

[Blazin]

I took my recent manufacture Miroku Winchester 1886 45-70 apart to remove the rebound hammer feature. Getting it apart was no issue, and I was impressed with how tightly everything fit together, definitely a quality piece of machinery. I removed the rebound strut, polished the hammer spring strut (it needed it), clipped one coil off the stiff hammer spring, lubricated everything, and started reassembling the gun. No issue until I go to reinstall the rather tight hammer screw.

The screw does install all the way through the lower tang hole and the hammer, but with all internals installed I cannot get the hammer screw to start catching threads on the right side of the receiver. I can get it to catch threads and install fine without the hammer and lower tang installed, and with the lever all the way open, but with all the internals installed it’s not catching threads. I noticed quite a bit of wear marks on the hammer screw shaft (especially for a gun with less than 100 rounds) so I polished the shaft with hopes that would help my situation. Nope, still unable to get it to catch threads. I’ve tried grease, Kroil, lightly tapping the screw head with a non-marring hammer, but at this point I’m stumped.

I think the spring tension on the hammer screw from the hammer/sear/trigger is just enough force to cause this issue, because, as I said, I can install the screw with the internals missing. Since I can install the screw (without internals) the screw and receiver threads are fine.

This screw appears to be in stock at Midwest Gun Works and I’m considering buying one just to try.

Would appreciate any advice.

[NSB]

Get hold of this guy or visit his web-site. He posts on here sometimes and he really knows his stuff. His book give good assembly instructions, etc.
http://www.texas-mac.com/

[indian joe]

I took my recent manufacture Miroku Winchester 1886 45-70 apart to remove the rebound hammer feature. Getting it apart was no issue, and I was impressed with how tightly everything fit together, definitely a quality piece of machinery. I removed the rebound strut, polished the hammer spring strut (it needed it), clipped one coil off the stiff hammer spring, lubricated everything, and started reassembling the gun. No issue until I go to reinstall the rather tight hammer screw.

The screw does install all the way through the lower tang hole and the hammer, but with all internals installed I cannot get the hammer screw to start catching threads on the right side of the receiver. I can get it to catch threads and install fine without the hammer and lower tang installed, and with the lever all the way open, but with all the internals installed it’s not catching threads. I noticed quite a bit of wear marks on the hammer screw shaft (especially for a gun with less than 100 rounds) so I polished the shaft with hopes that would help my situation. Nope, still unable to get it to catch threads. I’ve tried grease, Kroil, lightly tapping the screw head with a non-marring hammer, but at this point I’m stumped.

I think the spring tension on the hammer screw from the hammer/sear/trigger is just enough force to cause this issue, because, as I said, I can install the screw with the internals missing. Since I can install the screw (without internals) the screw and receiver threads are fine.

This screw appears to be in stock at Midwest Gun Works and I’m considering buying one just to try.

Would appreciate any advice.

you have two springs leaning on that screw
1) pin the hammer spring
2) slacken the screw up under the top tang that holds the lifter spring
parts no longer under tension life gets easy!!
likely gonna need a decent 90 degree angle screwdriver for that one up under the tang
until you do this you run serious risk of ruining the thread on that screw (if you manage to get it to catch) I had this same problem with a Browning 71 wasted hours till I figured it out.

[Blazin]

you have two springs leaning on that screw
1) pin the hammer spring
2) slacken the screw up under the top tang that holds the lifter spring
parts no longer under tension life gets easy!!
likely gonna need a decent 90 degree angle screwdriver for that one up under the tang
until you do this you run serious risk of ruining the thread on that screw (if you manage to get it to catch) I had this same problem with a Browning 71 wasted hours till I figured it out.

Indian Joe: Yes, I think that'll work, in fact I think just compressing the hammer spring may do the trick. I've searched Brownells and am having a hard time finding a small coil spring compressor that is small enough to fit, but I may buy a small engine valve spring compressor.

[indian joe]

Indian Joe: Yes, I think that'll work, in fact I think just compressing the hammer spring may do the trick. I've searched Brownells and am having a hard time finding a small coil spring compressor that is small enough to fit, but I may buy a small engine valve spring compressor.

didnt work for me - needs to release the pressure from that carrier spring as well. I used a pair of vicegrips with a leather padded jaw to compress the carrier spring (couldnt get the screw out as I didnt have the 90 degree driver bit) would not recommend my method - one slip and you scar the finish on the outside of the reciever with the pliers. Its a desperation move - dont do it.

[Blazin]

Thanks Indian Joe, I got it back together. Was a two-man job, so I enlisted my retired master machinist friend. We released the carrier spring tension, then backed out the screw that holds the hammer spring/strut mechanism to release the hammer spring tension, then screwed the hammer screw in, then reassembled everything else.

[indian joe]

Thanks Indian Joe, I got it back together. Was a two-man job, so I enlisted my retired master machinist friend. We released the carrier spring tension, then backed out the screw that holds the hammer spring/strut mechanism to release the hammer spring tension, then screwed the hammer screw in, then reassembled everything else.

Good job ! I was thinking after I posted maybe the miroku dont have a way to pin the mainspring under tension? (thats a mod for next time) for sure mine was an absolute mongrel of a thing to get back in. The original 86 flat spring with the stirrup on the hammer was such a good reliable setup and easy to work with - why would they change it ? might save two bucks in the manufacturing process ??????