It's been a long time coming. I've dreamed of doing this since bringing this rifle home.
Why? There are many reason I can come up with but, to anyone asking "Why," no reason is good enough. Lets just say I'm tweaking an already very-good rifle to my own preferences.
On Wednesday I had the day off so I made an action-wrench shaped specifically for the K31 receiver. On ThanksGiving morning I used this action-wrench to remove the barrel from the receiver and I was surprised to see how close the tolerances were of this old Swiss rifle. For being a rifle built pre-CNC, it is really surprising to see this level of accuracy.
From the measurements I was able to get off of the receiver, it looks like "Truing-The-Receiver" won't be necessary. I'll have to wait till I get farther along to do double check though.
The barrel threads appear to be metric. I say this because my standard thread pitch gauge had nothing on it that would fit the threads on the barrel tenon. I'm presently waiting on my newly ordered metric thread pitch gauge to arrive. I'll be taking lots of pics as I move along with this project; and I'll be doing this job my own way.
I have to state up front that I'm not a gunsmith and I'm not a machinist. I'm sure there are several ways to go about this but as I've just stated, I'm doing it my way; which may or may not be the right way.
I generally don't post my projects any more until after I've completed them. This is due to the ever present Trolls, Nay-Sayers and well-meaning Dream Killers; as well as the Self-Appointed-Experts. Few things are worse than one of the above trying to tell you how to do something when we know that it's not likely they've ever undertaken such a project themselves. Insight from those with hands-on experience is always welcome and appreciated; negatives from the Self-Righteous and All-Knowing among us, not so much.
Following is the list I made pertaining to this project. I laid it out for myself. It's in the general order that I'll be approaching this project. And, I forgot to mention; I'll be re-chambering to 6.5 x 55 Swedish.
I'll be back with updates as they happen.
HollowPoint
K31 Re-Barrel Project
Materials needed:
(1) Steel for Making Action/Receiver Wrench--Two Large Bolt/Washer/Nuts Done
(2) Steel Tube for Bolt/Receiver Truing Fixture--Eight Bolts/Spiders Done
(3) Wood for Barrel Vice Done
(4) Drill Rod for Truing Receiver Done
(5) 4140 Rod for Making Barrel Nut and Recoil Lug--2" diameter 4" long Done
(6) Dykem Layout Dye Done
(7) Barrel--Chamber Reamer--Range Rod--Go Gauge--Loading Dies--Brass--Bullets Done or On The Way
Measurements needed With Barrel Still On The Receiver:
(1) Back Of Receiver to the Breech Face =_______ Done
(2) Back Of Receiver to the Cam Face =_______ Done
(3) Back Of Receiver to the Case-Head =_______ Done
Measurements Needed With Barrel Removed From Receiver:
(A) Front of Receiver to the Receiver Lugs =_______Done
(B) Front of Receiver to the Bolt Face =_______Done
(C) Front of Receiver to the Bolt Lugs =_______Done
Steps In Sequence:
(1) Check Bolt-Lug Contact Before removing Barrel (Lap Lugs if Needed) Done
(2) Remove Barrel from Receiver Done
(3) True Up Receiver, Receiver-Threads and Bolt-Face Done
(4) Measure New Receiver-Threads for New Tenon Dimensions Done
(5) Index Barrel in Lathe and Cut Outside Tenon Dimensions Had To Go To Plan-B
(6) Cut Threads Done
(7) Short Chamber With New Chamber Reamer Done
(8) Dykem Barrel Tenon, Screw into Receiver, Mark Extraction Notches and Cam Position Had To Go To Plan-B Done
(9) Make Cam Template with aluminum sheet metal Done
(10) Remove Barrel from Receiver and Cut Extraction Notches and Barrel-Cam
(11) Make Barrel Nut and Recoil Lug Had To Go To Plan-B
(12) Assemble and Head-Space
(13) Make New Scope Mount Done
(14) Disassemble and Powder Coat Flat Black then Reassemble. Done (I Powder-Coated while I was waiting for the new barrel to arrive; also sanded and refinished the stock.)
(15) Safety/Function Testing Done--Project has now been completed and Proof-Tested successfully.