This is a follow-up to my previous message (in August?) announcing my intent to cut and thread a barrel to fit inside a trimmed and threaded barrel stub, thereby rechambering a standard weight 30-30Win. Handi into a heavyweight 32-40Win.
Well guys, I have a bit more to do, but the "sexy" portion is done. We sawed off the 30-30Win barrel just at the taper beginning. Then we dial-indicated and trued the chamber portion of the stub and opened the hole to 0.625" with a 5/8" drill bit. We made several passes to open the whole stub up to 0.687". The front (towards the muzzle) was opened up to 0.760" and then, using a tap, we made threads (3/4-16) inside the stub to within an inch of the rear.
The barrel was full length turned to 1.110"- which was the same O.D. as my chamber stub, we cut the outside of the chamber end of the barrel to match the inside of the stub, adding about 0.1" to the OAL so we'd have extra to allow the face-cut at the chamber. It was a tight fit for the last 1/4 turn, but putting an adjustable wrench on the lug allowed us to close the gap between the stub and the back face on the barrel. -The muzzle has the smallest ID, as determined by slugging both end and measuring the slugs.- For cutting the muzzle, we dial-indicated to the outside of the barrel and made passes from the inside-out with our carriage set to 11 degrees. This will be a cast bullet gun, hence the 11 degrees.
-Personally, I think this may have been a mistake, as we should've dial-indicated to the pilot bit that I had made for guiding our chamber reamer into the bore. It was a tight fit and should've allowed us to have a muzzle that was concentric to the bore, rather than one that is concentric to the outside of the barrel. -Details, details...
We cut the chamber (32-40Win) by hand, indicating against the bore-pilot and the far end of the barrel to ensure that the chamber wasn't as crooked as most Remington off-the-rack (go ahead, flame-on -then check for yourself) rifles. We guided the reamer in using the tailstock and turned it with a wrench. This took awhile.
Polishing the full length of the barrel was also time consuming, but worthwhile...
We cut a groove for the extractor (uses the same extractor as the 30-30) and, while we were on the mill, drilled our holes on the front end of the barrel for the front sights.
The front and rear sights are on half inch bar-stock that I carved lengthwise to fit the barrel saddle-style. I made a .4" dovetail on the top to fit my sights as well as the 3/8" dovetail scope mounts. We drilled the holes through these bars to match the holes in the barrel, and they were set aside.
We then flipped the barrel over and cut an internal dovetail for the forearm retention block.
Remaining (piddly-a$$ detail) projects include:
Drill the counterbore into the mounts so the screwheads will be recessed.
Tap the front sight-mount holes in the bbl. -Rear mount uses all of the existing holes.
Drill 2 more holes through the rear mount and into the bbl for #8 screws. Tap these holes and auger appropriate counterbores in the mount. -The rear mount serves as a breech-seating cleat, and so requires more strength. -See my previous post "strange guy" for clarification on the seating method of shooting.
Finish opening up the forearm for the 1.10" OD barrel. The wood is done, but I forgot to open the plastic piece.
Shape and install a block for mounting the forearm wood to the barrel.
Polish and prepare the mounts for bluing.
Cut a cross-groove into the rear mount's underside.
Complete and assemble the breech-seating tool.
Inlet and install the base of the palm-rest underneath the forearm.
FIRE! Test, evaluate, contemplate, complicate... repeat!
Blueing will occur in the spring-time.
In this project I learned that we could have done things a bit differently to have a better "trueness" to the overall finished product. ALSO, I learned that mass-production does not lend itself well to precision of final products. We spent more time dial-indicating and head scratching than we did making shavings. If the factory got the job within .010" to .015", they got lucky!!
I also learned that a camera would've been nice for you guys. I've got shots of the finished piece that I will be posting within the next week, but no pics of the job in progress. SORRY! :cry:
Keep an eye out for those pics. I'll also have shots of the breech-seater, as well as my (rough) mounts prior to buffing and polishing. I'm excited to get this thing on the line and start slinging those tapered SAECO 200gr pb FP's. If anybody else is considering a project like this, consider the pressure and OD of the cartridge you're using. For this, the 3/4-16 was a large enough support thread in the bbl stub. I'll be running pressures below 30k c.u.p. But if you are running 40k-50k+ c.u.p. consider keeping your intact bbl OD larger, and turn out a bit more of the stub.
This was a bit of an involved project, but thorough research and planning of our tasks got us through pretty well.
Watch for those pics!!
Dean
