The year was 2011 and I was standing in front of an interested crowd giving a power point presentation in a Country Club just outside of San Antonio Texas. I was doing my best to visually show those assembled the steps required to modify, blue print the receiver, then fit and chamber a barrel. The next images showed me modifying the underside of a current production Model 70 receiver to except one of my floor-plate, bow and magazine assemblies. Then I did my best to described the art of surface grinding the receiver to install a set of my scope mounts. Fitting the stock came next and then going over the final finish work to turn the project into a finished Legend rifle.
D'Arcy Echols & Co.
Thursday, August 12, 2021
It took a Texan to state the obvious
The year was 2011 and I was standing in front of an interested crowd giving a power point presentation in a Country Club just outside of San Antonio Texas. I was doing my best to visually show those assembled the steps required to modify, blue print the receiver, then fit and chamber a barrel. The next images showed me modifying the underside of a current production Model 70 receiver to except one of my floor-plate, bow and magazine assemblies. Then I did my best to described the art of surface grinding the receiver to install a set of my scope mounts. Fitting the stock came next and then going over the final finish work to turn the project into a finished Legend rifle.
Sunday, June 6, 2021
Converting a Pre-64 30-06 to 300 H&H Part 3
OK now lets tie all this together. The first thing to do is file the different flat widths we've cut into that wasp waist shape between each feed rail. Had we been using a CNC we could have programed this step hit the RUN button and watched these mirrored contours take shape.
Instead we must make the modification blend by hand. This is best done with 6" to 8" medium cut mill files followed up with a # 4 cut file blending our stepped cuts together in an uninterrupted transition from front to rear. Since we made these mill cuts into the rails with use of the digital readout, both the depth and length these two apposing sides should blend out in almost a mirror image. The upper and lower edge of each rail must also be filed with a slight corner breaking radius. The transition along both rails should feel smooth and interrupted. The plan is to just blend these milled flats not hog out more rail width than is necessary.
Then starting with 180 grit W&D paper both rails should be polished top and bottom, front to rear. This sand paper work should be continued up through 320 grit. Keep the radius theme on both sides of the rails
Next you need to file an angular ejection bevel on the underside right leading edge of the rear bridge as we have left a very sharp corner that will catch on every cases being ejected. In addition any sharp corners generated by and end mill need to be chamfered with a file and then paper.
You must remove the sharp corner at the rear of the feed well wall that we've generated by widening the feed well. 1st with a pillar file, then a stone and finally with paper we need to turn that sharp corner into parabola shape. Failure to do so will cause the belts on the case to hang up on that sharp corner.
Next we begin blending the 90 degree shelf above the leading edge of the magazine box ID we have established by cutting the feed well forward with the existing angle of the 30/06 bullet ramp. Some would suggest making this new angle straight from the top of the mag box to the rear edge of the flat behind the lower recoil lug seat, you could. However if you blend the standing material into the established bullet ramp angle with again a parabola shape you will in fact be leaving much more steel in the ramp area than Winchester ever left behind on factory 300 H&H receiver. This leaves the lower lug area with significantly more material and removes the knife edge effect at the top of the bullet ramp found all too often on a factory 300 or 375 H&H receiver. Another advantage of this extended parabola shaped ramp also puts the bullet nose in contact with the ramp sooner allowing the bullet nose to begin its rise towards the chamber as well as rolling the base of the case into the bolt face and under the extractor sooner. Remember the beaten to death term "controlled round feed" in my experience the sooner this control starts as the bolt is pushed forward the better the entire concept design becomes.
Say what ?????????
As an example the extractor groove diameter on a cross section of six different manufactured 300 Winchester cases I measure a while ago showed a + and - .020 variation in the six brands of brass.
The fit of the extractor hook to the chosen manufacture case should allow the extractor spring away from the bolt body .004 to .006 when the case is rolled and centered into the bolt face in the chambered position in my opinion.
The larger the bullet diameter or the further away the bullet nose is from the centerline of the action the more material will need to be removed. This can take 5 minutes to a number of hours depending on the case and cartridge design. When you feel you have the best shape working for you then you can use a Foredom hand tool with the proper sized cartridge rolls and or the rapid break down stones to go over and remove the file marks and then I paper polish entire bullet ramp. You want that bullet ramp smooth as a Beagle's ear.
Wednesday, August 26, 2020
Converting a Pre-64 30-06 to 300 H&H Part 2
A majority of machine work has now been completed to the magazine cavity and feed well but the rail width modification is still required. The OD of the belted case as well as the shoulder OD is larger than the 270/30-06 class of cases so additional room through the rails must be made to accommodate for these larger case diameters.
It is the height of the case that protrudes above the rails and allows the lower edge of the bolt face to engage the protruding case and then allow the bolt to shove it towards the chamber. The case must stick up through the rails ENOUGH as its pushed forward or the bolt face will override the case head and cause a jam. Most 270/30-06 Model actions are approximately .545 to .550 in width from one feed lip or rail to the other side at the very rear of the feed well opening directly above the magazine box and then widens to .600 to .610 directly above the bottom of the bullet ramp. This geometry has work since the 1st Pre-64 stepped off the bus so it's hard to argue that it isn't adequate, is it prefect? well...............
All the next cuts will be made from the center-line of the receiver so you must establish the best means to do so. Again the fixture I use allows me to do this very easily. Finding the center-line I start off and finish using only a 3/32" carbide end mill. I widen the existing width at the rear of the rail from the original .545 to .610. Taking a photo of this operation is difficult at best due to the close proximity of the mills spindle being so close underside of the action.
With the help of the DRO I will now cut stepped flats into the rails in incremental lengths from the rear forward and later on file and blend these transitions. If you had a CNC you could write a program to do this parabola shape, push start and step back.
To confuse the issue even more below is a standard Pre-64 action and OEM follower that is chambered for 280 Remington that has the ejection port opened up the 3.416. Note the tail of the extractor showing with the bolt in full closed battery and then the tail tucked under the rear bridge as the bolt is opened. The result is a longer loading port and a captured extractor tail.
The wonder of it all !
A lot depends in any conversion or modification on the the materials at ones disposal. You will see similar adaptations of this on many of the Magnum length actions chambered for long cartridges. Note the visible exposed tail on this extractor fit to this H&W magnum 98 action, lift the bolt and the tail end slips under the rear bridge before the bolt rotates completely up the extraction cam, no fuss-no muss.
Sunday, August 9, 2020
Converting a Pre- 64 Mod-70 action from 30-06 to 300 H&H Part 1
In the late eighties as I began to set up or build more 375 H&H's for hunters and finding suitable actions/rifles to do so could be a challenge. By this time I had used quite a few original Pre-64 Model 70's that had left the factory as 300 H&H and 375 H&H rifles and while they all mechanically worked except-ably there were a few things that seemed to crop up over and over again with these factory long-magnum receivers that could use some attention to detail and revision.
I began to consider using the standard 270/30-06 receivers as they came from the factory and modifying them to remove the factory idiosyncrasies that I felt I could correct. Do they need correcting ? Yes, No, Maybe, so let's see.
A radial notch was then cut into the rear edge of the front ring and another large radial cut was added to the front of the rear bridge to allow loading the rifle quickly from the top side of the action with these longer rounds. All was great when those rifles were fit with the Lyman or Redfield receiver sights or even kitted out with the shallow V's found on many older Model 70's. You had an opening in the top of the receiver you could fill the magazine as you back peddled away from danger.
Scope use changed this paradigm radically. Once the 1 piece scope mount became vogue you then had to really practice to load that rifle quickly. A fault ???? not in the original design idea but the system still worked day in and day out. Especially by those that had to make a living with these Model 70's.
Thousands of standard length 98 actions have been altered too except the 300/375 H&H and those suffered the same fate. It works, no doubt about it and still does.
You also need to understand that this is not a one hour conversion, requires a milling machine, carbide tooling and a very secure way of holding the receiver while it is being modified. The barrel should be removed and in this case the rifle receiver was also going to be fit with my scope mounts. So the 1st course of action for me was to true up the underside of the receiver as my fixtures for fitting a set of my mounts are made to work with the underside of the action being machined flat, so we're now killing two birds with one sledge. With the underside of the action leveled off the feed rails I then make a number of passes along the bottom of the receiver with usually with a 4 Flute 1/2" carbide end mill until the bottom side of the feed well and trigger area and tang are of the same level. Then I insert a 1/2" end mill into the collet that has a .030 corner ground onto the end mill. I then cut the recoil flat pocket behind the recoil lug so it is also flat. At the same time the recoil flat pocket is being cut the back face on the contact surface of the recoil lug is also being machined 90 degrees to the the recoil flat. The pic below illustrates why this alone should be done.
While not the same Pre-64 we're going to open up the photo below display's a very common occurrence with all Model 70's and that is the recoil Lug being originally machined into a wedge shape unfortunately being wider or thicker depending on your perspective at the BOTTOM of the lug. All with complements from New Haven.
Below .006 has already been removed from the back of this G -series recoil lug face and were still not cleaned up or perpendicular. Tightly Glass Bed such an action with this integral wedge into a stock and you risk breaking the stock before you get the barreled action back out of your bedding job. This issue is more common than you think with the Model 70 having machined a couple hundred of them I can guarantee this anomaly.
Since we're converting a 270 action to 300 H&H the next step is to carefully begin to open up the feed well originally set up for the 3.400 width and length magazine box. Now we're making room for the longer and more tapered 3.630 length 300/375 OEM mag box.
Since the client supplied and original 300/375 magazine we begin fitting the new box into the feed well cavity. We measure the thickness of the back wall of the magazine and note its .030 thick. The box will rest on the lip at the rear of the mag well. Usually this lip is recessed approx. 200 deep into the feed well just ahead of the middle guard screw. The 270/30-06 magazine box back wall is approx. .050 thick and the 300/375 box is .030 in wall thickness. So we can move the back wall of the feed well even further to the rear by another .015 to .025 usually.
The lip that the rear of the box sits on is machined to the same thickness as the back of the 300/375 mag box. There must be a seamless transition for the base of the belted mag cases to slide up the magazine and into the feed well. As the 300/375 magazine is wider at the back of the feed well the width on our 270 action must also be modified to reflect this new width. Measure the width at rear of the 300/375 box and cut away for the center-line of the action accordingly on either side at the rear.
Note the 2 red arrows as they show other areas I will need to machine to allow for the proper width in the feed well with the new 300/375 magnum box.
But first the forward end of the receiver must be cut away to the overall extend length of the longer mag box. The cavity being cut will also serve as a Depth Stop for the forward end of the mag box like the shelf in the rear of the feed well. So it will also be cut to the same depth as the rear shelf at .200.
This OP is best done with a 1/2" end mill to match the radius on the front of the 300/375 magazine box. Cutting away from either side of the actions centerline establishes the front cavity shape. Again care must be taken to the cut this overall length to the numbers, now is not the time to be sloppy
Wednesday, July 15, 2020
Hmmm ?
Recently I was asked to machine and partially replicate a Holland & Holland 98 Mauser stock. When the rifle was in my hands there were two things that really stuck out that I have yet to encounter in the past.
Chambered for 458 Winchester the H&H scope mounts had been installed with their own answer to heavy scopes moving under recoil. You simply drill through the ring bands and install set screws that bite into the scope tube.
I'm not sure if the Zeiss warranty covers this type of upgrade ? It would have been interesting and easier to have actually left the appropriate .030 gap between the upper and lower ring halves to see if that might have solved any recoil movement issue with proper ring tension. Clearly no attempt was made in this regard. Rifle making at its best.