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My broach-less Remington 700 action report

taiwanluthiers

Cast Iron
Joined
Dec 6, 2016
Location
Xinjhuan District, New Taipei City
So my machining of a Remington 700 action from scratch is a success. I do not have a broach, EDM, or any fancy machines. Heck, I do not even have a lathe!! All I have is a modified Grizzly G0704 benchtop mill. Not the best but it's adequate for the job assuming carbide tool is used.

I started with this:

414 pre heat treated bar stock 1.575 4 MM x 249 MM 9.82 long ground OD 38-42RC | eBay

I can attest that this material is hard, and not the easiest thing to machine either. It's just the right size for a receiver however. This is the operations I took:

Bore out a .700" hole - not the easiest thing to do and it actually took a long time due to not having the right tool. The material eats HSS drill bits for breakfast. The hole must be drilled in increments.

Form the bolt locking abutment - While the receiver is clamped vertically, I used a short boring bar to bore the front of the receiver to 1 inch in diameter. The problem with a boring bar is the abutment will not be even... so use a counterbore or a 1" end mill to smooth that out.

Thread the receiver - I used a very cheap 1 1/16" - 16 tap I found from an ebay seller in China (similar tap can be bought for around 35-45 dollars). I didn't care about the spec as long as it was 1 1/16" -16 (and it fits a stock Remington 700 barrel properly). If you are not using a tap wrench (recommended, make sure you put even pressure on BOTH sides) you must take care to put pressure on BOTH sides or else it will cut at an angle, which happened to me. I corrected it by flipping the receiver and chasing the thread by putting pressure on the OPPOSITE side. That fixed it but the thread is looser than I like... but the receiver held up fine.

Mill out ejection port - Yes, VERY counter-intuitive, however this step is necessary because it forms a good portion of the bolt raceway. The idea is, use standard machining process to form the bolt raceway however by milling the raceway through the ejection port, you cut the length that you must broach from over 8 inches (for short action) or 9 inches (for long action) down to 2 inches or less (doesn't matter the action length).
001.jpg

Broach the raceway - Stand the receiver straight up again. Using a 4 flute 3/8" end mill (you may want a ball end or corner radius end mill for this), DRILL down into the abutments. Do this until you cut into the raceway made in the precious step. Take light cuts, use SHARP end mills, and high-ish RPM. You don't need to take off a lot of material but you do need to take off a steady amount of material. Some deflection is possible here. When you get done making semi circles approximately the width of the bolt locking lugs, switch to a smaller end mill and make that corner smaller. You need end mills that are at LEAST 4 inches long for this so don't get too carried away with small end mills, 1/4" is the smallest you can do before you start breaking them. When you get done with one end, flip it over and repeat.

FILE the raceways - Yes, use a GOOD file to file the raceways until the bolt fits. This is going to take quite some time but keep at it. Good things come to those who are patient. After enough elbow grease the bolt will start fitting... do this until it slides in and out without difficulty.
001.jpg

Cut both the extraction and chambering cam - This is where I messed up... I cut a good chambering cam by using a dremel bit and a 4 flute 1/8" end mill until I get a good ramp. However I completely forgot about the extraction cam and as a result, I do not really have one. I may wind up gluing a piece of steel to the back of the receiver for this but I can still extract the bolt by pulling HARD on it after opening.

001.jpg

Finishing touches - Now you can drill for the scope mount, mill for the magazine, chambering ramp, hatcher hole, etc. and blue the metal with whatever... I didn't mill out a magazine pocket because this will be a single shot rifle. I will try again and see how it works.

As you can see from the bottom pics, I have test fired it by loading a starting load of 30-06, and fired 2 shots at the range. I didn't go with a "proof" load because I'm not able to secure the rifle in a vise and fire remotely... so far there are no pressure signs on the cartridge (it didn't know it was fired by a homemade gun), there are no difficulty with extraction, and there are NO sign of abutment setback (I took the rifle apart and looked).

003.jpg004.jpg

This receiver isn't perfect... I messed up on a lot of things, for example the stock mounting screw is off by about 1/8 of an inch because I had bad blueprints (the blueprint is for a short action), I had to modify the stock to fit. I also made the receiver square instead of round since I did not have a lathe. So the stock had to be modified to fit. It also does not have a bolt stop... I will probably make one eventually by drilling and tapping a hole and using a small bolt as a "bolt stop". I can't make the factory bolt stop work (I need to mill a very narrow slot in the bottom of the receiver) and the "external bolt stop" is very expensive.
 

Doug W

Hot Rolled
Joined
Sep 22, 2003
Location
Pacific NW
Wow you have perseverance!!

I bought a USPS large flat rate box of those PH bar stock from the same seller (recommend) and had a couple checked for hardness and they were within specs.

I plan on making a gundrill setup for the drilling and modifying std keyway broaches to cut the lugways.
Gathering up used broaches off ebay for the modifications.

So, when are you making #2?
 

taiwanluthiers

Cast Iron
Joined
Dec 6, 2016
Location
Xinjhuan District, New Taipei City
I just ordered 3 more of that same pre hardened round bars... I really need a reamer for .700 but I do not know anyone who makes them. I drill from both ends to avoid the problem of drilling too deep, it's the only way to do it without needing a drill bit that's too long. I upgraded the motor on my mill so I can take slower cuts at greater force because the stock motor weren't cutting it. I have not hardness tested the steel by the way but according to the ebay seller, someone hardness tested it and it comes to around 38-40 RC. Based on how hard it machines, and how often it wears bits, I believe it. A file will still cut it but very slowly. I need a better way of cutting the chambering and extraction cam however because I free handed it with a dremel, so it's really rough, but it does the job.

I got a standard keyway broach but I don't have the setup to take advantage of it. I'm thinking of taking some HSS tool bit blanks and turning it into a mini broach of some sort to facilitate squaring off inner corners. I might be able to rough it out with a diamond saw at school and then I can precision grind it later on. The idea is to be able to broach with the milling machine, or a drill press/arbor press by pressing down on it like a wood mortising machine.
 

taiwanluthiers

Cast Iron
Joined
Dec 6, 2016
Location
Xinjhuan District, New Taipei City
Thanks... I just found one on ebay for 9 dollars plus shipping. Must be good timing.

One reason to make my receiver square by the way is to facilitate installation. I don't want to buy special action wrench or barrel vise, so I used a standard 12" adjustable wrench to tighten the action. I milled a small flat on the chamber end of the barrel which I can clamp the barrel into the milling vise and tighten to my heart's content without scratching up the barrel. I already scratched it up badly once because I tried to secure it in a milling vise which didn't work. It was a 20 dollar Remington take off barrel so I don't really care... I think if I order a custom barrel I'd probably ask them to either mill a small flat at the chamber end of the barrel, or I will do it myself...

001.jpg

I tapped a M5 thread into the top of the receiver for scope mounts... It's bigger than they need to be however I had difficulty tapping such small holes, I broke a tap inside the receiver trying so I had to drill them out with a carbide end mill. The operation mangled up the thread so I had little choice. I am using a strip of blank weaver rail on top of the receiver as a scope mount. I will be able to make a custom M5 bolt to install it.
 

Doug W

Hot Rolled
Joined
Sep 22, 2003
Location
Pacific NW
Use a pilot when tapping the receiver threads, it prevents tapping at an angle and reduces the chances of breaking a tap.

I think I would cobble up a simply, low cost rack and pinion 'shaper or slotter' to shave the lugs if I didn't have broaches and a press.
Got to be faster and more accurate.

I drilled one blank to try it from one end with a series of longer bits. Then used a series of chucking reamers to get to 45/64".
The bore came out straight and with a good finish.
But yeah, the bits required frequent sharpening, lots of oil and no lingering.

That is why I what to step up to a carbide gundrill.
 

elysianfield

Cast Iron
Joined
Feb 28, 2007
Location
Myrtle Point, Oregon USA
" piloted tap from Brownells costs around 200 dollars. That is a lot of money for a tap. I do not know how to modify a standard tap so that it accepts pilots"

Why not grind the lead of the tap to the required pilot diameter, and then re-grind the remainder of the tap with the correct lead, or grind the lead of the original tap to a pin that will accept whatever pilot diameter you would require?
 

taiwanluthiers

Cast Iron
Joined
Dec 6, 2016
Location
Xinjhuan District, New Taipei City
It's not that simple. First of all, I do not have the right tool to grind taps to a precise dimension at all, and also I'd have to grind a large portion of the tap off, as the tap pilot would need to be longer than 2" for it to work. I can machine a jig with a hole in the right place to hold the tap.
 

Sea Sick Steve

Cast Iron
Joined
May 1, 2011
Location
The Buckeye State USA
Applying blue wonder. The stuff looks really good by the way. Only thing is, you have to get the metal HOT when applying the blue.

View attachment 187336

It looks as if the barrel is fluted rather deeply along the sides of the chamber wall,is this the case? This is not an area that typically gets fluting on a rifle barrel.Im not trying to be a D and Im not an engineer or an expert on such things. It would seem to me that the chamber wall integrity would be reduced by fluting in such a manner. I might be all wet and im sure others who are more knowledgeable will weigh in. It looks like it was not fluted in the earlier pictures in the thread. My apologies in advance if my concern is not warranted
 

taiwanluthiers

Cast Iron
Joined
Dec 6, 2016
Location
Xinjhuan District, New Taipei City
It was not fluted at all. I milled a small flat at the chamber end of the barrel, about .20" and it only barely kissed the back end of the barrel. I did this so I can put the barrel in a normal vise to keep it from spinning while I tighten the action to it. The "flute" you saw might just be reflection.
 

Sea Sick Steve

Cast Iron
Joined
May 1, 2011
Location
The Buckeye State USA
It was not fluted at all. I milled a small flat at the chamber end of the barrel, about .20" and it only barely kissed the back end of the barrel. I did this so I can put the barrel in a normal vise to keep it from spinning while I tighten the action to it. The "flute" you saw might just be reflection.

My apologies I guess my eyes deceived me carry on
 

Doug W

Hot Rolled
Joined
Sep 22, 2003
Location
Pacific NW
By the way, anyone with a gun drill setup, what would be the cost for me to send it to you for drilling?

I have tried several shop that do gun drilling including a couple of barrelmakers. They really aren't interested in doing small one off jobs.
That pretty much goes for the grind shops too, and I why I seem to end up doing it myself, or not doing it at all.

Maybe you will have better luck??
 

GreatLandKennoZ

Plastic
Joined
May 10, 2017
This thread just show the futility of gun control. I wonder if someone makes the serial number say Guncontroldontwork01

who all remembers a few years back when 30 round mags were about to get banned and all the panzies were crying about 3d printers making poopy plastic mags, and being able to print a "gun" :crazy:
 








 
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