designing/machining own action

[fusionrider]

I have started drawing up plans for a bolt action. It will be just big enough to cycle a 221 fireball with long or heavy bullets. It is very similar to a rem 700 but: Smaller,.5" bolt body and 1" total action width X ~5.5" long), left hand feed port right bolt, side bolt relese, sako extractor, and fixed blade ejector,unless plunger ends up being more practical).

My questions so far are:

What type of steel for action and bolt,harden bolt head)? This action will only have to handle the .221 or a .20/.17 variation.

What clearances are needed between bolt lugs/body and the raceway to be tight but still move freely?

Also what would the minimum barrel shank length be? I have it drawn up as aprox. 5/8" depending on bolt to barrel clearance.

 

[Taildrag15X]

Go back to your Engineering Handbook 101.

Diameter of threads = Depth

 

[sjk]

It's not too clear what you really possess in knowledge to take on this kind of work, so I can't comment much on metals, fatigue, PSI and so forth ad nauseum. I will however state that if you want accuracy, It's hold the tolerances as close as possible., Female .500 +.001-.000, male surface of engagemnet held to .500 +.000-.001 for an example, depending where you want to wind up). RC 30/45 is a wide range. Having something on paper and then trying to fabricate it are two complete and opposite ball games. You'll find that the Engineer 101 is where you have to start as stated. It's good advice

 

[KRP]

If he isn't selling it and can legally own a firearm he doesn't need a license to build it.

 

[butchlambert]

KRP is correct.
Butch

 

[gunsmithatwork]

Interesting CAD/computer drawings I must say mate. I'm a gunmaker myself and can tell you right now it is not that simple as it looks on paper. Not trying to discourage you here, but I'm just wondering what your trade background is? You would need some lenghty metal-working experience, machining-, tool-making & preferably some CNC- machining/programming skills to produce one or multiple units yourself. Not to mention any of the gunmaking-skills to build complete rifles out of them!
Material selection would certainly be one of your last worries; I would suggest making a working model first out of some cheaper 'standard' low-grade toolsteel; see how you like it to work with this material & see if you can get a working model?
I hope you're succesfull in your new venture; just let it not be another Rem. 700 'clone', but something new & refreshing? Something like a 'miniturised' version of the Heym SR30 "Straight-pull"? Good luck mate.

 

[Clark]

http://www.homegunsmith.com/cgi-bin/ib3/ikonboard.cgi

That is forum of people who make guns from scratch.

 

[fusionrider]

The only area of the metalwork that I am not familiar with is the EDM cutting of the bolt ways. but I have a good teacher who is donating the machine time and his time to help set it up and run it. I am in a Tool and die program and doing quite well. None of the machine operations that I forsee are above my current skill level. That being said I am not an engineer but am fairly mechanical minded with a few drafting classes and am in search of design recomendations.

As it is now,after a re drafting to enlarge and beef up the lugs and front end) I still am looking for a good bolt stop design and extractor/ejector combo. Any ideas? leaning towards rem700 extractor and a mini plunger style ejector, but still looking.


Please comment all critisizm helps!

 

[gunsmithatwork]

Some experience I see and yet another 700 clone in the works. Forget the Remington clip-extractors as these are a waist of time! If you start from scratch and a controlled round feed/claw extractor ala M98/Win 70 are no options, then you're better off with the 2nd best type of extractors: Either Sako/Tikka or M16/Howa-type will work best. Bolt-stops are in fact quite simple gadgets: the Sako 75/85's are good or else look at the websites of some of the other 700's clones for new boltstop ideas,ie: Stiller, Stolle, Pierce, Bat, Nessika Bay, Barnard, the new 2008 Badger Ordnance Action, ect....) As for tolerances: don't start off with too tight a tolerances, else you'll run into 'galling' trouble quite quickly! Hope this helps mate??

 

[Rustystud]

Here are some of Butches' pictures:

 

[butchlambert]

I like the Anschutz bolt stop-release. It has a much cleaner look than the others.
Butch

 

[fusionrider]

Here is the latest draft. I have changed the slope on the top of the action to and arc as opposed to a straight chamfer to allow for a uniform thickness around the barrel and bolt lugs. This shouldnt be a machining problem if the action isnt to long for the wire EDM. The extracting cam is on now and from all i can calculate "in time" but it will proably need some hand work to smooth it up later. I still havent taken the measurements off of a remington trigger so the trigger slot and pin holes arent in yet. The action has been sized up in all ways. The bolt is bigger the lugs are bigger and the barrel shank can now be .75 or longer if I recess the barrel for the nose of the bolt.There is also more material behind the "top" lug. The bolt handle Is looking to be a fun project with alot of hand work,the modeled one isnt quite what i am wanting but works for basic clearence testing).

 

[prestonpritchett]

I think your action looks good. Lots of advantages by adding the recoil lug and the scope rail all in one pc.,Rifle Accuracy Facts by Harrold Vaughn)
On your steel most have close to the same tensile strengths if they are the same HRC. Most actions we have tested are around HRC 40
On your Extraction cam if you will rotate it in the 4th axis of your mill you will get 100% contact between it and your bolt surface when you rotate your bolt.
On your extractor it is debatable. My friend Red Cornielson former bench rest hall of fame. In his later days loaded the wrong powder in his 22-284 and the sako extractor came back into his face. This is the reason we don't use the sako.
On your clearance one thing to think about is if you will program the outside diameter of your bolt to have a increased surface on the back section and also behind your locking lugs you can remove the metal from the top and bottom and leave it behind your lugs and it will help with alighnment on both the front and the back. We do this on our target bolt. Also if you will use 4140 and have the heatreaters keep track of the draw temp and then send it and have it nitrided it will give you a case hardening effect so you won't have to worry about gualding.
Also when you drill your fireing pin hole it is benificial to keep your hole long enough to keep the firing pin from falling out of alighnment. It will help you reduce vibrations.
If you use a pin in your bolt stop be sure the pin doesn't take the shock when the bolt is cycled. The marine corp had this problem. On ours we have the bolt stop bottom out so the pin doesn't take any shock.
Good luck and have fun with it. When and if you decide to go into production holler, I would like to buy one of your first ones.
Thanks
Preston

 

[fusionrider]

Thanks!

I decided on 17-4 for the action and 4140 for the bolt. I have obtained most of the materials and the stainless has a date with the EDM Monday. I am thinking 40Rc for the action and 42Rc for the bolt to hopefully avoid any chance of galling. The barrel tenon and corresponding action dimensions may be again lengthened for more barrel support. But the action should still be noticeably smaller than a rem or similar action. With the 1" 4140 round bar I have for the bolt I could integrate the bolt extracting cam directly into the bolt body and forget the brazing or silver soldering of the rem style bolt handle but leaving me with a stub for maybe a different type of threaded in or bolt-on-handle,good,bad,OK idea??). As for the cocking mechanism I am going to buy a rem style and turn the shroud to fit the raceways and turn the firing pin to the proper profile, why spend the extra time just basically making the same thing.

One thing still has me concerned though.. the extractor. I have decided for strength reasons that it will be rem700 style but what is the best way to cut the recess for it? the sako is straight forward but the Remington looks like it could be problematic if the geometry isn't just right. What is the best way to install one? could I grind a cutter to the right width and indicate the bolt off a set amount and cut it in to "fit" or is this an operation best suited for the mill and a special slotting cutter?


Thanks guys for all the interest and input!
Sawyer

 

[ICANHITHIMMAN]

Wow I think Its great you are making an action. Why dont you put a M1913 rail along the entire length of the reciver? I just dont get why that is not done more.

What I would like to see is a LA modeled after the controled round feed win M70 with a intigral full length M1913 rail. Now that would be cool and NEW not some other clone.

Like the other guys said though the tolerences have to be tight. I spent big bucks on a mcmillian rifle only to be told by my smith when it was time to rebarrel that it was not true and he could not make tooling to do it. Man I was pissed with mcmillian

 

[CPorter]

I had looked at doing the plans for an action too. Which program are you using? Solidworks, ProE or AutoCad Inventor?

Look into using Spiralock threads for the action. It's mentioned by Harold Vaughn in his book. Spiralock also has tools available for cutting the threads.

http://machinedesign.com/Content/Site305/Articles/01_08_2004/fjrg1bjpg_00000037634.jpg

The threads spread the force out past the first three threads like the conventional 60 deg threads.

I've wondered why bolt lugs aren't TiN, TiCN or TiAlN coated to prevent galling and smooth up the feel. Maybe it would be a better idea to coat the ramps on the action to keep them from wearing since the bolt is easier to replace.

 

[fusionrider]

ICAN,
The reason for the interrupted rail is size. The action is quite small and a full length rail might crowd the feed port and limit access for my fingers as I am not planning on having an ejector quite yet.

CPorter,
I have seen the spiralock threads and researched it for a while but they seem prone to galling and I believe they are quite temperamental If the cut isn't perfect. As for the TiN coating I have seen some people who have done it but I cant remember the sorce...It is a neat idea.

The program is called "Alibre Design" It is a free trial version that I am trying out. I learned on AutoDesk-Inventor but thought Id try something new. The program has given me no problems and Is pretty straight forward, If you have used Inventor or autoCAD.

Thanks,
Sawyer

 

[prestonpritchett]

The main thing to get rid of the gualding problem is to have dissimilar metals. I talked to a metallurgist about this and the easiest way is to change the molecular structure. By nitriding this will do it and as long as it is done at a lower temp than the draw cycle when you heatreat you will not see any warpage in your part. We have some forgings coming in on Dec 8th. If you want one if you will pay for the forging and the shipping I will send you one. I don't remember off the top of my head the cost of the forging I think it is less than $20 and this way you can have your bolt all in one PC. It will increase your machine time and work your brain a little more but the end result is a bolt that you can't break the handle off of. Nitriding is expensive but when you get it done holler and we will throw it in with ours and you can pay your % of the bill. We do 100 at a time and your bill will be 1% of the total cost. This will get rid the chance of gualding. We have hard chromed and Tilan coated the bolts and the end result was we went with the nitriding because of temp of the vender's doing the work on the nitriding and the nitriding is going to be still going when your grandson is shooting your rifle and we are pushing up daisies.
On your extractor, your right as in it is a lot harder than the sako but the end result is a lot stronger and safer product. We took a bolt to the local vo-tec and put it on a cmm machine to get the inside profile. Take you a wood ruff key cutter and grind it to allow you to do your profile. This is what we did,
When you do your shroud be careful to not cut to far in on the bottom flats. These flats is what bottoms out and starts your sear engagement moving to the rear. If not done right the sear engagement will hit on the side of the trigger housing causing premature wear and a safety hazard.
They also make a spiral lock incert for your threading tool on your barrel. This can also be achieved by having a slight amount of taper to the threads on the inside of your action.

Like you guys we are constantly learning and any advice is appreciated to make our product better.

 

[butchlambert]

Preston, I remember when that happened to Red. It was about the time that he furnished me with a 700 parts rifle in order that Sam Lair could make me a 22x284. Sam Lair is another story. I bought a pickup load of stock blanks from Bonnie. I also bought all of his brass, bullets, reloading dies, loaded ammo, powder, and other things that was more than a pickup load. This was after Red passed away. He was a very kind and generous person. If you knew Red, you probably knew John Bunch. After John and Red passed away, I ended up with a lot of Benchmaster receivers, bolts, and fixtures that Charlie Williams used to build the actions.
Butch

 

[prestonpritchett]

Butch
I was just getting started as a machinist in the local factory. Having liked to shoot since I was a kid I wanted to learn how to true up a Rem 700 so I would go down and ask him some questions and then come home and got to thinking about well how do you do that. So I would go back down and ask some more. I am still learning. I did not get to meet John but got to know a guy named Rex Renoue he can't shoot very well but he sure can fish. If you know him be sure I told you that and he will tell you a story.,just funning on the shooting also a hall of famer)
Did you know Red shot down a jap zero that was straifing them. when the plan crashed in front of him the prop came off and whacked him on the head exposing some of his thinking parts. They called for a medic and the medic came and said this man is gone. They pulled a pistol and told the medic that he was going to work on him untill it was over. Its my understanding in a matter of weeks he was on morphine and back with his unit.
Red also told me when he got out he went to Springfield armory and ask them about the 1903s that had the intergal scope mounts The guy in Springfield said we didn't make any. He said I know good and well you did because we had 3 in there unit. If anyone out there knows anything about this I would be interested in knowing. If they had one for sale I would give a dollar two ninety eight for one.
Any of you guys get to central Okla please stop in and see us.
Thanks
Preston