View Full Version : Building an Action - Steel?

12-30-2007, 12:10 AM
I have a few questions about steel. I am planning to build a couple actions for myself and have read a bunch of old threads about the subject.

First 416 or 416R? 416 is easily aquired and 416R is not. I notice that the 2 are interchanged in the most posts although they are different. 416R is used for barrels. Would 416 be adequate for an action 1.400 diameter?

17-4PH type 630 is also available. Would it be acceptable to machine this before hardening or does it need to be hardened first.

I noticed Bat said they harden first, but I saw a post where Stiller made it sound like he hardened after.

One last question for now. If the bar is hardened first will the Wire EDM cutting of bolt raceway affect the hardening?

Thanks Gary

george ulrich
12-30-2007, 03:36 PM
i have made actions of the materials you have mentioned so i'll try to answer. 416 will work fine 416r which is resulfurized will work fine cuts a little easier 17-4 yes you can machine first then heat treat it's a precipatating hardening so 900 degrees per inch cross section allow air cool. wire won't affect heat treatment i have done both ways with heat treat first then finish and heat treat after. 17-4 did not move and yes i did check before and after. good luck any ? email me george

jackie schmidt
12-30-2007, 09:26 PM
The main difference in 416 and 416R, besides the re-suphurization as mentioned by George, is 416R is manufactured under the strictest procedures, insuring a steel that is very "clean", and very exact in it's chemical composition. This allows the steel to adhere to the advertised physical properties while offerring excellent machinability. 416R, developed by Crucible in conjunction with some of the top barrel manufacturers, offers a steel that has excellent machining qualities while maintaining adequate strength and corrosion resistance for the manufacture of precision Rifle Barrels.
The same steel can be bought under the heading: "Steel used for the manufactuer of pump shafts to be used in Nuclear Power Plants".
In the end, though, 416 does have better impact qualities than 416R, but neither one is that good when compared to the Martensitic Stainless Steels, (410, 420), the age hardening, (precipitating hardenning), grades such as 17-4 and 15-5 PH, and standard alloy steels such as 4140 and 4340.
If you look at the physical qualities that these precipitating hardenning Steels, (17-4), offer, you would figure that they would be ideal for the manufacture of Actions. They just about are. You can go through one simple agging proccess, (where the steel is brought to a specific temperature for a specific time, and then air cooled), that produces the desired properties. For instance, H1150 17-4 means the steel was heated for exactly 4 hours at 1150 degrees, and then air cooled. The 900 grade as mentioned by George is usually the highest strength level reached, but machinability and ductility do drop conciderably.
The 1050 grade gives a good combination of ductility, hardness, tensil, and yeild strength.
The drawbacks to the precipitating hardenning steels as opposed to regular alloy steels is initial material cost, and the fact that for high production work, they are pretty hard on tooling. However, some of the improvements in cutting tools, and machinery, in the past decades has negated some of this.
416 will make a perfectly good action, Remington has been using it (as the rumor says), for their Stainless Actions for years. I can't amagine anything being more abusive than a Ultra Mag with 100+ grns of powder packed in.
Of course, there is still the choice of 4140, or 4340. The advantages of these are initial lower material cost, ease in machining, and good physical properties. They do have to be heat treated, (final temper draw), before final machining, as they will warp and creep. And of course, they will rust.
Since 416R does give up some ductility, it would not be my first choice. It's superior machinability makes a lot of difference when trying to establish a small diameter precision hole in a 29 inch long barrel blank, but there are no such obsticles in the machining of an action.
It is no secret why custom action makers prefer 17-4 or similiar precipitating hardenning stainless steels for actions. They can purchase annealed and normalized bar stock that is just about to size, do all of the criticle machine work, then age harden it for the best combination of strength and ductility with little fear of creep or distortion. (some do heat treat before final machining) On top of that, it doesn't rust.
You did not say what you would use for the bolt. I believe that S-7 tool steel is the best choice, but 4140, and 4340, are not far behind. I say S-7 because it has unique properties that allow a high RC hardness, (for anti- galling qualities), high tensil and yeild strengths, while still maintaining a very high degree of ductility.
The drawback to S-7 is that the heat treat proccess MUST be adhered to in a strengent manner. There is very little tolerance in the temperature, or the time of heat.
A final note, what ever steel you choose, be sure to get as premium of a grade as is available. For instance, in 4140, and 4340, I would settle forno less than the "premium aircraft quality". These grades are manufactured with a typical VAR proccess that insures the cleanliness of the steel at the molecular level. This is VERY important when considering the important ductility factors.........jackie

12-30-2007, 11:14 PM
Thanks George and Jackie.

Based on what you have said I think I will give the 17-4 a try. My only reason for considering the 416 was the posts that I read about 17-4 galling easily, however I have shot a Nesika made from it for a long time and never had problems.

When you speak of 17-4 being harder to machine are you just saying that you have to slow the speed and feed some and take your time, or is it like some stainless that work hardens to the point that you can hardly drill a hole in it?

As for the bolt I have not decided if I will try to make the bolt or just go with one from Dave Kiff.

Again thanks for the replies and I am sure I will have some more questions as I get further into the project.

Gary Breiling

12-31-2007, 01:28 AM
I would like to add to the great reply that Jackie gave. 17-4 is typically purchased in Condition A, which machines similar to 304 CRES. After machining the material is aged to increase strength. As 17-4 is aged, it will shrink slightly due to the copper precipitation. The shrinkage is in all directions and will be approximately .1% for Condition H1100. Since the ageing temperature is so low, there will be VERY little distortion. I have had good luck buying the material in Condition H1100 and machining with carbide tools, getting a good finish. As Jackie said, make the bolt of 4140, 4340 or S-7.
I have never made an action, so take my input with that in mind.

Paul Thompson

12-31-2007, 05:17 PM
For an action 17-4 SXR stainless from Crucible, for a bolt and/or an action Flexor from Pensylvania Steels or HYtuf from elsewhere would be my personal choice of material if I would go to the bother of making an action. also 4340 modified with higher content of silica would be by far superior to any of these steels recomended by an expert Jackie. Since you do not mention to run a production line bore through fraction smaller(deep hole drilling) harden as recomended by steel manufacturers chart (for desirable hardness/toughness) and then do all the machining after on a single set up. To go to all the bother to make your self one off action and use something like 416,4140 and even 4340 is criminal.

happy New year


george ulrich
12-31-2007, 06:57 PM
peter , i have used 4340 aircraft quality i can't recall i think it was 4340arv also have used 4140 prehard it all works well except you have to blue 4000 series where 400 and 17-4 are better against rust. and you don't have to blue didn't say that they don't rust but there is less problems with it. george

jackie schmidt
12-31-2007, 11:26 PM
I am not sure Flexor will have the same impact resistance as S-7 at a comparable hardness, say in the 48RC range, where a better anti-gall quality would exist.
Carpenter Custom 465 might be better than any other precipitating Hardenning Stainless Steels. Depends on whose advertisment you are reading.
I didn't mean to get too specific on the wide variety of different grades and alloys that can be used for specific applications. I was just trying to give a simple outlay as to the differences, in general, concerning some of the various grades that are used in the manufacturing of actions and bolts..........jackie

01-01-2008, 12:40 PM
I agree with you where steel manufactures are crapping about their fantastic products are concern. S7-S5 and similar shock resisting tool steels are obviously offering some desirable shock resisting properties.
The sad part of all this is that there is hardly any manufacterer in the whole World who would put the same emphasis on Impact value. There is not an even impact unity in place. The several versions that are commonly used have totally different values. Most steel manufacturers don't even bother stating impact value.
Thyssens 2767 or Bohler 600 (the same steel) is regarded as the toughest of the tool steels. This steel is also used in high performance racing car gearboxes at 46-50HRC and that may speak for itself.
17-4 as an action main body and 4340 nitrided bolt body with interchangeble bolt head made of some fancier material, ala Gilkes bolt and Geske long threaded locking ring.
Both locking parts can be replaced damn easier than the whole action if they don't work as desired. One can do much worse than that.

Good luck

01-01-2008, 01:29 PM
I don't know how ThyssenKrupp's 2767 or Bohler 600 steels compare to Carpenter's "solar" S-2 steel, but Solar used to be the toughest tool steel known.


01-01-2008, 06:41 PM
as Jackie said it depends on what advertising do you read. I don't want to defend my claim or dispute yours or Jackies. Looking through Carpenters website and they have some very, very hot stuff.
Should one ever select any of the ultra strength high impact hightec steels regardless of what manufacturer and it will make the physical properties of the commonly used action steels look silly, even thought they are perfectly adequit.

best of luck