Building an Action

L

Leeroy

Machinest / Gunsmith
G'day all.

I have gone as far as i can with my other projects for the moment and i'm looking at having a crack at building an action from the ground up.
Has anyone here actualy built there own action?
Probably sounds crazy to most but i am seriously considering this.
Second hand Rem actions are getting very hard to find for a reasionable price here in Australia. And the cost of importing a custom action quickly gets out of hand when you consider the Aussie Dollar, 30% import duty, customs stamp dutys etc, then another 10% for the dealers cut. A $1000 USD action comes in at about $1650 AUD. Not to mention all the paperwork to do this!!I'm sure i can build an action for less than this.
Looking at a remington 700 action, the machining looks pretty straight forward. One thing that did have me wondering is how the internal locking lug
ramp/helix are cut?
Would i be better off going for a rebated 3 Lug design, negating the need to cut lug racways in the receiver? Or just stick to the 2 lug design and EDM the raceways?
I'm a machinist by trade and have access to a good manual lathe, CNC 4 axis mill, slotting/broaching machine. I also have a mate who works in the tool and die industry and has access to CNC EDM/wire cutter.
Realy after some general info, hints and tips/ traps and pittfalls.
Looking at using 4140 or 4340 for the receiver as i like the look of Blued steel over stainless. Can anyone recomend a material for the bolt?
Also some info on correct heat treatment? I read somewhere that the receiver should be heat treated to 38 Rc?? Then finish machined..

Cheers
Leeroy
 
Action action.

I am not going to be of much use to you Leeroy, but I am real interested in where this thread will go.
How would you do the rego thing? Like old fire arms with no number,they allocate one and you stamp it in?
The omark 44 is a simple machine, bolt and round action, but those lock receses in the barrel would give you the same problem as the rem 700.
Could maddco shine some light on this for you?
This would be a good opportunity to put all of the best bits of many actions together, and mount a real good trigger.
Action, little thing, few moving parts, big job, needs lots of time.
That cnc edm wire cutter should get you there.
Good luck and I wish you succes in this project
 
Actions

Do a search I think there are several threads with some of the basics. Good luck and have fun with it. Also there are threads dealing with material hardnesses also.
 
Search for threads concerning making actions, there's plenty of them with all your questions answered already.

It sounds like you have a pretty good start on things. Whatevery you do, don't just copy someone's action (lame). All you end up with is all the shortcomings they have, but get to do the work yourself.

Don't re-invent the wheel. Let those things that can't be improved upon alone. Re-Invent all the other stuff that needs it. If it isn't ideal to you, change it. Try to leave room for re-work so you can change it again if need be.

As for materials, pretty much, everything is a comprimise. Look into availabliity first, then choose a product. Doing it the other way around will probably have you looking for something you can only buy if you take 5 rail cars full of it.

Last but not least, heat treat a piece of the steel you buy and make certain it treats and works out before you start making chips. If you take a finished action out of the oven and it's soft, you're gonna be upset.
 
Leeroy-did you busted your Sako?

With the selection of material, try Thyssen 6580 (a variation of 4340) but tougher and better weare and it's supplied in prehardenned condition 39-43HRC. All you have to do is to machine it.

I always use 6580 and it's as good as it gets. I bought mine lot about 8-10 years ago and I've tried to buy more not long ago and I was told, that the 6580 is no longer available. Pity, but try anyway.

If that fails try Bohler/ASSAB for EN26 or V155 both do come in prehardenned condition up to about 38HRC. Bohler V155 is equivalent to a common 4340.

If you'r going to use heat-treaters and go for a different hardness keep in mind that it may give you a grief.

Also keep in mind that most of the Bohler/ASSAB reps there are imbeciles, so do you home work.

Once I was after a tough "mechanical" steel and the imbecile rep was offering me a D2 tool steel. The things got even better when a second imbecile rep stepped in and started to deffend the claims what the first imbecile gave me.

Shoot better
Peter
 
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Leeroy

Another thing you should be aware of is the particular grade of what ever steel you choose.
I have always liked Jorgenson Steels definitions of the various grades within a particular alloy. For instance, you can start off with plain old commercial heat treat 4140, then go up a grade to Aircraft quality, then go to Premium Aircraft Quality.
They offer these grades in most of the popular construction alloys.
The difference in the grades is in the manufacturing process. The premium Air Craft Quality Grades are manufactured by the VAR proccess with the highest attention paid to maximum and minimum on the alloying elements. What this does is produce a steel that is extremely "clean" at the molecular level.
This is important for maximum ductility. You can take a standard commercial grade of 4340, and heat treat it to the exact same tensil and yeild levels as the premium aircraft grade. But, what it will lack is the ductility, or, as we like to say, impact strength. The reason for this is simple. Any imperfections in the steel, (oxidants, particulates, etc), will actually be between the molecules of alloy, sort of microscopic flaws.
The same can be said for the free machining steels. It is a characteristic of just about every free machining element that is introduced into steel, whether it be sulphur, or lead, that it will hurt the ductility. As an example, 4140L, which has lead added in the pour to enhance machinability, will pass the same tensil and yeild test as standard 4140. But, the ductility, whether measured by Charpy or IZOD Impact, will be as much as 1/2 that obtained by the non free machining grade.
As for me, I would use Premium Aircraft Quality 4140 for the body, then Premium Aircraft Quality 4340 for the bolt. Have it normalized and annealed, then rough out everything to within 1/16 inch. Then, have the final hardenning and temper drawn, preferrably a double draw on the temper.
As for the hardness, you want to achieve maximum tensil and yeild just before the ductility starts to fall off. You also want it hard enogh so as to introduce a anti-gall quality. With 4140, this is at about 35 HRC, 4340, probably about 38 HRC.
Consult your Heat Treater. This is what they do for a living. I would no more trust a "commercial" grade heat treat as I would a piece of steel with no markings on the end, or paper work to accompany it.
As Peter noted, there are many grades of steel that have quite similiar properties to the grades that are commonly used. Many of these have added alloying elements to enhance a certain property of the steel. Some, however, are little more than a "brand name" that a particular manufacturer will tag on to help distinquish his product.........jackie
 
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Ok gentleman some good info there.. Thankyou.

I'll have to make a few calls to the suppliers and see what grades of 4140 and 4340 i can get. For most of the jobs i do at work we use just a generic grade 4140 and 4340. ie the cheapest! :D

No Peter i didn't blow up my Sako.:D It's basicly finished and i'm now waiting for the new Barrel and a reamer to turn up. While i'm pretty happy with the end result of the sako, it aint no custom/BR action..

If i do go ahead with the build i'll probably make 2 actions, a Remo compatable rippoff and a larger heaver BR action.
Would still like some advice as to weather to go for a 3 lug or 2 lug design. I'm leaning towards a 3 lug design as there's no lug raceways to cut/EDM, which will save lots of time and one less favour i owe my mate.:)
However if i go for a 2 lug design i can use a Kiff Rem replacment bolt, and save a lot of time here also.
Will definatly go for a sako type extractor and i like the Sako manual ejector also.
Will probably go for a detatchable mag of some type, any sudgestions?

Cheers
Leeroy
 
Fat bolt-two lugs, perhaps

Leeroy said:
Ok gentleman some good info there.. Thankyou.

.
Would still like some advice as to weather to go for a 3 lug or 2 lug design. I'm leaning towards a 3 lug design as there's no lug raceways to cut/EDM, which will save lots of time and one less favour i owe my mate.:)
However if i go for a 2 lug design i can ?

Cheers
Leeroy
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,,,,,,,,,,,,,,,,,,,,,,,

Leeroy

You can also have a "fat bolt" and two lugs, instead of three. No raceways and no favours to your mate.

You may probably most likely have to have a "feeding ramp" a slanted pre drilled surface to feed the round. (ala Wichita).

Thyssen 6580 for both bolt/receiver as supplied 39-43HRC, if other,,,,,

Bohler V155 (4340) for both, the bolt and the receiver, or V155 (4340) for the receiver and EN26 for the bolt and/or the receiver. Both as supplied 38HRC. If lucky, the smaller size of the bolt material can get you an extra 1-2HRC, but don't deppend on it.

With my personal experience that I've had with the heat-treaters here I have an advice for you:

Do anything and everything to avoid them. The problem with "most" of them is, that if you have a small piece of steel and you want something special, they'll put your small thing into the furnace with something else and your small thing may have to wait before it can be tempered for too long until cold also somewhere with something else and finally be tempered for uncontrolled period of time or a temperature. Far too risky for my comfort.

If you have a furnace or two and you can take control of everything go for it by all means. Otherwise???

I didn't think that you would blow up the Sako, but rather ran into a another obstackle.

Shoot well
Peter
 
Leeroy, if you do a search on this forum you will see mention of a couple of actions i built some years back. In 2001 i built the action i called the Remroid, just an expanded Rem 700 with a few little extras worth while adding. Anyway, the steel used was 709M. Essentially this is a free machining 4340 with the addition of calcium to enable it to machine easily. In its mill form it is supplied at around 30 Rockwell C. Both the bolt and reciever were made of the same 709M and then rather than hardened and final machined, i opted for a chemical nitride process that had virtually zero distortion. Nitriding has often gotten a bad reputation for distortion with things like crankshafts, but this usually says more about the material used than the process itself. I had one thou bolt clearance to the reciever bore and when the items were returned i panicked because the two would no longer fit. It turned out that the process had left a salt like layer preventing the fitment and once oiled and wiped clean the two went together perfectly.
The side benefit was that the particular nitride process used left a satin blue gray finish that has lasted with little maintenance to this day. The internal hardness is about 40 RC and the external hardness is beyond 60 RC for a layer of about 0.0015". The mating lugs have never shown anything more than a polishing where there is contact. The action has fired literally thousands of high pressure 300 WM cartridges with virtually no evidence of wear and tear. Peter Van Muer has used a TiN coating process as used in roller rockers and valve stems for engines on the bolt and reciever lugs of one of his own actions with similar results to the nitriding i have used. But i cannot comment with experience on the distortion of such a process but would think it would be similar or possibly better than the nitiding. Hell of a lot more expensive though. The nitiding cost less than a good bluing job from your local gunsmith.
Be wary though, all steels and some metal treaters are not equal and some nitriding i have seen on gear sets and shafts made of tool steels and 4140 and 4340 and even some of the ENs of dubious origin have been unusable beyond scrap value.
Take a piece of PG in 709M of about 3/4" diameter and about the length of the bolt or longer, true and centre spot the ends. Then send it to the treater and when it returns check for straightness and distortion. Good test for both the treater and the material used.

Tony Z.
 
If I may ask a related question, how do you know the steel is good?

Does this mean this 4140 is tough enough for an action? Its 3" round, is there a heat treat issue with that diameter VS 1 1/2"?

Oh, and no, I'm not building an action.

Cheers,
Rob
 

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Leeroy-something else

I've forgot to mention here is, that there is a company about 70km south from you, that makes after market axels for Land Rowers 4WD.

The material they use is a Bohler V 136 in other names known as a Hy-tuf or 6418. They do order about a ton each time directly from Bohler as a special order, because this steel isn't available in their normal steel range.

Hy-tuf is a special purpose steel with high 1.5% of silica (silicon?). Due to this, it can be tempered at low temperatures and keep very high ductility and toughness.

Used for landing gear, rock drill bodies, earth moving machinery, racing cars gear, shafts etc. Specially designed to work at 150-165 MPa. range with very high ductility and impact toughness.

I've spoke to them about a year ago about to purchase some and they did say that it may be possible. They didn't say definitely yes, or definitely no. They do send the axels to the heat-treaters that apparently do a lot of work with the Hy-tuf, which is always a good sign.

If you would be lucky, I would sugges to pre-bore the material including the "loading ramp" and organize with this mob to have your "hollow bar(s)" as a part of their shipment. That way you would be assured, that your small bits do get the proper heat-treatment attention. They have their axels done at 155MPa range, so it tells you something.

The Impact value for the Hy-tuf at this range 48HRC is around 48fp (65J) and 4340 at 38HRC has about 28fp (38J).

This material is rare and you won't find much of the info. anywhere. Even the Bohler Website has just a brief line, rather than just to have a empty page. Their info is also incorrect.

The Hy-tuf is supplied in annealed condition about 24HRC, so whatever you do you'll have to heat-treat. If you would go "with them" to have your pre-drilled bars done the same way, the material would be some 46-48HRC.

I would turn it between centres and than finish the entire interior on a single set up. The material will be hard on tools and quiet difficult to machine but it can be done and you'r not going to have a production line.

For your purpose the material has the most tougness if tempered between 235-250*C anything over that temperature and the tougness starts to fall off. The good news is that even than it's still tougher than 4340.

(I have a Impact chart faxed directly from Bohler WA branch that's original chart from a Comsteel and on the same page they list the Impact Value at 65J and five lines later in an another table at 45J. So if these Impact figures are incorrect I do appologize for myself, but not for those Imbeciles who provided me with them).

Hardness 47-48HRC

150-165Kg/sq mm - UTS

133-138Kg/sq mm - YTS

Impact (65J) - 48fp.

PH. number 07-55 30 39 34

I don't remember what sizes they use and what it would cost. Try them and find out.

TonyZ had some very good advice on the material issue for you also. Keep that advice in mind too. Do not! get caught by the heat-treating practices. This is why I do anything and everything to avoid them.

Leeroy if I was you, I'ld keep the words (receiver, rifle, gun etc.) out, as this day and age as soon as you mention that you like guns, you'r immediately being seen as a " blood thirsty, revenge seeking terrorist".

You now have some variations in advice so now it's up to you to decide what to do and which way to go.

Shoot well
Peter
 
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PEI Rob said:
If I may ask a related question, how do you know the steel is good?

Does this mean this 4140 is tough enough for an action? Its 3" round, is there a heat treat issue with that diameter VS 1 1/2"?
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While my method of testing isn't particularly scientific, it suits me. What I do is heat treat the steel with an exact target hardness, both as quenched, and after draw. I test the steel in both of these conditions. If it's not exactly where I expect it should be, I assume something is wrong. Even two points of rockwell would make me concerned, but in my experience, the steel is generally dead nuts on the money when testing after watching temps closely. If these hardness numbers match up, I assume the rest of the properties are on the money also.

On the occasions when I've seen something wrong, it's drastically wrong. I never needed to even check the hardness. I could tell just picking the part up that the hardness was wrong.

Yes, there is almost always an additional time in the oven when dealing with thick parts. Commonly you will see an additional 20 minutes per inch of recommended soak time. All your data sheets will make note of this.

As for the certs, they all look the same. Basically they just mean the steel company is confident of the chemistry which should make folks like me sleep well.

Tons of actions have been made using 4140. It's very cheap, readily available and easy to work with. For bolts it's not an ideal choice but certainly has been used by enough manufacturers over the years.

Back in the old days, if someone built an action, odds were, it would see 100 rounds in it's life and never see service again. Nowadays, folks like you talk to here on brc will build one, and really put it through it's paces. Literally thousands of rounds per year in some cases. In those instances, choosing a really overkill material is a good choice because if these actions decide not to break, they sure will have given up a good chance to.
 
Thanks

All very good advice... Thank you fellas..

We occasionaly have jobs sent out for heat treatment at work and Peter i guess it's a global problem as they have an appaling record for crap work.
We were pretty quiet last year so in the down time i made my self a nice set of Vee blocks from some old offcut 4140. Milled them down to shape and sent them off to be through hardened then i would finish grind them.
They came back from the heat treaters nitrided! :mad:
Sent them back to be through hardned and they came back hardened but one had some surface cracks and they had done the hardness testing right on the top of the Vee which they then attepted to grind/polish out. I had to grind them back almost 4 thow to get rid of the test marks!!
As we say in Australia "NOT HAPPY JAN":mad:

However they arn't the only heat treaters in Brisbane and so i'll ring arround..
You are right also about not saying anything about it being a rifle action..
I'll just say that they are "safety critical items" the failure of which could result in severe injury or death of the customer. I'll also ask for a test certificate of the hardness with the finished job..

As for material choice it will realy come down to what i can get my hands on.
I will definatly try and get the "Pre hardned" stock and then just machine it.. No heat treatment to go wrong, no distortion and at only 38 HRC pretty easy on the tooling..
I also like the idea of Nitriding. The Satin silver nitriding looks great and is pretty wear and corosion resistent also..

Thank you all for the replys and if anyone else has more to add, please do i'm all ears..:D

Cheers
Leeroy
 
Update

Ok so after looking at a few steel suppliers webistes i can get 4140, 4340,
EN26 in hardned and tempered condition 31-38 HRC from interlloy.

I can also get 709m and V-136 Hi-Tuf from Bohler, but not sure of the supplied heat treatment, supplied as annealed i think.

So as work have an account with Interlloy i'll probably go for the EN26 in hardned and tempered state, for the receiver and bolt and just machine it. No heat treatment required. Then mabe look at the chemical nitriding..
BTW Tony Z who did your chemical nitriding?

What do you think Peter? According to interlloy website En26 in treated condition has a UTS of 1150 MPA. I will definatly get the supplied steel hardness tested to confirm it's strength before machining.

Cheers
Leeroy
 
Not trying to tell you what to do, but, my brother tried a receiver in 4140 PreHard 2" diameter. It was a total POS. He scrapped it. Had it been me, it would have gotten less of a chance than it did. Be certain to check the hardness if you do decide on prehard cause if it's on the soft end of the numbers you just said, (32-38) it's gonna suck.
 
4Mesh said:
Not trying to tell you what to do, but, my brother tried a receiver in 4140 PreHard 2" diameter. It was a total POS. He scrapped it. Had it been me, it would have gotten less of a chance than it did. Be certain to check the hardness if you do decide on prehard cause if it's on the soft end of the numbers you just said, (32-38) it's gonna suck.
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4Mesh,

Can you elaborate on the failings of the 4140 Prehard? Did the receiver suffer setback? Did it gall the lugs? Did he consider having it re-heat treated? Just curious about the negatives he encountered.

Jay, Idaho
 
Steels

Leeroy, If you can get 709m ,i would not go anywhere else . . PS..heat treat done at Wilkersons in Atherton ..pic supplied
Leeroy said:
Ok so after looking at a few steel suppliers webistes i can get 4140, 4340,
EN26 in hardned and tempered condition 31-38 HRC from interlloy.

I can also get 709m and V-136 Hi-Tuf from Bohler, but not sure of the supplied heat treatment, supplied as annealed i think.

So as work have an account with Interlloy i'll probably go for the EN26 in hardned and tempered state, for the receiver and bolt and just machine it. No heat treatment required. Then mabe look at the chemical nitriding..
BTW Tony Z who did your chemical nitriding?

What do you think Peter? According to interlloy website En26 in treated condition has a UTS of 1150 MPA. I will definatly get the supplied steel hardness tested to confirm it's strength before machining.

Cheers
Leeroy
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416 stainless.

What do you think about Remingtons use of 416 in their stainless actions?

Has anyone had galling problems between these actions and 416 stainless barrels?.....................Don
 
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