Need technical info on making a bolt

B

BenKeith

Guest
I want to make a Remington style bolt to go in a mauser style action. Other than the lugs being a little wider and it being .005" smaller, the 700SA bolt is almost a drop in fit. Bolt handle is in almost the identical spot and space between the lugs, firing pin cocking/release lug is in almost the identical spot and the receivers are very close to the same, other than the stipper clip slot in the top.

I have an excellent machinest that's going to do the work and I will be getting a set of head space guages.

What I need to know is what grade steel I need to get, and a good source for getting it. Would it be better to use chrome moly or stainless.

Will it need to be heat treated after making it and if so, to what hardness?

If heat treated, does that normally distort the metal to where we should leave a a few thousandths for final machining or can we machine to fit before heat treating?

How much clearance would you leave between the outer face rim of the bolt and the barrel for powder residue and gung to keep the bolt from being hard to close after being shot a few times?
 
4140 in a prehardened state will machine very nicely if good tooling is used.

Around 38 Rockwell C will work just fine. Really wanna make it slick? Consider surface nitriding. Bake in a nitrogen/ammonia salt and it'll get the surface hardness way up while keeping the meat underneath soft enough to tolerate the impact/shock loading.

I personally would avoid SS. There are some grades that will get hard enough (15-5ph and 17-4ph in solution annealed H1150 condition could work) but all stainless's are prone to bubble gumming (galling). It isn't very lubrice.

A commercial heat treating facility that understands guns will be able to mitigate the effects of thermal distortion. Hanging the part vertically, centralizing it in the furnace, bringing it up to critical temp in a controlled state, and ensuring its all done in an inert atmosphere free of oxygen during the process are all part of making sure you have a functional part afterwards and not a hard banana.

Bolt to breech face clearance is often highly debated. On a single shot "bench queen" type rifle that operates in a relatively sterile environment I run them tighter. If it's a "working gun" then it should be opened up IMO.

Your Bolt's swept OD on the lugs is going to be limited by the width of the raceways. The important thing to consider here is obtaining the most surface contact area you can while still having functional operation. The surface area distributes the tensile load developed when the chamber starts building pressure and pushing on things. More is always associated with better in this case, but as stated, your limited by how much available room you have.

Speedy metals in WI is where I buy a good portion of my tool steels from. Ask for Marty. Super cool, super sharp guy.

Good luck! Take pics!

Chad
 
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Thanks
That's exactly the info we needed. The guy doing the work is an execellent die maker and has all several CNC mills and lathes, and can do the hardening. He's just never make any rifle parts so we needed that info.

I've been sitting here for the past hour examining both bolts and there measurements are so close to each other it's scary. Add .105" length to the bolt in front of the 700SA's lugs, cut the sides of the lugs .020" and it would drop right in and work, it's just .005" smaller in diameter. Everything else measures almost identical.

One more question. I notice on the 700 the bolt handle is machined and bonded to the bolt body. Would you do that again or machine all that into the bolt body with a square lug sticking out and weld a curved bolt handle to it.
 
Factory Remington bolt handles are silver soldered. One stubborn case extraction that forces a guy to resort to a soft mallet will likely send the bolt handle whirring across the firing line.

One piece is the way to go but it does slightly complicate the manufacturing process. TIG welding is another option.

I personally advocate the one piece.

If it were me I'd take a stab at making a "mock bolt" from a chunk of aluminum or maybe even a stable plastic. Just to work the kinks out. Things like this rarely go 100% the first time. If you use plastic, avoid Delrin as it'll move all over hell once you start whittling on it.

Good luck.
 
Ben

Believe it or not, there is an advantage to soldering on a bolt handle. You can jig it up and get the timing perfect. If you miss, you can take off, and start over. With a fully machined bolt, well, you know what can happen. There are thousands, and thousands, of Rifles out there with soldered on bolt handles.

You are aware that a Remington Bolt Body is also two pieces. The nose piece that contains the luggs is seperate from the back part.

As for the Remington style couterbored barrel and bolt nose, it serves one purpose. That is the vaunted "Three Rings Of Steel" that, in case of some catastophic event, will allow the bolt nose to expand into that counterbore, keeping any heavy shrapnel contained. In it's unmodified state, it does work. The clearances are usually in the .008-.010 range, both in the radial and linear plane.

Even though there is a steel for just about every purpose, it is still hard to beat good ole 4140. But, not all 4140 is created equal. I would not use some sort of "pre-heat treated" stock because you have no idea what they started with. What I am talking about is the quality of the steel, mainly arrived at during the manufactureing proccess. In a bolt, I would want to start with no grade lower than standard AirCraft Quality. That insures that the steel was manufactured by some type of VAR proccess that dictates the cleanliness of the steel at the molecular level. This is very important when determing a very important factor, that being Ductility.

Were you going to use a Remington Extractor? ...........jackie
 
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Makig Bolts

I can do my own machine work and because time is money I have Dave Kiff at PT&G make my bolts. An I mean not just Remington or clone bolts.
You might check with him and see what he has available.

Nat Lambeth
 
Since we are cloning two different bolts, I'm looking at a more conventional extractor that will sit into a small slot machined into the side of the bolt with a spring under it. The barrel already has the relief cut for the mauser extractor so there will be no problems there. I've read a lot about people installed Sako extractor's in Remingtons and was going to see what that is. I can't use the remington extractor because it has the base of the bullet sitting too deep in the bolt face and that would not work without taking the barrel off and maching the back of it, and I don't think that's gonna happen.

Yes, I've noticed they did their's in several pieces actually. It looks like the lugs and face are one piece, the bolt body is another, the firing pin stop/guide in the bottom of the bolt is pressed in and held by the firing pin retainer pin and the handle is another. I'm taking him the two bolts today and see if he thinks he can do it. My main concern is a boring bar or reem that will do the inside cut. It's gotta be dead straight all the way in and that's going to be tough to do if we make this a one piece bolt, even if we make the stop/guide seperate and press it in like Remington does.

The reason I'm looking at going this route is the shorter 260 shells drop out of the mauser extractor before they get to the ejector and about half the time are left sitting on top of the next bullet, even though this action has the same Identical lenght bolt as the 700SA. I can stick a longer piece of brass like a 270 in and it will flip them several feet everytime. I've installed the feed shoe and spring from a 700SA and a block in the back of the magazine to make the magazine the proper length but that didn't help. The bolt also has a steel band around it that holds the extractor and nothing about the way the bolt slides is real smooth and don't like the feel, so I figured if I've got to keep on modifing to make it work, I'll just try another bolt.

The biggest benifit is his work is not costing me anything if he can do it.
 
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The extraction problems can

be fixed by fitting a new extractor. The .260 is formed from a more modern Post-War cartridge w/a differently shaped extractor groove than the 57mm case's groove, which is the same as the '06 and .270. :eek:;) HTH
 
Pressed in?

the rear "bolt shroud" on a rem 700 is threaded in (1/2-13) to the rear and the cocking piece is pinned to the firing pin. The inner bore of the bolt is close to the minor dia of the shroud threads, it might be a bit bigger than the standard tap drill for 1/2-13.

straightness of the bore is not critical just as long as it is smooth as to not hinder the firingpin travel at all. I have just drilled and reamed the bore with good results.

good luck, quite the project and dont be afraid of barrel removal they either go or they fight alot... the most recent mauser I did let go with very little fight after a wee bit of heat and a soak in 50/50 acetone - atf.
 
If I may suggest/offer an idea.

Most R/H bolts use a conventional R/H thread pitch for the bolt shroud. This means that when the bolt is out of battery the shroud is pulled up close to the bolt and it separates from the bolt when in battery.

This is completely backwards from what I think (stress think) should be going on.

1. A shroud also serves as a final defense against a chamber "sneezing" when a case ruptures. Gas checks do the bulk of the work but pressure will take alternate paths. (which is why I've always understood Mausers to have big/gawdy shrouds)

2. Spend any amount of time on this forum and the subject regarding bolt/shroud thread fit will surface. Guys use tape, hammers, and what ever else to tighten this tolerance up all in the name of accuracy. Moving the shroud away from the bolt seems completely azzbackwards to me as its only going to get worse this way.

So, my thoughts are to use a L/H thread for a R/H action and vice versa for a lefty.

Ideas:

Perhaps a taper that'll "just snug up" as you go into battery which would make for "zero wiggle" when the striker drops and things get busy.

Perhaps a recessed high durometer o ring in the face of the shroud so that it becomes an interference fit when things clam shut.

Since your on a blank sheet of paper why not right?

Have fun with your project.

Chad
 
I just paid McGowen almost $800 to make this barrel and install it, with a few xtra's. It's shooting very good groups right now and I've just started working loads, I don't think this barrel is coming back off anytime soon.

I just emailed Dave Kiff at PT&G to see what he has to say about doing it for me. If he doesn't make my jaw hit the floor, I may just let a professional do it. I've been checking, looking and measuring the past two hours and it's probably going to cost as much for the extra tooling pieces we will need as it will to have it made, unless we do it as the three piece bolt like remington. I'm not to sure I would want my granddaughter behind a three piece bolt that was the first one either one of us made. We will just have to see how Mr Kiff talks.

My friend knows his stuff when it comes to machining, he makes very high dollar injection molds but those don't go karboom in your face if things are not just right. If we can't do it as a one piece, I will have to give it some long and serious thought before we make a three piece.
 
Bolt Strength

All of the bolt strength is in the bolt head. There is no difference in strength between a multi-piece bolt, like Remington and Savage, and a one piece bolt, like Mauser and Springfield. You could make the bolt body out of aluminum or plastic and the bolt head out of steel, and it would probably still be as strong as an all steel bolt. Having seen many bolt failures, all were caused by cracking in the lugs.
 
Bolt Bodies..

Keith you are right. Many factory bolt bodies are tubing made on a mandrel.

I have Kiff make me new Savage Bolt bodies that are machined from 4140. Some round and some fluted. The factory bolts are cheap .696 tubing that has been chrome plated. I have the kiff bolts made .701 and they fit like a glove.

Kiff is adding new equipment just to make bolts and will be adding several additions to his line of products. He is always very accomodating to make what you need.

Nat Lambeth
 
Why not cut off the front of the Mauser bolt at the Extractor collar groove and then weld a new bolt head made to your specs with integral short section of bolt body to that?

If a cartridge is too short to work properly with a standard length Mauser action some have shortened the entire action, strength of a rewelded receiver is no big problem since the locking lugs are up front far from the portion of receiver welded after removing a section.
A smith once told me of his having done this, the bolt itself was cut, one end was counter bored the other turned down to fit the counterbore then slid together and silver brazed rather than welded. The join would be stronger than a soldered on handle for sure.

Whether there could be a problem of the rewelded receiver having a dead spot in harmonics I wouldn't know, and can't say whether or not it would have any effect on accuracy if it did.
 
There are a couple of reasons for going with a new bolt. It's not just the shell ejection problem, I'm pretty sure I could come up with a fix for that. The main thing is I've got a ton of money already spent on this rifle because it was my dads and I'm doing if for my granddaughter, who both loved each other very much. The current bolt is not very smooth, actually not smooth at all. Being an old military action, the bolt has a lot of free play when opening and closing and the ring holding the extractor drags. I just figure why not go ahead and make it a truely nice rifle by installing a pretty, smooth working bolt.

Now, I've got a couple of more questions which I may need to start another post because this one might be getting old.

I was wanting to install a Sako style extractor, but looking at how little relief is on the bolt face, that's problaby not possible. The barrel has an inlet cut for the mauser extractor, if we take the barrel off and cut the bolt inlet down to the relief cut and then let the bolt face fill in that area, just like remington does, it will have a deep inset for the bullet looking just like a stock remington. Then I can do the Sako extractor just like I would for any reminton. Will that be safe since there will be approx a 1/2" of barrel area where that extractor relief cut is not supporting the bolt, only the bolt face will be covering the shell. Doing this moves the area on the rear of the shell approx .110" forward so that much of the base of the shell will be sticking out of the chamber and into the bolt. It's still back in the heavy part of the bullet base and it will be covered by the bolt, it's just the bolt won't have that addional metal the remington barrel provides. Doing this will give me the room I need for the extractor, which will then be installed in the same location as if it was a remington.

Next question, If I take the barrel off, will it tightened back into the same location. I had some very special ingraving done on this barrel and I would not want it to get buried in the stock, I would like for it to stay in the same position it is right now.
 
If it is like every Mauser action I have seen the extractor cut you are seeing is not on the barrel. It is in the action. The Barrel screws up tight against a ring in the action that has the bolt cut out in it. The bolt actually sits flush against the back of the barrel when it is in the battery position. All of them that I have seen have the extractor flush with the end of the bolt nose on the top and the bolt nose is cut away on the bottom so it can rotate around the bolt head when opening and closing.

It could be modified to use a Savage bolt head without changing the barrel or action.

I haven't tried this but is see no reason that a Savage bolt head couldn't be modified and attached to another bolt body by silver soldering instead of doing the whole floating head thing. It could be soldered with a medium temp silver solder with out danger of changing the heat treat.

Thanks Gary
 
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Why not have the machinist spend the time making money and then give you the money to buy a decent action ?
 
BenKeith said:
There are a couple of reasons for going with a new bolt. It's not just the shell ejection problem, I'm pretty sure I could come up with a fix for that. The main thing is I've got a ton of money already spent on this rifle because it was my dads and I'm doing if for my granddaughter, who both loved each other very much. The current bolt is not very smooth, actually not smooth at all. Being an old military action, the bolt has a lot of free play when opening and closing and the ring holding the extractor drags. I just figure why not go ahead and make it a truely nice rifle by installing a pretty, smooth working bolt.

Now, I've got a couple of more questions which I may need to start another post because this one might be getting old.

I was wanting to install a Sako style extractor, but looking at how little relief is on the bolt face, that's problaby not possible. The barrel has an inlet cut for the mauser extractor, if we take the barrel off and cut the bolt inlet down to the relief cut and then let the bolt face fill in that area, just like remington does, it will have a deep inset for the bullet looking just like a stock remington. Then I can do the Sako extractor just like I would for any reminton. Will that be safe since there will be approx a 1/2" of barrel area where that extractor relief cut is not supporting the bolt, only the bolt face will be covering the shell. Doing this moves the area on the rear of the shell approx .110" forward so that much of the base of the shell will be sticking out of the chamber and into the bolt. It's still back in the heavy part of the bullet base and it will be covered by the bolt, it's just the bolt won't have that addional metal the remington barrel provides. Doing this will give me the room I need for the extractor, which will then be installed in the same location as if it was a remington.

Next question, If I take the barrel off, will it tightened back into the same location. I had some very special ingraving done on this barrel and I would not want it to get buried in the stock, I would like for it to stay in the same position it is right now.
Click to expand...

I think Brownell's used to sell some super thin hardened washers to take up slack when rebarreling military rifles with take off barrels. I was told that Arisaka actions often needed this sort of washer.
If the barrel were not already decorated you might be able to upset metal at the shoulder evenly enough to return it to the same torque value and still clock in, but its a crap shoot.

Your idea of making a replacement bolt would be more productive if there was a market for such a bolt, then the machinist and yourself might profit from the expense and time invested later on.


According to some books I'd read on the Mausers many years ago some Mausers have the bulkhead arrangement inside the ring while others have the breech of the barrel unsupported and the extractor groove cut directly into the barrel shank.
Its been many years since I gave any thought to the Mausers, but I seem to remember that there are two Eastern European Mausers with similar designations and one uses the bulkhead while the other does not. A friend bought one of these specifically because it was different from the others and he said it would have superior strength and ridgidity for his purposes.
IIRC the model designations had a number 24 they were either Czech or Yugoslavian , I think one was a CZ and the other a VZ.

I'll be looking those up anyway since I'm considering building a .280 on the best Mauser receiver I can find.
 
"others have the breech of the barrel unsupported and the extractor groove cut directly into the barrel shank." That's this one. They charged an xtra $30 to make the extractor cut.

Understand, this is not the orginal barrel. I just got this one back from McGowen Barrels about a month ago from having this new barrel installed on it. That's why I was thinking it might come back off without major problems and go back on in the same spot. The orginal barrel, they had to do a relief cut just in front of the action and still like to have never gotten it off.

As for getting another action, correct me if I'm wrong but I thought the action was what deremined how everything else fits. So, to replace the action with a different kind, would mean, getting another stock to fit that action and toss this $1,000 stock, then another trigger assy that worked with it. Then there's the having another barrel 260 barrel made that would get it back to the same caliber I wanted for her, and throwing this one I just paid $800 for in the trash. Let's see, that leaves me with a scope, a recoil pad that might or might not work, and a sling. None of which were part of her great grandaddy's rifle we are buildning for her.

Trust me, had it not been for whose rifle it was and who it's for and the fact that other than the new barrel, I had done most the other stuff 40 years ago, I would have just bought her a rifle. That way she would have a $1,000 rifle that would still be worth that or more years from now, not a $2,000 rifle that's probably worth $200. The dollar value is not what's it's about though.
 
There should be some way to modify the action for reliable ejection without making a new bolt head.
Perhaps modifying the ejector itself with a longer leg, a relief cut inside the receiver might be needed.

No.1 Enfield actions rebarreled for much shorter cartridges were routinely fitted with alternative ejector mechanisms. The original being a shoulder cut inside the receiver wall and a small screw protuding through it.
The alternative ejector used a slot cut in the wall for a blade ejector, some used a separate spring, and with others the blade was twisted 180 degrees and screwed down on the outside of the slot to act as a integral spring.

A No.1 action I have had a problem with ejecting modern commercial cases.
The problem turned out to be that its extractor blade was too thick where it engaged the rim, it was pushing into the small relief cut turned into the case above the rim, military cases seldom have this sort of cut so it had no problem with those. Sharpening the edge of the extractor allowed it to do its job without hanging up in the cut.

As adaptable as the Mausers have proven to be for such a wide range of cartridges there must be an easier fix, one that when you do hit on it you'll slap your forehead and say "dang it why didn't I think of that first, its as plain as the nose on my face".


PS
The bit about the Enfield cases brought this to mind, why not try several different makes of cases, one or more may extract and eject without the same problem.

This part of the problem
The current bolt is not very smooth, actually not smooth at all. Being an old military action, the bolt has a lot of free play when opening and closing and the ring holding the extractor drags. I just figure why not go ahead and make it a truely nice rifle by installing a pretty, smooth working bolt.
Click to expand...
Might be handled by a sleeving operation, or a thick electroless nickel plating.
You might replace the extractor collar and polish it to prevent drag.

The case drawings of the .260 suggest that the main difference is the width of the extraction groove, perhaps a thicker extractor blade would be called for, metal could be added by welding and filed to shape by hand.
 
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