Progress on rifling machine and rifled choke tube!

[Ballistics in Scotland]

Well, I have to say that I am impressed!

I have contacted Holland & Holland twice now and have received two responses to my questions from the London gun room manager. First was to ask the rifling twist and the second was in response to a question as to rifling form which appeared to be conventional rifling in a photo I found in a link on the H&H site ay Classic Shooting Co.

The gun room manager sent me the Fosbery patent drawings which I already have and a couple of photos which clearly show the rifling being a ratchet style rifling (though not exactly like the patent drawing) which he said was Baker rifling.

He did not have a definitive answer as to why the rifling twist was so fast for the Paradox boolit which should stabilize in no faster twist than about 1:60", simply that they had measured several original Paradox guns to determine that 1:30" was the twist originally used.

I am very impressed that someone in his position would take the time to respond to my questions and to respond quickly as well.

Should I ever win a lottery and desire a fine gun (who wouldn't!?!) H&H would be my first stop and a side by 12 bore Paradox gun first on my list.

I doubt I will ever be able to afford an H&H Paradox gun or for that matter any of their fine guns as prices for used guns seem to start at tens of thousands of dollars and range up to hundreds of thousands of dollars.

There are some other makes that are only a few thousand dollars used so maybe one day...

Back to rifling...

There is a photo of a Westley Richards Paradox gun in the NRA museum that appears to have rifling exactly as per the Fosbery patent drawings:

http://firearmshistory.blogspot.ca/2...radox-gun.html

http://www.nramuseum.org/guns/the-ga...e-shotgun.aspx

The photo of the H&H Paradox muzzles looks more like conventional rifling with a ramp on the trailing side of the rifling rather than the ratchet style Fosbery patented:

http://www.classicshooting.com/blogs...-a-paradox-gun

Longbow

The picture on that last website is a drawing, not a photograph, and possibly just how someone imagines the Paradox rifling might look. You often don't get a good look into muzzles in a museum. I haven't read the patent, but it is likely that the ratchet rifling is something Fosbery and Hollands, as his assignees, could stop others using while it remained in force.

The "Paradox" book looks good, and Fosbery was an interesting man, with a lot of other good work behind him. I have fond memories of a friend's inherited Webley-Fosbery automatic revolver, which his grandfather carried in the First World War. But there are cheaper places to buy the book on www.bookfinder.com , part of my life support system, than that website.

[longbow]

BIS:

Yes, you are right. The patent drawing does look different than the photos of Paradox muzzles sent to me by Holland & Holland:



Here the rifling appears to have a bit of a flat or gently sloping land then a radiused "scoop" back to the next land with vertical face rather than the more exaggerated scoop in the patent drawing. The "scoops" being a ramped groove.

Not quite sure what purpose that serves over conventional rifling other than possibly less distortion to the boolit?

Also not sure why some other company could not use the idea but with conventional rifling unless the patent included the smoothbore with short rifled choke. In the end there were apparently several "knock offs" using the same type of rifled choke.

When I asked why the twist rate is so fast at 1:30" he didn't have a good answer, just that is what they measured from original guns.

I have a copy of an old Ross Seyfried article "Holland & Holland Paradox" where he says Fosbery tested a variety of rifling with from 5 to 20 grooves and many different boolit styles and weights before settling on what we now know as Paradox rifling and boolits.

I will buy the book once I am gainfully employed again. I have always had an interest in the Paradox guns but will certainly never be able to afford one with current price being 70,000.00 pounds ($87,150.00 US) for the round action and 90,000.00 pounds ($112,000.00 US) for the standard action. A bit much for my budget!

I have not made a lot of progress on the rifled choke tube other than to modify the design a little partly to make improvements (I think) and to shorten things up some as I cannot bore as deep as I wanted but it will still be longer than the 3" rifled Paradox choke.

I did cut and anneal a piece of steel which will be turned, bored and rifled shortly. Once successfully rifled I will finish turning the outside to final dimensions and then thread. Then comes the muzzle brake and barrel adapter.

In the mean time I have made up several new smoothbore slug designs to test. Mostly rehashes of previous good tests but looking for improvement. I may get them tested this coming weekend. I hope.

Longbow

[Cap'n Morgan]

Longbow,
I wonder if the rifling profile was designed that way to aid the shot load in partly skidding the rifling (which would otherwise blow the pattern) while still being able to impart a spin on a solid projectile.

[Ballistics in Scotland]

I meant the picture you now show on the right is a drawing, or perhaps a computer enhanced photograph. People do sometimes enhance things the way they imagine, and I think Fosberry's rifling had a steep side on the side that actually turning the bullet, and a shallower slope, probably right to the next land edge, on the far side. It would, to some extent, produce fliers by deforming birdshot, with a pattern normal in the centre but thinning at the edges.

Centrifugal force would surely spread the pattern wider than the choke would make it, but it is quite a pronounced choke, and I think it would pattern rather more closely than a cylinder bore. It isn't like the typical user was going to shoot high driven pheasants with it. The danger of getting a doughnut pattern with a hole in the middle through centrifugal force is much exaggerated. For the pellets near the centre of the charge are spinning in a much smaller radius than the outsiders.

[longbow]

Cap'n Morgan and BIS:

I hadn't really thought of the shot aspect as it is of little concern to me. In my case if this rifled choke tube works the idea is that it is for slugs and a standard choke profile for shot. However in a fixed choke gun of course the effect of the rifling on the pattern would be a big concern. There are certainly less sharp corners to deform shot with the ratchet style rifling.

Now having said that, I have been thinking that if it works then it is possible that I could buy a side by with choked barrels and rifle the chokes but then I would be concerned about the rifling profile. At this point I am not going to change things and try a fancy rifling cutter to make ratchet rifling. Also, at the much slower twist I will be rifling there will be less centrifugal effect so maybe the pattern won't be affected as much as with faster twist. That would also have the issues with regulation where I have been thinking choke tubes could be made slightly eccentric then rotation set by shims or ? to bring POI of both barrels together.

Anyway, I want to try the deep rifling and slow twist so see if it works. That has been and still is the plan.

I believe that the photo on the right is actually a photo but possibly computer enhanced. I hadn't considered it to be a graphic but you may be right there. I zoomed in on it after your comment and it does look somewhat "bland" without much character like a graphic would be but there are also inconsistencies in the solder lines so hard to say.

The photo on the left is for sure a photo and shows the same rifling profile though so not much question as to what the profile is and it does look somewhat different than the patent drawing (which is what I thought you were referring to).

Also, I have to say again how impressed I am with the responses from H&H. They have sent me a 2016 brochure and price list... like I can afford one of these things! Should I ever get the money I will pay the H&H London gun room a visit for sure. In fact if we are in the UK visiting relatives, I would check out the cost of using the H&H gun range for an hour or so and see if they have a Paradox gun I could shoot. It would be nice to handle and shoot one even if I can never own one. Hey, maybe they have discounts for showroom models...

Longbow

[Ballistics in Scotland]

They used to say of the Rolls-Royce (not, I am pretty sure, as an advertising slogan) that if you have to ask how much it costs, you can't afford it. I'm sure you would find these videos interesting, especially the rifle barrel regulation:

https://www.youtube.com/watch?v=qUXoNUzAyvk

https://www.youtube.com/watch?v=RLxDRb7yWnw

https://www.youtube.com/watch?v=1itgVCzelWg

Somebody has to do it! I once visited the workshop of Ian Crudgington, who now owns George Gibbs of Bristol, and does work very, very hard to distinguish from Holland's or Purdey's at far less cost. It is amazing how the people and the workshops sound and look like ordinary technicians. But they aren't. I feel for the firms that are in that situation and relatively unrecognised, and those which have vanished in the past. It is a reputation-based world, and not always with good reason.

I recently saw someone online bemoaning the fact that Ruger couldn't supply the new firing-pin his now-discontinued Red Label needed after only 300 shots. Here is the automatic safety actuating rod from my well-worn and cheap Gibbs sidelock. It is mid-way through silver soldering a piece of high speed steel to replace the end where just applying the safety has worn it shorter. I can only guess how much shooting that took, and yet the rest of the gun was nearly as tight as it was made.



I think the purpose of the ratchet rifling in rifles was to minimise the opportunity for fouling to cling. Both the rifling forms used by Metford (one just plain very shallow and gain-twist, the other rounded) were probably better at this. But the muzzle is a place that would foul very little anyway. I agree, the purpose of it in the Paradox, which needed the rifling to be deep, was to minimise distortion of birdshot.

As to rifling the choke of an existing smoothbore, well maybe, but I wouldn't buy one sight unseen for the purpose. Smoothbore chokes and the lead to them vary considerably in length, and making them too long defeats their purpose. They operate by giving the shot an inward movement, and if the parallel section of the choke is too long, it ceases before the shot exits. I think the Paradox requires the chokes to be longer than most.

I notice that one of those advertisements posted in this thread says the person with a Paradox and a .450 Express would be armed for everything from snipe to tiger. I am not sure the same wouldn't apply to a smoothbore game gun and a .450. But it is a fascinating concept.

[longbow]

BIS:

I don't have to ask... I know I can't afford it. That applies to the Rolls Royce as well as any H&H guns. I can still admire them though.

Yes, a very tedious procedure to get the barrels regulated. What I have never figured out is why over and under guns are easier to regulate than side by side but that is what I have read. It should be the same procedure. I am a bit baffled on that one. I have always had a soft spot for side bys, they just look right. Over and unders do nothing for me.

Thanks for posting those links. That was a good watch.

I am surprised there is still so much hand work at least at roughing stages. I would have thought that CNC machines would be used where ever possible to at least rough out metal parts and wood then hand finish but it appears that much is done start to finish by hand with a few power tools. Of course we are not seeing the entire operation in those videos as well.

You may well have a point with the ratchet rifling and fouling. I have been assuming that Fosbery designed his style of rifling specifically for the Paradox guns to suit the shot and bullets being used. He may well have just chosen a suitable style of rifling that had been proven and suited his use.

Smokeless powder was already in use by the time the Paradox guns were made but BP was also still in use and his research undoubtedly started prior to common availability of smokeless powder. So Fosbery may have considered the fouling issue as well.

Not sure what the Paradox knock offs by other companies used for rifling twist, length or style but I know there were other successful guns similar to the Paradox. On that note, I should contact Westley Richards to see if they can provide any details of the Explora ball and shot guns. That would also be interesting. I also found some online books on ball and shot guns that I downloaded but have not reviewed yet.

Longbow

[Cap'n Morgan]

Yes, a very tedious procedure to get the barrels regulated. What I have never figured out is why over and under guns are easier to regulate than side by side but that is what I have read. It should be the same procedure. I am a bit baffled on that one. I have always had a soft spot for side bys, they just look right. Over and unders do nothing for me.

A side by side will vary it's impact in both the horizontal and the vertical plane depending on the loads. An over and under will only be affected in the vertical plane.

[longbow]

Cap'n Morgan:

Please indulge my ignorance. Why would a side by side vary impact in two planes and an over/under only 1 plane? The basic construction of the barrel sets is the same.

I have to think you are right because over/unders tend to be cheaper than side by sides especially in rifles but I am having trouble understanding why they are easier to regulate and/or just don't throw POI
off in two planes.

It has never made sense to me and I have never had anyone explain it to me.

On the up side of things, I have started turning and drilling (prep for boring) the choke tube. Unfortunately I am finding that I have a lack of tooling for the length of stock I am using so may have to build or buy a steady rest otherwise cuts will have to be very shallow. External turning should be fine because I can use a center but boring could be a bit difficult. If I have to I will take the choke tube to a friend who has a much bigger lathe, much better tooling and a much better skill set than I do as a machinist.

Anyway, progress is being made.

That and I just made up a bunch more smoothbore slugs to test as well. I have re-initiated the copper tube skirt slugs for round three.

Longbow

[Andrew Mason]

PM me if you need some 4140 cm, i cand send you some, just pay shipping.

[Cap'n Morgan]

Longbow,
Notice how the barrels on a double barreled shotgun are not parallel, but are set in a slight angle to compensate for the recoil moving the muzzle before the shot has left the barrel. This is because the point where the stock rest against the shoulder is below the centerline of the barrels. In a side by side the centerline(s) are slightly off in the horizontal plane as well, causing a slight sideways muzzle movement on top of the vertical lift.

That said, I would think a side by side would be less finicky to regulate, as the barrels are symmetrical and closer to the centerline in the vertical plane compared to an o/u, but I'm certainly no expert on these matters...

As for boring out your choke tube, perhaps you can get some ideas from this guy:

https://goo.gl/xpNRqW

[longbow]

Cap'n:

True enough, I hadn't thought about that or the reasons why. It seems "normal" for a side by to converge its patterns and so the tapered barrels tend to be lined up more or less parallel under the rib where it seems O/U's are more like parallel on bore centerline. I guess it would take some examination but that is how it seems to me anyway.

Regardless, I like side by's and always have so for me side by it is.

In any case, I am beginning to wonder why I picked such a hard road to follow here as I am sure there are suitable side by's with suitable screw in chokes and I could have simply made a pair of choke rifled tubes to fit. However, I have my old single shot slug gun and decided it would get an add on choke tube Pachmayr like so here I am! The single shot is the test subject to see if my rifling idea works well enough to proceed.

I have asked H&H if they have any comments on why the rifling twist in the old Paradox guns was so fast but so far no comment except that is what they measured. To my knowledge the bore guns used much slower twists in 12 bore.

Anyway, progress is being made... slowly but progress anyway. I have been out of work for the last month so have had time but find that it gets away from me as I have been out to the archery range and fishing along with catching up on other things. Funny how that works.

My big concern now is boring the bar stock because I don't have a steady rest and my lathe chuck is too small to slide the bar in half way for support so I have an overhang of about 4". I may be able to make a steady rest but there is little room for one on my small lathe. Alternately, I was thinking about making a guide tube that slides over the outside of the round bar to stabilize it while I am boring. I will drill to 5/8" diameter then bore from there. My plan is to bore to finished inside diameter of about 0.710" or a little less then cut rifling with groove diameter just under the shotgun bore diameter so about 0.010" deep rifling.

The rifling machine worked well for my test of rifling 3/4" pipe so it should be good for rifling the bar stock.

I will have a read through that book in the link you sent. Thanks for that, it looks like good info when I scanned through it.

Longbow

[longbow]

Andrew:

Thanks for the offer but I already have material for the parts. I am using an old axle out of my old Chevy truck. I annealed it and it seems like pretty tough steel. It will be a medium carbon steel at least as the axle bearings run right on the axle.

I had planned on buying some 4140 at a local machine shop but decided I would use the old axle.

Re-looking at things I will be able to put a steady rest in which will solve the unstable boring issue but I will have to build a steady rest now. They aren't terribly expensive but I am currently unemployed so will be building one not buying.

Another project! Just what I need. Oh well, once the steady rest is made that should be the last hurdle before I can finish up the choke tube. I should have looked at this some time ago and planned out what tooling I needed.

Longbow

[longbow]

Well, I kinda brought this back from the dead!

As I've mentioned on several other people's threads, I have restarted this project. Restarted in a slightly different manner but same end goal.

I decided it was going to be a lot of work and a bit much for my limited machining skills and tooling to make a Pachmayr type barrel adaptor, muzzle brake and choke tube plus I would have to make all my own choke tubes as well... so, I bought a barrel adaptor from Brownells along with a cylinder choke and a blank choke with Mossberg thread.

I bored the blank choke to 0.705" and am in the process of rifling with the intent of reaching 0.725" groove depth (or better... up to 0.729"), so 0.010"+ rifling.

The equipment and procedure is the same as used for the 3/4" pipe I experimented with at the beginning of this thread (pics are there) except I had to remake my rifling head because it was too big to fit into the choke tube. Same style just smaller.

Progress is SLOW! It appears that my cutter has dulled and I rifling is only about 0.002" to 0.003" deep so far after hours pushing and pulling on the rifling head. The current cutter is ground from a file and uses the edge of the file for cutting teeth per instructions I found. Traditionally the cutter was a hook cutter that scraped a small amount of steel from each pass through the groove. I figured the file would be more than adequate and after all, it is a file! However, my cutter is not cutting much at this point so I'm trying the acid sharpening method so I don't have to replace the cutter. So far the acid method is not working but I'll try again.

If acid doesn't bring the edges back to cutting sharpness I'll try grinding a hook edge on the cutter while it is in the rifling head (epoxied in). If one of the two methods doesn't work then i'll have to re & re the cutter. BAH! If so I my grind a hood cutter so I can sharpen it because once the file is dull, its dull. Id acid etching doesn't refresh the edge it is no good.

I am wondering if the choke tube material is particularly tough. I have read that modern choke tubes are made of stainless steel because it is more resistant to damage by steel shot. Not sure if that is common with all brands or just some and not sure why hardened stainless would be any better than hardened carbon steel. If stainless that may explain why cutting is so slow. Stainless is tough tends to work harden... depending on grade. Hmmm maybe that's why it is resistant to steel shot damage?

Anyway, I will be back at it after I get the cutter sharp or replaced. I'll post pics when I have something better than the rifled 3/4" pipe!

Longbow

[Cap'n Morgan]

Longbow

How many teeth does your cutter have? Too many teeth engaging at a time will need quite some pressure to get the individual teeth to "bite". As you write above, traditional cutters normally is a single-tooth affair.

Maybe it would probably be possible to etch the rifling? I once fooled around with "King's Water" acid to put "engraving" patterns on a shotgun; The part is heated slightly, and a thin layer of beeswax smeared out on the surface. The pattern is drawn using a machinist scribe and the acid is applied to the surface (taking great care only to cover the pattern) My "engraving" turned out so-so, but that was more to my lack of artistic skill than the actual etching process.

Various rifling methods described here:http://firearmshistory.blogspot.com/...-chemical.html

[centershot]

longbow, in my experience (as a machinist for over 20 years), I'd rather sit through a root-canal procedure than work with stainless steel. OK, a bit of an exaggeration, but you are absolutely correct when you said that SS was a tough material to work with. It IS tough, not particularly hard, but tough. It doesn't machine as easily as 4140 or any of the more popular "gun-type" steels, it's a PITA for sure! Cap'n Morgan is probably correct, a single tooth hook-type cutter is probably the best choice. You'll have to play with the angle on the cutting face to find what works best. Go slow, you'll get there!

[W.R.Buchanan]

LB: OK you need to grind a single tooth cutter out of a Hi Speed Steel tool blank, available at any industrial supply for a few $.

The problem with your file cutter is that you are spreading the cutting force (that which pushes the cutter into the work ) out over several teeth and thus it will take forever as you are essentially wearing the grove into the material as opposed to cutting it. A file is hard enough but spreading the force out over many teeth reduces the force on any one tooth to next to nothing.

Also when you push the cutter back thru the cut for a new stroke you will dull the cutter. This is why you need a HS Steel cutter as it can take that .

Randy

The Stainless they use is 17-4 and it is not any harder to cut than 4130, and you'll get a nicer finish.

[longbow]

I used the chunk of file as recommended on some site about rifling. I know the traditional cutter was a single hook cutter but the way this thing works I doubt a single tooth cutter will be suitable because it will have to exit the material totally and will spring up a bit so will hang up on the next stroke.

The file started out well and was removing material quite well but it dulled fairly quickly so as Cap'n Morgan states with load over many teeth the pressure against the cutter has to be quite high and removal rate has dropped significantly now.

I see that Bookie at Toad Hall used saw teeth which is a thought (power hacksaw blade?). What I will try next is to cut hook teeth into the file with a carbide cutter. If I set them up with flat faces I can use a diamond hone to sharpen the teeth frequently. I am thinking 3 teeth should allow one tooth to exit while two remain in the groove so not allowing that spring and catch issue. Only two will be cutting but they should be close enough in height that letting one exit should be an issue (I hope!).

If that doesn't work then I'll pick up some high speed steel and try Randy's suggestion.

I am currently about 1/3 to 1/2 depth on the rifling so not a total failure to cut. It started fast and now has tapered off. If I made another file cutter or preferably get the current one sharp with the acid bath then I should be able to finish this choke tube reasonably quickly. If I do another I may try a different approach with the cutter... and may have to to finish this one.

I am thinking the hook cutter with 3 teeth is the easiest to try. However, it won't be real easy to replace the current cutter with exactly the same width new cutter. If it is even a few tenths wider it will bind in the grooves. Better to be a bit narrower.

Also, I'll have to set the cutter into a groove then reassemble things to maintain timing and that will be a bit of a pain!

I did have trouble boring the blank choke tube and did not get as smooth a finish as I would have liked plus there was a spot in the tube that seemed softer than the rest and I see a noticeable groove there. Not likely more than a thou or so different diameter but obvious to the eye with a light in the tube. I tried honing and got most of it but... Of course that is gone in the grooves now but I'll have to lap to remove from the lands. It may not hurt anything but I don't like it.

I will keep at it until done this time though.

Longbow

[longbow]

Hah! Found it whilst looking for rifling cutter alternatives:

https://www.bevfitchett.us/antique-r...-2/cutter.html

That's Bookie using a piece of file!

At his site he uses a piece of saw blade with quite coarse teeth. I have some power hacksaw blade but I doubt its wide enough. I'll double check but I am sure it won't be as wide as the file I started with.

I am now waffling between hook cutter and scraper style. Scraper style is likely slower going but should allow a single point cutter to leave the groove and not hang up on re-entry. I think for hook cutter the way I am set up I will need at least two teeth so one can leave then re-enter without hanging up on the edge.

I'll figure it out!

Longbow

[tomme boy]

What does your cutter look like?

Would you be able to rig up a tooth off a circular saw blade with a carbide tip?

Heck the ones at Harber Freight are pretty cheap.