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Double Rifles, Single Shots & Combinations >> Building Double Rifles & Gunsmithing
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Ron_Vella
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Reged: 29/04/05
Posts: 432
Loc: Oshawa, Ontario, Canada
6.5x57 Rimmed Double Rifle Project
      #243699 - 13/03/14 02:52 AM

Recently, I started to build my seventh double rifle. I want to have one that is very light-weight, and in a calibre that is legal in my immediate area, where we are not allowed to use a rifle of greater caliber than .277”. I chose the 6.5x57 Rimmed for a number of reasons. First, it’s a very fine cartridge. Second, I found a pair of arsenal-new Swedish M-38 barrels at an attractive price, and which I re-contoured and re-chambered. Third, because I already load for my Sako rifle in calibre .264 Winchester Magnum, I have a large supply of 140 grain Nosler Partition bullets in 6.5/.264 calibre.

The shotgun that I ultimately bought as the “host gun” for this project is a Zabala boxlock, extractor, in .410 bore. I want to end up with both shotgun and rifle barrels, fitted to the one action. Obviously, this entailed making a new mono-block to accept the rifle barrels. Fortunately I have a good friend who owned his own tool and die shop, and whose son took it over upon Peter’s retirement. Using the .410 barrels as a pattern, Peter wrote a CAD/CAM program on his computer. Using that program, plus the latest laser- duplicating technology, they supplied me with the mono-block shown in the accompanying photos.





The dimensions of this mono-block are so close to the original that in only two hours, working with candle, file, and stones, I had it fitted to the circle and on-face as shown in the two photos. I am showing you what CAN be done with modern technology and the right friends. I imagine that the cost to have this kind of job done would probably be cost-prohibitive otherwise, but it CAN be done.



Because the .410 action is so small, and the tolerances so close, I don’t feel comfortable to thread the barrels and the mono-block, as I have always done in the past. I therefore decided to shrink-fit the barrels into the mono-block by shrinking them with liquid nitrogen first. I turned the shanks of the barrels down to within .006” of the .625” bores in the mono-block. I then took them to a local precision-grinding shop and they finished the shanks for me to .626”. The cost to have this done was very reasonable, only $40.The last photo shows a jig that I’ve made up, out of some aluminum bar stock, and two lengths of ¼” threaded rod. I believe that the photo, showing the washers, heavy coil springs, and large nut, is self-explanatory. This will be used to clamp the chilled barrels tightly into the mono-block, as the temperatures normalize. I’m hoping that this will result in a fairly close-fitting seam. More to follow…



Edited by CptCurl (04/05/14 09:12 PM)

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Sarg
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Reged: 20/01/07
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Ron_Vella]
      #243710 - 13/03/14 06:19 AM

That is fantastic, thank you for sharing this with us, cant wait to see more !

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Waidmannsheil
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Reged: 19/04/13
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Sarg]
      #243717 - 13/03/14 07:33 AM

Nice work. Are you going to leave the join line between barrel and mono-block visible. Several companies are now TIG or laser welding the join so that it becomes invisible after striking up. Laser welding in particular is very good as there is next to no heat and the blueing looks perfect after woods. Keep posting as this looks like a good project. Nice cartridge too.

Waidmannsheil

--------------------
There is nothing wrong with vegetarian food, so long as there is meat with it.

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Matabele
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Waidmannsheil]
      #243720 - 13/03/14 08:16 AM

Looks great so far! Please keep posting I love to see these kinds of builds.

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kamilaroi
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Reged: 18/12/04
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Matabele]
      #243721 - 13/03/14 10:24 AM

outstanding stuff!

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Ron_Vella
.333 member


Reged: 29/04/05
Posts: 432
Loc: Oshawa, Ontario, Canada
Re: 6.5x57 Rimmed Double Rifle Project [Re: kamilaroi]
      #243724 - 13/03/14 11:33 AM

W,
I'll be very honest, a faint demarcation line does not really bother me. I build these guns to shoot them and to hunt them, not for re-sale. On my .450 #2 NE, 9.3x74R, and .303 British doubles, where I screwed the barrels into the mono-blocks, after polishing and rust bluing, the seam is virtually invisible. In many cases, until I have pointed it out to a viewer, they have not even been aware that there is a seam there.

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Ckhobart
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Ron_Vella]
      #243731 - 13/03/14 04:34 PM

Verrry cool.

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HeymSR20
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Reged: 23/11/11
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Ckhobart]
      #243755 - 14/03/14 01:22 AM

Like what you are doing. I've an old English double 410 by WJ Jeffery. Barrels very pitted and one day it will become a double rifle. Given the size of the action will you have enough wall thickness to withstand the pressures of the 6.5x57r ? Did you think about doing a shoe lump joint rather than a mono block so that you can keep plenty of barrel thickness. This is the approach Heym take - http://www.heymusa.com/heym_tech.htm. No criticism implied or intended - just a question.

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doubleriflejack
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Reged: 11/11/07
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Re: 6.5x57 Rimmed Double Rifle Project [Re: HeymSR20]
      #243774 - 14/03/14 06:39 AM

Ron said: "Because the .410 action is so small, and the tolerances so close, I don’t feel comfortable to thread the barrels and the mono-block, as I have always done in the past. I therefore decided to shrink-fit the barrels into the mono-block by shrinking them with liquid nitrogen"
_______________________________
You certainly are not afraid of innovation. I would have simply soldered them in place, while keeping the solder away from the seam area. Soldering them alone; not threading, works because the soldered surface is so large. I have used half threads/half soldered, and fully soldered; not threaded at all, both systems worked. Now, I am anxious to see how liquid nitrogen tight shrink fitting works.

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Waidmannsheil
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Re: 6.5x57 Rimmed Double Rifle Project [Re: doubleriflejack]
      #243775 - 14/03/14 06:48 AM

Beretta have even used a Loctite type product on some of their models to attach the barrels to the mono-block.

--------------------
There is nothing wrong with vegetarian food, so long as there is meat with it.

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transvaal
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Reged: 19/01/13
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Loc: South Carolina
Re: 6.5x57 Rimmed Double Rifle Project [Re: Waidmannsheil]
      #243794 - 14/03/14 11:27 AM

Ron;

Per comments of HeymSR20 above: What is the thickness of the monobloc at the breech end. If my calculations are correct the 6.5x 57R cartridge chamber diameter at the base is about .470" and your barrel stub OD is .626" leaving you wall thickness of .156" at the breech. With the monobloc under compression with the shrink fit, are you depending upon the monobloc to add strength to compensate for the lack of substantial wall thickness for the cartridge dimensions? Additionally, are you planning on the typical 48,000 or so psi for loading the 6.5x 57R?

Edited by transvaal (14/03/14 01:37 PM)

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Birdhunter50
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Reged: 03/06/07
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Re: 6.5x57 Rimmed Double Rifle Project [Re: transvaal]
      #243819 - 15/03/14 05:15 AM


Ron,
I would not want to try and build anything much bigger on a 410 frame than a .22 Hornet. Your barrel stub walls are only goiung to be .078" thick and that is if you get everything just right. If I HAD to do this conversion, I would bevel all the joined areas front and back, down at a 45 degree angle and have it filled in with a micro TIG welder. That way if you do not get all the holding strength by shrink fitting the barrels to the monoblock, the weld will add enough to make sure you don't blow out a barrel.
I think that actually doubleriflejack has the right idea, make them a slip fit and solder them in with High Force 44. I'm still unconvinced that the monoblock will stand up to this much pressure. Are you planning to download this somewhat? Bob

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Dumprat
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Reged: 20/02/14
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Loc: Vancouver island bc.
Re: 6.5x57 Rimmed Double Rifle Project [Re: Birdhunter50]
      #243820 - 15/03/14 06:21 AM

I for one think he is on the right track. The shrink fit has huge holding force. Well beyond what solder can achieve. And welding can create a weak point that will not visible unless X Ray is used. An end cap weld could be used for redundancy but is not needed. .

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Ron_Vella
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Reged: 29/04/05
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Loc: Oshawa, Ontario, Canada
Re: 6.5x57 Rimmed Double Rifle Project [Re: Dumprat]
      #243836 - 15/03/14 01:52 PM

Gentlemen, not be be "snippy", but I'm not a "new boy on the block". I've built 6 double rifles already. I have fired many thousands of rounds through those rifles safely. I understand metallurgy, hoop strength, etc. What is amusing is that there are critical posts here from guys who have been sending me personal e-mails for years, asking my advice on how to do this job. Suddenly, everybody's an expert! The combined wall thickness of my mono-block and the barrel stubs is .245", most of that being the best, modern, 4140 steel. After shrink-fitting the barrels into the mono-block, I had their rear faces micro-tigged to the mono-block, so nothing short of dynamite is going to move them. My regulation load is a 140 grain Nosler Partition at 2200 fps. That load will produce well under 40,000 psi. My proof loads are the same bullet at 2650 fps. Three of those loads, fired remotely through each barrel, will tell the tale. I'll post some more photos in a day or two when I have the time.

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Dumprat
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Ron_Vella]
      #243841 - 15/03/14 04:40 PM

Well put. Most people out the realm of engineers and some machinists don't fully understand the forces and stresses the metal is under.

Keep on doing what you are doing. If you feel the need to put the naysayers to bed, after proofing get the mono block run up on a manga flux bench. All the bullshit ends there. Fusions, inclusions,voids, cracks all show up under the black light.

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dpcd67
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Dumprat]
      #243867 - 16/03/14 04:26 AM

Very nice; good job.

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tinker
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Re: 6.5x57 Rimmed Double Rifle Project [Re: dpcd67]
      #243869 - 16/03/14 05:07 AM

Wow

Tiny
Can't wait to see it done!





Cheers
Tinker

--------------------
--Self-Appointed Colonel, DRSS--



"It IS a dangerous game, and so named for a reason, and you can't play from the keyboard. " --Some Old Texan...

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4seventy
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Ron_Vella]
      #243898 - 16/03/14 03:13 PM

Ron,
Thankyou for the photos and description on your seventh DR build!
This one will be so trim, and should be a delight to use when completed.
That's a neat way of fitting the barrels to the monobloc.
I'm guessing that now that you have a faster easier way to produce a monobloc with the CadCam, that you are probably already thinking of number 8 double rifle project.
Please do post some more photos when you get the chance, as like always, there are many here including myself who will really enjoy following the build.

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NitroXAdministrator
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Ron_Vella]
      #243902 - 16/03/14 04:43 PM

Quote:

I have a large supply of 140 grain Nosler Partition bullets in 6.5/.264 calibre.



Hi Ron,

Looking forward to your build progress and photos, hint.

A question re your intended projectiles to use. It is obvious then, you don't think the solid shank in the partition bullets to have an effect on your barrels or solder in the future then? Any comments on that? Perhaps the barrel profile you are using is thicker than usual?

--------------------
John aka NitroX

...
Govt get out of our lives NOW!
"I love the smell of cordite in the morning."
"A Sharp spear needs no polish"

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DarylS
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Re: 6.5x57 Rimmed Double Rifle Project [Re: NitroX]
      #243915 - 17/03/14 03:29 AM

John - as to the solid web section of a Partition bullet creating extra hoop stress inside the bores, possibly damaging the soldering, would not the bullet be engraved at the breech end of the barrel and properly fitted to the grooves prior to the 'load' reaching full pressure anyway? This, of course, is due to the ctg. developing maximum normal pressures some inches down the bore, longer for slower powders, close for faster ones.

Loads developed for the bullet in question would not produce any more pressure than the person who loaded them, wanted them to produce. Once fully engraved, I cannot "see" how the hoop stress would be continual during it's trip down the tube - afterall it is then the proper size and not attempting to expand against the lands. It is possible the web of a partition bullet could cause a more rapid climb in pressure at the breech as the powder charges gasses expand, however that trend would be taken in stride with normal safe handloading practices of starting low and developing the loads from the start.

--------------------
Daryl


"a gun without hammers is like a Spaniel without ears" King George V

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Shotgunlover
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Re: 6.5x57 Rimmed Double Rifle Project [Re: DarylS]
      #243916 - 17/03/14 03:42 AM

Shrinking the tubes, as opposed to expanding the monobloc with heat, is a fascinating variation on the Cannons Frettes method. Would it make any practical difference regarding the tube being shrunk in and then expanding to contact the monobloc rather than the other way round?

Really impressive is the surface finish quality on the monobloc. Is this surface finished-polished after the machining or is it direct from the machining? It looks like it has been beadblasted but that might be the photo quality.

I would love to get that kind of result from machining alone!

--------------------
Shotgunlover

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Ron_Vella
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Shotgunlover]
      #243923 - 17/03/14 05:02 AM

John, In fact, these are the lightest barrels that I have ever done, only .440" at the muzzles. I am taking every possible step to get this rifle as light as possible. I have even skeletonized the Leupold QRW rings that it will wear, pic below. This actually shaved 1/2 ounce.



I tend to agree with Daryl re the Partitions. I'm only loading to 2200 fps, a very mild load.

Shotgunlover,

The finish that you see is exactly as I received the monoblock. The machine work was done with EDM wire-cutting. They applied some type of finish, that looks just like phosphating, afterwards to prevent corrosion. That is the matte look that you see.

Edited by CptCurl (04/05/14 09:13 PM)

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Ron_Vella
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Reged: 29/04/05
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Ron_Vella]
      #243924 - 17/03/14 05:17 AM

Here are a few photos of what I've been up to for the last few days. Photo below shows the original extractor from the .410 barrels on the left. On the right is the extractor which I've made for the rifle barrels. Once it is fitted to the barrels I will finish-contour the radii and cut the rim recess, using the chamber finishing reamer.



I also had to fabricate a forend hanger for the rifle barrels. Photo below shows it beside the original on the .410 barrels.



Another job still to be done is the machining of the combination top rib / quarter rib. Photo below shows a piece of cold-rolled steel, temporarily soldered to a square tube, which is clamped to a very rigid piece of aluminum I-Beam. This will be clamped in two milling vises for machining.




More to follow.

Edited by CptCurl (04/05/14 09:14 PM)

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Dumprat
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Ron_Vella]
      #243926 - 17/03/14 05:38 AM

Nice work.

he EDM process uses a fluid sort of like cutting oil. That is probably the coationg you are seeing. We get a few heli parts cut with the EDM and they come back the same way.

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Aaron_Little
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Re: 6.5x57 Rimmed Double Rifle Project [Re: Dumprat]
      #243930 - 17/03/14 07:44 AM

Wire EDM's typically use water to flush out the cut during machining, at least ours does. It can leave behind a "scale" type finish that looks like the finish above. Sinker/spark EDM's use a oil that submerges the part.

Im of the school of thought that when dealing with wall thickness and monoblocks, your structural support/ pressure holding is all done with the wall thickness of the sleeved portion of the tubes, not the sleeved portion of the tubes and the thickness of the monoblock added together. My reasoning for this is because of the joint at the front of the monoblock and the tubes. The monoblock thickness cant add any strength at this joint, the sleeved portion of the tubes is what contains pressure at this point. Another issue with this joint is it is in a area where pressure is highest, and it also has a 90 degree angle. As im sure you are aware cracks are prone to form at 90 degree joints.

Do I think your gun will fail at normal pressure...Not really. But as a manufacturer I have to add additional safeguards in place to prevent from rare circumstances causing failures. As an individual doing work on personal guns, you cant hold yourself liable if failure occures...not without a good lawyer anyways.



None-the-less, keep up the work and tutorials.

Edited by Aaron_Little (17/03/14 08:22 AM)

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