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Double Rifles, Single Shots & Combinations >> Building Double Rifles & Gunsmithing
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akjeff
.300 member


Reged: 20/01/04
Posts: 121
Spanish proof marks
      #149287 - 02/01/10 09:53 AM

Hello all. Been away from the forum for a while. Finally got set up with a lathe and mill, and ready to try a conversion project.

I have a Ugartechea 10ga, that I'm considering for a basis for a .450 #2 NE. It's a circa 1989 gun, and has no third fastener, just double underlugs. It has the Spanish proof mark of a BP inside a shield, which, according to the Directory of Proofmarks means 12, 090 psi. In addition, the flats are stamped 1000 Kp/cm2. Trying figure out what that converts to in psi. I think it's 14,500 psi, but not convinced. Will then have to crunch the numbers to see if the breech pressure is compatible. Any thoughts on this? I've emailed Ugartechea, as to the proof pressure of this gun, but still awaiting a reply.

Thanks,

Jeff

Edited by akjeff (02/01/10 02:04 PM)

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DoubleD
.400 member


Reged: 23/11/03
Posts: 2485
Loc: Retired in Oklahoma
Re: Spanish proof marks [Re: akjeff]
      #149297 - 02/01/10 01:43 PM

Here's a handy desktop widget for this sort of stuff

http://joshmadison.com/software/convert-for-windows/

I didn't find kp/cm2 but 1000Kp coverted to 145.0377 psi.

--------------------
DD, Ret.

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akjeff
.300 member


Reged: 20/01/04
Posts: 121
Re: Spanish proof marks [Re: DoubleD]
      #149298 - 02/01/10 02:24 PM

DD,

Thanks for the widget.

Further searches turned up, what I believe "1000 Kp/cm2" represents. I believe it means 1000 Kiloponds. A Kilopond is one kilogram of pressure on one square centimeter. This converts to 14,223 psi. This is also 1000 Atmospheres(Technical). Still hope to hear back from Ugartechea, and get it straight from the horses mouth.

Jeff

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Bramble
.375 member


Reged: 29/07/06
Posts: 950
Loc: England
Re: Spanish proof marks [Re: akjeff]
      #149300 - 02/01/10 02:51 PM

Pressure in the "old" metric system was indicated with several different units:
- as kp/cm2 where kp is coming from gravity, e.g.. 1 kp = 9,80665 N.
The gravity varies depending where you are.
- as atm which comes from the atmospheric pressure that was also indicated
as torr and measured as mm of mercury. 1 atm = 760 torr = 101,325
kPa = 14,696 PSI
- as "technical atmospheric pressure" at, this was used to so that the "ambient
air" was considered as 0 at. This helped to distinguish vacuum and pressure. 1 at
= 1 kp/cm2 = 98,0665 kPa = 14,5038 PSI
Common to these units was that they were not very "exact", the way they were
defined.
Pressure in the "new" metric system is indicated in "pascal" Pa.
1 Pa = 1 N/m2
1 N (newton) = 1 kgm/s2, this comes from "a force of 1 N
will accelerate an object of 1 kg at 1 m/s2.
When this SI system was introduced, it was realized that it can be difficult to
"understand" as 1 kp/cm2 is 100 000 Pa, too many zeros and even 100 kPa can be
confusing, so a "transient" unit was developed, a bar.
1 bar = 100 kPa ~ 1 kp/cm2.

Hope that helps

Regards

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akjeff
.300 member


Reged: 20/01/04
Posts: 121
Re: Spanish proof marks [Re: Bramble]
      #149302 - 02/01/10 03:35 PM

Helps a lot Bramble, I was hoping you would see this and comment.

When you calculated the breech thrust/pressure on your 450#2, did you base the area on head diameter, rim diameter, or the diameter of the vessel i.e. the diameter of the inside cavity of the case at the base?

I found some factory specs of 450#2 ammo, namely 80gr cordite and a 480gr jacketed bullet. Looks like they generate anywhere from 13.0 to 13.7 ton. 13.7 ton converts to 30,688 psi. If the 30% rule is used, a "proof load" would need to generate around 40,000 psi?

I do believe this 10ga proofed at 14kpsi, should be a good candidate for a 450#2.

Regards,

Jeff

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Bramble
.375 member


Reged: 29/07/06
Posts: 950
Loc: England
Re: Spanish proof marks [Re: akjeff]
      #149303 - 02/01/10 04:11 PM

Hi Jeff

Well the long and short answer is that whatever you do it is an apples and oranges thing. The 13 tons (approx) of the 450#2 is a base thrust measurment using a base copper crusher and is not really directly comperable to any other measurment to a degree that can be exactly proven.
I would take the whole rim dia for the calculation so that you get a worst case scenario
Hoop pressure/stress is not going to be an issue if you are using commercially availible 4140 (En19/24T) barrels. What is is breech thrust. Now if the 10 G has 11mm + wide bites and a decent length of watertable then I would think that you will be fine (that is not a warrentee or anything like it for the litigious.
What is likley to happen IMHO is that it may come off the face for the proof loads and need to be re-hooked. This is not because it is in danger of imminent failure, rather that when building a new DR it is made super tight (ie you have to force it closed) this is to allow things to bed in for the first few shots it is then eased off in finishing. Now this gun you have will already be bedded in and may move a couple of thou off face. This can be easily corrected if it happens (I think it will) by going to a shop that does industrial hard chrome plating and have a few thou or whatever is needed plated onto the hook and then stone her back in (you need diamond stones/files for that incidentaly it is super hard)
Obviously things have come a long long way since I did that conversion. I would not if I were in your position use the old monoblock and sleeve. It is just as cheep to make a set of dovetail lump barrels, which will give a better finished job, allow you to re-file the detonating and standing breach (as it is certainly too big and clumbsy in a 10 G) and it will make a far better finished job for the same imput for you and cost.
If you want a JPG of a dovetail set up to help you on your way then drop me a PM and I will take a JPG off of the CNC program for you. It is a $ 200 for a machine shop to make the parts from 2 profiled barrels and a $20 peice of 4140. I would imagine it would cost you about $ 50 to get brazed up by a specialist.
It is much more satifactory and you will be hooking it correctly from the get go.

Regards

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akjeff
.300 member


Reged: 20/01/04
Posts: 121
Re: Spanish proof marks [Re: Bramble]
      #149308 - 02/01/10 04:56 PM

Bramble,

Again, thanks for the most helpful info. I checked the bites, and they are only about 9.6mm wide, and the water table is 55mm long. Perhaps this one is best left a shotgun? The strikers, which are bushed, are 2mm in diameter. It locks up rock solid, and has been fired very little(I bought it from the original owner).

Regards,

Jeff

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Bramble
.375 member


Reged: 29/07/06
Posts: 950
Loc: England
Re: Spanish proof marks [Re: akjeff]
      #149334 - 03/01/10 02:30 AM

Sorry Jeff,
the sensible answer is that it would not be a good idea to proceed in these circumstances. IMO there is not enough metal there to do what you want. Given all the money that you will end up putting into this project it is better to start from a firmer foundation.
However....there is a good chance that it will be perfectly OK. So if you want to proceed then I would do it on a dovetail lump, because if you make it up, test fire it, and it moves then you can have the joint heated again remove the dovetail and use the same barrels for a different action with a new dovetail. But if you turn the barrels for a monoblock for that action then they will fit nothing else and will be scrap if it dosent work.
That action will be no different from those that the Spanish use for their DR's it is just that they make the underlugs wider when they make a DR and the bolt corrispondingly wider. Sometimes they leave bolsters on the action sides streaching up to the fences when they chisel them up but as you have a 10g there then the metal is still there anyway.

Regards

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akjeff
.300 member


Reged: 20/01/04
Posts: 121
Re: Spanish proof marks [Re: Bramble]
      #149344 - 03/01/10 04:38 AM

Bramble,

I believe I will just keep it as a "goose gun", and search for an action better suited for conversion. I appreciate the help. Also, I think with any conversion I do, I will make my own monoblock, and leave the shotgun barrels alone. I would prefer to have the option of a shotgun at the ready.

Jeff

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AkMike
.416 member


Reged: 19/11/05
Posts: 2576
Loc: Anchorage, Alaska
Re: Spanish proof marks [Re: akjeff]
      #149793 - 08/01/10 12:23 AM

Hey Jeff, if you're interested I picked up a set of new RCBS dies for the 450 #2 in a trade and don't need them... PM me if you're interested..

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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akjeff
.300 member


Reged: 20/01/04
Posts: 121
Re: Spanish proof marks [Re: AkMike]
      #149800 - 08/01/10 02:17 AM

Appreciate the offer Mike, but I've got a set of CH4D dies, and am all set! Have been loading for my Ruger No.1 450#2. In the process of re-building it now.

Jeff

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AkMike
.416 member


Reged: 19/11/05
Posts: 2576
Loc: Anchorage, Alaska
Re: Spanish proof marks [Re: akjeff]
      #149980 - 09/01/10 06:47 PM

Cool! Take lot'sa pics of the build.

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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akjeff
.300 member


Reged: 20/01/04
Posts: 121
Re: Spanish proof marks [Re: AkMike]
      #150036 - 10/01/10 03:58 AM

Mike,

I'll do that. I have a bad feeling my barrel contour will have the rifle come in under my target weight of 10 to 10.5 pounds. I have to weigh the parts, and see if I need to regroup.

You going to the Wasilla Gun Show next weekend? I may have a table there. Stop by for a visit. We can swap contact info via PM, if you'd like.

Jeff

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AkMike
.416 member


Reged: 19/11/05
Posts: 2576
Loc: Anchorage, Alaska
Re: Spanish proof marks [Re: akjeff]
      #150044 - 10/01/10 05:38 AM

I just returned from a month and a half in Ukraine and Egypt late last night after missing a flight.. So I'm not up on the current news of the show. Thanks! I'll be there.
PM sent

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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akjeff
.300 member


Reged: 20/01/04
Posts: 121
Re: Spanish proof marks [Re: AkMike]
      #150079 - 10/01/10 01:00 PM

Welcome back! PM back at ya.

Jeff

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vikram
.300 member


Reged: 29/07/04
Posts: 105
Loc: Warwickshire,England
Re: Spanish proof marks [Re: akjeff]
      #150706 - 15/01/10 11:03 AM

Will this link be of any help in understanding Spanish Proof marks?

http://web.jet.es/rafa/b_punzones_eibar_1931.html


Best-
Vikram

--------------------
"Routine is death to Heroism."- P.G.Wodehouse

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