Author Topic: Bofors barrel what t I do what to do?? (Read 3455 times)

Joey V. · « **on:** December 11, 2012, 02:17:05 AM »

Hey all

I scored a 40+" bofors 40mm barrel section and don't know which way to go. I decided on making it a Hugh's or a hotchkiss as I want a full size gun. My concern with the hotchkiss is that if I try to stay true to scale there is little to no sleeve over the powder / shell chamber. Knowing the barrel is a anti aircraft gun I believe it would be well within the strength factor for say a max charge of a 2oz black. Anyones opinions would be mighty helpful!

Thank you!
Jv

moose53 · « **Reply #1 on:** December 11, 2012, 08:27:23 AM »

Congratulations on your barrel , is it the front or back section ? Depending on how you set it up the barrel itself is good for pretty much what ever you want. The true Hotchkiss breech will be a interesting challenge. Looking for your build photos

KABAR2 · « **Reply #2 on:** December 11, 2012, 09:59:29 AM »

Before doing a Hotchkiss you may want to contact ATFE and get a letter on this they may view it as a modern DD in which case you will have to go through getting the proper approval and pay for the tax stamp

Cannon Cocker · « **Reply #3 on:** December 11, 2012, 11:49:43 AM »

Here is a digital book with period drawings of the Hotchkiss 2 pounder. Go to page 59.

http://books.google.com/books?id=yeUxAQAAMAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

Cannon Cocker · « **Reply #4 on:** December 11, 2012, 12:21:12 PM »

A few other guns that would work depending on how long your sections are: 3 pounder muzzle loading Whitworth, 3 pounder BL Whitworth, and the 1.92" ML Whitworth. The last one is the the simplest with a straight tapered barrel of 54 5/16", a breech dia. of 5 7/16", and a muzzle of 3 9/16". This might be slightly larger than the greater dimensions of the Bofors barrel though.

The Jeff · « **Reply #5 on:** December 11, 2012, 12:58:03 PM »

Quote from: KABAR2 on December 11, 2012, 09:59:29 AM

Before doing a Hotchkiss you may want to contact ATFE and get a letter on this they may view it as a modern DD in which case you will have to go through getting the proper approval and pay for the tax stamp

I've been toying with the idea of a 1" bore 3" Hotchkiss mountain gun. It's my understanding that some of the early versions were fired via a friction primer which is certainly an antique ignition system. Are your concerns about the brass cartridge that has a disk inside that obturates after firing?

KABAR2 · « **Reply #6 on:** December 11, 2012, 01:14:30 PM »

The slide breach could considered modern, though friction primed still uses fixed ammo, I would play it safe with either friction primed or percussion primed fixed ammo and get a determination from ATFE as to what they will allow not worth the legal issues otherwise.

cannonmn · « **Reply #7 on:** December 11, 2012, 03:32:21 PM »

If it will help the discussion, I can assure you that "Hotchkiss 2-pounder mountain guns" built either by Hotchkiss or the US licensee, American Ordnance, which were made in or after 1899, regardless of ignition system, are NFA weapons requiring Fed. registration.
I am painfully aware of this because of a registered 1899 example with very rare US Army markings that lived about a mile from me, privately owned by a friend. He wanted to sell it, and I wanted to buy it, so I we did all the transfer paperwork and sent it to the local sheriff as required, on its way to BATFE. The sheriff refused to approve the transfer paperwork (or anyone else's during his short term in office,) so the friend wound up selling the gun to some out-of-state "class 3" firearms dealer. I am not going to discuss it further as this board frowns on that kind of thing, but what I've written so far I thought would be helpful to the poster.

Cannon Cocker · « **Reply #8 on:** December 11, 2012, 07:15:31 PM »

So don't stamp any date later than 1898 on the gun you make!

Joey V. · « **Reply #9 on:** December 12, 2012, 03:50:27 AM »

after all this I am not building the Hotchkiss... It is a pain in the butt so forget it. I am however going to send a letter to the ATF regardless of what I build just so I have it! Last thing I need are issues! That said how would a Hughes cannon build fare? It's a breech but takes bag charges? I know guys have built those I'm still wrighting a letter so I guess it wouldn't matter either way.. Lastly can someone give me an example of a letter and the address?
THX
Joey V.

Double D · « **Reply #10 on:** December 12, 2012, 04:26:39 AM »

I have written several letters to ATF for determination. Her is the one I wrote on my Long Cecil project.

Quote

January 31, 2012
Bureau of Alcohol, Tobacco, Firearms, and Explosives
Firearms Technology Branch
244 Needy Road
Martinsburg, West Virginia 25405 USA

Dear Sir or Madam,

In 1899 during the 2nd Anglo Boer War, the Boer Army laid siege to the town of Kimberly, South Africa. The British army forces defending the town were out ranged by the Boer Artillery and could not return effective fire. The engineers of the De Beers Diamond Mine used common materials found in the mine engineering shop and in 22 days built a 4.1 in breech loading field gun to engage the Boer guns. This unique historic gun became known as Long Cecil.

I wish to build a scale model replica of this gun. The gun will be built as a hobby project and will be used to shoot blanks for signal purposes and projectiles for target shooting.

The gun will be built as close as possible to the original.

• It will have a miniature screw breech with an 1877 de Bang obturation system.
• Loading the gun will be via loose black powder. For safety purposes the powder will be contained in tin foil packets.
• Cast lead or standard surplus projectiles will be used for target shooting.
• The original gun used typical mid 1800 friction primers for ignition. This model will not have sufficient mass to safely use friction primers so ignition will be via common black powder cannon fuse.

I am aware of the Antique replica provisions of GCA and NFA and since the original gun was made 1899 to 1900 I know it will not qualify as an antique. It may qualify under the antique ignition provision.

Please advise what if any permits are needed to build this model gun in either 1/5 scale using a surplus 20mm barrel or 1/8 scale using a surplus 50 BMG barrel.

Sincerely yours,

Douglas B Dickens

Cut Bank, MT 59427

I got a response in October-10 months later saying good to go.

Here is second letter I wrote on the Stokes style Bowling ball Mortar.

Quote

November 4, 2011
Bureau of Alcohol, Tobacco, Firearms, and Explosives
Firearms Technology Branch
244 Needy Road
Martinsburg, West Virginia 25405 USA

Dear Sir or Madam,
I moderate an Internet discussion board for blackpowder cannon and mortar enthusiasts. We have a clear mandate that allows only the discussion of blackpowder muzzle loading cannons and mortars that were made before 1899 and replicas thereof. We do not allow nor offer interpretation of the GCA or NFA. We refer, anyone asking, to ATF for the proper interpretation of those laws.

One type of cannon that we frequently have inquiries about is a bowling ball mortar. People want to know if they are legal to build. We always refer those inquiries to ATF for an answer.

Most frequently the design inquired about replicates a Stokes mortar designed in 1914.

The mortar is constructed from a high pressure gas bottle. The bores size is 8.815 inches. The bottom end of the pressure bottle is cut off and a powder chamber is made to go in the neck of the bottle. The bottle is attached to a base plate and legs are attached to support the upper barrel like the Stokes. Base plates and legs can be actual surplus T&E equipment or fabricated. The gun is fired by loading from the muzzle, a blackpowder charge into the chamber, then lowering a bowling ball down the barrel from the muzzle over the charge in the chamber. The gun is fired by a standard cannon fuse.

Some argue that the bowling ball mortar made to replicate the Stokes design is exempt as it is a muzzle loaded mortar. To resolve this issue I am writing for a determination of the status of the Bowling ball mortar replicating a Stokes design. How is it classified under GCA/NFA?

Once I receive your response, with your permission, I will post the letter on our discussion forum for future guidance.
Sincerely yours,

Douglas B Dickens

Cut Bank, MT 59427

Response to this letter came in three months say good to go.

Joey V. · « **Reply #11 on:** December 12, 2012, 05:07:25 AM »

Thanks a million for the info!!
Is it possible to pay the $200 get a stamp or whatever and then build whatever I want? I'm only interested in cival war type anyway but I just hate the idea of doing something wrong and not even being aware of it..

Double D · « **Reply #12 on:** December 12, 2012, 05:54:34 AM »

Quote from: Joey V. on December 12, 2012, 05:07:25 AM

Thanks a million for the info!!
Is it possible to pay the $200 get a stamp or whatever and then build whatever I want? I'm only interested in cival war type anyway but I just hate the idea of doing something wrong and not even being aware of it..

You still have to get permission to build and most likely won't, paying the $200 NFA Tax Stamp.

The ACW stuff should all be antique exempt anyway and there is no need for the applying for the Tax Stamp.

If it is ACW, I would just build and not worry about it. I would be very surprised if very many folks here have letters for their guns. They just aren't needed.

The two letters above are for items that were questionable in their coverage under the Antique exemptions of GCA and NFA.

If you want the cover of a letter then write it.

KABAR2 · « **Reply #13 on:** December 12, 2012, 06:43:34 AM »

Quote from: Joey V. on December 12, 2012, 05:07:25 AM

Thanks a million for the info!!
Is it possible to pay the $200 get a stamp or whatever and then build whatever I want? I'm only interested in cival war type anyway but I just hate the idea of doing something wrong and not even being aware of it..

The way it works is this, you apply to build a destructive device with the application you send in a set of finger prints a check for 200 dollars a discription of what you are building including caliber length of barrel etc. you also need to get a Chief Law Enforcment signature on the form..... it takes about 6 to 8 months to get an approval or denial, once you have the tax stamp in hand you can build your DD. Now if one has money and chose to purchase an already manufactured DD and wish to avoid dealing with the need for a Chief LEO signature you can either incorporate or set up a Revocable NFA trust these do not need a signature. the problem is building requires a person not a corperation or trust so signature needed.
.
That being said a design like the Whitworth would not be considered a DD and if you check Cannonmn's thread on Springfield open house on the descussion is no 7 a 1.5" Whitworth that a 40mm barrel would work well for.
.
http://www.gboreloaded.com/forums/index.php/topic,269869.0.html
.
http://gs19.inmotionhosting.com/~milita8/cmh/member/member.cgi/read/13322
.
http://springfieldarsenal.files.wordpress.com/2012/12/cmh-presentation-12-1-12r3.pdf

Joey V. · « **Reply #14 on:** December 19, 2012, 05:17:58 AM »

Hi all,

Well I began work on the Bofors barrel and have cut the front 20+ inches off leaving me with a back barrel section around 40". As I am waiting for my ATF approval on the Huges Breach loader, I will make a Parrot cannon of the front section. So far I cut the barrel with an angle grinder and externally threaded the breach on the lathe. All looks great so far and the barrel is magnetic?? Anyone know what kind of steel they are made from? Im using hardened 4140 for the breach threaded on with 3" of 12 TPI Fine. I was also planning on pinning in the breach but read that Pinning actually makes it weaker.. Any thoughts?
Thx!!

Cannon Cocker · « **Reply #15 on:** December 19, 2012, 05:35:36 AM »

All the Bofors barrels I have seen are magnetic. Don't know the actual composition (it's been discussed before about testing one), but I would think it's some kind of gun steel similar to 4140 or 4150. If I were you (or if you were me!) I'd make the thread count bigger because it looks better (could be stronger, but don't know the rules on that).

Cannon Cocker · « **Reply #16 on:** December 19, 2012, 10:08:16 AM »

What I meant is bigger threads, less per inch.

cannonmn · « **Reply #17 on:** December 19, 2012, 11:06:48 AM »

Rsn the barrels are magnetic is that the recycling facilities (nice word for junk yards) that handled them all use large electromagnets on cranes to move the stuff around the facility. Magnetism is contageous.

Joey V. · « **Reply #18 on:** December 19, 2012, 12:31:40 PM »

Thanks guys!

Double D · « **Reply #19 on:** December 19, 2012, 04:49:21 PM »

Quote from: Joey V. on December 19, 2012, 05:17:58 AM

Hi all,

Well I began work on the Bofors barrel and have cut the front 20+ inches off leaving me with a back barrel section around 40". As I am waiting for my ATF approval on the Huges Breach loader, I will make a Parrot cannon of the front section. So far I cut the barrel with an angle grinder and externally threaded the breach on the lathe. All looks great so far and the barrel is magnetic?? Anyone know what kind of steel they are made from? Im using hardened 4140 for the breach threaded on with 3" of 12 TPI Fine. I was also planning on pinning in the breach but read that Pinning actually makes it weaker.. Any thoughts?
Thx!!

If you are waiting for an ATF letter for Hughes gun why aren't you also waiting for a letter for a Parrot rifle?

megawatts · « **Reply #20 on:** December 20, 2012, 01:53:00 AM »

I have attached for the readers interest a photo of club members 40 mm rifled cannon. It was constructed without any hassle under England’s firearms regulations.

Cannon Cocker · « **Reply #21 on:** December 20, 2012, 04:12:34 PM »

Here's a link you may not have seen.

http://civilwarwiki.net/wiki/1.5_inch_Hughes_Breechloading_Cannon

The Jeff · « **Reply #22 on:** December 21, 2012, 10:28:49 AM »

Quote from: Cannon Cocker on December 20, 2012, 04:12:34 PM

Here's a link you may not have seen.

http://civilwarwiki.net/wiki/1.5_inch_Hughes_Breechloading_Cannon

Some of the best pictures I've seen of how the Hughes gun works are on the Robinson's Battery website. Apparently they just built one last year.

http://robinsonsbattery.org/250634.html (scroll to the bottom)

cannonmn · « **Reply #23 on:** December 22, 2012, 02:31:26 PM »

If you are having trouble visualizing what Joey's barrel looked like when he got it, I'm betting it looked pretty much like one of these.

cannonmn · « **Reply #24 on:** December 22, 2012, 08:59:59 PM »

For those wanting to build a Whitworth repro, here's what one hobbyist did with a 40mm cannon barrel (use password "attack" to view this 33-slide show.) This repro Whitworth "3 pounder" breechloader is as I recall over 7 feet long and probably weighs 400+ pounds.
http://s17.photobucket.com/albums/b62/cannonmn/miscforumsetc/forums64/Whitworth%203%20pdr%20repro/?albumview=slideshow
The gent who did it was a master machinist who spent his working life as a tool and die maker, then as a machinery-maker for a major brewery.

GGaskill · « **Reply #25 on:** December 23, 2012, 03:55:17 PM »

Well done. I assume the hexagon muzzle is for show only.

cannonmn · « **Reply #26 on:** December 23, 2012, 04:17:26 PM »

Quote

I assume the hexagon muzzle is for show only.

I'd tend to agree.
Or maybe that was for launching hexagonal grenades. If they existed.

Double D · « **Reply #27 on:** December 23, 2012, 06:04:39 PM »

Wasn't the Witworth hexagonal bore?

Cannon Cocker · « **Reply #28 on:** December 23, 2012, 06:47:24 PM »

It was, but this reproduction was made with a Bofors 1.57" milsurp barrel and the last inches were made into a hexagonal shape for appearances only.

cannonmn · « **Reply #29 on:** December 23, 2012, 07:02:27 PM »

Quote

Wasn't the Witworth hexagonal bore?

If Joseph Whitworth were here, he'd be correcting us, since he called the bore "Polygonal." If you look at an engineering drawing of the cross-section of the bore, it is only very rougly hexagonal; in detail it is a more complex shape than that, with "corners" radiused and some other non-linear portions, as I recall.