Cannon Construction Recommendations
Below you will find the construction recommendations of the GBO Black Powder Mortar and Cannon forum. These are not universally accepted by all forum members; they were not established by a democratic process and voted upon by forum members. They are in fact the standards of two nationally recognized organizations. There are some parts of them that are confusing and contradictory, but they are what they are. There is no point in debating them.
People come to this forum looking for construction help or validation of previously constructed cannon. Our recommendations are our recommendations. We cannot engineer a different recommendation to fit materials and designs that are presented because we have no control over the materials or methods used by builders. We feel that our recommendations, while extremely conservative, have stood the test of time and we cannot in good conscience give advice beyond this.
The one exception to this is building scale models of professionally designed cannon, usually cannon designed in the 18th and 19th centuries using bronze or cast iron. If you build these designs in steel, you are OK as the material is much stronger than the original material. However, keep in mind that cannon of these designs were not used indefinitely; bronze guns were recycled after approximately 500 rounds and cast iron ones failed on average by 1500 rounds.
If you have the education and experience to engineer a design that is different, by all means do so. If you publish it, be sure to emphasize the requirements of following the design accurately in all particulars so as to not give a false impression that, for example, any old piece of scrap steel is appropriate for use. Also, if there are any limitations in use, such as retirement after firing 5000 rounds to prevent fatigue failure, be sure to state them.
One specific warning right now; DO NOT USE WATER PIPE for cannon barrels. A casual internet search on water pipe will reveal that only the smallest diameters are rated over 1000 psi (and not much over 1000 psi) and the larger sizes are rated less than 1000 psi. This is way too low. A cannon made from water pipe is a pipe bomb waiting to happen.
In the end, you will have to bear the responsibility for any cannon you build because you are the one who made the decisions. If you decide to build to some other standard, that is your choice; this also applies to the amount of powder you use in your gun. Keep in mind there are usually other people around when a cannon is fired; you are responsible for their safety as well as yours. And another point; cannon usually survive their makers, so don't make a substandard gun with the belief that you will only use "safe" charges. The next owner may not know that is a limitation of the gun.
GG Warning and disclaimer: Shooting cannons is not like shooting a big over sized muzzleloader. There is a completely different set of internal ballistics involved. Read up on cannon shooting before you acquire a cannon. Suggested reading is
THE MORE COMPLETE CANNONEER By M.C. Switlik with selected excerpts from other artillery manuals The book can be ordered from these two suppliers.
The Complete Cannoneer from Matt Switlikand
South Bend Replica Guidelines for Cannon Construction. The North-South Skirmish Association and the American Artillery Association publish a set of minimum standards for construction of full size cannons and mortars for use in their competitions. It suggested in the interest of safety that these standards also be used as a minimum standard for construction of model cannons. Knowledgeable builders will recognize that there are safety margins built into these standards and some original guns may not meet these standards. These standards appear to have been written to extend the safety margins of the original designs. Excerpts from their standards follow. Please refer to the N-SSA and AAA websites for complete and current rules.
NOTE: Any question about the definition or meaning of any of the standards listed below should directed to the N-SSA or AAA as appropriate. The standards are their standards and they should define them.North-South Skirmish Association National Rules.10.2 ELIGIBILITY
Actual or exact scale replicas of Civil War artillery pieces may be fired. The term “Civil War” applies to any artillery piece whose model antedates April 26, 1865. replicas of artillery pieces must duplicate original pieces. All reproduction barrels must be made of iron, steel or bronze. All reproduction barrels and those original failing inspection must be lined with a bore liner of extruded seamless steel tubing of a minimum ANSI standard and of a minimum 3/8-inch wall thickness.
Figure 10.1
The liner must be closed at the breech end with a steel plug, sweat-fitted into the liner and welded. The breech plug must have a radius of at least 25 percent of the bore radius and be at least 1 inch thick at its thinnest point. (See figure 10.1).
(N-SSA has advised us the term sweated means shrink fit.)
All reproduction barrels manufactured after March 1, 1986 must have pictures of the liner and breech plug before and after welding. No reproduction barrel shall be approved after March 1, 1986, that does not have one caliber’s thickness of metal surrounding the bore at the breech unless approved by Artillery Ordnance Officer. (See figure 10.2 for example.) Liner may be affixed by casting barrel around the liner or by other approved methods such as bonding with high strength adhesives. The method of locking the liner in the barrel shall be approved by the Artillery Ordnance Officer. The gun and its crew must pass the inspection specified in Section 18. A gun crew shall consist of a minimum of four members of the organization. Effective 1 February 1996, all artillery pieces must be originals or full-size, exact replicas to be approved.
National Safety Rules and Procedures for Shooting Muzzleloading Artillery, as adapted by the American Artillery Association March 2000These rules adapted by the American Artillery Association, March, 2000, from rules which were compiled by The Artilleryman magazine and reflect a consensus of safety procedures developed from historical records and practical experience of many present shooting organizations. They were written and edited by Matthew C. Switlik, author of The Complete Cannoneer; George McDonald III, Clark's Battery, N-SSA; Bernard Kurdt, 120th NYVI, N-SSA, Union and Confederate Volunteers, and American Artillery Association; and C.Peter Jorgenson, Artilleryman editor and publisher. These rules have been tested in our competitions, with our safety officers and procedures in place, and are not intended to be recommended in any other circumstance. The original version of the rules is available on the Civil War News website:
http://www.civilwarnews.com/artillerysafety.htm.
GENERAL INFORMATION
The following safe shooting procedure presumes the crew is firing blank charges or projectiles with a muzzleloading artillery piece made (or altered) to modem safety standards. (If firing blanks skip Step VII and see Safety Rule 10.) The bore should be lined with seamless steel tubing with a minimum 3/8-inch wall thickness and a yield strength of 85,000 p.s.i. or greater. The breechplug should be threaded and pinned; welded and pinned breechplugs can be equally strong but require expert installation by competent manufacturers. Sand-cored bores are not recommended for shooting. The vent should be drilled in a threaded copper bolt similar to original cannon vent liners of the 1840-1865 period in order to provide an unbroken passage through the casting and the liner, into the bore.
Safe LoadsFor guns under 2 inch use the chart below. National Safety Rules and Procedures for Shooting Muzzleloading Artillery, as adapted by the American Artillery Association March 20001. Powder charges should not exceed 2 oz. of Fg or 3 oz. FFA or Cannon Grade Goex powder per inch of bore diameter. No excessive charges. Use black powder only.
2. Prepare powder charges in advance using heavy duty aluminum foil. Baggies may be used inside the foil, taking care not to allow excess air in the baggies and removing excess plastic where unnecessary.
N-SSA National Rules for Cannons10.8.1 CHARGES
Maximum powder charges for all cannon shall be limited to that amount permitted by the chart as published below in Table 10.1. Only commercially manufactured black powder of American standard Fg granulation (150,000 granules per pound/ or 220 granules per 10 gr. wt. (avdp.) sample), or a coarser granulation, may be used. Charges must be wrapped in a powder “bag” fabricated of at least one complete layer of heavy-duty aluminum foil.
For specific load for you bore refer to
N-SSA National Rules for Cannons Table 10.1. Page 71 of 194 in the PDF file.
Moderator note: For guns smaller than 2 inch THE MORE COMPLETE CANNONEER compiled Agreeably to the Regulations of the War Department as published in "Artillery Drill" by George Patten, 1861 and Containing Other Observations on Antique Cannon By M.C. Switlik with selected excerpts from other artillery manuals Appendix I has a load chart which is posted here by permission of the author.
To see a large view of this chart click on this link:
http://www.fototime.com/90BD33C5013C58D/orig.jpgThis load chart is maximum load of a unpatched ball attached to a sabot.
Addendum For mortars and howitzers the diameter of the powder chamber is the considered the bore diameter.
Both Associations recommend for safety reasons that larger caliber cannons not be loaded with loose powder, instead use foil wrapped cartridges. Some locales have safety regulations requiring the use of foil wrap cartridges. Mortars generally are still loaded with loose powder, but check your local regulations to be sure. Click on this link to be taken to the post on loading cannon cartridges
Making Cannon Cartridges 
