Author Topic: Suitable Barrel Liner Material (Read 1131 times)

muskeg stomper · « **on:** April 19, 2012, 06:32:08 PM »

Some time ago I posted photos of a rough cast brass cannon barrel that I purchased. I'm preparing to get it bored out and have a liner installed in it. I found a metal supplier selling through eBay with a couple of types of tubing that would dimensionally work well for the liner but I know nothing about the properties of the metal. I'm solicating the opinions of you knowledgable folks on such things to give me a yah or nay on either of these for use.
http://www.ebay.com/itm/110525825577?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
http://www.ebay.com/itm/310345366304?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
I appreciate the info folks.

Double D · « **Reply #1 on:** April 19, 2012, 07:56:53 PM »

DOM is welded seam, it is not seamless

muskeg stomper · « **Reply #2 on:** April 19, 2012, 08:16:23 PM »

Not doubting you at all DD but reading both descriptions lead me to believe that there is both seamless and welded seam DOM tubing. I do not know if that is really the case or not. Do you know anything about the properties of the steel listed? When I see the word alloy in one of the descriptions, I have my doubt about the composition of that metal.

Victor3 · « **Reply #3 on:** April 20, 2012, 01:38:34 AM »

Muskeg stomper,

You might have a look at this thread for further info regarding DOM tubing...

http://www.gboreloaded.com/forums/index.php/topic,247969.0.html

Soot · « **Reply #4 on:** April 20, 2012, 01:41:20 AM »

Suppliers often call DOM seamless, I believe this is because there is no apparent seam.
DOM starts as a flat plat, drawn over a mandrel (DOM) and welded.
Manufacturers of DOM tubing never call it seamless.

muskeg stomper · « **Reply #5 on:** April 20, 2012, 04:50:06 AM »

Gents, thanks for the feedback thus far but I have to tell you, I'm still a little confused. I've read through the thread on cleaning DOM lined bores several times before and all the discussion it contains. The whole DOM vs Seamless thing is what has me thinking that maybe I need to try a different approach. For the record, I'd rather subscribe to the "safer is better" theory. So on a different tact, " What would you recommend for a material to fabricate a liner for a 1" bore brass cannon?"

Double D · « **Reply #6 on:** April 20, 2012, 06:31:05 AM »

You may not need a liner. What type of brass and what is the diameter of the brass over the breech?

Yes some folks who are very knowledgeable on metals, metallurgy and the issues of welded seam tubing and who have no knowledge of the reasoning AAA and N-SSA has for recommending against the use of that type tubing, have muddied the waters.

GGaskill · « **Reply #7 on:** April 20, 2012, 09:05:58 AM »

Depending on the size of your barrel, it might be practical to make a liner from a solid piece instead of tubing. Certainly gives you a good breech plug that way.

muskeg stomper · « **Reply #8 on:** April 20, 2012, 09:35:55 AM »

The exact type of brass the barrel is cast from is a mystery to me. I bought it off of a guy who found it "as cast" in a barn on a property that he purchased. Perhaps I really shouldn't say "as cast" because while the casting is still as poured on the outside, someone did start trying to drill the first few inches of the bore. I have the barrel sitting in a machine/line boring/welding shop right now while the shop foreman is looking for suitable liner material before he does anything to it. That is what prompted me to start this thread in the first place.

The barrel dimensions as nearly as I can remember without having it here available to measure now was either 2.75" or 3" at the breach end and 2" at the muzzle end so a 1" bore should have sufficient material around it. There are no observable voids in the brass either on the exterior or in the few inches of existing bore. Am I being overly cautious or is there no such thing? I would like to have a nice strong liner in it.

GGaskill · « **Reply #9 on:** April 20, 2012, 12:32:41 PM »

What is the smallest diameter on the barrel where the liner would go?

flagman1776 · « **Reply #10 on:** April 20, 2012, 12:38:29 PM »

Link to your original post & photos

http://www.gboreloaded.com/forums/index.php/topic,247646.msg1099436434.html#msg1099436434

Victor3 · « **Reply #11 on:** April 21, 2012, 01:28:24 AM »

Quote from: muskeg stomper on April 20, 2012, 09:35:55 AM

The exact type of brass the barrel is cast from is a mystery to me. I bought it off of a guy who found it "as cast" in a barn on a property that he purchased. Perhaps I really shouldn't say "as cast" because while the casting is still as poured on the outside, someone did start trying to drill the first few inches of the bore. I have the barrel sitting in a machine/line boring/welding shop right now while the shop foreman is looking for suitable liner material before he does anything to it. That is what prompted me to start this thread in the first place.

The barrel dimensions as nearly as I can remember without having it here available to measure now was either 2.75" or 3" at the breach end and 2" at the muzzle end so a 1" bore should have sufficient material around it. There are no observable voids in the brass either on the exterior or in the few inches of existing bore. Am I being overly cautious or is there no such thing? I would like to have a nice strong liner in it.

Just my opinion, so take it only as that...

You have a sand-cast barrel of unknown material and integrity (possibly with undetected porosity, inclusions, cracks, etc.). Therefore you don't know much about its strenght, regardless of wall thickness over the breech area.

If you're unable to determine the alloy and integrity of the casting (and thus be able to calculate its strength), you'll only be guessing as to how much the outer barrel "shell" is adding to the strength of the bbl + liner assembly. In that case, the only truely safe liner will be one that's safe to fire by itself.

Cannoneer · « **Reply #12 on:** April 21, 2012, 10:34:29 PM »

Victor,
What can I say, when you're right, you are right.

flagman1776 · « **Reply #13 on:** April 22, 2012, 04:37:17 AM »

The logic of this is unrefutable.
Russ

Quote from: Cannoneer on April 21, 2012, 10:34:29 PM

Victor,
What can I say, when you're right, you are right.

muskeg stomper · « **Reply #14 on:** April 22, 2012, 07:41:05 AM »

Agreed, so what are you recommending for a liner material, i.e. type steel, dimensional thickness, and possibly even a source for material?

GGaskill · « **Reply #15 on:** April 22, 2012, 11:29:02 AM »

Still need to know the smallest barrel diameter the liner would pass through.

muskeg stomper · « **Reply #16 on:** April 22, 2012, 12:46:17 PM »

"The barrel dimensions as nearly as I can remember without having it here available to measure now was either 2.75" or 3" at the breach end and 2" at the muzzle end so a 1" bore should have sufficient material around it."

Zulu · « **Reply #17 on:** April 22, 2012, 01:04:59 PM »

From looking at your pictures, 2" at the muzzle is not the smallest diameter of the barrel. The smallest diameter is behind that. That is the measurement that George is looking for.
Zulu

muskeg stomper · « **Reply #18 on:** April 22, 2012, 01:15:30 PM »

That smallest area is where it measures 2"

Victor3 · « **Reply #19 on:** April 22, 2012, 11:15:04 PM »

Quote from: Cannoneer on April 21, 2012, 10:34:29 PM

Victor,
What can I say, when you're right, you are right.

Well, you know what they say about blind squirrels.

Muskeg stomper,

You could have your machine shop make a very safe (as far as deadly weapons go) 1" bore liner out of 1.5" dia 4130 steel bar. You'll want to have them include a reduced diameter powder chamber. 5/8" dia x 2" long should be plenty for as much of a charge as you'd want for a 1" cannon.

The above liner wouldn't likely fail under normal circumstances using BP, and any added strength the brass might provide is gravy.

One thing though - If the smallest diameter of your bbl is indeed 2", the liner I describe will leave you with only 1/4" of brass wall thickness at that point. If that 2" area is out of round (common on sand castings) and/or if the shop bores it off-center, you may not even have a 1/4" wall all the way 'round the circumference of the bbl.

Even if you do have 1/4" of wall, the muzzle swell ahead of the thin area is a heavy piece of material. It's possible (although maybe not likely) that under recoil, the thin area may crack. Especially if the casting isn't sound in that area. However, if you use a strong epoxy (or better yet, solder the liner in full length), the above probably won't be an issue.

jamesfrom180 · « **Reply #20 on:** April 23, 2012, 08:32:27 AM »

This is just a thought and by no means do I think it is what "should" ultimately be done. But, how about buying a 10 gauge shotgun barrel and making a salute gun. Have the machine shop cut the onion and breach off the bronze billet and bore a simple bore to be sleeved by the shotgun barrel. Then using appropriate technique and mechanical ingenuity build a breach that hinges and latches closed over the blank cartridge. There are plenty of striker designs out there for center fire strikers.

NOTE: As is indicated below legal issues would be a limiting concern.

GGaskill · « **Reply #21 on:** April 23, 2012, 01:55:04 PM »

I would ask the ATF for a letter before proceeding with this idea as you are making a short barrel shotgun otherwise.

Double D · « **Reply #22 on:** April 23, 2012, 05:17:14 PM »

Search old posts by Powder Keg for an ATF Letter on signal guns. THat letter will give you guidance, but is always better to have letter with your name on it.