doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com Starting a new project- testing the barrels

We're getting started on the next double flint project. We have a set of 10 bore barrels that came from an unknown Parker Brothers model. They have a very nice plain twist Damascus pattern and the top rib is patterned too which is ideal for a double flint replica. But, there's a few problems with this barrel set and they may be unfit for use. We'll first ring them to see if they're solid. In the video clip a solid barrel set is checked as a reference. Notice the clear, sharp tone. A dull thud with a bit of rattling comes from the Parker barrels.

Parker barrel test video

The dull thud and rattling could be something as simple as loose ribbing or a major issue like a crack in one of the barrels somewhere or a combination of both. Next we'll break out the Magnaflux kit and do some additional testing.

Hank

Magnaflux is finished. We needed to check the ribs; both top and bottom have major gaps in the solder joints. This is easily fixed. Two other areas concerned me:



This spot is 4" back from the muzzle on the right barrel. It Magnafluxed OK. The other area:



This area is 13 1/2" up from the muzzle. Bad news:



There is a small crack or separation in the laminate indicated by the thin red line. I would not use this barrel set as is. Relining the barrels is an option. Separating them to use the left barrel as single barrel fowler is another option. It's a beautiful barrel set having very clean bores. I'm not ready to give up on them yet. Further opinions of the assessment?

Hi there Hank01
I don't know squat about damascus bbls,apart from that they look very beautifull. but that red line crack doesn't look good...starting to get close to the left hand hold.
Though I see you say you wont use that one.
I wish you luck with the bbls....keep us posted ...that last on you made looked Great, at least to me
cheers
franc
PS...is magnafuxing like X raying the tubes?

Thanks Franc. There are two types of Magnaflux testing: magnetic particle and dye penetrant. Magnetic particle requires special equipment which far exceeds my budget. Dye penetrant is what you see up there. It's a three step process all of it coming out of spray cans. The process is simple. Clean the area to test, spray on the penetrant then wait a few minutes before wiping away the excess. Spray on the developer and there you have it. Cracks show as red lines against the white. It's a simple but very effective way to find defects otherwise invisible.

Magnaflux spot check website

Hank

Interesting stuff. Can a crack like that develop in fluid steel barrels too or is it really a case of the twist separating"

does the test indicate if the crack goes right through?

Its interesting - in the UK guns are generally just sold based on proof and sometimes wall thickness - i wonder how many guns that are considered safe and in proof have flaws in them!

The pitting really wouldn't bother me.

the cracks a bit concerning - one of those things once seen cant be un seen - would i want to knowingly put hours of work into a potentially flawed barrel set; no.

Would i line the barrels? eeegh probably not for what its worth.

the picture you shared in the other thread shows some great skill in making these guns - have you thought about making a barrel set from scratch - although yes you wont get damascus tubes you will be able to build the breaches and properly replicate the less tapered more svelte barrels of the original flinters.

Belgian gun makers perfected a technique for "imitation" Damascus, so with a bit of practice getting a twist Damascus appearance could be possible.

Judge, I suppose it is possible for something of this nature to develop in a modern steel barrel. But, as I see it, is highly unlikely unless the steel is very poor quality or a portion of the wall has become exceedingly thin for whatever reason.

Demonwolf, the test can indicate a straight through defect. A more pronounced bleed of the penetrant indicates a more severe defect. The thin red line in the photo above indicates a surface flaw but if you look at the barrel/rib seam just above it there is considerable bleed of the penetrant. This indicates a void in the solder joint.

It's interesting you mention barrels passing proof which may otherwise have a defect somewhere. While doing research I recall reading one of the early makers, I've forgotten which one, actually tested barrels using pressurized water before sending them off to proof. I'll look that up to relearn who practiced this process.

Lining the barrels is out of the question and no way will this barrel set be used as is. It's conditions such as this that gives Damascus barrels a bad reputation. That barrel is compromised and I shudder to think the potential, even with a black powder load. It's a disaster just waiting to happen in my opinion. We'll separate the barrels, scrap the one with the crack and save the other for a single barrel fowler project.

Yes, we are in the process of developing modern steel barrels to replicate the original form of the early sporting barrels. Setting the barrels into the stock will be much simpler and the barrels will be more historically accurate in appearance. As for the faux Damascus pattern, I know of only one person here in the states who has mastered this process. Will he divulge his secrets? I haven't the nerve to ask. In the meantime we'll continue to experiment and hopefully arrive at the "perfect solution".

Hank

More likely a laminate separation- the red line is not dead money vertical, but follows the radius of the laminate, as shown by the Magnaflux dye process. In two of the boiler and pressure vessel shops where I welded to ASTME codes in my working years- the Magnaflux process was used a great deal--first time I have seen such good photos of such a dye penetrant Magnaflux test on shotgun barrels- Bravo--

It's good to check questionable barrels, or any Damascus barrel for that matter, before beginning any kind of work on them. That barrel may have survived proof testing but who's to say how long until it completely opens up? One can not be too careful when it comes to gun safety whether it be scratch built or restoring a 100 year old relic. That's my sermon of the day.

It's a shame the Parker barrel set is unusable but we have two more sets under consideration:



Both are 12 bore, the top set is 31 3/4" long and carries Belgium proof marks dating it to the early years of the 20th century. It's stamped "Laminated-Steel" on the top rib and shows a faint hint of twist striping around the forearm lug. This appears to be fake striping as acid testing other areas produced no visible pattern.

The bottom set is 30" long, carries no proof marks or marking of any kind to identify its origin. It is a true plain twist, the stripes relatively wide, wider than that typically found on Belgium made barrels. The pattern and width of stripes closely resembles that found on British made barrels from the latter part of the 18th century. The ribs are joined to the barrels by soft solder again typical of British made barrels. This set could not have been sold in the UK, at least legally. Since 1813 proof laws in the UK make it an offense to sell or offer for sale any unproved firearm. Since this set carries no proof marks it is unproved in the eyes of the law. So, what road has this barrel set traveled to finally end up on my workbench? We'll never know.

Both sets have 3" chambers, relatively clean bores with mild to moderate pits scattered about within. Rarely do you find an old barrel set free of dents. Neither set has any dents and the muzzle end of both show no physical signs of abuse. Both sets are solid and ring well. The bore scope comes next to have a thorough look at the pit situation.

Hank

Been working (fighting actually) with this bore scope for the past couple days and finally got some pictures that are kind of presentable. The Belgium made set has pits ranging from moderate to severe:



In the left bore, this is 13 1/4" inches up from the breech. They appear to be moderate and given the wall thickness at this point should pose no problem. The largest part can be cleaned up with the hone. From the right bore:



This is 6" up from the breech and a bit more severe than the left. Trying to completely remove the worst of it could make the barrel wall too thin. Since this falls within the "high pressure zone" we'll hit this area with the hone to clean it up as much as possible and let it go it that. It may or may not cause problems with the shot pattern.

The unmarked set has nearly pristine bores with extremely mild pits just ahead of the forcing cone in both barrels. They show signs of considerable use but the previous owner(s) obviously took very good care of these barrels. Next we'll fit both barrel sets with breech plugs and proof test them. Both should proof in fine order.

Hank