Feels like a bulge but mics out ok ?

[sundog]

I just got a Seneca in .45 cal at a big church run community yard sale. Looked it over and for $150 it was mine.
When I got it home I ran patches down the barrel and Ah Oh a loose spot in the barrel, a place where the patch runs with little resistance for a couple of inches. The spot is about 2 inches back from the underlug.
I dropped in a bore light and saw nothing unusual then I used my micrometer and the barrel is not showing any deviation in that area.
I am trying to figure out what the heck is going on with this barrel before I shoot it.
Im stumped.

 

[Stumpkiller]

Did you check all four parallels? Could also be a spot with less than normal machining marks. Someone may have tried "fire lapping" the bore with odd results or scrubbed off some rust with aggressive steel wool or a 3M pad.

If it checks externally with no bulge I will say there is no make of barrel I'd feel safer shooting round balls in than a T/C. Just don't go insane with the powder.

 

[Zonie]

My guess is probably the same as yours. The barrel is "ringed" from someone firing the gun without the ball resting on the powder charge.

Because of the thick walls on a muzzleloader this often won't show up as a bulge on the outside of the barrel.

IMO, it is not a safety issue and the barrel will be totally safe to shoot.
How well it shoots is another question.

I've seen barrels like this that won't hit a watermelon at 50 yards but I've seen barrels that were lightly ringed that are still accurate.

The only way to find out which one you have is to shoot it with various powder/ball/patch combination's to see if you can find one the barrel likes.

 

[sundog]

Thanks guys. I am going to take her to the range today and try some loads.
Figure I will start with 45 grains of 3F and a PRB.

 

[contenderfan]

I agree with Zonie, a ringed barrel will not always cause an external bulge on the barrel. I have seen several ringed barrels that appear normal on the outside, even when measured with a mic.
The accuracy may not be affected, or it may be completely gone...only way to find out is to shoot it. Good luck with it.

 

[LRB]

Just curious, but if the bore is ringed enough to easily feel while loading, and does not read out on the out side, where did the swelling go? Steel does not compress, so it would have to show on the out side. In a case of this nature, I'd say it was done when it was bored or reamed. Not that it would matter I guess, a loose spot is a loose spot.

 

[paulvallandigham]

Where does the water in a calm pond go when a rock is thrown into its surface and creates a round dish, we call a "splash"????

A. it goes to the sides( outwards) and upwards.

In gun barrels that exhibit a ring on the inside, but not on the outside, a careful measurement( using tools not available to most people) you will find that there is a slightly raised section both fore and aft of the "ring". This slight rise if often mistaken as part of the "ring", when you just run a tight patch down to feel the "ring".

The raised section is much Wider and shallower than the depth and width of the "ring". ( Just like the width of the splash, when a rock hits water, is much wider than the diameter of the rock.) I dare say that my brother,Peter, would be talking about this in terms of "Fluid Mechanics", since he is a Mechanical engineer.

Remember that there is substantial heat AND PRESSURE at the moment that a "ring " is created in the bore. At that moment, the steel barrel is NOT as hard, nor as strong a surface, that it is at air temperature.

 

[LRB]

That makes some sense, I think.

 

[Zonie]

IMO, when a thick walled barrel is ringed, yes the material goes somewhere but, because the wall is very thick it moves the material ahead of and behind the ring just a little bit as well as outward.

Put another way, a fairly long area of the barrel does swell in size just a little bit.
Without knowing the exact size of the barrel before it was ringed it is difficult to know if its size being .9383 is actually a .9375 (15/16) barrel that is swelled or if that is just the size that the barrel was made to.
Also, because the expansion is spread out along a fairly long length, the size directly above the ring will be almost the same size as a measurement taken several inches ahead of or behind the ring.

Folks seem to think of steel as being very hard but in reality it is quite flexible and easy to move. That is the reason the bulge isn't concentrated right over the site of the damage.