Determining Barrel Bulge

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nw mb

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...i recently bought an H&R 10 gauge on the EE

...i use 10 gauge in shooting ducks and geese and wanted a cheap 10 gauge to use with black powder

...i will eventually cut off the choke to produce a cylinder bore...a 30 yard gun

...but in the mean time i notice that running my fingers along the end of the barrel there is a wave in the steel...it's almost as if the choke (full) is welded onto the barrel...a constriction and then an opening up of the barrel diametre which is then straight to the muzzle

...looking inside the cleaned bore there appears to be no wave inside the barrel

...anyone have a way for me to measure the inside diametre of the bore to see if there is an interior bulge, if there is such a thing (without cutting it off first - lol)?

thanks

RsPQzOR.jpg
 
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It might be normal on some guns with a screw-in choke... but I have a mossberg 535 that when you look down along the gun towards the end of the barrel, you can see a slight bulge about where the choke starts. It's always had the modified choke in it, has never had anything bigger than BB fired through it, and has never had anything stuck in the barrel
 
nw mb said:
...i recently bought an H&R 10 gauge on the EE

...i use 10 gauge in shooting ducks and geese and wanted a cheap 10 gauge to use with black powder

...i will eventually cut off the choke to produce a cylinder bore...a 30 yard gun

...but in the mean time i notice that running my fingers along the end of the barrel there is a wave in the steel...it's almost as if the choke (full) is welded onto the barrel...a constriction and then an opening up of the barrel diametre which is then straight to the muzzle

...looking inside the cleaned bore there appears to be no wave inside the barrel

...anyone have a way for me to measure the inside diametre of the bore to see if there is an interior bulge, if there is such a thing (without cutting it off first - lol)?

thanks

RsPQzOR.jpg
Click to expand...

There are dial bore gages available that you could run down the tube and see the size variations if there are any. They look like a set of inside calipers with a dial to read out on the other end.

They are worth more than the gun is.

Shoot it, spend more time on that than on hand wringing. Esp. if you are planning on hacksawing it shorter anyways.

They were not exactly spending a whole lot of time on fit and finish on those at the factory. If you cannot see and apparent bulge when sighting through the bore from either end, like as not it came of the lathe that way, and someone called it good enough.

For another dozen or two dozen thousands of dollars, you can buy a (used) bespoke English gun, and be assured of not having such issues!

Cheers
Trev
 
If you look through a barrel, a bulge would show up as a distinct dark ring. (because it is larger than the shiny bore and doesn't reflect the light as the smooth bore does)
 
zuke said:
Place a steel ruler on the barrel and see the gap
Click to expand...

That will show if the outside of the barrel is not smooth, but will tell nothing about the inside.

Reality is, these firearms are marvels, in that they sell for very low retail prices, and are as good as they are. They don't get much in the way of care and attention to detail beyond what it takes to make them work.

If sighting through the barrel does not reveal any obvious bulge, like as not, nothing whatsoever wrong.

Cheers
Trev
 
If there is no evidence of a bulge on the outside of the barrel but it appears that there is when looking through the bore, it may be that someone has polished out the bore to create a"jug choke" that could increase the effect of the existing choke. Typically the jugged area will be an inch or so long and an inch inside the muzzle. I have a Navy Arms percussion double 12 ga that was apparently manufactured with cylinder bores. A previous owner jugged both barrels about .010 to create some choke effect and it worked: it really smashes clay targets even beyond 30 yds.
Shoot a couple of patterns on paper and see what effect you get - that is the only test that really counts anyway.
 
...thanks all...it wasn't a real concern to me...i just see it as an opportunity to learn and was looking for a way to measure the inside in a way that would reveal a weakness...

...took the barrel to a friend who's a machinist yesterday and he used a gauge to determine the inside diametre...turns out that while there is a clear wave in the outside of the barrel, there is no bulge, so that's good to see how that's done...

may use it with some factory loads this fall before i get around to setting it up for black powder

nw mb
 
zuke said:
Place a steel ruler on the barrel and see the gap
Click to expand...

trevj said:
That will show if the outside of the barrel is not smooth, but will tell nothing about the inside.

Reality is, these firearms are marvels, in that they sell for very low retail prices, and are as good as they are. They don't get much in the way of care and attention to detail beyond what it takes to make them work.

If sighting through the barrel does not reveal any obvious bulge, like as not, nothing whatsoever wrong.

Cheers
Trev
Click to expand...

I think he is saying to place a steel machinists rule inside the barrel not outside to check (maybe :) ).
 
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