Bore too smooth?

[subsonic]

Can a bore be too smooth to shoot PRB well?

I hear stories about etching bores once they wear out from shoving PRB down them.

One Encore barrel I had seemed to experience this phenomena. Could it be from a lube buildup? Working it over with JB bore paste didn't fix it and T/C sent a new replacement when I sent it to them complaining of a loss of accuracy.

[Hickory]

I have heard that theory espoused about high power rifles and jacketed bullets, that a very smooth bore will cause more fouling than a rougher one.

[wgr]

i can not buy into that for a patch round ball. you might wear out the crown and need it redone. they used to freshen the rifling if they got rough

[waksupi]

I have heard of them shooting smooth. Old remedy was to pee down the bore, dump it out, and let it rust over night.
Over the years, I have had rifles that seemed to go sour and not shoot, that eventually came back. No idea why.

[excess650]

I believe the phenomenon is called "shooting slick". Cures vary from "freshing the barrel" to simply roughing it lenthwise with coarse lapping compound. I wouldn't expect this to happen in a "gun barrel" steel barrel, but maybe in a leaded screw stock type barrel or old iron barrel.

[Boerrancher]

Now I have had guns go to hell on me while they sat in the safe or closet for many years. They just seem to shoot all over the map. It usually takes 3 to 4 trips to the range and several boxes of ammo to get them back to shooting again. It seems this always happens to them when they go unused for long periods of time.

Best wishes,

Joe

[subsonic]

I have heard of them shooting smooth. Old remedy was to pee down the bore, dump it out, and let it rust over night.
Over the years, I have had rifles that seemed to go sour and not shoot, that eventually came back. No idea why.

That is exactly the way I heard it. Except they now use vinegar.

Do you think it might be from a buildup in the bore? All of the "cures" involve acid or abrasives that would likely remove a buildup.

I also think an explaination could be that the edges of the rifling could loose sharpness. Although I'm not sure why pee would sharpen them back up.

[curator]

According to Harry Pope, the smoother the barrel the better the accuracy potential. That's why match barrels are precision lapped.

[excess650]

According to Harry Pope, the smoother the barrel the better the accuracy potential. That's why match barrels are precision lapped.

Barrels are lapped to ensure that all marks are going lengthwise in the bore. Lines lengthwise in a bore are no problem for cast, and in fact, are a place to hold lube. Lines areound the circumference of a bore act like a file as a projectile runs across them.

Pope's barrels were "choked", as in tighter at the muzzle, and gaintwist. Boolits were pushed through a false muzzle and down to just ahead of the chamber. These boolits had passed the choke, so were undersize at the breech, hence, the change in twist (gaintwist) held the boolit in place.

We're talking apples and oranges here in regard to a MLer barrel shooting slick.

[405]

That is exactly the way I heard it. Except they now use vinegar.

Do you think it might be from a buildup in the bore? All of the "cures" involve acid or abrasives that would likely remove a buildup.

I also think an explaination could be that the edges of the rifling could loose sharpness. Although I'm not sure why pee would sharpen them back up.

Yes, I too have heard the wive's tales about "too slick" ever since getting serious in the muzzleloader world. In some ways seems counter intuitive but I'm not dismissing the idea entirely either. I agree that there may more to the story than just too slick. My suspicions like yours would include build up of some sort or land leading edge wear, etc. Could be, as has already been posted.... in an attempt to cure what was thought to be too smooth.... the REAL solution was accomplished merely as a by product of that action without even realizing or understanding it. All a mystery to me.

Bottom line is- I'm not dragging out my muzzleloaders that have really nice smooth bores any time soon and roughing them up!:)

[subsonic]

I agree with leaving it alone if it's shooting!

But that encore was really odd. It came back and shot at one point after JBing it the first time and going to a tighter patch & ball. But it didn't last long and went away for good the next time.

I tried:
New box of balls
Larger balls
New patches
More and less lube on the patches
Inspecting crown
New can of powder
New box of primers

Nothing fixed it and the crown looked fine. With the QLA, I would find it hard to beleive that we hurt the crown, as It seemed nearly impossible to even touch it with the ramrod on purpose.

[405]

Hard to say when trying to repeat some earlier accuracy standard. I wouldn't think loss of accuracy was due to being too smooth. Has the rifle fired any lead conicals in the past? They can lead a bore. Have you tried basic cleaning between shots- solvent patch followed by dry patch? Could also be that the lands are simply wearing down and the leading edge is wearing or losing its edge. Another thing is it's hard to take a close look at right where the ball sits and just in front of where it sits when loaded without a bore scope. My theory is it's a very critical area of a ML bore that is often overlooked- with most attention focusing on the muzzle when working on accuracy issues. Another possibility is a bulge somewhere in the bore- can usually be detected by feeling for looseness when slowly running a tight oiled patch on jag thru a clean bore. Yet another possibility is a change of stress or tension or pressure point exerted on the barrel by the stock. And yet another possibility is a bent barrel. Strange as that sounds I've seen it. It was the last thing I was looking for when a friend asked me to see what was wrong with his ML. Hard to detect if not looking for it- but it will kill accuracy. He loaned his rifle to a friend to hunt with, wouldn't shoot when he got it back. Somehow his friend had bent the barrel. :shock:

[waksupi]

Something else that comes to mind. When I have a gun go sour during an extended shooting day, I clean the breech face. For some reason, a fouled breech can throw your shots all over the place.

[subsonic]

That barrel is gone now, since T/C replaced it, and as you can imagine, PRB was not really it's forte anyway.

Since it had a removable breach plug, i was able to inspect the bore very well. It did have some minor corrosion near the breach end, but it had that from the day I picked it up from the gunshop. It was a used barrel. I did replace the breach plug with no improvement and also checked for bulges several times. I never checked for a bend, but would think that woul be pretty obvious with the breach plug out while looking down the bore. It shot pretty well (2"@50yds or so) whenmy son and I first started using it, but when it would have this issue, you'd be hard pressed to hit a paper plate at 50yds 3 out of 10 times.

[wgr]

didn,t know it had a QLA. i got one with the QLA barrel and had to lap the QLA part of the barrel

[405]

That barrel is gone now, since T/C replaced it, and as you can imagine, PRB was not really it's forte anyway.

Since it had a removable breach plug, i was able to inspect the bore very well. It did have some minor corrosion near the breach end, but it had that from the day I picked it up from the gunshop. It was a used barrel. I did replace the breach plug with no improvement and also checked for bulges several times. I never checked for a bend, but would think that woul be pretty obvious with the breach plug out while looking down the bore. It shot pretty well (2"@50yds or so) whenmy son and I first started using it, but when it would have this issue, you'd be hard pressed to hit a paper plate at 50yds 3 out of 10 times.

A slight bend is very hard to see while looking down the bore or along the outside edge of a round barrel. An octagon is a little easier but still not very obvious with a subtle bend.

As to accuracy potential. Given decent open sights, a good bench and rest and paying attention to load details... my accuracy threshold for a decent ML is closer to 1/2-1" at 50 yards. But like everyone, some days I just can't shoot as well as others. IMO, the 2"@ 50 group is right on the upper margin of what most decent MLs should do. The "pattern" all over the backer especially with a PRB load, even if the rifle has a slightly faster 48" twist, does indicate something WAY bad! Minor load problems, ball irregularities, powder, patches, bore wear, some bore pitting, some fouling, sight picture error, etc. usually won't account for that much. Very few things would cause that much. I don't believe minor crown irregularities would do that much with a PRB group @50. I've seen a fair number of original ML crowns with file marks for freshening the grooves at the muzzle and even crude hand coned muzzles that shot PRB fairly well. But even a very slightly bent barrel will really scatter them! So the real cause may forever remain a mystery.