sights on swamped and tapered barrels

[jmforge]

How do you compensate for the "slope" of a swamped or tapered barrel when installing sights?  Seems to me that with a swamped barrel, the rear sight would be going "downhill" whihc seems like an issue if you are using say a multi-leaf jaeger or English sight.

[rich pierce]

Swamped barrels are set up perfect for sights because it gives the rear sight just a little elevation autpmatically.  Helps avoid that tall front sight you'd need if the barrel was tapered but not flared.  I think this may be one reason they made swamped barrels (breech thickness, overall weight and balance being the main factors).

The angle is not enough to worry about, a couple of degrees is all.  I normally make sure the back edge of the rear sight is higher than the front edge, to keep glare down.  With a swamped or tapered barrel this happens automatically.

[Stophel]

My front sights almost universally end up about half as high as the rear sight.

[northmn]

If the rear sight bothers you in that matter compensate with the dovetail cut.

DP

[jmforge]

If the rear sight bothers you in that matter compensate with the dovetail cut.

DP

But how would you do that with something like a 3 leaf sight where the dovetail is over an inch long?

[Stophel]

I'm still not sure what the problem is.   

[jmforge]

I'm still not sure what the problem is.   

I guess the point is that your sight base would not be level unless it was specifically built for a tapered barrel.  The multi leaf "express" sights that I have seenon expsnive guns have been mounted on a quarter rib that has been machined to fit the taper of the barrel and still have a flat top.  Regular sights for such modern rifles seem to be built so that the bottom of the sight follow the taper and circumference of the barrel, but the top is flat.  I;m not sure how you do that with an "off the shelf" dovetailed sight.  It probably doesn't make much of a difference with a single rear, but I would think that it might if you were using say the Pedersoli 3 blade English sight.  Like I said, the dovetail required to mount that sigh is over an inch long, so you would be going downhill, so to speak.

[T*O*F]

Barrel thickness + rear sight height above the flat gives your starting measurement.  You can run a rod thru the bore to measure from.  Once you have that measurement, your front sight should be the same with the blade making up the difference.

Shoot the gun and file the front sight until it's on at 100 yards.
Then you can use your express sights and see what range they are zeroed for......if you can shoot that far.  They will be load dependent.

[D. Taylor Sapergia]

So what?  You have to file the leaves of the express sight to zero at their ranges anyway.  They don't come sighted in, just because it is stamped 200 meters.
Forgive me if I am assuming something.

[rich pierce]

The angle is so slight as to mean almost nothing over an inch.  Everybody mounts sights with dovetails parallel to the top flat.

On a D weight barrel like the Marshall barrel profile, the taper over the first 12" is .125".  That is about 15/1000" taper per linear inch.  I think that's like 1/64".  So a 1" dovetail is tipped down 1/64" relative to the bore.  I am sure each blade of your express sight is taller or shorter than the next one by more than 1/64".  In any case, they are not separated by 1" so the effect is negligible.

[Pete G.]

If it really does bother you either file the bottom of the sight base to a slight angle or cut the rear end of the dovetail a hair deeper. Either way I think it is much ado about nothing, but we do these things to make ourselves happy (at least in theory). If it bothers you now, you will never be happy with it in the future.

[Stophel]

You mean the rear surface of the sight is not perfectly vertical?  Eh.  wouldn't worry about it.

If it concerns you, it is easy to simply file the face of the sight to angle back slightly.

 

[jmforge]

You mean the rear surface of the sight is not perfectly vertical?  Eh.  wouldn't worry about it.

If it concerns you, it is easy to simply file the face of the sight to angle back slightly.

 

I was wrong.  The length of the Pedersoli 3 leaf express sight base is slightly over 2 inches.  I wouldn't be so worried about the slight angle, but whether or not the "drop" would render the too taller flip up sights too short to be effective without filing down the V notch on the fixed blade a lot.  On the old guns, this would not have been a problem because every part of the gun custom built around the barrel, but in this day of off the shelf parts and in the case of some swamped barrels, very exaggerated "waistlines" I was just wondering.

[Dphariss]

You mean the rear surface of the sight is not perfectly vertical?  Eh.  wouldn't worry about it.

If it concerns you, it is easy to simply file the face of the sight to angle back slightly.

 

I was wrong.  The length of the Pedersoli 3 leaf express sight base is slightly over 2 inches.  I wouldn't be so worried about the slight angle, but whether or not the "drop" would render the too taller flip up sights too short to be effective without filing down the V notch on the fixed blade a lot.  On the old guns, this would not have been a problem because every part of the gun custom built around the barrel, but in this day of off the shelf parts and in the case of some swamped barrels, very exaggerated "waistlines" I was just wondering.

Honestly a sight like this really has little place on a swamped barreled Kentucky. The typical bore size limits them to 100-140 yards for hunting and most will shoot "flat" for big game to that distance so extra leaves are a waste of time. If you play around shooting farther it might be interesting.
If you must have a 3 leaf sight make a small one or have someone make one.
I have a short base one on the 16 bore and have never zeroed the tallest and have done only a little shooting with the middle one.

Dan

Dan

[jmforge]

You mean the rear surface of the sight is not perfectly vertical?  Eh.  wouldn't worry about it.

If it concerns you, it is easy to simply file the face of the sight to angle back slightly.

 

I was wrong.  The length of the Pedersoli 3 leaf express sight base is slightly over 2 inches.  I wouldn't be so worried about the slight angle, but whether or not the "drop" would render the too taller flip up sights too short to be effective without filing down the V notch on the fixed blade a lot.  On the old guns, this would not have been a problem because every part of the gun custom built around the barrel, but in this day of off the shelf parts and in the case of some swamped barrels, very exaggerated "waistlines" I was just wondering.

Honestly a sight like this really has little place on a swamped barreled Kentucky. The typical bore size limits them to 100-140 yards for hunting and most will shoot "flat" for big game to that distance so extra leaves are a waste of time. If you play around shooting farther it might be interesting.
If you must have a 3 leaf sight make a small one or have someone make one.
I have a short base one on the 16 bore and have never zeroed the tallest and have done only a little shooting with the middle one.

Dan

Dan

Actually, I was looking at the TOTW English sporting rifle kit and it comes with a swamped jaeger barrel.  I have read one place that some Purdeys had swamped barrels, although I haven't seen one that looked as swamped as some of the currently available ones.  Others say that some had tapered barrels and some of the big bore gun barrels look straight or ever so slightly tapered.  I have also seen Purdey shotguns that had swamped center ribs, so I'm still trying to figure this whole thing out..lol.

[J.D.]

IMHO, you are over thinking this. Once you get it finished, just take it out and shoot it. If the long range leaves are too short, make longer leaves, or inserts for the existing leaves.

There is nothing that says anyone has to live with production parts, as they come from the vendor.

God bless