I have a Ruger O/U 45-70, it was converted from a 20 ga, and a RIFLED 20ga SXS. Yesterday I had the 20 ga out and was going to mount the Red Dot sight on it. Figured I'd save myself some time at the range and "boresight" it.

So I set it up and immediately realized that when one barrel was pointed at the top of a telephone pole about 150 yards away the other barrel was pointing a few FEET off to one side.

As I've shot it before and it seems to be regulated fairly good I found this odd.

So I got the O/U 45-70 out and did the same with it. Haven't shot it lately but last time I did it was well regulated too.

And low and behold I get about the same thing with the 45-70!!

I mean the two barrels look like there is no way in heck they could possibly impact the same place.......

This just seems counter intuative.

I understand that regulating is something of a art but is it possible that there could be so much deviation between the bore picture of the two barrels and yet the two barrels shot to the same POI?????

Someone look at theirs and tell me if it's the same and then someone really smart explaing how this can work.

Yes

Search regulation.

Boresight it with the right barrel.

Then shoot your first shots up close, say 25 yards.

Because the recoil forces from the two different barrels, cause the gun to recoil different for each barrel, and the gun is recoiling while the bullet is still in the barrel....

The slower the velocity the farther apart the barrels must "look", because the bullet is in the barrel longer.

.............. It's magic!

The line of sight through the barrels will always look to be crossing, and lower than the point of aim when the rifle is static. What I mean by this is, the right barrel will be pointing at a point that is low, and on the left off the point of aim, while the left barrel will be pointing to a point that is lowand on the rightof the point of aim on the target. but at different amounts.

As NE 450No2says this is because of the barrel time, and the fact that each barrel's recoil arch will be different. The right barrel, for a right handed shooter, will recoil BACK, UP, and to the RIGHT, and the left barrel, for a right handed shooter with recoil BACK, UP, and to the left, but at different amounts, while the bullet is traveling down the bore before exiting the muzzles. If the rifle is regulated properly, and a proper regulating load is used the rifle doesn't cross at any range, but shoots paralell! When shooting a double rifle one should never be place dirrectly on sand bags,or any rest, but must be held in the shooter's hands, with the rifle not touching anything other than the shooters hands face and shoulder to shoot properly to the regulation built into the rifle.

I hope this is a little clearer than Mississippi mud!

I'm still confused but the rain will let me I've got about 40 rounds of different 20ga slugs, all made for RIFLED barrels, in hand and we'll see what happens when they go down range.

As a follow up on the issue of regulated double rifles, and the "dwell time" of the bullet in the barrel during recoil, will a much higher velocity round, say '06, 308, etc. be able to be bore sighted and yet be fairly close to where the round will impact?? Reason for asking is that later this year will end up with Merkel double in cal. 308. and the velocity of the rounds will be in the area of 2700fps. Don't mean to interrupt the thread, but figured you all would know what I am asking. Thanks,

martin

Took a while to actually get to the range to check on it.

Only shot a few rounds of each brand, all off a rest but supporting the gun in my hand with my elbow being what rested on the rest.

Sights were a little off to begin with but I adjusted the as I went.

First group is Remington Reduced Recoil.
Second is Brenneke.
Third is a couple of Hornady Sabots.

I was very surprised at how they all shot to about the same POI.

The Brenneks had the stoutest recoil. But that said, and even though it weighs less than 7 pounds, none of them kicked all that much.

As things turned out as they did I guess the fact that the boresighting of the different barrels was way off did not matter.

What distance were these?

Only about 30 yards. I don't know if the barrels are still converging or if they are diverging or what.

Need to go back and get the sights right and then shoot for effect at 50 yards.

Gun was built to hunt hogs with here in our FL swamps so shots will seldom be more than that.

Will most likely stick with the Managed Recoil as they shot good and I'm guessing they stress the action less.

Gun is built on a FN Sidelock, was a 16ga, from the 30's.

And I am sure they have enough power for a hog at those ranges.

So far so good, but it will be interesting to see 50yds. Should kill the snot out of pigs

With those patterns, our porcine friends will arrive on the barbecue!
Barrel magic at its best- it is amazing how many different things happen just after we squeeze the trigger!

bswiv,

ever dated a girl with crossed eyes? Same principle, I think...

Rich