Different POI on double?

Dave R · June 21, 2001, 10:23 AM

I just got my first double--a well-used 20ga SXS. When I patterned it, I noticed that one barrel (modified choke) shoots a nicely centered pattern. Right at POA.

The other barrel--the full choke--shoots low and right. That is, POI is low and right of POA. The center of the pattern is close to a foot off at 25 yards. The upper left part of the pattern catches POA.

Is it possible to adjust that POI of that barrel? Is it hideously expensive?

When I shot my first box at clays, I was able to hit reasonably (for me) often with the full barrel. I even made some "2nd shots" and hit one big piece after a break, but I had to consciously hold high and left to do it. Would hate to have to remember that come hunting season.

Dave McC · June 21, 2001, 10:42 AM

This isn't all that uncommon, Dave. Many doubles have convergence probs. It's one of the reasons good doubles are expensive, they "regulate" the bbls to coincide patterns of a particular type of load at a given distance.Have you "Rung" those bbls to see if any separation has occurred?

Also, is there any dings on that bbl and/or muzzle?

For those unfamiliar with Ringing...

Break your gun down and hang the bbls from a piece of coat hanger or something. Take a pencil,hammer handle, or piece of wood and lightly tap the bbls someplace around the middle.
Listen...

If a clear, bell-like sound keeps reverberating for a while after a tap, the bbls are OK. Try again in another spot,tapping the other bbl.

If a thud or short ring dies off fast, there's probably a separation, like a soldered joint coming apart between a bbl and rib.Separation can be fixed,but it's not cheap and the weapon needed refinishing afterwards.

There is an answer, expensive but not hideous. Briley will either thread that left bbl for tubes and make you a set of them bored eccentrically to bring those bbls into convergence, or possibly rebore the choke on that bbl eccentrically.

Another possibility I've heard of in these cases is the removal of 1/2" at the muzzle and recrowning.This is a sometimes cure.

All of the above are to be done by qualified smiths.

Dave R · June 21, 2001, 06:13 PM

Yup, I rang 'em. I learned that in _Unintended Consequences_.

Thanks for the review of options. I appreciate your informative posts, Dave McC.

Dave McC · June 22, 2001, 07:14 AM

You're welcome,Dave.

Even classic doubles from famous makers have this problem. An acquaintance's LeFever puts both bbls on center, but the left bbl hits about 70-30 while the open bbl shoots flat.He says he wishes it were the other way around, a high shooting load works well for flushing pheasants, and a flat shooting bbl for when they level off after climbing to escape altitude.

Much as I like classic doubles, I doubt I'd buy one now w/o a bit of shooting, some patterning, and a thumbs up on it from a smith I trusted. That last is a short list.

One other thing you can do that's not as costly, or as sure, as all that expensive gunsmithing.

Like other firearms, different loads have different POIs. Try patterning that tight bbl with every load you've available in the house, and see if one of those hits where it should. Getting one to exactly duplicate the other bbl/load's POI is a PITA, but you can find one that puts you close enough to work.

If you find that load, definitely possible, see how it works in that open bbl. You may have a new pet load.

Dave R · June 22, 2001, 11:50 AM

!!!!!!!!!!!!!!!!! What a great excuse to do some more shooting! I'm on it.

June 21, 2001, 10:23 AM	#1
Dave R Senior Member Join Date: January 7, 2000 Location: Idaho Posts: 6,073	Different POI on double? I just got my first double--a well-used 20ga SXS. When I patterned it, I noticed that one barrel (modified choke) shoots a nicely centered pattern. Right at POA. The other barrel--the full choke--shoots low and right. That is, POI is low and right of POA. The center of the pattern is close to a foot off at 25 yards. The upper left part of the pattern catches POA. Is it possible to adjust that POI of that barrel? Is it hideously expensive? When I shot my first box at clays, I was able to hit reasonably (for me) often with the full barrel. I even made some "2nd shots" and hit one big piece after a break, but I had to consciously hold high and left to do it. Would hate to have to remember that come hunting season.

June 22, 2001, 07:14 AM	#4
Dave McC Staff In Memoriam Join Date: October 13, 1999 Location: Columbia, Md, USA Posts: 8,811	You're welcome,Dave. Even classic doubles from famous makers have this problem. An acquaintance's LeFever puts both bbls on center, but the left bbl hits about 70-30 while the open bbl shoots flat.He says he wishes it were the other way around, a high shooting load works well for flushing pheasants, and a flat shooting bbl for when they level off after climbing to escape altitude. Much as I like classic doubles, I doubt I'd buy one now w/o a bit of shooting, some patterning, and a thumbs up on it from a smith I trusted. That last is a short list. One other thing you can do that's not as costly, or as sure, as all that expensive gunsmithing. Like other firearms, different loads have different POIs. Try patterning that tight bbl with every load you've available in the house, and see if one of those hits where it should. Getting one to exactly duplicate the other bbl/load's POI is a PITA, but you can find one that puts you close enough to work. If you find that load, definitely possible, see how it works in that open bbl. You may have a new pet load. Last edited by Dave McC; June 27, 2001 at 03:46 AM.

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June 21, 2001, 10:42 AM	#2
Dave McC Staff In Memoriam Join Date: October 13, 1999 Location: Columbia, Md, USA Posts: 8,811	This isn't all that uncommon, Dave. Many doubles have convergence probs. It's one of the reasons good doubles are expensive, they "regulate" the bbls to coincide patterns of a particular type of load at a given distance.Have you "Rung" those bbls to see if any separation has occurred? Also, is there any dings on that bbl and/or muzzle? For those unfamiliar with Ringing... Break your gun down and hang the bbls from a piece of coat hanger or something. Take a pencil,hammer handle, or piece of wood and lightly tap the bbls someplace around the middle. Listen... If a clear, bell-like sound keeps reverberating for a while after a tap, the bbls are OK. Try again in another spot,tapping the other bbl. If a thud or short ring dies off fast, there's probably a separation, like a soldered joint coming apart between a bbl and rib.Separation can be fixed,but it's not cheap and the weapon needed refinishing afterwards. There is an answer, expensive but not hideous. Briley will either thread that left bbl for tubes and make you a set of them bored eccentrically to bring those bbls into convergence, or possibly rebore the choke on that bbl eccentrically. Another possibility I've heard of in these cases is the removal of 1/2" at the muzzle and recrowning.This is a sometimes cure. All of the above are to be done by qualified smiths.

June 21, 2001, 06:13 PM	#3
Dave R Senior Member Join Date: January 7, 2000 Location: Idaho Posts: 6,073	Yup, I rang 'em. I learned that in _Unintended Consequences_. Thanks for the review of options. I appreciate your informative posts, Dave McC.

June 22, 2001, 11:50 AM	#5
Dave R Senior Member Join Date: January 7, 2000 Location: Idaho Posts: 6,073	!!!!!!!!!!!!!!!!! What a great excuse to do some more shooting! I'm on it.