A friend has a BT99 trapgun with choke tubes
It patterns almost a full pattern to the left
of the point of aim
Are there any cures for this problem??
Thanks Sydney

Bend the barrel

Does it do it with all of the choke tubes? Have you patterned it or is it just your friend? Check the rib and make sure it is straight and true and parallel to bore. Outside chance barrel could have been reamed and threaded off axis for the choke tubes.

Biobster's on the righ track..First, have a couple people shoot it to see if the issue is consistent.

If only the owner, poerhaps some stock fitting is the cure.

If two folks have the same pattern, start looking over the barrel...but I'd suspet some whpperjawed tubes.

I remember Bill Nittler changing POI by working on the forcing cones, overboring...etc, he was a wizard.

In 1970's, I think, the Grand American Trap shoot was at Rochester Brooks gun club. Art Goodwin told the story of Remington's factory shooter shot a few practice birds, walked over to his pickup where he had something mounted on his bumper into which he inserted the barrel of his 1100 and tweaked it a bit, went back and shot a few more and then did it again. I guess it's all in the guy doing the tweaking.

Hi Going to pattern it again with 2 shooters
should give us a true picture
Thanks Sydney

I've tweaked my shotguns POI by putting thin plastic shims where the buttstock matches up with the back of the receiver. I cut the shims from bleach and detergent bottles. But I dealt with 10% pattern shifts...not 100% off.

If you point the shotgun with both eyes open at a target then your eyes are the rear sight and then yes stock shape, cast, bead height, correct use of master eye, etc., will all affect the centre of impact of the pattern.
If you aim the shotgun at a target, like a rifle using a centre bead or rear centre of the rib and the front bead, off eye closed, then this will give an indication if the barrels and or chokes are 'bore sighting'. If not then as others have mentioned it could be a barrel, choke or rib issue which will manifest itself no matter who does the shooting.

quote:

Originally posted by Sydney:
Hi Going to pattern it again with 2 shooters
should give us a true picture
Thanks Sydney

Results?

Hi I passed all the info to my friend
and he still has not patterned the
shotgun
I guess he s not too interested in
fixing the problem
Thanks for all the relies
Sydney