How much of a change in impact vs point of aim is there when you change chokes?

Super-Dave · February 16, 2009, 09:57 AM

How much of a change in impact vs point of aim is there when you change chokes?

Hardly noticable or do you need to re sight the shotgun?

hogdogs · February 16, 2009, 10:36 AM

If properly machined... the POI/POA should vary little if any. That is obviously to center of pattern.
Brent

JWT · February 16, 2009, 12:23 PM

Agree with Brent. A properly made tube should not change POI/POA when changed to another choke.

BigJimP · February 16, 2009, 04:34 PM

It shouldn't make any difference if the choke is properly made - but you can't necessarily believe the markings on the choke in terms of the size of pattern you will get at the kill range you are testing for. If I have 4 Modified chokes - hopefully - if they're concentric the point of impact ( center of pattern ) will be the same ( maybe plus or minus 6" which can be a lot and I may see some holes in the pattern - meaning one choke is a hair tighter or looser than one of the others vs a given gun .

You can drive yourself crazy with this stuff - but its a good idea to check the pattern on every choke you have - for every gun you intend to shoot that choke in.

Now changing guns is different too - the choke is a function of the amount of constriction vs the inside diameter of the bore of the gun ( not all 12ga's are the same ) so you have to check every gun. I have a number of Browning O/U's - and the bores on them vary more than you might think. If you're only shooting one gun with the chokes you are checking - its a little easier to keep track.

kirbythegunsmith · February 17, 2009, 06:33 PM

I will offer the opportunity to see if anyone can explain under what circumstances a set of accurately machined choke tubes (shot with identical loads and conditions) will have different points of impact.

There is definitely one situation that can be understood to cause that particular effect, and I wanted to give some bright individuals a chance to mull this over before unveiling the answer.

If you think you know the answer, don't divulge it here, instead email me and I will show a list of those that did pass, but I won't post those that didn't pass.

Class dismissed.

Kirby

February 16, 2009, 09:57 AM	#1
Super-Dave Senior Member Join Date: February 1, 2008 Location: Florida Posts: 795	How much of a change in impact vs point of aim is there when you change chokes? How much of a change in impact vs point of aim is there when you change chokes? Hardly noticable or do you need to re sight the shotgun? __________________ If you want a vision of the future, imagine a boot stamping on a human face - forever. George Orwell

February 17, 2009, 06:33 PM	#5
kirbythegunsmith Member Join Date: February 15, 2007 Posts: 75	This is a test I will offer the opportunity to see if anyone can explain under what circumstances a set of accurately machined choke tubes (shot with identical loads and conditions) will have different points of impact. There is definitely one situation that can be understood to cause that particular effect, and I wanted to give some bright individuals a chance to mull this over before unveiling the answer. If you think you know the answer, don't divulge it here, instead email me and I will show a list of those that did pass, but I won't post those that didn't pass. Class dismissed. Kirby __________________ [email protected] New gunsmithing website: http://theshotgunshop.net/ Articles containing valuable information are on every page.

February 16, 2009, 10:36 AM	#2
hogdogs Staff In Memoriam Join Date: October 31, 2007 Location: Western Florida panhandle Posts: 11,069	If properly machined... the POI/POA should vary little if any. That is obviously to center of pattern. Brent

February 16, 2009, 12:23 PM	#3
JWT Senior Member Join Date: March 16, 2007 Location: Southern Arizona Posts: 3,888	Agree with Brent. A properly made tube should not change POI/POA when changed to another choke.

February 16, 2009, 04:34 PM	#4
BigJimP Senior Member Join Date: February 23, 2005 Posts: 13,195	It shouldn't make any difference if the choke is properly made - but you can't necessarily believe the markings on the choke in terms of the size of pattern you will get at the kill range you are testing for. If I have 4 Modified chokes - hopefully - if they're concentric the point of impact ( center of pattern ) will be the same ( maybe plus or minus 6" which can be a lot and I may see some holes in the pattern - meaning one choke is a hair tighter or looser than one of the others vs a given gun . You can drive yourself crazy with this stuff - but its a good idea to check the pattern on every choke you have - for every gun you intend to shoot that choke in. Now changing guns is different too - the choke is a function of the amount of constriction vs the inside diameter of the bore of the gun ( not all 12ga's are the same ) so you have to check every gun. I have a number of Browning O/U's - and the bores on them vary more than you might think. If you're only shooting one gun with the chokes you are checking - its a little easier to keep track.