16ga.com Forum Index
Author Message
<  16ga. Guns  ~  O/U Sight Picture
Brewster11
PostPosted: Thu Aug 12, 2021 2:28 pm  Reply with quote



Joined: 08 Feb 2009
Posts: 1301
Location: Western WA

We've noticed something at the trap range with our lightweight O/U guns: The correct "sight picture" (i.e., the amount of barrel/rib showing) is different between the upper and lower barrels. The upper barrel needs less rib showing than the lower barrel, presumably because of the increased recoil setback by the upper barrel during firing, resulting in the upper barrel having a higher POI than the lower.

It is quite evident when demonstrated by our target breaks. We start at station 3 and adjust our sight picture until we get ink blot breaks. The result is very consistent: Lower barrel needs more rib/barrel showing (sometimes much more with the lighter guns) than the upper, meaning a higher POA needed with lower barrel and lower POA for the upper barrel. This effect seems most pronounced with the lightest guns.

The standard rule of seeing a figure 8 mid bead / muzzle bead doesn't seem exactly right with either barrel - too little bead for the lower and too much bead for the upper.

I have not been able to validate this effect at the pattern board, but it is extremely obvious on the trap range. I should say this occurs with the 16 ga Citori and 20 ga Beretta. Not so much with a heavier 12 ga Beretta.

I'm wondering if anyone else has observed this effect, and how it is accommodated during multi-shot events like Continental.

V/R

B.
Back to top
View user's profile Send private message
AmericanMeet
PostPosted: Thu Aug 12, 2021 6:15 pm  Reply with quote



Joined: 26 Apr 2010
Posts: 3172
Location: NCWa

I haven't noticed it when using either a Browning Superposed 20 or a Merkel 201 12, but then I'm not a proficient enough shooter to have that degree of accuracy.
Back to top
View user's profile Send private message
MSM2019
PostPosted: Thu Aug 12, 2021 6:39 pm  Reply with quote



Joined: 04 Mar 2019
Posts: 1819
Location: Central ND

My Citori shoots to the same POI with both barrels as does my Beretta Onyx.

If what you say was true, you would have to compensate for each barrel in the field or when shooting trap doubles, or skeet doubles or sporting simo pairs, etc., which is not the case.

Sounds to me as if you folks are looking for the bead/target relationship rather than looking at the target.

You would be correct if you were shooting a Kreighoff and could adjust the POI with the barrel hanger.

_________________
Mark...You are entitled to your own opinion. You aren't entitled to your own facts.
Back to top
View user's profile Send private message
AmericanMeet
PostPosted: Thu Aug 12, 2021 9:36 pm  Reply with quote



Joined: 26 Apr 2010
Posts: 3172
Location: NCWa

With trap i generally shoot the bottom barrel because the recoil is straighter with less rise, but it is frustrating because on the rising birds I bring the gun up and fire when it blocks out the bird and if I really smoke it I don't get to see the smoke, just when i lower the gun after follow through, there is no bird. so I guess I really smoked it, but everyone but me got to see it. As for sight picture I don't know- with either barrel I shoot it the same: when the gun blocks out the target I shoot. But anymore, I find I shoot SxS more than the OU.
Back to top
View user's profile Send private message
double vision
PostPosted: Fri Aug 13, 2021 3:30 am  Reply with quote
Guest





It's quite common for an OU to print its top barrel higher than the lower. It's a barrel regulation issue.
Back to top
Hammer bill
PostPosted: Fri Aug 13, 2021 7:13 am  Reply with quote



Joined: 09 Feb 2015
Posts: 815

Personally I think you guys are reading to much into this. I've never worried about that before. I just learned to shoot where the gun points and not to change the poi with stock adjustments.. Wants I realize where the gun shoots I make sure I mount the gun the exact as possible everytime during competition.
As for hunting I use field gun.
Back to top
View user's profile Send private message
Hammer bill
PostPosted: Fri Aug 13, 2021 7:13 am  Reply with quote



Joined: 09 Feb 2015
Posts: 815

Personally I think you guys are reading to much into this. I've never worried about that before. I just learned to shoot where the gun points and not to change the poi with stock adjustments.. Wants I realize where the gun shoots I make sure I mount the gun the exact as possible everytime during competition.
As for hunting I use field gun.
Back to top
View user's profile Send private message
Brewster11
PostPosted: Fri Aug 13, 2021 2:02 pm  Reply with quote



Joined: 08 Feb 2009
Posts: 1301
Location: Western WA

Well there are certainly skeptics out here, but I suggest you to try it in the range yourselves before dismissing it. I only started noticing the issue when I began using tighter chokes: why was I not splattering them with the upper barrel like I was with the lower? Only after I changed the rib/bead picture did I totally dust them again, not merely lame partial breaks and misses.

As for pattern board POI, I think it may be misleading if not totally useless. Why would a POI be meaningful while violating the cardinal rule of trap/skeet, i.e., shooting with a stopped gun? There is little or no correspondence there with shooting a moving target where the gun is swinging before, during, and after the shot.

I may be off base here but my recent testing experience tells me something is there, at least with the guns I tested.

V/R
B.
Back to top
View user's profile Send private message
John Singer
PostPosted: Fri Aug 13, 2021 3:00 pm  Reply with quote



Joined: 03 Sep 2014
Posts: 398
Location: Rochester, MN

Brewster11 wrote:
As for pattern board POI, I think it may be misleading if not totally useless. Why would a POI be meaningful while violating the cardinal rule of trap/skeet, i.e., shooting with a stopped gun? There is little or no correspondence there with shooting a moving target where the gun is swinging before, during, and after the shot.

I may be off base here but my recent testing experience tells me something is there, at least with the guns I tested.

V/R
B.


You are off based here. Think about it. A shot charge exits the barrel at a velocity exceeding the speed of sound. Therefore unless you have the superhuman ability to swing a shotgun at a speed exceeding that, a shot charge is the same if fired from a moving or stationary shotgun.

Patterning your gun should verify your experience on the trap field. If it does, I suspect that either your barrels are not properly regulated or one of your new choke tubes is damaged.

_________________
John Singer
Back to top
View user's profile Send private message
Hammer bill
PostPosted: Fri Aug 13, 2021 3:21 pm  Reply with quote



Joined: 09 Feb 2015
Posts: 815

Brewster11 wrote:
Well there are certainly skeptics out here, but I suggest you to try it in the range yourselves before dismissing it. I only started noticing the issue when I began using tighter chokes: why was I not splattering them with the upper barrel like I was with the lower? Only after I changed the rib/bead picture did I totally dust them again, not merely lame partial breaks and misses.

As for pattern board POI, I think it may be misleading if not totally useless. Why would a POI be meaningful while violating the cardinal rule of trap/skeet, i.e., shooting with a stopped gun? There is little or no correspondence there with shooting a moving target where the gun is swinging before, during, and after the shot.

I may be off base here but my recent testing experience tells me something is there, at least with the guns I tested.

V/R
B.


Brewster. It might be just me but choke manufacture has a lot to do with it.if u try a different brand of choke with the same bore dims. You may find the gun shoots opposite from the previous choke. Many times people will stumble on to one that is the dream of all dreams. Then the same brand and dim. but different ck shoots completely different. L I have bought chokes from well know to makers and found some to be not centered.. You can have a company like briefly Make chokes to shoot where ever you want it at a specific distance within reason. I have also found chokes with the bore ID NOT exactly round. As I said before i just find where the gun shoots and adjust myself to it. Most of my clay guns are with original factory stocks. Don't take what I say to the store. It's just my way of doing things. But there try a few different brands off chokes. It might or not tell you something. And then again you may be completely right.
Happy shooting Bill.
Back to top
View user's profile Send private message
Hammer bill
PostPosted: Fri Aug 13, 2021 3:22 pm  Reply with quote



Joined: 09 Feb 2015
Posts: 815

Brewster11 wrote:
Well there are certainly skeptics out here, but I suggest you to try it in the range yourselves before dismissing it. I only started noticing the issue when I began using tighter chokes: why was I not splattering them with the upper barrel like I was with the lower? Only after I changed the rib/bead picture did I totally dust them again, not merely lame partial breaks and misses.

As for pattern board POI, I think it may be misleading if not totally useless. Why would a POI be meaningful while violating the cardinal rule of trap/skeet, i.e., shooting with a stopped gun? There is little or no correspondence there with shooting a moving target where the gun is swinging before, during, and after the shot.

I may be off base here but my recent testing experience tells me something is there, at least with the guns I tested.

V/R
B.


Brewster. It might be just me but choke manufacture has a lot to do with it.if u try a different brand of choke with the same bore dims. You may find the gun shoots opposite from the previous choke. Many times people will stumble on to one that is the dream of all dreams. Then the same brand and dim. but different ck shoots completely different. L I have bought chokes from well know to makers and found some to be not centered.. You can have a company like briefly Make chokes to shoot where ever you want it at a specific distance within reason. I have also found chokes with the bore ID NOT exactly round. As I said before i just find where the gun shoots and adjust myself to it. Most of my clay guns are with original factory stocks. Don't take what I say to the store. It's just my way of doing things. But there try a few different brands off chokes. It might or not tell you something. And then again you may be completely right.
Happy shooting Bill.
Back to top
View user's profile Send private message
MSM2019
PostPosted: Fri Aug 13, 2021 5:46 pm  Reply with quote



Joined: 04 Mar 2019
Posts: 1819
Location: Central ND

When I shoot an O/U I do not have two different bird/bead relationships for the upper and lower barrels.

I have competed in trap, skeet, sporting clays, FITASC, 5 stand and upland hunting, not once have I ever seen a difference of POI between two barrels of an O/U shotgun that is properly regulated. Not on the pattern board not when shooting clay targets.

The only way what is being presented is true is if the upper and lower barrels shoot to a different point of impact.

Think about it, if the gun is properly fit, you don't change the cheek pressure of your mount for different barrels. If you do.......

Trap doubles are shot very quickly, how would you ever have time to change the mount and get to the second bird in time?

What is being presented is not correct.

_________________
Mark...You are entitled to your own opinion. You aren't entitled to your own facts.
Back to top
View user's profile Send private message
Brewster11
PostPosted: Fri Aug 13, 2021 10:47 pm  Reply with quote



Joined: 08 Feb 2009
Posts: 1301
Location: Western WA

Quote:
Therefore unless you have the superhuman ability to swing a shotgun at a speed exceeding that, a shot charge is the same if fired from a moving or stationary shotgun.


John, that is true only if you eliminate muscular response, which is different between a static and moving gun, and reaction time. As Fred Etchen discusses exhaustively in his book, a motor reaction time of 200 milliseconds irrespective of decision time can amount to an enormous shift in POI when swinging on a moving target. As such, I’m not sure what a pattern board POI is telling me.

And Mark, a remount should not be needed for doubles if the POI changes with the upper barrel; only a different firing picture is needed.

Notwithstanding the objections noted above, I suggest that this can be readily demonstrated by going to the range, set up on station 3, and firing a dozen or two rounds with an identical choke in both upper and lower barrels and prove to yourself whether or not your hit quality can be improved by adjusting vertical POA.

I have performed this test multiple times now with different o/u guns and have demonstrated to my complete satisfaction that this is absolutely the case, albeit to varying degrees with different guns. “Registering” my barrels on station 3 has not only improved my scores, but erased years of frustration with the different POI of my various guns, and also loads for that matter.

V/R
B.
Back to top
View user's profile Send private message
Hammer bill
PostPosted: Fri Aug 13, 2021 11:15 pm  Reply with quote



Joined: 09 Feb 2015
Posts: 815

Maybe to prove it to yourself is take a friend to the range with you. Get on station 3. Have your friend load the gun standing behind you so you don't see what barrel is loaded. Provided the gun is single trigger and your friend selects the trigger and you don't look at the selection. Don't open the gun or look at the reciver after firing. Let your friend unload the gun and reload . Repeat this several times. With each time your friend should record which barrel was fired along with the hits and miss. If you concern about the problem it might tell you something. Just a thought.
Back to top
View user's profile Send private message
MSM2019
PostPosted: Sat Aug 14, 2021 7:33 am  Reply with quote



Joined: 04 Mar 2019
Posts: 1819
Location: Central ND

Brewster11,

Go to a good shooting Instructor and explain this. I will bet 100:1 that the instructor will see the problem in less than 5 minutes of working with you.

You should never have to change anything between shots with an O/U IF, the mount is correct, the fit is correct and the barrel regulation is correct.

You mentioned sight picture......does that mean you are seeing the target or are you looking for the lead? If you are looking for the lead.......

_________________
Mark...You are entitled to your own opinion. You aren't entitled to your own facts.
Back to top
View user's profile Send private message
Display posts from previous:   
All times are GMT - 7 Hours

View next topic
View previous topic
Page 1 of 2
Goto page 1, 2  Next
16ga.com Forum Index  ~  16ga. Guns

Post new topic   Reply to topic


 
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum




Powered by phpBB and NoseBleed v1.09