1. Attention: We have put together a thread with tips and a tutorial video to help with using the new software. Please take a moment to check out the thread here: Trapshooters.com Tutorial & Help Video.
    Dismiss Notice

Unsingle combo POI

Discussion in 'Uncategorized Threads' started by Dodgeram, Mar 23, 2008.

Thread Status:
Not open for further replies.
  1. Dodgeram

    Dodgeram TS Member

    Joined:
    Sep 12, 2007
    Messages:
    40
    My son is shooting a SKB unsingle combo and have adjusted the top barrel of the double barrel to shoot 2" high(moved the comb up) at 13 yards which I think translates to 6" high at 39 yards. The problem I'm having is when we go to adjust Unsingle to shoot the same at 13 yards the highest we can get it to shoot with the adjustable rib all the way down in the front is only about 1" high. Also the measurment from the top of the rib to the center of the top barrel on the double barrel is 5/8" and on the unsingle the measurment from the top of the rib to the center of the barrel is 1 5/8".

    I have two questions. Do I need to compensate for the differnce in distance when checking POI at 13 yards between the rib on the top barrel of the double barrel and the unsingle? Also what can I do to make the unsingle shoot higher if there is no adjustmnet left in the rib and I don't realy want to change the comb because my son likes were the double barrel shoots now.

    I would appreciate any comments. Thank you, Doug from Iowa
     
  2. ramorton

    ramorton TS Supporters TS Supporters

    Joined:
    Jan 8, 2006
    Messages:
    1,775
    Location:
    Driftwood, Tx
    They now have a height extension for the rib on the unsingle. Call SKB and ask them if this makes the gun shoot higher. Hopefully, you will get someone that knows. Also, ask them how much higher. Then maybe you can set your POI to match the O/U barrels. Hope this helps, Roy
     
  3. jimrich60

    jimrich60 Member

    Joined:
    Aug 15, 2007
    Messages:
    810
    Dodgeram:

    You have followed the correct procedure for adjusting the POI on a combo with fixed rib on double barrels, and adjustable rib on the unsingle. For example, on my Beretta combo, raising the comb gives about a three inch change in POI with each spacer used. This is true whether it is the unsingle barrel or the double barrels. The rib adjustment, on the other hand, makes about a 1 inch change in POI for each adjustment marking on the rib. (these movements are according to the Beretta manual) Actual may vary with each individual of course. Since you are getting the desired POI with the double barrels, I would venture to guess that you are not using the same sight picture when changing over to the unsingle barrel. While many people seem to think the purpose of the rib adjustment is to alter the sight picture, this is a false assumption. It is supposed to change POI. But you must remember that if you hold the gun (after adjustments) in such a way that that you do not change sight picture (ie, the relative angle between middle and front beads, etc) you have basically defeated the POI change. As you raise POI, you will in fact see a different relationship between middle and front beads, and will (should) see more of the rib. If you (consciously or unconciously )move head position on the stock to keep the nice figure eight view, then are are overcoming the POI ajustments since you are then keeping the sight picture and relationship between beads and point of aim the same. So once the gun is set with the comb for POI (on the o/u barrels, then work on the unsingle being sure to see the bead and rib alignment in the same way, then change the rib remembering that the alignment of bead/rib will change (sight picture) and do not try to compensate hold, etc to try to get sight picture back to previous.

    Hope this helps
     
  4. Dodgeram

    Dodgeram TS Member

    Joined:
    Sep 12, 2007
    Messages:
    40
    I called SKB today to check on height extentions for the rib and they do have them but they said it would only make the gun shoot lower. I also asked them about the problem I'm having with not being able to get the unsingle to shoot higher than the double barrel after we had the comb set for the double barrel we liked. They said the gun is designed to be able to get a higher POI with the unsingle and realy couldn't tell me to do anything differnt to fix the problem I'm having. They did offer if I wanted to send the gun they would check the POI to see if it's in manufacture tollerences. For now we will check the sight plane to make sure it changes from the O/U to the unsingle and recheck POI. If we can't figure it out from there I will try find someone localy to help us out with it.

    Thanks to everone that responed.

    Shoot a lot and have fun, Doug
     
  5. Dodgeram

    Dodgeram TS Member

    Joined:
    Sep 12, 2007
    Messages:
    40
    As jimrich60 and 24st8 mention I think we have sight picture problem. Question? When the sight picture is different from the O/U to the unsingle barrels do people adjust the back bead(maybe move it up) so it's the same figure 8 so to speak between the two barrels? This way you would have the same point of reference no matter which barrel was being used.

    Doug
     
  6. hounddog41@charter.net

    hounddog41@charter.net Member

    Joined:
    Jan 17, 2007
    Messages:
    341
    Set you comb with sometype of washers. I use plastic. You can get different thicknesses. Either make a mental note or write down hom many you use for over/under and how many for the single barrell. Just raise the comb to get the point of impact you want with whatever barrell. I do this with my Browning top single. Dont cost anything. alex
     
  7. Hap MecTweaks

    Hap MecTweaks Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    9,229
    Location:
    Mesquite, Nevada
    Dodgeram, did you also shoot the bottom barrel of the O/U for POI at 13 yards, if so where did it pattern in relation to the top? One more question, did you pattern the unsingle at 39 yards to see where the pattern center might actually be at that range?

    You can use a 12 ga. deprimed hull in the chambers and a deprimed 20 ga. in the muzzle end to create a "peep sight" which will tell you how all the barrels are regulated. To use this method properly, you need a gun vice to hold the barrel. Sight through the shell openings and have a helper mark that spot on paper at 40 yards. Do the same thing with the bead and mark that spot. Very crude method but it works great. Hap
     
  8. RAScott

    RAScott Member

    Joined:
    Feb 28, 2008
    Messages:
    813
    There is a web site called www.keensite.com makes tapered ribs to adjust your point of impact up-down and no change of POI. you may consider that if you cant get them to match.
     
  9. victoria K

    victoria K Member

    Joined:
    Jan 29, 1998
    Messages:
    71
    keensights.com
     
Thread Status:
Not open for further replies.