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Add on rib....??

Discussion in 'Shooting Related Threads' started by starship, Jul 9, 2009.

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  1. starship

    starship TS Member

    Joined:
    Jul 18, 2007
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    I have a Browning XT with adj comb. Comb is currently raised about a half inch.

    Was reading about the Keen Sight add-on rib. This has now got me wondering what is the benefit of adding more rib?
    Other than the BBQ effect:) (I knew someone here would bring it up)

    Will this align my eye (now raised with the comb) to look straight out the rib instead of the somewhat down and out now?

    Will this effect the POI that I have raised the comb to achieve?

    Just what is this high rib thing all about? I understand the raise and lower comb issue but not sure I understand what then happens with the raised rib issue.

    Any and all info is appreciated.
    Chuck
     
  2. jimrich60

    jimrich60 Member

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    To answer your main questions, the primary purpose of a higher rib is to position your head in a more upright position. Some (I am one of them) find a more heads up stance more comfortable to shoot and it allows longer shooting sessions with less fatigue. But not everyone likes this heads up stance of course. Also, some do not like a higher rib simply because they have more difficulty shooting this way. This seems to be because some shooters sub-consciously use the barrel as part of the pointing process, and the higher rib prevents this. Others like the the higher rib because it places the barrel "out of the line of sight" and makes it easier to see the target without the barrel partly obscuring it. I am in the latter category. In this sense, the higher rib works much like a bottom barrel single, versus the top barrel single. Most I know who have tried a higher rib like it, but not everyone.

    Second point is that, yes, it will change the POI. In order to maintain the same POI as you now have (whatever that is with whatever degree of comb height), in order to keep that same relationship, you have to raise the comb by the same height as the added rib height. For example, if you normally shot with the comb raised 1/4 inch, and added a 1/4 inch rib, you would have to raise the comb another 1/4 inch to keep the POI the same (a total of 1/2 inch in this theoretical case) If you added rib height without adding to the comb height, you would, in effect, be lowering the comb in relation to line of sight, thus lowering the POI.

    I would advise a trial with added rib height prior to investing in an add on rib. I have found the best way to do this is to get a strip of balsa wood of appropriate thickness (near rib width), cut a strip to the height of rib you are thinking of trying, paint it black, and then attach to your rib with a bit of black electrical tape. In fact, you can easily make several "trial add-ons" this way, and try various heights (say 1/4 inch, 3/8 inch and maybe 1/2 inch to see what works for you, or if an add on rib works for you at all.

    If you do go the add on rib road, I recommend going with Keen Sights. Vicki Keen is great to work with, can make the rib just about anyway you would like (including cutting to increase or decrease POI, etc) and they make a first class product. Other rib makers also do some nice work in Delrin (Vicki's are aluminum.

    Hope this helps.

    Jim R
     
  3. Easystreet

    Easystreet Well-Known Member

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    1,463
    Excellent response, Jim.

    Easystreet
     
  4. Jollytrapshooter

    Jollytrapshooter Member

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    As a rib builder, I agree 100% with Jim's response. The balsa wood test rib is the best way to find what will work best for you. It's a good idea to know what you want before you have someone make a permanent rib. Josh
     
  5. mike31z

    mike31z Member

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    Location:
    Highland, WI, USA
    I agree so much that after a couple trial balsa wood versions, I went to a 1 inch version out of oak flooring and have had it that way for three years. I shoot a BT 100 and do not have an adjustable comb I added a leather comb from cableas for an addition height of 1/2 to 3/4 inch and increased my average to 95's only practice and price of shells keeps me from higher scores.
    I have pic of my 1 in add on.
     
  6. starship

    starship TS Member

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    Thanks to all for the great info.
    Especially to Jim, just what I was looking for and easy to understand. Thanks again.

    Chuck
     
  7. ddrsuz

    ddrsuz Member

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    Jan 29, 1998
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    Starship:
    I second the info on Keen Sight and trial info mentioned previously, but I would mention that the POI should change a little if you keep everything parallel. If you raise the comb 1/4" and add a 1/4" rib, I think your pattern will go down 1/4", but in the grand scheme of things, dealing with small changes, that would mean nothing at 40 yds. I had Keen to my 1.5" add-on and it looks great.

    The reason I say the pattern will drop is imagine if you raised the rib 4 feet and raised your comb 4 feet, I don't think the gun will still shoot in the same place. The good news is that Vicki can make any pattern adjustments you would like............well maybe not the adjustment for a 4 foot add-on.

    Another thing to remember is that you will want to do some tweaking and experimenting with your comb settings when you change it. I found as I went to a more upright head position, I think the comb made contact in a different way on my face, necessitating some adjustments.

    d
     
  8. KEYBEAR

    KEYBEAR Active Member

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    3,222
    I have a low add on rib from Keen-Sights for sale use about one month as new
     
  9. ExFedex

    ExFedex Active Member

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    Jan 29, 1998
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    ALF-99 I need a low add-on rib to fit a 34" BT-99 barrel. Can you send me the dimensions on your rib in PM? Thanks. Bill H.
     
  10. KEYBEAR

    KEYBEAR Active Member

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    Bill H will do give me 5 min .
     
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