Question on LOP-Drop at comb/heel. etc.

[DanL]

I have had Right shoulder surgery/replacement to correct certain issues. I had and now still have range of motion issues that do not relate specifically to the surgery. I am left with somewhat different range of motion than pre-surgery.  I typically Free hand shoot long arms right handed but can shoot either handed with a prop.  All that to preface my question....

Some of my muzzleloaders still fit well and function as before the new shoulder. Some of my muzzleloaders now do not fit good enough to be comfortable. I am ameliorating the situation as best I can by adjusting (Shortening) butt stock "lengths" on some and it seems to help with the shooting comfort. Other Muzzleloaders will probably need restocking with a different drop and maybe a different LOP. 

I mostly understand what LOP, drop at comb, drop at heel & drop at toe all mean.

IF the drops are changed, what change, if any, will there be in the LOP?


IF, for instance, a straight English style sporting rifle stock is say 13.75" LOP but it no longer fits as it once did. Will a little drop on the butt stock affect the 13.75" LOP?  How does the drop affect LOP ?

Does the drop affect LOP at all?
 
I know a try-stock is the best solution but I currently have not built a try-stock to answer my questions.

What say you ( very much more than I) accomplished gun builders??

Respectfully,
Dan

[James Rogers]

Unless you have a buttstock parallel to the barrel, changing the LOP changes the comb drops making them less than before. Depending on how much you shorten, some of that fit if decent before can be adjusted by stance and mount. LOP just needs to be comfortable to mount and hold. There is no magic formula. All other measurements should be built around it, especially the drops.

[EC121]

Mount the rifle or try stock comfortably level with your eyes closed.  When you open your eyes, you should be looking down the sights.  If not, adjust the try stock.  Then measure things.

[rich pierce]

Not sure how you plan to increase drop. Bending or removing from the comb? Change in LOP will be negligible either way.
If you shorten the buttstock then typically drop at heel will be somewhat less than before and drop at nose will stay the same.

[DanL]

If i feel the need to increase drop, i would restock the components of the rifle in a different stock.

Years ago, i heard folks talking about drop. It was said that, given the same shooter, if drop is increased, a longer lop would be needed to fit that person. Thus, the more the drop, the longer the lop a person could comfortably tolerate (to a point of course). I honestly do not know.

So if one has a rifle without much drop and say 13.75” lop. This person wants to restock the components with a stock with more drop. Does his lop change with a stock with more drop?

Given the human structure, Is one closer to the trigger with lots of drop or the same distance to the trigger with less drop? Interesting triangle relationship.

Assuming the same LOP with a stock of lessor drop and same LOP with a stock of greater Drop, Is LOP from butt plate to trigger a point on a arc of a circle with the same measurement (plate to trigger) or the line of a triangle with a different measurement?

[rich pierce]

I think you meant to communicate, “is it necessary to adjust the LOP when changing the drop to make a gun give the same sight picture?” I thought you were asking if length of pull would be altered by you changing the drop on an existing stock.


Find a gun that fits you well and come close to that. All the calculations in the world mean nothing if you can’t see the sights pretty closely aligned upon mounting the gun. Ideally you’ll find a rifle that fits well and use that as a guide.
But, if you have a shotgun that fits you well enough to kill flying birds and bust clay pigeons, check the dimensions on it.

Weight and balance and pitch are factors as well.