How Do You Calculate LOP?


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rhubarb
December 28, 2006, 07:39 PM
I plan to buy a cheap used .22 bolt gun for my 4 year old son and cut the barrel and stock down to fit him (ala Chipmunk). He has a hard time getting a good cheek weld on my Marlin 60 when he holds it under his arm. If the butt is against his shoulder, he can't reach the trigger.

Is there a formula or rule of thumb for figuring the correct length of pull depending on height, arm length, etc.?

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fal 4 me
December 28, 2006, 07:51 PM
In the hunting biz LOP refers length of pull -- the measurement, in inches, between the curve of the trigger and the edge of the butt stock. The quote is from this article http://www.gundogsonline.com/Article/You-and-me-and-the-LOP-Length-of-Pull-Page1.htm

As a general rule of thumb, when gripping the firearm, the butt should rest in the crook of them elbow when the stock is laid on the arm.

LHB1
December 28, 2006, 09:31 PM
Sorry, I don't buy that old song about the distance from elbow to hand for measuring stock length. Doesn't take into account several other factors that affect the length of stock needed. Buy the gun and cut the stock off 1 inch at a time until you get to the length he can handle. Have him wear the same clothes during fitting as he will wear when shooting the gun. Thicker clothing, jacket especially, can require a shorter LOP than shooting in shirt sleeves.

Good shooting and be safe.
LB

DogBonz
December 28, 2006, 09:36 PM
But Great question. I'm all ears.

Btt

Don't Tread On Me
December 29, 2006, 12:26 AM
You measure from the center of the trigger to end of the stock at the center of the buttplate/pad to get LOP on the rifle.


This isn't a standard, but many like to measure from the opposite side of the elbow (where the crease is) across the forearm to the tip of the trigger finger. You take that measurement, then either add or subtract 1" (can't remember).


The best thing to do is to find a stock that fits well. Determine this by visually inspecting the hold and the mechanics of stance, where the arms are, is there scrunching, is there reaching etc....if good, measure that rifle and use it as a guideline. I'm sure a GOOD gunshop that has helpful staff and decent inventory would be willing to assist in trying out different rifles for a fit on your child. Gunshop prices are higher, but that's what I expect for some customer service. That's assuming the gunshop is nice.

1911 guy
December 29, 2006, 09:19 AM
LOP of the gun has already been discussed, from trigger to buttstock. LOP for the shooter is >usually< from the inside of the elbow to the first joint of the trigger finger. For an adult in cold weather hunting clothes, I'd knock off another two inches for clothing bulk. For a child, an extra inch off should do it because of the proportions.

When you cut the stock, drill it for dowels first. Then cut the stock in 1" increments. When you need to add length as he grows, you can add sections back on and they will be relatively straight. It won't be pretty, but he'll have a rifle that fits him as he grows and a rifle to pass on to his kids for them to learn on. I bought a cheap romanian .22 bolt action for my son. He'll learn on that, when he's done growing he'll get an "uncut" rifle.

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