View Full Version : Shotgun length of pull
August 9, 2002, 11:28 AM
I need to cut down a stock on a 20 ga shotgun to fit a 12 year old. What is best method to determine proper LOP?
August 9, 2002, 04:03 PM
A real quick way would be to have the child put the butt stock in the crook of his elbow and see if he can reach the trigger. He should be able to reach the trigger with the first joint of his finger. If not, he might need a shorter stock, you can just measure the distance from the first joint to the trigger and shorten the stock by that amount.
I saw it on a shotgun show on OLN.
Hope this helps.
August 10, 2002, 09:07 AM
Brian, that method is an old, old myth that serves as a very rough guide for adults. But, kids need something a tad more precise.
I suggest ending up with a LOP that just misses having the kid bump his/her nose on their strong hand thumb.
And, I'd be careful and add a good, untrimmed pad. Leaving it untrimmed will mean a larger surface area, thus lowering felt recoil or kick.
Also, some shims under the pad to alter pitch will add to the comfort.Add them at the toe or heel, see how it feels, and go from there...
August 10, 2002, 11:09 AM
Daves answer much better than mine would have been.
How bout usin Brian Newbill's response for gettin the cut figured and then Daves's for fine tuning ?
I would, however, look at the possibility of adding material to the grip area, in front of the pistol grip bump, to move the little hand a bit closer to the trigger.
August 10, 2002, 11:57 AM
You could look up a good shotgun coach and have him fit your son with a try gun. And spend a few hundred bucks.
Dave's method is probably the best:D
Experienced and knowledgeable shotgunners will tell you that the crook in the arm method is a crock:D
August 10, 2002, 12:49 PM
(and no, it didn't hurt...much.. LOL)
I measured my two best hitting shotguns per gauge, 1100 20 ga and SKB M600 20 ga and my 870 12, SKB m600 12 ga.
The length of pull varied a bit, but 13.5 inches is a good average. On the 20's my thumb was about a half inch off my nose, the 12's more like an inch.
I also have a 2" x 4" level and ruler that's used for construction. It has one of the skinny sides marked off in inches. When I mounted my level like a shotgun and slid my thumb back towards my nose, the distance was about 10 inches.
If we reverse the procedure, perhaps that would serve as the proper length of the stock? Have to use thumb placement as the start point for the measuring. I grasped the SGs normally and used a piece of scotch tape to mark the spot.
All four SGs came out about 3 inches below LOP which validates these numbers for me..
Have to snag one of the kids around here to double check this...
(based this on the revalation by Dave about thumb placement, BTW. Thanks Dave!)
August 10, 2002, 01:50 PM
Experienced and knowledgeable shotgunners will tell you that the crook in the arm method is a crock I don't think it's a crock.
Rather, a quick way to get a ball park figure.
Which will then need to be fine tuned.
August 10, 2002, 02:09 PM
AH! But using the crook method only measures the length of the forearm, which can vary considerably. It has absolutely nothing to do with proper LOP.
LOP depends on a lot of different measurements, including how big your chest is, arm length, amount of flesh on your jowls, hand size, shoulder development, length of your schnoz etc.
I have seen the forearm method used and more often it doesn't work, particularly with women.
Check out the writings of Brister, McIntosh, Hill, Zutz, Churchill et al. They all agree the crook method is useless. (Of course, they would all agree my opinion is useless also!)
I am more interested to see how Gizmo's system works. Sounds like the "Try Guns" some fitters use. They have built in measurements and the stocks can be adjusted in several planes. Once they have the right measurements for that particular type of gun they can be transferred to other guns.
Most fitters use a try gun of the same type you will shoot, eg SXS or O/U. Apparently measurements can vary for each individual for different types of guns.
Come to think of it, I have never seen a "TRY" gun for Autoloaders. Did see one for pumps once.
When I use the Forearm crock method I have to bend my wrist to reach the trigger. But then I am no threat to Dan Bonillas or Gabby Hulgan either.
August 10, 2002, 03:36 PM
Be interested if the slide the thumb towards the nose on the level works for anyone else..
BTW, when I use the crok of the ellbow method, the longer stocks (12 ga) are about an inch short of touching my elbow.
I have 36 inch sleeves, if it matters.
August 10, 2002, 05:26 PM
I have 36 inch sleeves, if it matters. Only if you are 5' tall. :D
August 10, 2002, 08:55 PM
Add a foot....
Call me tripod....
August 10, 2002, 09:59 PM
I've always found this to be a "personal preference" thing, to some extent, too...For example, I have VERY long arms for the rest of my body (I'm very average, but buy "long" suits, and sleeves are still 1" too short!) And for some reason, I find I like shotgun stocks to be shorter than most others my size would....So, the stock on a shotgun that I like the "feel" of, is fully 2" or more shorter than it would be using the "crook of the arm method"!....(this does place my thumb really close to my nose, BTW)
August 11, 2002, 12:05 AM
Let us not forget that the thumb/nose interface is affected by a lot of things other than length of pull.
Drop at heal.
Height of comb.
Rib or no rib.
Type of gun, top break, pump, A5 type
August 11, 2002, 08:33 AM
(Opening fresh can of worms)...
IMO, everyone either pays too much attention to LOP or too little.Lots of us shoot well with less than ideal LOP. Maybe 40% of us can make the factory standard stock work OK, and there's a few things more to proper fit than just LOP.
For instance,like someone said, distance from grip to trigger is oft overlooked, and most folks would do with a tighter radius on the PG to reduce the length needed best fast squeezing.
Pitch varies as much as LOP, but few folks try to get it right. And, since pitch affects comfort greatly, an afternoon spent shimming and testing would do lots of us good. Instead of porting,etc, a small piece of cardboard or leather might be more helpful in cutting kick.
While most of us ignore cast, a tough of cast at the tow oft aids comfort by putting the butt more into the "Cup" of the shoulder,matching the physiognomy of the joint. Easy to test, take out the toe screw on your pad, twist it a bit away from the vertical and secure it with masking tape. Mount it and see how it feels. After getting it twisted optimally, shoot a few rounds and se ehow it feels and works.
August 11, 2002, 11:46 PM
Let us not forget that the thumb/nose interface is affected by a lot of things
So, what I've found effective is to mount the shotgun with my thumb firmly inserted in my nose (right nostril for right-handed shooters) and then measure the distance from my nose to the safety (Mossberg 500 ) and then take the square root of the cosine of the ... oh, whatever...
no offense intended, just couldn't resist the image of the "thumb/nose interface"
August 12, 2002, 08:31 AM
Of all the measurements, LOP is the one that is the least important and, as noted previously, varies depending on gun type and shooting style. I currently own guns with LOPs ranging from 14-1/2 (Remington 870) to 15-1/4 (double trigger sxs). The guns do however all have the same drop at comb and, with one exception, the same cast which are more critical measurements.
August 12, 2002, 09:31 AM
Bruce....I used to do it that way.
Don't try it with the hiccups.
Had to get thumb surgically removed.:D
I like short pull. Then can still mount gun rapidly with heavier clothing.
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