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View Full Version : Proper "Trigger Pull" (distance between butt and trigger)


gosparx
08-13-2008, 11:19 PM
I've always just been happy with 'what feels right' but I am curious if there is a more scientific or mathematical way to find out what the proper distance is for the "trigger pull" for a given shooter (namely ME)

Just to be clear what I am asking about, it would be from D-D in the following diagram:
12008

Somewhere I read that the average is 13.25"-13.5", but I'm not sure it that was for shotgun or rifle (or if there is a difference) or if it really does just come down to what feels right.

Anyone have a more technical answer then, "yeah that feels good".

sb_pete
08-13-2008, 11:55 PM
Measure the distance from the inside crook of your elbow to the first joint in your trigger finger. This is the general rule for ideal pull length.

That assumes normal body mass and nothing like body armor or heavy winter clothing in which case it would be shorter.

As far as I can see, it shouldn't make any difference whether shotguns or rifles, but the context that I learned that rule in was for rifles.

Hope that helps
-Pete

gosparx
08-14-2008, 12:08 AM
Thanks!

Given that measurement on me, kind of explains why the 13.25" pull on my M1A with a new GEN II JAE stock feels a little short. I'm taking it out to the range for the first time tomorrow and see how it feels after I've put a few rounds down range.

If it still feels short, I'll plan on ordering a couple spacers for the butt plate.

Now I'm curious to go measure the rest of my longarms to see what the various pulls are... and see if there is any correlation (which would be expected) between which guns I feel more comfortable with and which ones I'm typically a better shot with!

Thanks again!

Knight
08-14-2008, 12:13 AM
I usually do a "field test" by putting the butt in the the crook of my arm while holding the gun. Basically it's measuring what Pete said, only a quicker/rougher estimate.

SI-guru
08-15-2008, 1:20 AM
I think it is also a function of where is the eye relief/focal plane of your scope (or your rear iron sight) relative to your eye.
Take a look at an UZI for example, anything less than 13" will put your eye on top of the iron sight (because the iron sight is way behind the grip).

http://www.hdps.org/htm/UZI-SMG-IMI-d.jpg

Now compare that with ar-15 iron or scope eye-relief which is behind the trigger and grip.

http://www.theshootersbox.com/store/images/firearms/dpms_RFLRT-SASS-B_ar15.jpg

The LOP should be a function of the eye-relief placement or the iron sight location.

leelaw
08-15-2008, 1:38 AM
I think it is also a function of where is the eye relief/focal plane of your scope (or your rear iron sight) relative to your eye.
Take a look at an UZI for example, anything less than 13" will put your eye on top of the iron sight (because the iron sight is way behind the grip).

The LOP should be a function of the eye-relief placement or the iron sight location.

Generally the length of pull relates to the fit of the firearm to the person.

The feel is the feel, the sights are the sights. They don't determine the other.

The way I understood to measure the "proper" length of pull, is the inside of the elbow bent at 90 degrees, to the first knuckle of the trigger finger.

SI-guru
08-15-2008, 9:07 AM
The feel is the feel, the sights are the sights. They don't determine the other.

.

I used to think the same until I handled the UZI. I never understand why its LOP is 15+ until I try to sight it.

gosparx
08-15-2008, 10:16 AM
I've since gone through my collection and found that the LOP varies as much as 2.5 inches... mostly depending on what kind of sight I have on the gun.

On an M1A with a NightForce scope I like 14+ inches while on the same gun and stock, but with a Trijicon ACOG (TA55A), It's closer to 13 inches. (both guns have JAE-100 stocks)

Then on my BMG50 there is almost 15" LOP!! (mostly due to the 1" rubber pad on the back!) I may experiment with that gun and see if it doesn't feel more natural a little shorter because 15" sounds like a lot. On the other hand, I'll also have to see where the scope is relative to the rest of the gun. It may be mounted back a bit further on the BMG then on my other rifles??

I'm 6', but have a long torso for my height, which may, or may not, effect the proportions of my arms, hence affecting a proper LOP.

Sounds like the the measurement from the inside of the elbow to the first knuckle of the trigger finger is a good place to start, but then lots of other things come into play; scope/sights, design/style of the stock, body proportions and probably several other things I haven't figured in yet.

Sounds like it really comes down to feel, so when you cheek the weapon, it's just natural to check and hold the weapon the same exact way every time and every shot.