Lock Time?

F

Fremmer

New member
Lock time is a term used to describe the amount of time between the trigger pull and ignition of the primer, correct?

How significant is it when it comes to accuracy?

What kind of work would a Smith do to reduce lock time?

Thanks in advance for the info!
 
lock time

Sir:
Lock time is important - no doubt about it, and a fast lock time in really advantageous to accuracy. I'm all for it. In some of my Mausers I've used the Wolf striker springs.
But, in the old muzzle-loaders (and those old guys strove for fast "lock-time too - that's where the term came from I'd guess) you had a hammer fall that was set off by a set trigger striking a rod, that unhooked the hammer and-------------! The groups shot by them are in many cases unmatched even today.
You, know - I think pressing the trigger correctly and FOLLOWING-THROUGH were and are most important.
Light triggers, fast strikers, short firing pin fall, in my opinion, efforts by some, to counteract flinching! It just won't work! But, I agree, I too like fast "lock-time.
The "old guys" would have used our modern advantages too - had they had them!
Harry B.
 
Last edited:
Lock time does play a role in accuracy but in attempting to improve your lock time you could set up different barrel harmonics, which in some instances will have the opposite effect to which you seek. You can play around with spring weights and different fining pin weights and maybe you will be able to tell a difference. Most shooters never see a difference but at least they know they improved their lock time somewhat and that might be worth something. I’ve never seen a difference myself when I’ve changed spring weights or changed over to a titanium tipped firing pin or a combination thereof. A proper bedding job and good gun handling seem to be the ticket for decent groups or scores.
 
I hear good things about lock time on Remington rifles. Are there certain gun brands that are well-known for their fast or slow lock times?
 
One issue with lock time is the amount of movement induced to the rifle by a variety of sources (vibration, heartbeat, wind, muscle movement, etc) between the time the trigger is pulles and the firing pin actually strikes the primer and detonates it. The longer the lock time, the more this movement will affect the rifle bore's position relative to the desired point of impact. Theoretically, if you could make a rifle with instantaneous lock time, the bullet would strike point of aim each time.

Remington made its mark on the benchrest world with its short lock time. Mausers have a very long lock time compared to many modern rifles, and so are not typically used for super-accurate benchrest rifles.
 
Harry nailed it.
Consistency at the bench, from breathing, to sight picture, to hand pressure on the stock, to trigger squeezing, to FOLLOW THROUGH are where it's at.
When I have my act together at the bench, I know by my follow through that I've made a good shot.

Martyn
 
The phrase "trigger pull to ignition" is a bit imprecise. Lock time is really sear release time to primer impact of the firing pin, so the human element (like reaction time or the time taken up compressing the finger pad) is not involved. The main problem is that getting enough energy in the firing pin for reliability is a function of two elements, velocity and mass. A slow, heavy firing pin is reliable, but so is a fast, light one. Trouble often begins when someone decides that speed is the only thing that counts and makes firing pins out of light material with little mass. Military rifles have usually leaned toward heavy firing pins AND strong springs for the greatest possible reliability under adverse conditions.

A third element is that the design, of whatever type, has to be operable. A very light firing pin and a very strong spring might be fine, but if it takes a three foot pipe on the bolt handle to cock the gun, not many people will use it.

Jim
 
The Remington 700 has one of the fastest lock times there is. Read that in Stuart Otteson's book, The Bolt Action Rifle, Vol. 1. I wish Otteson would do a Vol III.:o
 
So lock time is just the time from trigger sear disengagement until primer ignition, and it doesn't include the time it takes to pull the trigger and cause the sear to disengage. Interesting.
 
I am not sure there is a good way to measure "the time it takes to pull the trigger", since the human element is involved. Even if we measure or can discount any reaction time, something as simple as the hardness of the hand will affect the time from the beginning of the trigger pull to sear release.

Lock time is purely mechanical time, and that is usually either calculated or measured using an instrumented firearm in a machine rest, no hummin' beans involved.

Hi, Scorch,

You wrote: "Theoretically, if you could make a rifle with instantaneous lock time, the bullet would strike point of aim each time."

Point of aim of the rifle, true, but the point of aim at the instant of firing will not necessarily be the point actually aimed at (e.g., the 10x ring) because of those human factors you mentioned. No matter how fast the lock time, other factors (human movement, recoil, etc.) are causing the rifle to move at all times, even while the bullet is moving down the barrel.

Jim
 
I see what you mean, Jim. I was just thinking that the amount of time it takes to pull a trigger on a gun with a very long triggerpull (like a double action pull) to disengage the sear probably takes much longer than the locktime after that sear has been disengaged.
 
For a gun like an S&W revolver, the DA trigger pull time, even with a lot of practice, is many times the lock time. On a single action revolver, like the Colt SAA, the trigger pull time is fairly short, but lock time is long since it takes time for that big hammer to move that distance. That is the main reason that type of SA revolver is seldom used in target competition, not lack of accuracy.

Jim
 
You must log in or register to reply here.
Back
Top