PCP Lock time?​​​​​​​

[oldsparky]

I do more offhand shooting than bench. One thing I notice is follow through is even more critical on air guns than powder rifles do to slower lock time and probably barrel time also. I am not familiar with all the valving systems on PCP’s so I have little to compare. So I thought I would reach out to the forum. I did get to shoot Daystate and Brocock when AOA had the invitation a few years ago to Daystate customers. I found the electronic guns seemed easier to shoot offhand. It seems reasonable that the lock time may be faster. But I don’t care for a electronic gun for myself. Which leads to my question. Which mechanical system has the fastest lock time?

 

[Vetmx]

Surprisingly a hammer that you cock with your thumb that smacks a pin on the valve is the quickest I experienced on an airgun. It’s the complete opposite on a real gun. Airguns that use a slug for a hammer being pushed by a big long spring are slow in comparison. I have an expensive Rohm pistol and a PP700 that both have hammers. When the trigger breaks, the gun instantly goes off and it is noticeably quicker than my Taipan, Edgun, RTI, and so on.

 

[Franklink]

I think it just depends on the gun. The USFT has a hammer like vetmx mentioned, and many consider the longer lock time of the USFT to be one of it's few weaknesses. 

I personally don't see it with my USFT, but I shoot a lot of springers so follow through isn't usually one of my problems.

 

[nervoustrig]

If you want to minimize the time between the sear breaking and the pellet leaving the barrel, your best bet is to use a lightweight hammer (MDS nylon or PEEK) and use a relatively high pressure for whatever velocity you’re wanting to obtain. Because the hammer is light, once the sear releases it, it accelerates to hit the valve stem more quickly. Then the brief (short dwell) high pressure pulse accelerates the pellet comparatively more quickly. 



Two additional benefits are that this type of tune makes efficient use of air (softer report, and generally higher shot count but not necessarily), and because the hammer is so light, it does not contribute as much vibration which can help with staying on target in the follow through.

 

[nomojo65]

I’ve never actually measured lock time of any of my Airguns but by the way the valve is actuated I have to believe the Daystate RW and Safari are the quickest! my RAW BM-500 seems really fast but probably is one of the slower ones? The FX...?

 

[STO]

So I actually MIGHT an answer to this! Not on all guns, for sure, but at least on three: an FX Crown .30, and FX Crown .22, and an AAA Slayer. 

So I do moderator tests, which means I get sound captures of guns going off. Things get a little complicated from here because in firearms lock time is defined as the time from when the trigger breaks to when the pin strikes the primer. These aren't firearms though, and the valve being impacted is very different from the pellet moving. And pellet acceleration may be slower as different guns have different initial pressures despite the same operating pressure. So we might more loosely define it as the amount of time between trigger pull and pellet exiting the barrel. Here it is a bit less clear what the beginning and ending sounds are precisely, but let me show you some data and you can draw your own conclusions:

An FX Crown .22 with Pilum. If you look at the scale on the bottom, the uncorking event (pellet exiting the moderator) is clear. The x axis scale on the top trace is 2x that of the bottom (obviously), so two ms. 

An FX Crown .30 with a Mus

An AAA Slayer in factory config:

So I included three of the .22 Crown to show that no, it is not background noise, it is consistent and linked to the gun. So lets do a little napkin math and work backward on these traces to see about plausibility, basically "does this pass the sniff tests?" So a Mus is 170mm long, estimate the length of the brake and barrel nut at 30mm, and a 600mm Crown barrel on the .30 and you have 800mm roughly. The gun has a muzzle velocity of about 850fps roughly, so lets say the average pellet velocity in the barrel/mod is 450FPS. So that would suggest that it is .00583 seconds from the pellet starting to move to it exiting the moderator. To my eyes anyway, that looks like the time on the trace is about 4 milliseconds. So what we're seeing is PROBABLY the amount of time from the hammer-valve impact to pellet exiting the barrel. It is all just a guess, but it is an educated one at least. Interestingly the Slayer doesn't appear dramatically different, despite its ostensibly MUCH faster valving, high muzzle velocity, and relatively short barrel/mod. *shrug* 

I hope that provides some helpful insight anyway, even if it may not answer your question. :/ 

 

[Guest]

Thomas. I own an FWB 800 FT as well and that's damn fast as well. The Anny 9015 is another quick one. Steyr with a 10m barrel as well. One of the things they all have in common is a 16" or less barrel lenght. My Thomas's is 15". So that's part of the equation. I can't speak on the Anschutz or Steyr but my Thomas and FWB use entirely different valve and hammer configurations. I've also shot many Air Arms, a few Daystates, FX's and other's in comparison.

 

[bucketboy]

This is one of the areas I am trying to improve on my sub12fpe fx impact,, the hammer travel is 22.5mm from sear disengagement to valve strike, compare this to 7mm on my other (easier to shoot) guns, the shorter run up before the hammer strikes plus the stronger spring required to get the hammer up to speed decreases lock time.



Bb

 

[oldsparky]

Thanks for the reply's. This is interesting.

 

[boscoebrea]

I went through this lock time thing quite a while ago with both powder burners and air guns;yes air guns are much slower.

I too was shooting off hand and could not afford those expensive target rifles;one reason they are expensive is because of all the do-dads they have on them to make them comfortable to hold and shoot.

In the end I just made my rifle fit me better and learned stance,sight picture,breath control and follow through by practicing with a champion target shooter.....he showed me the hows....I am only saying this because lock time is an inherited trait of the rifle you are shooting and even with one that is fast you still need a great follow through with it..... as people said there are tricks that can help "lock time" .and that was a good question with much info,.The older I get the more I need to shoot between the wobbles.

 

[BlackICE]

Defining lock time is from the time the sear releases the hammer to the time the projectile leaves the bore.

The lock time of air guns is really bad compared to modern cartridges using primers and smokeless power, but great compared to a flintlock.

 

[Springrrrr]

Defining lock time is from the time the sear releases the hammer to the time the projectile leaves the bore.

The lock time of air guns is really bad compared to modern cartridges using primers and smokeless power, but great compared to a flintlock.

And I think "lag time" is the time from the bore to the muzzle. Please correct if I am wrong.