Does a Level 7 bolt require a heavier trigger pull vs a Level 10 bolt?

[GoatBoy]

Some of the technical stuff in this thread is a little questionable.

A properly configured LX bolt should reduce trigger pull.

While you do have to increase pressure slightly with the LX bolt, the difference on the on/off pin is not that much compared to the bolt pressing forward on the sear itself.

The first stage of the LX bolt pushes forward with less pressure (even with the increased chamber pressure), AND the springs you're supposed to use push back on the bolt harder.

Those both make actuating the sear (trigger pull) lighter.

The L7 springs are "lighter" than the LX springs.

As a test, you can put an L7 spring on an LX bolt setup and pull the trigger.

Then put a heavier LX spring in there and pull the trigger again.

You should be able to feel a difference right there.

If you don't want to listen to any of that and only want "appeal to authority", I believe AGD stated that it was the LX bolt that made the ULT practical. Otherwise there would be no point. I.e. the bolt/sear interaction swamps the on/off action. You guys can google-fu that one and correct me if I'm wrong.

As far as efficiency, I wasn't able to get a clear difference between the bolts. Like the difference between the two was probably within the margin of measurement error.

I would say the efficiency difference would be you can't quite shoot as deep into a tank due to increased operating pressure, and the LX bolt being slightly more prone to very tiny leaks (and I suspect that is where all the perceived differences come from).

Whether or not this is worth it, I'm not even going to try to address.

[athomas]

A level 10 bolt setup will only be lighter under certain circumstances. If you go with a really stiff spring and aren't using the optimum barrel length the increase in chamber pressure and resulting force on the on-off pin more than offsets any decrease in friction force due to the sear interacting with the bolt. This results in the level 10 having a heavier trigger pull. However, if you utilize a setup that keeps the chamber pressure lower, then the lower forward force of the level 10 bolt will result in lower friction and the increase in force on the on-off pin isn't as dramatic so the overall result is a reduced trigger pull force.

If you measure the trigger pull force on a mag, and then measure the force required to push the on-off pin without the bolt installed, you will find that there isn't as much differece as you would expect. This would indicate that most of the force is actually caused by the on-off pin and not the friction of the sear on the bolt.

The efficiency of both bolt setups depends heavily on the barrel length used. Each has a different optimum value. You can't compare efficiency unless you find that optimum value. For most user setups, I think that the level 10 bolt causes the barrel length to fall farther away from the optimum length value, which is why most users experience reduced efficiency. That inefficiency is a direct result of how the level 10 dumps air compared to the level 7. Using that information, the idea for using inserts in the chamber was tried and was actually found to provide better efficiency.

[GoatBoy]

I suppose that's a valid point.

If you have the most misconfigured mag possible, it is possible that the LX bolt will turn on you and actually make your trigger pull harder and your efficiency way worse.

The majority of my testing has been with brass Freak inserts which are a close fit to the paint used. They aren't the optimum length, but a close paint match still goes a long way.

As such, those are my results -- trigger pull is noticeably lightened, and the per-shot difference in air consumption was not measurable.

Anyways, let's talk numbers. I don't have any measurements or numbers or sear geometries in front of me; this is just off the top of my head.

The on/off pin is 1/8". That makes the area 0.0122718 square inches.

Ballpark, let's say operating pressure of an L7 is 450PSI. That puts the pressure on the on/off at: 5.52 lbs.

Now let's say an LX bolt takes 75PSI more, or 525PSI. That puts the pressure on the on/off at 6.44 lbs.

That's not exactly a massive leap in my opinion. Human perception of things usually happens on logarithmic, order of magnitude type scales.

On the other hand, that same chamber pressure is pushing against the L7 bolt. Again... off the top of my head, isn't the L7 bolt 1/4"?

Surface area of that is 0.0490873 sq in. Or, literally, 4 times more surface area than the classic on/off pin.

I don't have the forward surface area of the LX bolt, but the math is leading toward a fairly obvious conclusion, even without adding in the fact that there's a heavier spring holding it back.

[athomas]

AGD indicated that the L7 bolt operated at about 350psi. The L10 bolt has been found to operate at about 550 psi in most setups. That's a 56% increase in force on the on-off pin. The diameter of the L7 bolt is 0.250" and the diameter of the L10 bolt is 0.164". At the psi values indicated, the L7 has 17.7 lbs of force going forward and the L10 has 11.6lbs. Thats a 34.7% decrease in force from the L7. So, the increase in force on the on-off pin is about 60% larger than the decrease in force on the sear when going from the L7 to the L10. Now, if the frictional forces at the L7 setup are are 60% larger than the forces on the on-off, then the decrease in friction and increase in on-off would cancel each other out. Venturing away from these values is where the trigger pull either gets lighter or heavier for one setup over another.

Given that the calculated force values for a L7 on-off pin are 4.3 lbs and the real trigger pull is indicated by AGD to be about 4lbs, I would have to say that the friction component probably doesn't have as much impact on the trigger pull force.

[GoatBoy]

I'm taking the shortcut now:

Up until Airgun Designs released the Level 10 bolt kit, bolt pressure was a major factor determining the weight of the trigger pull in their mechanical guns.

http://www.warpig.com/paintball/technical/training/agdtech03/

[Spider-TW]

AGD indicated that the L7 bolt operated at about 350psi.

I think The Electrician measured a typical L7 setup around 425psi on HPA. The velocity, gas (HPA/CO2), barrel length & bore, and spring length should be able to cover the span of 350 to 450 pretty easily. I know that you can devolumize a classic enough on CO2 to cause the relief to pop at 280fps, which is around 600-650psi, so there is a lot of variation available in the operation of the automag. HPA fills are often ... less than accurate, to the point that a 10% loss of capacity is not huge deal (if that is what someone sees in number of shots).

[GoatBoy]

Disclaimer: had to fix previous post which had some bad math.

I think you used numbers in the act of obscuring numbers.

Assuming your lowball chamber pressure of 350PSI*, the numbers look like this:

L7 On/off force: 4.295146206
L7 Bolt Force: 17.18058482

More realistically (L7 at 400, LX at 550), the numbers look like this:

L7 On/off force: 4.908738521
L7 Bolt Force: 19.63495408

LX On/off force: 6.749515467
LX Bolt Force: 11.61823795

The LX loses a little on the on/off force, and gains a larger amount on the bolt force no matter how you slice it. On the order of 5-8 lbs. Both have springs pushing the bolt back, but the LX bolt spring is much stronger on top of that, so the difference between the two will still be sizeable.

Only part of that difference needs to translate to the sear (and I'm not assuming it's dominated by friction) to produce a net gain against what was lost in the on/off.

I can't explain the "trigger pull" numbers that you're using as I haven't verified them, and mechanical geometries may affect those numbers. (If there is mechanical advantage in the sear or where the measuring point on the trigger was taken, then the way you're doing the direct comparison is invalid.)

My gut feel is that the original L7 + classic on/off trigger pull was ~10lbs "at the trigger", and at least half of that is due to the L7 bolt pressure. I've never measured it, but I swear I saw it stated somewhere...

Here's a question: in the process of pulling the trigger, can you guarantee that the bolt *never* moves backward, even a tiny amount, prior to firing?




* Which I don't; from personal experience of having operated a gutted AIR where you can effectively measure chamber pressure, I believe an L7 is usually closer to 400. This should be doublechecked; I stopped running that setup a while back though.

Sources:

http://www.airgundesignsusa.com/rtchrono.shtml - easily above 350 at steady-state

http://www.warpig.com/paintball/tech...omag.faq.shtml - approximately 400

http://www.docsmachine.com/tech/pressure.html - 400 to 450

(And Spider's reference)

[Spider-TW]

(And Sp[i]der's reference)

One of my favorites. I didn't see the explanation of his hookup though; it's around. He made an adapter for the power tube tip to a gauge. He set the marker for velocity, then re-assembled without the bolt and with the adapter, and measured the working pressure.

http://www.automags.org/forums/showthread.php?130511-diameter-of-on-off-pin-in-the-ULT-on-off

[GoatBoy]

One of my favorites. I didn't see the explanation of his hookup though; it's around. He made an adapter for the power tube tip to a gauge. He set the marker for velocity, then re-assembled without the bolt and with the adapter, and measured the working pressure.

http://www.automags.org/forums/showt...the-ULT-on-off

Yes, much closer to what I would expect.

But the whole power tube adapter thing is taking the long way around though I think and probably gets worse results.

All you do is pull the reg piston from the AIR, and thanks to gas pressure laws, as long as you put a gauge anywhere in between the surrogate regulator and the dump chamber, you get the dump chamber pressure. And you can even fire it, although you need to give it time to reach steady state. My problem is I only have crappy gauges because good gauges are expensive and obnoxious.


Anyways, if you could fish up the trigger pull numbers for a classic, you would win. I know they were posted around the time of the ULT, and people were running around measuring trigger pull weights. Mechs came in maybe 5-7lbs, electros under an ounce, and then I swear someone posted the classic mag weight at 10lbs or more. You find that one, you win, thread closed.

Of course if people have been running around deleting posts, then ain't nobody finding crap.

Edit: found the damn thread. Problem was the... units used.

http://www.automags.org/forums/showthread.php?68168-How-to-Measure-Your-Trigger-Pull-WEIGHT&pp=40

[Menace_AO]

According to AGD's RT video (@4:45), trigger pull is 2 lbs, which was purported to be roughly half that of the classic, i.e., ~4 lbs.

Sure enough, in post #104, Tyril noted that his Autoresponse frame came in at 67.2 oz or 4.2 lbs. Certainly this is not the same as the classic frame, but the idea is there all the same.

This is what made the ULT such a big deal, in that it basically cut the RT trigger pull in half.


As for pressures, AGD notes in the classic manual that the valve operates at 450 psi.

And If memory serves, the L10 runs only 470, a negligible difference.

Either way, the L10 has much lower initial forward force, and the force difference on the on/off pin is negligible, so it should have a lighter pull.

Of course, if there's anything I've learned over the years, it's that the world as it is seldom matches the world as it is on paper.

Only way to be sure is to set up one marker, do the test with the L7 bolt, then do it again with the L10.

Then we'll know.

[Spider-TW]

Edit: found the damn thread. Problem was the... units used.

http://www.automags.org/forums/showt...l-WEIGHT&pp=40

That was measuring electro triggers for ULT planning, but I see your autoresponse reference.

Besides the 4 lb (classic on/off) and 2 lb (RT on/off) numbers, was the ULT 8 oz?

I've always used the chamber pressure on the diameter of the on/off pin shaft diameter (and head diameter minus residual chamber pressure). The sear arms are mostly equal in length, so I assume the exact length variations are well within actual chamber pressure changes off of 450 psi.

***

Seems like it (the ULT) calculates to 8 oz or so, but is generally taken to be 15 oz., perhaps there is 7 oz. of drag there that doesn't show up so much on the stiffer on/offs.

[Menace_AO]

As I recall, Tom indicated a 15 oz. pull, and given that was on the heels of the linked thread, that may indeed have been the actual pull.

[GoatBoy]

15oz is what the AGD store page says for the ULT.

The variance in the numbers is pretty staggering (consider the guy that hung the bag of wrenches off his trigger). They cover the entire range, which if you think about is not surprising given all the possible differences between people's setups.

The takeaways from that thread are:

1. It is really hard to judge the trigger pulls from one mech mag to another
2. People are really bad about judging trigger pulls in general

I still stand by my general logic and reasoning (otherwise it wouldn't be logic now would it?) -- within the same gun, bolt forward pressure matters to trigger pull. For L7, it has always been "significant". It can range from "significant" to "WTF?" For LX, it only takes a minor win from bolt pressure to make up lost ground on the on/off, and probably produces a really big win in the "WTF?" cases.

Just the specific numbers and relationships are hard to come by without controlled testing.

[Spider-TW]

15oz is what the AGD store page says for the ULT.

The variance in the numbers is pretty staggering (consider the guy that hung the bag of wrenches off his trigger). They cover the entire range, which if you think about is not surprising given all the possible differences between people's setups.

The takeaways from that thread are:

1. It is really hard to judge the trigger pulls from one mech mag to another
2. People are really bad about judging trigger pulls in general

I still stand by my general logic and reasoning (otherwise it wouldn't be logic now would it?) -- within the same gun, bolt forward pressure matters to trigger pull. For L7, it has always been "significant". It can range from "significant" to "WTF?" For LX, it only takes a minor win from bolt pressure to make up lost ground on the on/off, and probably produces a really big win in the "WTF?" cases.

Just the specific numbers and relationships are hard to come by without controlled testing.

I would agree. It's why I like to polish my sear pins, sears, on/off pin bottoms, and bolt edges, especially on RT setups. Some new sears have significant tool marks from being stamped, where the on/off pin rides.