Hacking The Benjamin Titan NP Break Barrel

[George Schmermund]

I was thinking of just the effort you have to put into cocking it normally. I checked mine by putting the (gun's) butt on the bathroom scale and doing a normal cocking using the barrel.  There's a cosine correction that's necessary to adjust the force normal to the scale, but a close guess is good for first approximations. Then subtract the weight of the rifle.

It helps if you have someone as a dial watcher if the scale doesn't hold the reading for a few seconds after applying the pressure. It can be a bit awkward at first so I'd recommend a few practice maneuvers before putting enough pressure on the barrel to actually hear the two clicks.

[WhatUPSbox?]

Just curious what that information might be used for.

[George Schmermund]

It's just another baseline. Mine cocks at ~ 45 lbs. If yours was different it might account for any differences in some of our measurements. It would also be useful if you see a change in pellet velocity outside of the normal spread when using pellets from the same tin. Is it the spring or the seals? Why guess when you can measure?!

[George Schmermund]

To keep things here from getting too stale I decided try something different. This trio of images is a series with 1, 2, and 3 of the previous wadcutters incrementally stacked in the breech. there are some things going on that may run contrary to predictions so everything will have to be sorted out when I do this again tomorrow. I think a lot of it will be guess work without a pressure transducer in the transfer port. Seal leaks may be one of the issues.

One item of interest is that the wire is taking longer to break. 3 pellets at once are a slow lot when they reach the muzzle.

[WhatUPSbox?]

That is an interesting dataset. A lot to chew on.

[WhatUPSbox?]

I tried to measure the cocking force. The scale approach didn't work for me because our scale is old and does not do well at low forces (I don't like how it does at high forces either  ). I tried an electronic fish scale attached about an inch in from the muzzle. Not real happy with the approach but I got just about 30 lbs. I found a spec sheet that listed 31 lbs. https://www.pyramydair.com/product/benjamin-titan-gp-nitro-piston-air-rifle?m=2603

I did not get close to the 45 lb number.

[mpbby]

Hi guys.  I am not capable to understand your thinking, but I would love some practical answers that we, that like to shoot scoped springers, could use.

I know this is off subject regarding this thread, but I would like a kind of dialogue with your knowledge and ability.

 Without rigor, I will try just to pass the idea.

The problems with a scope happen due the ‘efforts’ directly over it.  So, I would try to connect the sensors directly to the scope (or to a “replica”, as a simple 1” tube filled with some weight).  So, I will call the object being connected as “scope”. 

Considering holes for stop pins becoming oval, I would elect the longitudinal axis of the rifle as the main goal to study.  I will call this axis as – X.

I think we have 2 kind of dampa mounts easily available in the market.
 
For 1” we have the DM60 from Sportsmatch that works with rubber O-rings inside, placed horizontally; so, some part of the recoils along X are dampened.
We also have the ZR mount from Diana. Due the first and weaker recoil, when you release the piston, the little spring of the mount is compressed (to some extent). Then, the piston reaches the end of its course and you have the hardest recoil.  The idea of the ZR is that when this second recoil happens, the little spring is still compressed, and the scope would be without a rigid point of support (relative to X), not suffering this specific great impact.

So, I would proceed as follows:

When I think I have a trustable setup to measure the efforts upon the “scope”, and relative to X, I would use a regular mount (not a ‘dampa’) and repeat some times. The idea is to know how consistent are the results. Let’s say we may achieve a range of results, with its maximum and minimum (no matter the causes).  I would call it as ‘consistency interval A’.

Then, I would change the mount holding the “scope” to each of the dampa ones.  Repeat the tests to each one and compare with the regular mount. 

I think the practical/simple answers could be – compared with a regular mount, by how much would be dampened the impact of the second/hardest recoil if I use the DM or the ZR?

Again, it was just to pass the idea..

Thank you for your attention.

Marcos

[WhatUPSbox?]

I think if you look at the early pages in this thread you will see the scope simulators we are each using.

I've looked on the web for any testing of the ZR or DM60. I found one blog that tried to instrument a ZR with an accelerometer but the configuration they chose made the data challenging. I have not seen any data for the DM60, not even on the manufacturer's sight.   

[George Schmermund]

Marcos - Mikeyb (Michael) posted favorably about the Diana Bullseye Zero-Recoil mount. Maybe he'd be interested in doing the experiments that you've suggested. He mentioned that he might put together a test rig to do some of the things Stan and I have been amusing ourselves with.

My interest (this week) is in modifying the power plant part of a springer airgun to reduce recoiling. First I'll have to figure out how they work. This will probably take awhile at the present rate, but it's my way of seeking out the silver lining to a pandemic lockdown.

[George Schmermund]

Stan - your cocking force numbers are interesting. Maybe it just felt like 45 lbs when I did it. The old man effect probably. Now I'll have to contrive a dead weight test.

In the mean time here are a couple of images that may be helpful to use as a mental aid for visualizing what the DSO's acceleration trace means. The photo is obviously what the proxy scope looks like. I've rotated the DSO trace to show the direction the bar and accels are moving. I may be preaching to the choir, but the rotated trace keeps me oriented.

[WhatUPSbox?]

I like the rotated plot. Which way is time flowing? The first large sharp peak should be to the left if I understand it correctly.

[WhatUPSbox?]

Marcos,
I don't have either of the two damped mounts to include in the testing. I think the more challenging test for those mounts is how well do they re-establish zero. Given the general hold sensitivity of springers, I don't think that is an easy measurement to make to the accuracy of an expensive scope.

[avator]

How the heck do you guys turn all that off so you can go to sleep at night?

[WhatUPSbox?]

Actually, it is like counting sheep. It distracts the brain cells from the rest of the $&%! going on in the world.

[mpbby]

Thanks, and good luck with your challenges.

[George Schmermund]

Bill - What is this "sleep" you speak of?

[avator]

Yeah, that would be me... no way am I on the level of you guys but Betty Lou says that when I get something on my mind it's one track until it's finished.

Wait.... was she complimenting or what?

[George Schmermund]

Stan - Time is the purple line. It increases going upward. It's traveling along the zero value point of acceleration. The piston moving forward is the acceleration ramp on the right. I'll agree with you (for the moment) about the sharp peak.

[George Schmermund]

Stan - Thanks for going to the trouble of testing your cocking force. I had become complacent about the digital bathroom scale I've been trusting to give fair weight numbers. It works very well with comparison body weight measurements against other scales. I've just never tested it for accuracy using lower proof-weights. It turns out that mine doesn't do well with light weights either. If I put a known 30 lb steel plate on it and then let the display time itself out It will come back on with the plate tared out and the display reads 0.0 lbs. If I then cock the rifle pressing down against the plate the scale now reads very close to the numbers you've posted.

This would be another good use for the information. I'm now a wiser man for your effort!

[WhatUPSbox?]

I've been thinking that if the chunky end of the barrel were put in a v-block on a load cell of sorts, and the stock was used to cock the gun (upside down) then the force would be at right angles to the barrel for most of the motion and give the most consistent measurement. On the other hand it may be easier to just remove the gas ram and measure its compression force directly.