Hacking the Crosman Vigilante

[George Schmermund]

My method for adjusting the laser is to shoot a pellet somewhere on the target and then turn the set screws to line up the laser with the hole. This is all done with the gun in a vise. The sighter is self aligning at the muzzle because of the cone shape of the sighter's probe. The end that fits into the bore is kept concentric due to the tight fit of the pellets and the lathe centered drilled holes in them. The foible of this arrangement is that the sighter cone must be kept snug against the muzzle. This is where having a third hand would be useful. In lieu of that I use a rubber band over a front side of the laser and attach the other end to a lug on the scope. Under tension there is no movement of the sighter other than rotation. That leaves both hands free to tweak the set screws.

With little effort the sighter can be adjusted to rotate in a circle that just fits around the edge of the pellet hole in the target. It could be tweaked better I suppose, but it would offer no real benefit for my purposes. This is all done at 15 feet target distance at the moment. 

[Rob M]

I guess the real question is , is the gun laser accurate at 15 feet from a vice?

[WhatUPSbox?]

George,
With the gun in a vise, if you take the laser out and put it back in, how close does the spot repeat?

[George Schmermund]

I did the remove and replace test several times. The dot size at 15' is a nominal .20". After 10 tests the dot moves less than ~1/2 its diameter. My requirement is that I be able to put a shot group in each quadrant plus one in the center of a ubiquitous Gamo 5 1/2" target. I'm only interested in group size when testing different mods and different pellets.

The accuracy with this bore sighter far exceeds my requirements for the time being. I doubt that these results using drilled pellets to center the sighter could be reproduced if you had to use the adjustable rubber pieces that are provided. If anyone else is able to do the test using the factory setup as a comparison I'd be interested in the results. 

[WhatUPSbox?]

Those are good results.
Thanks

[George Schmermund]

One of the things that is worth mentioning when using the 2 pellet method on the end of the sighter is that the screw holding the pellets should be snug, but not tight. The sighter should then be held lightly when it's inserted into the bore. This will allow the pellets to seat into the rifling which will cause the sighter to rotate about 1/4 turn as it's installed. This will assure that the axial alignment is true. The rotation should reverse itself when the sighter is removed.

Check that the screw is snug before each insertion. don't over tighten the screw because it will over expand the pellets and make it hard to insert. Also, don't use any glue or such on the screw threads.

[George Schmermund]

I've been thinking about the suggestions concerning the measurement of pellet heads. Typically the skirts are larger than the heads. This is a good thing for gas sealing.

The alternative methods that are offered for making this measurement, if I understand the descriptions properly, don't allow the head to be measured without compressing the skirt. the method that I've described raises the caliper faces above the skirt and only measures the head. Am I missing something?

[Rob M]

the paralells could be elevated to  clear skirts I assume.

[WhatUPSbox?]

The parallels that I have are only 0.150" thick. I looks like, head down, the skirt on the RWS Basic wadcutter, is still smaller than the head when it clears the parallel.

For other shaped pellets, may need to do what Rob said and shim.

[George Schmermund]

Assuming that one's choice was to use Stan's method of thin parallels in a 'V' shape, it would not be difficult to electrically isolate each parallel at the vertex. A battery and LED could then be hooked up to indicate when the pellet filled the gap and lights the LED. This could produce an indication with very little pressure applied. It would probably make an interesting product. I'd buy one if it was priced right!

[George Schmermund]

Measuring pellet head size can be a daunting task. The setup described previously using the shimmed digital caliper on a glass surface should make the job easy and fast. The problem is that the pellet can be rotated using just the fixed jaw. This allows the measurement to be made again at a new set of points on the perimeter of the head. This maneuver most often gives a new number from the last one taken. Thinking that the head may have been squished a little, the pellet can be rolled back to where the last measurement was taken. I then get the first number back again. Back and forth, round and round. It appears that many of these RWS wadcutters have oval heads or something that makes them look that way.

This turns a 5 second measurement into several minutes of frustration on each pellet. I'm now suspicious of the accuracy of the gauges that rely on round holes of various sizes as way of assessing the actual pellet head diameters. It makes me think that the round hole devices, even if they're fibbing, could still really speed this job up. I have no doubts that the gauge holes are accurate If they're measuring something that is really round, like a gauge pin.

I realize that I could be getting myself into hot water even mentioning this dilemma, but sometimes the curtain needs to be pulled back a little. Or I need to be corrected by those who are able to use both methods and determine if I'm doing something wrong.

[WhatUPSbox?]

OK George,
As you requested, I made the Size-o-matic 2000.
Works pretty well, as set up each of the tick marks is .001" from .173 to .182" (sorry for the cell phone picture).
I think I'll make up some gages and set it to a shallower wedge. Maybe .005" over 3.5"

But yes, I notice the wadcutter heads are not round and sometimes have a little flashing.

Not sure what I'll do with the data, but it was a fun sidetrip.

[Rob M]

that looks perfect , does it respond to continuity ??

[WhatUPSbox?]

Yes, the LED comes on just as you feel drag on the pellet. I added the red plastic to get the friction down, that way you don't jam the pellet into the wedge. For a particular pellet, the drag point and continuity are pretty repeatable. On some pellets the first time through, it feels like there is a little flashing, continuity occurs slightly before a softer drag point.

As set up, it is probably .0005"ish for pellets.

[Rob M]

excellent , what are the 2 wall  surfaces made from ?

[WhatUPSbox?]

They are thin parallels I don't have the specs on them but the edges are ground flat. I don't remember if I got them from LMS, but they are very similar.
https://littlemachineshop.com/products/product_view.php?ProductID=2924&category=

[Rob M]

gotcha.. I use a harbor freight 35 dollar set, and the fact is , theyre more accurate than I am 

[George Schmermund]

It looks as though Stan has come up with a third easy way to measure pellet head diameter. I like his because it provides a different and accurate method to confirm that the heads on many 'quality' pellets can be out of round by a significant amount. This leaves me to believe that the whole concept of making the measurement by any means needs to be reevaluated. I was a little nervous about reporting the finding because of the great following 'sizing' has. Please don't shoot the messenger!

This new information makes me think that there's much more to be learned about pellets and muzzles. It opens the door for coming up with some new testing methods. I'm hoping that this onion can keep showing us more rings to peel back.

[AmBraCol]

I'm curious if anyone has measured any of the high end wadcutters, or just the "blaster" level of quality?  The reason I'm asking is, the Crosman and Gamo brands tend to be of VERY low quality control, no wonder there's a problem with oval heads. I've got a tin of Gamo "Match" pellets - that includes an obviously deformed "pellet" that made it into the tin from the factory.  Haven't taken time to measure them, but will be doing some photos and measurements one of these days.  Maybe I should break out some of my small stock of competition grade pellets and see how they measure up.   

[WhatUPSbox?]

My exercise was to see how the wedge approach works in measuring pellets in general. I have not measured (or have) any quality pellets. To be honest, I do not know what the criteria should be for acceptable eccentricity for a pellet head. If it needs to be less than .0005" or so, probably need a more refined measurement.