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PostPosted: Sat Sep 03, 2016 4:44 pm 
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Joined: Mon Aug 24, 2015 4:56 pm
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Location: Tecumseh, Ontario in South Western Ontario
I am satisfied with the shot count per fill. I don't like the idea of lowering the velocity to get an even steadier velocity range. I do however want accuracy so I'm asking how much variance between shots would it take to really affect a group size. The simple answer is no variance is best but there must be a point where a regulator won't make much of a difference. The graph below shows what the gun is shooting now.
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PostPosted: Sun Sep 04, 2016 9:52 am 
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With quality pellets, a good regulator should be able to keep the variance between 5-10fps

While I haven't played with non-regulated gun. I've found that the quality of the pellets will have a big impact on speed variance. R10 / Finale Match were usually between 6-7 fps. While some old Crosman I had laying around had a 15fps. (From a pistol shooting at around 500fps)


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PostPosted: Sun Sep 04, 2016 2:21 pm 
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Location: Coalmont BC
At 50 yards, a 4% ES (extreme velocity spread) will only make about 1/4" vertical difference in the POI.... I use that for my minimum ES for most guns.... If you are shooting at 100 yards, you need less than a 2% ES to keep the vertical POI within 1/2"....

For comparison, .22LR Rimfire ammunition, even the target stuff, usually has more than a 2% ES over a box of 50 shells.... and they do just fine at 100 yards....

Bob

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PostPosted: Sun Sep 04, 2016 6:27 pm 
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first of all, the difference between highest and lowest velocity within the "plateau" (in Ukraine we refer to plateau as to part of the graph where velocity is more or less the same) is crazy :shock:

a well-regulated system (without a regulator - not sure how you call it) should give a stable velocity of +- 5 mps (16 fps), or even less. Perfectly regulated system is very stable +- 1(2) mps.

a system with regulator should give a stability of +- 1 mps

so, in this case before trying anything else, I would start with thinking how to make the velocity more stable. Good idea would be to check if all metal parts move well. They should not be too lubricated. As they say, only the rifle itself and you should know that there is oil inside. Otherwise, the hammer (?? this metal thing which hits the valve to make the shot) can get stuck, or move slower than it should/ move with different speed and, as a result, hit the valve with different force, letting out different volume of air each time.

Also, check if air does not leak from any parts, check all the rubber rings and stuff. If there is leakage, it can also affect the plateau seriously.

If all of this does not help, you may try to tighten the coil inside of the valve. The tighter that coil is, the more stable is the velocity. That is a general rule.
You can also try to reduce the weight of the hammer. It has the same effect and tightening the coil in the valve.

This will not work, however, if you have a regulator. In this case the solution is to find how to fix a regulator or to replace it, cause such a span in velocity is not good.

In terms of the velocity. Again, the general rule is that each barrel "likes" its own kind of pellets, and both barrel and pellets "like" their own velocity. Usually there is a span within which your pellet shot from your barrel gives the best accuracy, but in order to reach the best possible group, you need to find the best velocity for both your barrel and the pellet you use. Again, only after you stabilize the PCP system.

Such aspect as caliber influence a lot. For example, same pellets - JSB exact shot from the same barrel can give different accuracy, if they have difference in caliber. As you know, in millimeters the caliber of JSB (within .177 caliber) can be, for example, 4.50 mm or 4.51 mm, or even 4.52mm All three types work differently with different barrels.

There are also a bunch of aspects with influence the accuracy, but those are basic ones.


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PostPosted: Sun Sep 04, 2016 7:02 pm 
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Location: Central West River Nova Scotia
To answer your question. A regulator is not worth it if all you shoot is tin cans. Unless the tin cans are at 100 yds and you want to hit fifty of them. Personally, I love regulated guns.

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PostPosted: Sun Sep 04, 2016 10:15 pm 
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I personally think that .177 is not worth it after the range of... 70 meters. if only you want stable accuracy and group, and not just being able to hit the can from time to time.


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PostPosted: Wed Sep 07, 2016 6:30 am 
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Joined: Mon Nov 14, 2005 2:45 pm
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Location: Toronto, ON
I'm impressed by your graph done by hand! That brings me back 20+ years :D

Traditionally in FT, an extreme spread of 15fps is desired. But as Bob said that 4% is also a great rule.

A properly designed and setup non-regulated gun is no less accurate than a regulated one.

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PostPosted: Wed Sep 07, 2016 1:10 pm 
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Joined: Mon Sep 05, 2005 10:55 pm
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Location: Rocky Mtn Hse Alberta
Here is what a reg can do


Attachments:
File comment: Regulator made by me lol
AT44CHPreggedString.jpg
AT44CHPreggedString.jpg [ 138.47 KiB | Viewed 319 times ]

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