qball:
For some reason I've seen the very same question that you are asking time and again...every new member asks the same question and they all expect a "Receipee"for an answer...There are lots of threads discussing the topic and you tube is plagged with "How to tune videos"...There is also a vast of information in the the database of this forum; search for "FX", "FX Tunning"or similar wording and go though all the information in those threads...
The receipee that some lazy people want means: What pellet to use, what velocity, what regulator pressure, what valve setting (if available) and trying to apply such an answer to your gun is not possible, every gun is different and reacts differently to the same tweaks...Read what velocities are people shooting as a ballpark and start from there.
You question don't specify: Caliber, brand and weight of pellets, regulator's pressure and valve setting, length of barrel, etc....This info is MANDATORY to start a conversatiion...Then you do not say if you are weighing and head sizing pellets, if you are not, this is a "MUST DO" to start tunning a gun; pellet tins usually come with a "Statistical Normal Distribution Curve" and you will encounter discrepancies that frequently go as high as 2 grains and I have seen as much as 4-5 gr...Buy a pellet gauge and use it for measuring heads.
Weighing pellets is MANDATORY for checking velocity consistency, then you will have to measure the heads of the pellets whenever you start tunning for accuracy....Your question about the minimum standard deviation or velocity spread shows that you have some misconception: A low standard deviation/spread does NOT mean better precision, you can have a gun with 5-7 fps, spread over a 20-30 shot group vs. another with 10-15 fps. spread and the later one coulde be more precise...If you want to know what is a good spread consider 1% of the velocity that you are shooting a very good number, but you can get slightly lower numbers. If anyone tells you that they are shooting 2-4 fps. over a 30-50 shot group don't listen to that, 2-3 fps. consistency over a series on long strings is JUST NOT POSSIBLE...Remeber that for achieving a 1% spread you will need to VERY PRECISELY weigh and head size your pellets, if you are shooting from the tin don't expect less than 20 +- fps. spread and many times more because every tin has about 2% of SCRAP pellets that weigh 4-5 grains more or less than the rest and those will be flyers without any precision...
Bottomline: Read time and again all the tunning threads and watch time and again all the You Tube videos about the same topic...Don't ask for a receipee, doing so denotes lazinessand and copying whatever others are doing is starting a tunning with your left foot.
Lastly: This forum is not an exception to the "Internet World Champions" who shoot with their keyboards, don't believe everything you read because there are some big egos behing a kehyboard shooting 1/4" and smaller groups at 100 yards and farther distances; you read those claims and try to emulate their claims and you will be frustrated...Use your brain (you should have plenty of that) to discriminate between reliable credible good info and BS.
Regards,
AZ
