Whats a good spread for target shooting fps?

[Richard300]

Hi. I was wondering what is a good spread fps for your pellet flight. What average do you want? I know if you could get a an exact ...single fps that would be perfect but that isn't going to happen. So what should I look to get and be satisfied with. What do you try to get. Within 5 fps each way higher and lower? more or less? How much speed really affects the flight of the pellet.Thanks Richard

 

[John "spysir" Blount]

 10 fps extreme spread from 1st shot to last would be fine.


John

 

[Zephyr]

Which rifles achieve an extreme spread of 10fps or better?

 

[Richard300]

Sorry...New at this ...is that 10 fps from the center....10fps up and 10fps down or 5fps up and 5fps down... so is extreme fps 5fps.each way?
thanks richard

 

[GLPalinkas]

"Richard300"Sorry...New at this ...is that 10 fps from the center....10fps up and 10fps down or 5fps up and 5fps down... so is extreme fps 5fps.each way?
thanks richard

First, I'm not an expert tuner but have done enough to maybe help you understand.

Extreme spread (or ES) is the difference between the lowest shot in the string to the highest shot in the string. An example would be 800 Low, 810 High and back down to 800 Low for an ES of 10fps. Now the number of shots in that 800-810-800 is what matters and if you can get a reasonable amount of shots, you have a successful rifle tune. Most folks will determine what they want the ES to be and use only those shots. In other words, in the example above maybe the string starts at 780 with a 3000 psi fill, goes to our high of 810 (at 2600 psi) and back down to 775 psi (typical desired bell curve, let's say 30 shots) You would then only use the shots that are within your acceptable range, i.e. 800-810-800 so fill your gun to say 2800 psi and shoot down to 2200 when the fps reaches around 800. Maybe you get 20 good shots in that 10 fps ES.

ps... an extreme spread of 10 fps may be overly optimistic in a non-regulated gun but using a percentage, like 3% ES for most folks is accurate enough (like maybe 25fps in our example). 

pss... another example is my .25 Marauder I tuned for more shots and just a little less power. 
771-792-772 25 good shots AVG 785 ES 23 SD 7.7 from 2650 to 1850 psi for about 35 FPE

Hope this helps.....

Gary

 

[Richard300]

Thanks glpalinkas...now i got it. I'm putting a regulator in my hatsan . 40-10 25 cal. Shot it today through chronograph looked bad....it shot: starting at 2900 psi 
808 808 813 808 811 816 817 811 814 814 812 799 798 794 786 789 779 775 775 768 Then it drops off fast. This was non regulated. I will try it again when I have time to put the regulator in and see what it will do then. Thanks for showing me what I needed to look for. Richard

 

[chasdicapua]

I get about 11 or 12 ES on my REGULATED FX 200 with 50 shots in the string. Yes, as Gary mentioned, the total number of shots at the particular ES needs to be taken into consideration as well. If don't care too much about shot count and only want as much shot to shot consistency as possible, then you wouldn't need a regulator and just shoot within the PSI spread where your ES is lowest. Regulated guns are great for a low ES, but, as I understand, not as easily tunable.

 

[Scott_Allen]

You can use chairgun or other ballistics apps to model POI changes with various pellets at 55 yards and velocity spreads. You have to decide on your own what kind of shot to shot variation is tolerable for you. The more accurate you can make your rifle the more margin of error you have in range finding, wind, and shooter induced variables. 

 

[Richard300]

Ive got a lot to learn ...before I get my gun shooting right. I have been looking everywhere to figure how to exactly set up my hatsan 44-10 in .25 cal. I have been getting good ideas here and other forum sights. Thanks for all the help.

 

[Richard300]

ok got my regulator in stock...didn't do anything to it yet. Hatsan 40-10 long .25. Here what it shot:
671 670 667 668 667 669 671 672 667 665 571 553 669 669 667 667 670 668 668 669 669 669 673 673 671 669 672 666 then it drops off.
man that's a lot better. I will be using this mostly for target shooting With working my way out to 80 to 100 yards with a little hunting time to time. What do you think I need to set my regulator pressure at? I have been watching as much as I can find on tuning the hatsan 44-10. So nixed I will start mod my regulator to see if I can get more out of it. I'm learning here so if you have any ideas just let me know. Thanks Richard

 

[Salticon]

I don't know what to say to this, when I tune my .22 Condor it took me a day of tweaking and a tin of pellets. I'm personally not happy with Es of over 10.
this is 50 shots from 3000 -2300, reg is at 2200.