Chrono test results - Daystate Prestige .177 X2

[blasterjudd]

Hi All

So I ordered a chrono HT X3005 off amazon this week quite an impressive bit of kit I must add.

So have now tested my Daystate .177 X2 Prestige out with Daystate FT Heavy pellets weighing 10.25 grains results are pushing out 10.8 ft lbs / 690 fps now my question is if I try a lighter pellet the fps will increase but will the ft lbs go up or down ?

Is 10.8 ft lbs low for a pcp with heavy pellets ? Hunting is my hobby now I've done very well with this gun had it for 5 years now and thought it time to see how shes performing over a chrono interesting to see only a 5 fps difference over a 24 shot string as well so that's pretty good is my 1st thoughts !

I shall buy some AA Diabolo and give them a try as am advised they may give higher fps and ft lbs as they fit tighter in daystates ...

Anyone else testing their pcps and what do you find with your results ?

Interesting topic ......

[Mr.C]

Well... I run my MPR at 775-780 with AA diabolo 8.4gr 5.52`s which gives me 11.3 and comfortabley under max in case of a very hot day. 

I dare say your quarry won't notice the difference if you do your bit though. 

[Mice!]

7 hours ago, blasterjudd said:

Is 10.8 ft lbs low for a pcp with heavy pellets

The general consensus is try a light medium and heavy pellet. 

I'm using JSB heavies they are doing around 715-718 giving 11.7-11.8 ft-lb

A 9.57 pellet (H&N extremes) was going 730 fps giving around 11 5 ft-lb

Order some samples and have a play.

[London Best]

Do any of you really believe that a decimal point of a ft lb makes any difference to anything?

[wymberley]

1 hour ago, London Best said:

Do any of you really believe that a decimal point of a ft lb makes any difference to anything?

I don't suppose many of us do, but we're potentially talking of 10 of the little devils here.

[wymberley]

14 hours ago, blasterjudd said:

Hi All

So I ordered a chrono HT X3005 off amazon this week quite an impressive bit of kit I must add.

So have now tested my Daystate .177 X2 Prestige out with Daystate FT Heavy pellets weighing 10.25 grains results are pushing out 10.8 ft lbs / 690 fps now my question is if I try a lighter pellet the fps will increase but will the ft lbs go up or down ?

Is 10.8 ft lbs low for a pcp with heavy pellets ? Hunting is my hobby now I've done very well with this gun had it for 5 years now and thought it time to see how shes performing over a chrono interesting to see only a 5 fps difference over a 24 shot string as well so that's pretty good is my 1st thoughts !

I shall buy some AA Diabolo and give them a try as am advised they may give higher fps and ft lbs as they fit tighter in daystates ...

Anyone else testing their pcps and what do you find with your results ?

Interesting topic ......

Now you have the kit, use it and measure the velocity downrange as it'll give you a far better idea. Also, where did your 690 ft/sec come from? I played around and was able to show that my velocity measured at 3 yards equated to an additional 0.4 ftlbs at the muzzle. Although for me, accuracy is the be all and end all, I rejected a couple of pellet choices which were faster at the 3 yards as their BC wasn't obviously up to scratch and they were slower where it mattered.

As ever, all is ish.

[Balotelli]

Correct me if I am wrong - Assuming  that the  ft lb  output would be a constant for that particular gun, as it is. If very roughly, mass x velocity (gun) = mass x velocity (pellet)  then the greater the mass of the pellet the lower the velocity of the pellet to balance the equation. My schooldays' science from memory and maybe wrong. But the simple equation explains why a .177 pellet being less mass will have a higher velocity, similarly, a lighter .22 pellet will have a have a higher velocity than a heavier .22  to keep the equation balanced. Completely, made up figures below

      Mass of gun X speed of recoil   =  Mass of pellet X velocity of pellet

          8kg           x   0.01                     =       0.0001         X       ?

             

?  =  8 x 0.01 / 0.0001     so as the mass of the pellet increases the speed of the pellet decrease

 

 

[Mice!]

5 hours ago, London Best said:

Do any of you really believe that a decimal point of a ft lb makes any difference to anything?

It means your under the 12.

54 minutes ago, Balotelli said:

Correct me if I am wrong

There is a formula for working things out, it's long and written down in my chrono instructions. 

[London Best]

Velocity squared x bullet weight in grains divided by 450240.

[Balotelli]

18 minutes ago, Mice! said:

It means your under the 12.

There is a formula for working things out, it's long and written down in my chrono instructions. 

OK Thanks, Mice, I was looking for simplicity. My eyes glaze over if it's too complicated!

Just now, London Best said:

Velocity squared x bullet weight in grains divided by 450240.

I get the kinetic energy bit  half mv squared, what is the 450240? 

[London Best]

7 minutes ago, Balotelli said:

OK Thanks, Mice, I was looking for simplicity. My eyes glaze over if it's too complicated!

I get the kinetic energy bit  half mv squared, what is the 450240? 

7000 times acceleration due to gravity (I think.

7000 grains in a pound and you want ft pounds. Alternatively, you need to put bullet weight in pounds, not grains.

example: .30-06, 3000 FPS 150 grain bullet. 
3000x3000x150 divided by 450240 equals 2998.4 ft lb.(the .4 doesn’t matter!)

Edited October 22, 2020 by London Best

[Balotelli]

2 minutes ago, London Best said:

7000 times acceleration due to gravity (I think.

7000 grains in a pound and you want ft pounds. Alternatively, you need to put bullet weight in pounds, not grains.

Gosh, we seem to have a right old mix of units, grains, ft lb, grams, mph, f/s, cm g etc. Scientific notation is all metric and maybe we should be consistent.  Unfortunately, I can remember all the old Imperial units and £ s d.

Why, we could price up a tin of pellets in real money £14 3s 4d. (14 pounds 3 and fourpence, now you are talking). I have in my loft some Ship brand pellets with a price tag on the tin of 2/6 and a pint at my local hostelry used to cost one and sixpence. 

[London Best]

£14 3s 4d was about the price of a new Airsporter in 1958!

[wymberley]

Two differing things going on here:

The energy of the projectile you've already got. The unit of gravity was changed a while back, so 2x7000x32.174=450436.

The recoil velocity of the gun is:

load weight in grams divided by gun weight in grams multiplied by load velocity in ft/sec.

(The MV of a Eley Impax No6 with an observed velocity of 1070 ft/sec would have been 1350.

A 1 oz load from a 6lb gun at 1350 is 28.35 divided by 2722 times 1350 equals 14. This is about as fast as you want for comfort and it's now obvious where it comes from and why the 96:1 ratio remains valid. Totally useless for air rifles of course.)

 

[Ultrastu]

Why are we talking about the weight of the gun .? 

 

Unless its felt  recoil we are interested  in  ?

[wymberley]

Heaven knows, but at 8 kgs it's certainly a big one.

[Ultrastu]

If a gun has a constant muzzle energy irrespective of pellet type then the lighter pellets will always go faster (at the muzzle ) than a heavier one .

But airguns don't have a constant muzzle energy ,  ever . And the pellet type can vary the energy loads .so often we find velocities higher or lower than we would expect .a good example of this would be a pcp with a short barrel (say 12 inches ) and 2 pellets the jsb 8.44 grn and the rws super dome at 8.3 grn 

In this gun (and many others ) the heavier jsb will have a higher velocity at barrel .

This is for a few reasons based on -  lead compound,  shape , and size .

Another pellet that is often beaten by the jsb  (velocity and energy ) is the Crosman premier  at 7.9 grns .

The above examples are based on pcps .

For spring guns the above can often  be turned on its head .

Best advice .is buy a pellet try it (for accuracy) and chrono it if you want  . And build up a picture  of which pellets do what .and how they work for you .

 

[Ultrastu]

also bare in mind (when worrying about muzzle energy ) that I often shoot and kill cleanly squirrels in my garden up to 20 yds with 5.5 fpe at the muzzle and around 4.5 fpe at the skull .

So I'd say 10.8 fpe with a jsb heavy will have enough energy to kill any thing you can hit at any range as long as you can hit the vitals .

 

This hw 30 makes 5.5 fpe with falcons and about 4.5 fpe with air arms match .

This squirrel didn't care which pellet it was .I can't remember exactly but I think it would have been the match pellet .

[London Best]

@Ultrastu: good common sense post.

[Mice!]

3 hours ago, Balotelli said:

OK Thanks, Mice, I was looking for simplicity. My eyes glaze over if it's too complicated!

This is the instructions for my chrono, sorry thought I'd put this on.

[Balotelli]

1 hour ago, Ultrastu said:

If a gun has a constant muzzle energy irrespective of pellet type then the lighter pellets will always go faster (at the muzzle ) than a heavier one .

But airguns don't have a constant muzzle energy ,  ever . And the pellet type can vary the energy loads .so often we find velocities higher or lower than we would expect .a good example of this would be a pcp with a short barrel (say 12 inches ) and 2 pellets the jsb 8.44 grn and the rws super dome at 8.3 grn 

In this gun (and many others ) the heavier jsb will have a higher velocity at barrel .

This is for a few reasons based on -  lead compound,  shape , and size .

Another pellet that is often beaten by the jsb  (velocity and energy ) is the Crosman premier  at 7.9 grns .

The above examples are based on pcps .

For spring guns the above can often  be turned on its head .

Best advice .is buy a pellet try it (for accuracy) and chrono it if you want  . And build up a picture  of which pellets do what .and how they work for you .

 

If mv(gun) =mv (pellet)  and mv for the gun is constant (the recoil), then the surely the mass of the pellet will be proportional to the speed of the pellet to keep the equation in balance. On that basis wouldn't a lighter pellet have a greater velocity?  Have I go this wrong?

On another point, why would the composition of lead pellets vary? Isn't lead lead, maybe some small amount of impurities but I would have thought negligible.

As for the chrono instructions there seems to be a load of gobbldygook. Kinetic energy is simply 1/2 mv² .

Edited October 22, 2020 by Balotelli

[Ultrastu]

No .lead is not lead .

Lead used in pellets usually has antimony added to it to make  it harder .

Pure lead is very soft and if used will deform badly in manufacture and transit and even irregularly upon firing .

So antimony makes it harder and more consistent. But this hardness can have a down side .it can make bore friction greater robbing the pellet as it flies down the barrel of energy .

Jsb tend to make a soft pellet with thin skirts which balloon (the skirt ) well in the barrel making a tight bore fit this reduces air blow past allowing for an increase in velocity .(the down side is bent pellets in the tin  and hence the sponges in the tins ) 

Rws add a lot of antimony. And I've yet to see a deformed rws pellet in a tin in 30 years of shooting  .

[Ultrastu]

I can put a 10.4 grn Bisley magnum in my bsa springer  and it will make 9 fpe .

The same gun with a jsb exact at 8.4 grns will give 11.4 fpe .

By contrast .my pcp bsa ultra will do .10.8  fpe with the same jsb 8.4 

But also do 11.8 fpe with the 10.4 grn  Bisley magnum .

How the air is delivered and a million other factors that come into play (i really haven't got the time ) all go to add up to the given muzzle energy for a given pellet.

ps can we stop talking about the weight of the gun its not relevant. 

Its about as relevant as the colour of the stock .

 

[blasterjudd]

8 hours ago, wymberley said:

Now you have the kit, use it and measure the velocity downrange as it'll give you a far better idea. Also, where did your 690 ft/sec come from? I played around and was able to show that my velocity measured at 3 yards equated to an additional 0.4 ftlbs at the muzzle. Although for me, accuracy is the be all and end all, I rejected a couple of pellet choices which were faster at the 3 yards as their BC wasn't obviously up to scratch and they were slower where it mattered.

As ever, all is ish.

Hi 690 fps is what the chrono measured on the end of the barrel it's a HT X3005 very good bit of kit it also calcs the energy too

[Chaz25]

last time I tested my PCP think its about 400 fps but it is pushing a 34 grn pellet so more bumble bee than wasp!