SDB Sport Velocity Test by SimpChrony

[Basu]

Basu

[greenrifle]

Thanks you both nice video
Thank you both for detailed review ... Thank you Basu Da ..


GreenRifle

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[Basu]

Dear Greenrifle,

Coming to the question of SimpChrony.
I found this instrument is much more comfortable to work with .
No sun light , no under light , no heat, no sweat.......tested in the room only.
no missing....once the sensitivity is set....
And coming to the Sport.
I got the power close to what I expected ,in fact i wanted to touch 900 fps, knowing it is a trade off between power and accuracy.

Basu

[Basu]

Today I tested the velocity of Sport with 8.4 gns Unitedshot PH pellet and I was stunned having seen the energy output.
It reached max 13.9 fpe.
With other pellet it normally hovers around 12 fpe .
No Indian springer can excel this except Artemis.

Basu

[vsraja]

For 870fps of 8.4grain pellet carries 14.12 fpe. Does the chrony is calibrated before test?

[Basu]

My SimpChrony is calibrated with F1 Chrony.
I fed the mass as 8.3 gns but manufacturer confirms it as 8.3-4 gns.

Basu

[prashantjha19]

What a terrific feat by your Sport, Basu Da! My compliments!!
I am sure, one of the first things you would be itching for now is to check the accuracy with this pellet (going at such a tremendous velocity)....and we sure will be hearing on this sooner than later, I bet.
I have two rather general queries though:

1. Is it a tuned Sport or is it in its factory tuned state? (By tuning, I do not mean adjusting of the trigger load and pull though); and

2. Why other brand pellets of the same or similar weights (assumedly even superior in quality, craftsmanship, built consistency, finish, etc.) such as Ph and others were unable to render this velocity? Of course, one has heard so much on "...do check out for the perfect pellet for your gun, and order in bulk...." stuff. However, I wonder, what all really go into making that perfect package though! Is it design dynamics (head and skirt), the groove patterns or the absence of it on the pellet, the respective lengths of the skirt-head, the seating in the breech, or how the skirt and head together engage within the barrel during the pellets' flight....or all of it together?

Your thoughts, and certainly those of many others on IFG, on this rather intriguing phenomenon would be a great learning lesson for learners like us....and we will look forward to you considered opinions please. I am sure it all would be coming from years of hands-on jobs and lived and felt experiences.
Warm regards,
Prashant

[Basu]

Dear Prashant ,
If you watch the YouTube video about the velocity of the Sport , you may notice that most of the pellets were delivering 12 or around 12 ft/lbs energy.
It is only this pellet in pic.did the wonder.
I knew that an AR with 3 kgs weight best upto 10 fpe.
Yet I stretched it with many extra yards of velocity.
There is no transverse vibes , only little back & forth movement.
At this velocity , very difficult to hit target off hand.One needs to have bench rest.
I deliberately opted for Velocity as I have GenNex as one holer.

Basu

[prashantjha19]

Indeed yes, Basu Da! I have seen the youtube video of yours with Kaushik Ji. But 13.97 fpe (as against 12) is close to a 16% jump, which is phenomenal, especially when the gun is already at its stretched out stage (12 fpe). By your own yardstick, you would give a 3 kg gun full marks for achieving 10 fpe.

That is why I felt that the feat calls for finer qualification - both the manner in which you stretched the gun "many yards for extra velocity", and the manner in which the pellet design and fit may have contributed. My apologies if I tended to over exceed in my curiosity. May have got carried over, ...just that these questions keep coming up over and over.
Sincerely,
Prashant

[Basu]

Dear Prashant,
I think the design of the gun is such that it can convert the potential energy into kinetic.
Unlike many other ARs , when harder spring is used , Velocity dropped due to excessive bouncing off piston.
Apart from standard tuning I did use a harder spring ,taken from the market.
I had SDB 45 for 3 yrs , and that could generate max 10.6 FPE after all things possibly could be done.
To my surprise in 45 harder did not yield the KE proportional to PE rather went other way.
I still say Sport is most under rated gun of SDB stable.

Basu

[prashantjha19]

Terrific! Very much the kind of qualifying we were expecting from you, Basu Da. This can come only from those who have tried and erred and dirtied their hands on the job...and not just rims of theory alone!

Finally, the old myth looks to be going bust..... So, It is not always that a hard spring is detrimental to muzzle velocity. If the gun mechanics is finely calibrated, they CAN result in augmenting power delivery!! Of course, the right size and weight pellets (to address piston bounce), minimized gaps and tolerances (to arrest twang /vibe), and all that remain as crucially significant as ever.

Much appreciate your revert.
Regards,

[Basu]

A testing is done after my Sport went past 500 shots
It was hitting 12+ fpe with Precipell 8.2 gns pellets.
The shot to shot velocity consistency was excellent.
It goes to establish that Precipell pellets suits well in SDB .177 barrels.

Basu

[prashantjha19]

Thank you for this very useful piece of information, Basu Da!

Just curious - Do these Precipell pellets perform similarly in your other SDB gun (Gennex) please??
Regards,

[Basu]

In GenNex it returns phenomenal accuracy.

Basu

[narach93]

Dear Basu da, yours advice is highly solicited. Can SDB O ring ( it is available at kovibazaar) be fitted into the breech of 1992 model IHP 35 ?
Also please help me getting a simple chrony.
Happy diwali.
Regards