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high power air guns?

Posted: Wed Nov 15, 2017 12:22 pm
by FPSguy88
i want to know that if someone have a air gun under 20joules energy but if energy exceeded to more than 20 joules by repair or modification then it would legal or not?

Re: hi power air guns?

Posted: Wed Nov 15, 2017 1:10 pm
by Basu
When the defined limit is 15 jules , anything beyond that will violet the law.
You may always have anything beyond 15 jules till you are questioned by administration.

Basu

Re: hi power air guns?

Posted: Wed Nov 15, 2017 1:13 pm
by mundaire
It would require an arms license unless it can pass the deal wood test (as outlined in G.S.R 662 dated 1962), without which it would be illegal to possess.

Added in 2 minutes 9 seconds:
The limit is not 15 Joules, it is 20 Joules which is 15 foot pounds. Joules and Ft Lbs are two different units of measurement, the first is based on the metric scale and the second on the imperial scale.

Re: hi power air guns?

Posted: Wed Nov 15, 2017 2:47 pm
by FPSguy88
mundaire wrote:It would require an arms license unless it can pass the deal wood test (as outlined in G.S.R 662 dated 1962), without which it would be illegal to possess.

Added in 2 minutes 9 seconds:
The limit is not 15 Joules, it is 20 Joules which is 15 foot pounds. Joules and Ft Lbs are two different units of measurement, the first is based on the metric scale and the second on the imperial scale.
i agree but if i used heavier pellet that will increase would be also illegal too. ie. i have a air rifle which gives 20 joules power on 7gr. pellet but i use 14gr. pellet then it will increase its power what would be in this situation?

Re: hi power air guns?

Posted: Wed Nov 15, 2017 2:52 pm
by narach93
By multiplying .738 with joule you will get ft lb. And by multiplying 1.356 with joule you will get joule. Thus 20 joule is 14.76 ft lb.

Added in 1 minute 18 seconds:
Sorry. By multiplying 1.356 with joule you will get figure in ft lb.

Re: hi power air guns?

Posted: Wed Nov 15, 2017 4:23 pm
by targetpoint
I and many others have SDB Artemis in .177 and is 13+fpe out of box.But after proper tuning it will definitely deliver 14+ that too with nice accuracy.

Added in 8 minutes 49 seconds:
I apologize for posting this as the information needed is of legal limit.sorry.

Re: hi power air guns?

Posted: Thu Nov 16, 2017 12:28 am
by narach93
If the manufacturer claim that its AR is capable of giving 13+ fpe, then the maker should divulge the weight of the pellet in grain and the muzzle velocity. Very few does. Take for example of diana 350. The maker claims that with 1250 fps it gives 30 joule. That means the wt of the pellet is only 6.37 grain. Another example is precihole NX .177. The advertised velocity is 800 fps and muzzle energy is 12 fpe or 16 joule. Thus the wt.of the pellet should be 8.44 grain. The energy output depends on the wt of pellet. Heavier pellets will travel in less velocity thus gives low muzzle energy. This information is based on a simple formula. Let me try to put in this way. Velocity × velocity × wt of pellet in grain divided by a constant 450240 is equal to muzzle energy in fpe. To substantiate my point let me try a 5.2 grain RWS Hypermax pellet in Diana 350. The calculation goes like this - 22.14 fpe x 450240 = 9968313.6
9968313.6 ÷ 5.2 grain = 1916983.385 . Root over of 1916983.385 gives
1384.55 fps. Now this velocity is much more than the adverised velocity. If a heavy pellet is used, then the velocity will decreased, but the energy will remain same.
But there is another formula to know the effect of wt of pellet on the enegy. M1÷M2 x initial velocity = resultant velocity. For example M1 is 6.37 gr and M2 is 5.2 gr. Initial velocity is 1250. Thus the resultant velocity is 1531 fps . Now using the first formula the resultant muzzle energy will be 27 fpe or 36.7 joule which is much more than 30 joule.
So if one using heavy pellets in artemis, then he can safely remain within the threshold of 20 joules or 14.76 fpe if not way below 13 fpe.
Sorry brothers, I am no expert in maths. Pl ignore me if there is any mistake. One youtube video about the comparision of energy between precihole Sx and SDB 65 shown that the energy output is way below (about 8-9 fpe) than the claimed power of precihole.similarly the foreign ARs are regulated for less than 20 joule.
Again very sorry of giving so much unsolicited gyan.
Regards

Re: hi power air guns?

Posted: Thu Nov 16, 2017 9:24 am
by SMJ
I believe the manucturers simply mean to say that even with the lightest given pellet in the caliber the air rifle will not exceed 20 joules

Sent from my SM-J701F using Tapatalk

Re: hi power air guns?

Posted: Thu Nov 16, 2017 11:51 am
by mundaire
As far as foreign made/ sold air-rifles is concerned, my experience has been that when an air-rifle is sold as a 12 ft lbs model (in UK, since that is the legal limit there), it usually produces 10-11 ft lbs max! This is because manufacturers (and retailers) quite obviously wish to err on the side of caution when dealing with legal compliance issues.

As to Indian manufacturers, I'd assume they would follow a similar pattern. A couple of years ago, I had Chronographed my son's Precihole NX 100(with a Shooting Chrony), the muzzle energy measured was in the range of 10 to 10.5 ft lbs.

I would be VERY SURPRISED if other Indian manufacturers are exceeding these power limits. Often a person may "feel" a given air-rifle is shooting "harder" than another, but this "feel" is meaningless. Only scientifically measured results can give you the correct comparison.

Anyhow, I am not a big fan of "High Power" airguns. For me accuracy is always more important than power ratings, in the words of Townsend Whelen "Only accurate rifles are interesting".

Cheers!
Abhijeet