Increasing Power of an Air Rifle

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aadhaulya
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Increasing Power of an Air Rifle

Post by aadhaulya » Mon Apr 20, 2015 10:44 pm

All my AR guru's and others,

Now that I have decided to take up Air Gunning, and being from the automobile sector I always love to experiment, even if some stuff gets destroyed in the process.
The Project that comes to my mind is increasing the velocity (fps) of an air gun pellet from the normal Indian AR's 500 to 600 fps to a minimum 750 to 900 fps or maybe up to more than 1000 fps.
The result would be increased range (accuracy remaining the same as the original AR). Increased power using the same pellet, remembering the famous formula E=mc2 here m (mass) remains the same but c (velocity, raised to the power 2) increases energy substantially.
For doing this I will be using an under liver .22 AR, so that the break barrel seals are eliminated to reduce points of pressure leak. Then I will do modifications to increase pressure. Something similar to turbocharging an automobile engine.
I would also need something to measure the velocity (mass remains the same) to check if I am headed in the correct direction.

Before I proceed further with my thoughts I would like to know if it is legal to play around with AR's, as I want to be sure that I can discuss the detailed project on this forum.

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Re: Increasing Power of an Air Rifle

Post by aadhaulya » Mon Apr 20, 2015 10:49 pm

Even if one is unable to go on a vacation. More than 50% of the fun is in planning and preparation. And I am going to enjoy myself thoroughly.

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Re: Increasing Power of an Air Rifle

Post by Basu » Tue Apr 21, 2015 8:09 am

Dear aadhlulya,
Such experiments are done is the past by many AR geeks.Yet some results.....no results...was the outcome.
My experiment took the output level from 10 fpe to 16.94 fpe by chamber detonation with lubricant oil but it causes harm to gun as a whole.
Most Indian underlevers are BSA type taploaders , and overtime it fails to retain compression intact.

The data is of chronoconnect mobile.

Basu
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Re: Increasing Power of an Air Rifle

Post by aadhaulya » Tue Apr 21, 2015 8:41 am

Dear Basu,

Thanks for giving me an additional idea of chamber detonation. But I do not plan to do that. My idea is to increase the air pressure developed by using the same spring but a better quality piston seal to increase its life under the added pressure. This pressure increase cannot be achieved without changing the dimensions of the cylinder, thereby increasing the compression ratio.
This modification is not possible as it involves a complete manufacturing process for all components. Therefore, I need to 'turbocharge' (my terminology for AR) it some how. It is going to be slightly expensive to get testing equipment and installing on the AR, thereby destroying one AR.

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Re: Increasing Power of an Air Rifle

Post by brihacharan » Tue Apr 21, 2015 10:40 am

aadhaulya wrote:Dear Basu,

Thanks for giving me an additional idea of chamber detonation. But I do not plan to do that. My idea is to increase the air pressure developed by using the same spring but a better quality piston seal to increase its life under the added pressure. This pressure increase cannot be achieved without changing the dimensions of the cylinder, thereby increasing the compression ratio.
This modification is not possible as it involves a complete manufacturing process for all components. Therefore, I need to 'turbocharge' (my terminology for AR) it some how. It is going to be slightly expensive to get testing equipment and installing on the AR, thereby destroying one AR.
Regards
hi aadhaulya,

> While all veterans in this forum probably appreciate your enthusiasm to experiment & boost the power of an AR - here are a few 'home truths' you must consider....
1. World over all ARs by & large are designed with standard dimensions to produce a 12 foot-pound energy at the muzzle...
2. This figure / performance ensures that the AR is accurate up to 35 / 45 yds, shoots with less / acceptable vibration ....in fact this is the most preferred performance for an AR....
3. This means that the terminal energy at 35 yds would be around 3 to 4 foot pounds, quite lethal for pest control...
4. Most factory assembled ARs in India shoot between 500 / 575 fps....
5. When tuned (Changing spring, rear guide, top hat, seal, lube + trigger adjustment) the AR may produce 600 / 610 fps = 12 foot pounds with a standard 14gr pellet....If one can achieve this - you got a winner :D
6. If an AR shoots beyond these out puts then it will suffer in accuracy & also cause vibrations....
7. Apart from magnums no standard AR will exceed 600 / 650 fps...if they do or claim then the pellet used must be around 11gr....
8. Good luck with your experimentation...look forward to hearing your progress / achievement :D
Briha
PS: Please go through this article written by an expert!
Have spring-piston air rifles reached their limits? - Pyramyd Air
www.pyramydair.com/.../have-spring-pist ... heir-limit

I like this quote:
"By fitting an extra large 'fuel tank' in your car - you can't expect it to go faster, than it's designed to do so" ROTFL

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Re: Increasing Power of an Air Rifle

Post by aadhaulya » Tue Apr 21, 2015 12:10 pm

brihacharan wrote: I like this quote:
"By fitting an extra large 'fuel tank' in your car - you can't expect it to go faster, than it's designed to do so" ROTFL
What you say is true Briha ji but I am an Automobile expert and know that extra large fuel tanks doesn't make the car go faster but turbocharging the same size engine will make it go faster. That is what I hope to do.
My understanding is as follows.
1. that the pellet shoots out before the piston comes to rest or else that sometimes the pellet will not shoot out in case of further drop in pressure developed due to wear and tear.
2. Hence increasing the pressure by a slight level, can be done by providing better sealing of leakages (I doubt if the spring has any role except bringing the piston to the rest position faster). This should not make any significant difference in the pressure developed.
3. The tuning kit will also help besides better sealing, if the initial volume is increased along with the travel of the piston by a redesigned piston. This is probably the reason for increase in pressure hence velocity.
4. In an AR we compress the spring to load it. But the air that is drawn into the cylinder is at atmospheric pressure.
5. Since we cannot increase the volume of the cylinder we can put in extra air under pressure to increase the charge (This is the principle of Turbo charging, used in Automobile engines).
6. The pellet will leave the seat much earlier due to the increased pressure. But the escaping air will continue to propel the pellet till it leaves the barrel. Hence, I have to find an AR with the longest barrel available.
7. Expenses would be in fabricating the additional fixtures for this project. Design and installation of pressure testing equipment in the AR. And off course equipment to measure the velocity of the pellet.
8. Once my basic design is ready on paper that can happen only by getting regular input from the experts on this forum, I would be in a position to go into the next level of execution of the project, by making a prototype.

Regards

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Re: Increasing Power of an Air Rifle

Post by sumanngon » Tue Apr 21, 2015 12:24 pm

Give it a try with aimco m300, now available under g d sports section in their website. The rifle has long barrel and pretty heavly built compared to other indian models. Let us know how you are proceeding. My last try with another rifle gave me very shaky gun.

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Re: Increasing Power of an Air Rifle

Post by aadhaulya » Tue Apr 21, 2015 12:55 pm

sumanngon wrote:Give it a try with aimco m300, now available under g d sports section in their website. The rifle has long barrel and pretty heavly built compared to other indian models. Let us know how you are proceeding. My last try with another rifle gave me very shaky gun.
Thanks Sumanngon,

All the inputs I can get are welcome. I will check out this rifle. But first I need ideas on turbocharging the gun, because if that does not happen the project will have to be scrapped.

Regards

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Re: Increasing Power of an Air Rifle

Post by sumanngon » Tue Apr 21, 2015 1:13 pm

Gamo whisper g2 has a turbo stabilising system, check pyramid air for this model and you can do some study to begin with.

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Re: Increasing Power of an Air Rifle

Post by aadhaulya » Tue Apr 21, 2015 1:18 pm

sumanngon wrote:Gamo whisper g2 has a turbo stabilising system, check pyramid air for this model and you can do some study to begin with.
This should be a good starting point.

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Re: Increasing Power of an Air Rifle

Post by estousandy » Tue Apr 21, 2015 3:04 pm

I guess you have some kind of idea already in your mind. Good. But a few things let me share. ALL the 8 points you have mentioned above are well known to most if not all in the AR modding community. TTI used to make a custom shorter piston for mod35 ARs to take care of the "more air" or increase air volume part, sadly everything related to that is no more. You can always experiment from where he stopped coz he did a pretty good groundwork. Shortening piston means lowering its mass, which needs to be balanced. More air means longer barrel needed which also increases the barrel drag on pellet.

About the air sealing, many of us run Diana & other better seals already in our guns instead of stock leather. Spring alone never does much to performance upgrade, it's a full package of processes.

Whatever we could do in reasonable limits to an AR, that's already done. The area which can be furthered is increasing air volume & Venturi port redesign. Both involves considerable physics. Ofcourse there must be an optimum performance point at which the best out of an Indian AR design can be attained, which i'm sure will be much above what we've so far. Hope you reach there fast & all the best to your effort.

BTW the gamo TSS seems to be an arrested piston stop system to reduce felt recoil. There is no added air pressure involved from what it says.
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Re: Increasing Power of an Air Rifle

Post by brihacharan » Tue Apr 21, 2015 3:21 pm

estousandy wrote:I guess you have some kind of idea already in your mind. Good. But a few things let me share. ALL the 8 points you have mentioned above are well known to most if not all in the AR modding community. TTI used to make a custom shorter piston for mod35 ARs to take care of the "more air" or increase air volume part, sadly everything related to that is no more. You can always experiment from where he stopped coz he did a pretty good groundwork. Shortening piston means lowering its mass, which needs to be balanced. More air means longer barrel needed which also increases the barrel drag on pellet.

About the air sealing, many of us run Diana & other better seals already in our guns instead of stock leather. Spring alone never does much to performance upgrade, it's a full package of processes.

Whatever we could do in reasonable limits to an AR, that's already done. The area which can be furthered is increasing air volume & Venturi port redesign. Both involves considerable physics. Ofcourse there must be an optimum performance point at which the best out of an Indian AR design can be attained, which i'm sure will be much above what we've so far. Hope you reach there fast & all the best to your effort.

BTW the gamo TSS seems to be an arrested piston stop system to reduce felt recoil. There is no added air pressure involved from what it says.
:agree:
IMHO arresting the piston' banging at the transfer port could be done by - perhaps by giving the receiver a 'cone shape' internally towards its end....
By this I mean that the ID of the receiver gets tapered (by a very small angle) - so that the seal just stops at that particular point where the taper begins....
Also shortening of the piston length to increase the swept volume ....herein the piston will not have a rod with sear at its end - instead the slightly flared end of the piston will act as the sear (by this the piston's weight is not compromised)
In fact this system is incorporated in all Precihole ARs.
Briha

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Re: Increasing Power of an Air Rifle

Post by sumanngon » Tue Apr 21, 2015 5:20 pm

Very good directives Briha da! I wish there had been a LIKE button here in this forum!

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Re: Increasing Power of an Air Rifle

Post by aadhaulya » Tue Apr 21, 2015 7:48 pm

estousandy wrote:I guess you have some kind of idea already in your mind. Good. But a few things let me share. ALL the 8 points you have mentioned above are well known to most if not all in the AR modding community. TTI used to make a custom shorter piston for mod35 ARs to take care of the "more air" or increase air volume part, sadly everything related to that is no more. You can always experiment from where he stopped coz he did a pretty good groundwork. Shortening piston means lowering its mass, which needs to be balanced. More air means longer barrel needed which also increases the barrel drag on pellet.

About the air sealing, many of us run Diana & other better seals already in our guns instead of stock leather. Spring alone never does much to performance upgrade, it's a full package of processes.

Whatever we could do in reasonable limits to an AR, that's already done. The area which can be furthered is increasing air volume & Venturi port redesign. Both involves considerable physics. Ofcourse there must be an optimum performance point at which the best out of an Indian AR design can be attained, which i'm sure will be much above what we've so far. Hope you reach there fast & all the best to your effort.

BTW the gamo TSS seems to be an arrested piston stop system to reduce felt recoil. There is no added air pressure involved from what it says.
estousandy,

I know about the 8 points because they are well known. Also I have no intention of playing around with the piston design, as the added power by these little modifications are of no use, in the vast difference in power that I want to achieve.
I am starting on the theoretical part to calculate what I want and then decide if it is achievable or not.
I am hoping that most of the practical data would be available on this forum. I would require minor data like pellet speed and weight of pellet for different guns that are supposed to be good in India.
Hope it works out nut even if it doesn't then half the fun of planning and preparation would be worth having.
Eventually the project can always be scrapped if it does not work out.

Regards

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Re: Increasing Power of an Air Rifle

Post by Basu » Tue Apr 21, 2015 8:04 pm

A dedicated gun...prepared with strength to withstand higher detonation , can be injected with atomised diesel into the swept area by an injector.....can outbeat any magnum powered AR but no more that can be called as AR....may be as DR or diesel rifle.
Just an wild thought inspired by Cadrew..when he says that power in essentially generated by some degree of dieseling/detonation.
Readers are advised not to try it without proper safety precautions.

Basu
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