Recoil will always be there especially in the case of 7.62 ammunition, but this can be controlled to a certain extent. Introduction of a SHORT STROKE PISTON will not just make the weapon lighter but will also reduce its recoil, But then even SSP based weapon has short a coming i.e systems are prone to a condition called
“carrier tilt.” Since the force is being applied directly to the top of the bolt the bolt carrier has a tendency to tilt. The rear bottom edge and the front top edge exert more force on the surrounding materials due to that tilt, and it has been known to wear holes in the receiver extension (but its not very frequent and is acceptable if compared to the added benefits).
Now compare it to a LONG STROKE PISTON our weapon will be heavy coz of the piston, It will have a strong recoil thereby affecting the accuracy because after every round fired the complete Bolt Assembly moves back along with the piston.
Now for FN FAL system. I have fired this weapon and i can assure you that you cannot control it if your firing it on Burst mode, Thier was a reason why Indian SLRs did not have an auto mode ( accuracy problem in subsequent shots) FN FAL system is an old hat in the trade.
If I am to buy a new gen weapon which is to be given to the Indian Army for its utilization for coming 20 years i would want the following min requirements:
1. Monolithic bolt carrier
2. Adjustable gas port
3. Ambidextrous safety and Mag release
4. Reciprocating, reversible charging handle
5. Integrated optics
5.56 or 7.62 well thats on Top bosses to fight for.
PS : my personal favorite will be FN SCAR 17
Long stroke piston is fine,recoil will be there,but they can reduce the perceived recoil (recoil which the shooter experience)
This can be done with new muzzle brake design,recoil pad on the stock,well engineered stock,a good buffer spring .
Beside recoil , if I am designing a new rifle in 2017,I'll keep few basic things in mind.
1 Floating barrel - to improve the accuracy.
2 Modular rifle - easily adjust to right and left hand shooting.
3 Adjustable stock - for the comfort of soldiers .
4 Full P rail on the top cover,along with quad rail on handguard -this is basic for a modern rifle.
5 A magazine design with window to view the number of rounds.
6 Sliding cover at the ejection port.
These are few fundamentals of the rifle design,you can do a lot more ,if you really want to!
My top 3 choice for a rifle in 7.62x51mm based on the user review and word of mouth all over the world are:
1 Hk 417 - I know HK does not sell to non NATO country,but if we really want it ,our government can make it happen.
2 SCAR H - It has set new standard for a 7.62x51mm rifle.
3 Galil ace - This rifle has proved itself in various military around the world.
Most importantly,I want all the rifles to compete, including the one offered by the OFB in a FREE AND FAIR trials and let the winner take the tender,irrespective of its origin,on condition of 100% TOT transfer and manufacturing in India with materials source from within India and promise of opening a R&D center in India by the private company holding majority shares of that JV.