I am trying to explain to coworkers the benefits of using a FA bolt carrier in a semi auto carbine. It looks like these are the same reasons for using a heavier buffer as well. Correct me if I am wrong:
The increased weight slows down the cycling, which in turn aids the extraction process;
The slower cycling rate also helps keep the weapon more steady when firing, aiding in quicker/more accurate followup shots;
More weight when the carrier is moving forward (increased inertia) helps ensure that the bolt locks fully into position (i.e. if you had a weak cartridge, weak buffer spring or excessively filthy chamber area).
What are the advantages of the FA carrier’s shrouded firing pin?
The shrouded firing pin helps to protect it more, and keeps the carrier group from getting locked up on the hammer. This can happen if you slowly pull the charging handle back and then stop at just the right spot. The top edge of the hammer as it is being cocked, can catch on the firing pin.
I used to have this problem and the shrouded carrier eliminated it. I beleive the shoulder of the firing pin locked on my notched hammer. It would happen during firing, not just when pulling slowly on the charging handle as Hawkeye mentioned.
Kisara, I believe you are correct on all accounts.
In an SP1 stype semi carrier (unshrouded firing pin) the firing pin is cocking the weapon after each shot. With a shrouded firing pin, it is the carrier that cocks the hammer back after each shot.
Edited to add: Sorry I didn’t see the replies to the original post, which basically said the same thing.
From a practical standpoint, when considering conventionally configured carbines, I agree with what your saying. But while this might seem counterintuitive, lightening things up, when combined with an adjustable gas block, can reduce recoil. A good example is a JP lightweight carrier and buffer combined with their adj gas block – virtually no recoil. Granted, those guns are typically equipped with muzzle brakes, but they still recoil less with the LW setup than with heavy buffers and/or carriers.
I don’t think those components are suitable however for a conventional carbine, it would be way overgassed and you’d have all kinds of cycling problems. So from a purely practical standpoint, a carbine will cycle more smoothly with a heavier weight buffer or carrier than a std components.
I beleive the shoulder of the firing pin locked on my notched hammer. It would happen during firing, not just when pulling slowly on the charging handle as Hawkeye mentioned.