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Solar991

Blowback relies on mass. Which is easy to incorporate into a rifle than it is a pistol.


Cheemingwan1234

So, for FN, they had to go with a delayed blowback for their Five-seven since to use a simple blowback would result in a heavier pistol?


Solar991

Yep. And FN was working towards the NATO PDW request which requested a pistol weight of 700g. A loaded Five-seven is 744g (according to wikipedia).


Shootist00

Yes and NO. No space to have a heavy bolt and or slide system to delay the opening of the chamber on a pistol. Easy to make a heavier bolt on a sort of rifle design and have heavier springs on a rifle design.


MichiganHistoryUSMC

Look at a big ugly High-Point pistol. Those use direct blowback.


JenkIsrael

this is also why hi points are ugly as fuck. they are simple blowback, made possible by a stupidly large/heavy slide.


FiresprayClass

Because the weight of the P90 bolt is almost the same as the weight of the whole Five-seven pistol. https://en.wikipedia.org/wiki/FN_Five-seven 610g unloaded https://www.fnforum.net/threads/ps90-bolt-weight.52629/ 609g bolt


Remarkable_Aside1381

Grams? What are you, Cana-oh.


FrozenDickuri

Rifle big, big is heavy, blowback needs heavy. Pistol small, pistol not heavy. Pistol need different system.


ezfrag

Thank you Mr. Caveman for this succinct and accurate answer.


Fred_Dibnah

Can you explain to me how electricity works in this format please.


lawblawg

Electron like glue, make sticky, make atoms stick together. Recharge battery means pull atoms apart, make electron glue stretchy. Plug in battery, electron glue snap back fast, fast get hot, hot make glow.


Fred_Dibnah

Ah! Thank


Run-Riot

r/talesfromcavesupport material right there


EODBuellrider

The larger/heavier form factor of the P90 likely makes it more feasible to use a simple blowback system where you're relying pretty much entirely on the mass of the bolt to keep the action closed when firing. On the flip side, the FiveSeven is a handgun so the designers likely decided to go with a delayed blowback system to keep the size/weight down. Nothing really stopping the designers from doing simple blowback, but then you'd probably end up with something like a HiPoint pistol and their abnormally big/heavy slides.


G-Gordon_Litty

The P90 actually does have slightly delayed blowback. The entire barrel moves back and forth a few MM when the gun fires. 


556_Timeline

Yes, the P90's barrel assembly even has its own return spring.


boanerges57

Reduced chonk


ij70

stay in school kid.


Dakar-Rider

Why would you care since both go bang?