Reinventing the wheel

[Sailormilan2]

I’m considering building an AR PCC in 357 Sig. Only the Sig will have its throat modified so that bullets can be loaded out, increasing the length. But, still retaining the ability to use standard, factory ammo.
This would take advantage of the extra length of my Glock and 1911 magazines. I might be able to add a little more powder for higher velocities. I realize that bottleneck cartridges in blowbacks can be problematic. But I think that using heavy 10mm buffer could fix that.
What say the hive?

https://imgur.com/a/XRJGkt1

[Spyder]

For what purpose? Would slower burning powder in standard chamber and brass 357 sig increase velocities to what you're looking for?

[Sailormilan2]

Slower burning powder, with a slight increase in the amount, should work well in the 16” barrel of a PCC. But, I don’t think anything slower than AA#9, though I may try some H110. H110 may be too slow for it.
case volume appears to be very similar to a 9x25 Dillon, because the bullets would not be seated as deeply in the case. One would also be able to use heavier bullets.
The cast bullet on the right is a Saeco 383, and weighs about 145gr. So, it should be up in 357 Magnum area.

[ar15barrels]

Maybe try the Maxim roller delayed blowback buffer system on that build instead of a traditional heavy buffer.

https://maximdefense.com/product/roller-delayed-systems/

If you want even more power, go to a 9x25 or something like my 357auto which is a 357 sig made 0.200" longer and formed from10mm magnum cases.
With the larger case, you can make it run gas operated.
It's simpler to just put together a 350 legend though.

[Sailormilan2]

It's simpler to just put together a 350 legend though.

That defeats the whole purpose. Having a caliber that can be used in a handgun and a rifle/PCC. Basically, one would have a 357 Magnum in a semi auto rifle and pistol.

[Spyder]

For me, the effort time and money isn't worth the miniscule increase that may be found.

[ar15barrels]

That defeats the whole purpose. Having a caliber that can be used in a handgun and a rifle/PCC. Basically, one would have a 357 Magnum in a semi auto rifle and pistol.

9x25 is a handgun cartridge.

[walmart_ar15]

SW 350

SW350.jpg

[walmart_ar15]

In a PCC, why not just use 10mm? More parts availability.

Maxim Defense suggests their roller delay is only for 9mm. Have people use them for other PCC calibers?

[Garbcollector]

A pcc in 357sig would be sweet too bad that round never took off