Anyways, because this point keeps coming up, pic related is a chart from rifleshooter.com showing 62gr M855 at various barrel lengths. For reference, when Buffman busts the RMA #1003 with 31gr SS190, which has far less sectional density, it is going 2,154ft/s. When he defeats another PE plate with 9x19mm DM91, it is going about 1,600ft/s. Again, that is 9x19mm.

As per the chart, M855 does NOT fall below SS190's velocity until you get to a 7" barrel or shorter. Keep in mind again that M855 is a 62gr projectile and SS190 is only 31gr, literally half the weight for the same projectile diameter. Huge reduction in sectional density and length-diameter ratio.

As it stands, since you obviously cannot control what barrel length an "ARP" is, you're severely at risk against ARPs when running PE plates unless you have credible test reports showing otherwise.