Accuracy of sub gun

[J.D.R]

So I am running a cobray m11 with lage slow fire upper and a gemtec viper can.

My sights are point of aim for 25 yards, I am made to understand that with 9mm 25 yards poa is 100 yards as well.

So it was raining yesterday and my range was half under water, so I try to shoot the 100 yards 10 inch gong and my shots are landing in puddles 3 ft in front of gong.

Ammo is federal 125 fmj.

Idk what to think, as I shoot rifles all the time with iron sights free hand standing and don't have issues.

 

[waterhouse]

Not sure about barrel length and sight height, but from my m&p pistol with an RMR I get about 5” drop at 100 yards from a 25 yard zero. Hitting 3 feet in front of the target seems excessive.

 

[entropy]

The sights, rudimentary as they are, sit way higher over the bore on that M11. It also has a very short sight radius. Your bullet probably is crossing the LOS on the way down already by 25 yards. Now combine that with open bolt operation (you did say SMG, right?) you could easy get more drop (you didn't say how much; you said the bullets were hitting 3 feet in front of the gong, not how far below.) If you want an accurate SMG, get an MP5. Closed bolt German technical accuracy.
Yes I've shot several PCC 9mm's, and hitting a 100 yard 10 in. gong with them is child's play. Literally. When my son was 10 he could do it with my SUB2000, every shot. In the Army,(the one time I got to fire them) we did headshots at 75m with the MP5's in semi to warm up, then 3 rd. bursts.

 

[CapnMac]

Some of that may be mis-matched ballistic expectations.
9x19 is whistling out around 1100 fps. Most rifle ammo is trundling along about 2500fps (over 3000 for the high-velocity stuff).
The 10-12" barrels on subguns are not going to "flat" the trajectory out so very much. Maybe a 16" carbine barrel might, some. Perhaps. Maybe.

On a Sterling, I'd expect to hold 2x 12 o'clock at 25 to be on target at 100. The converse, though for on-target at 100 ought to be on-target at 25 (if being high up enough to want a 6 o'clock hold).

 

[GarrettJ]

Not sure what was happening with your gun. 9mm shoots a fair bit flatter out beyond 100 yards than many people give it credit for. And that includes 9mm shot from short barrels like on handguns or the OP's M11/9.

So to prove this out to myself, I brought out a large piece of paper and stapled a standard bullseye target in the middle of it. That way, if I was hitting way off, I should still catch the bullet holes.

My M11/9 is sighted at 25 yards. I was shooting it with a Lage MAX-11 (gen 1) upper and a C-More red dot. With the optic's height over bore, any difference at 25 vs. 100 yds. even more pronounced than if I was using the iron sights. Actually, I likely would have had a better group if I was shooting irons, as the dot completely covered the black target. I had to just center up as well as possible. Also, I was shooting in semi-auto, but if you milk the trigger really slow, the sear will sometimes not catch the bolt and you fire a double. I had a couple of these. I expect those were the two shots at the right side of the target. You can see the target in the distance in the second photo.

But as you can see from the picture, I was only hitting around 6" or 8" low at 100 yards. Good enough to smack a 10" plate at that distance.

 

[CapnMac]

The above. From 100 out to 200 yards, really not that much difference.