I have metallic spinning targets on my range. I made a new target for my 5.56 using what I think is a 3/8" thick disc of H500 steel. The target is a swinging pendulum with the disc angled about 10 degrees to the incoming bullet so I figured the angle and ability to swing would allow the target to handle about anything.

Shooting it with 55 grain fmjbt .223 at 75 yards left a small pock mark on the surface. Shooting Federal Lake City XM193, also a 55 grain fmj, left a crater about 1/3 through the target and deformed the target on the back side. I am quite surprised at the different affect these two similar rounds had on my target. Has anyone else seen a noticeable difference between .223 and 5.56?

 

First, I am jealous about your steel targets on your range

I would imagine that it has less to do with weather it is .223 or 5.56 but more to do with the type/amount of powder that is in the case.

 

I have been looking at several steel target manufacturers and one mentioned that 3'200fps was the magic number for their targets. I don't have a chrono and I'm wodering if the 5.56 rounds were going just a bit too fast for the target to get out of the way.

 

It might also have something to do with the makeup of the bullet. Is that XM193 one of the rounds with the steel core?

 

I have tried many different types of bullets. Below about 3'200fps impact velocity the targets withstand it pretty well. Over 3'200fps no matter what kind of bullet (full metal jacket, hollow point, soft lead point...) there is a decent crater in the armor plate. I think you just reach a point where the target, even armor plate, cannot absorb the energy. And, at those velocities I don't think bullet material is as important. 55 grains of lead, copper or whatever going that fast is going to leave a mark.

Steel penetrators do leave quite a mark a much lower velocities so I do not use them (but I had to try once to see what would happen). I also do not like the possibility of a ricochett.

 

Is that 3200 fps muzzle velocity shooting at targets 75 yards away or are you measuring the velocity close to the target?

 

The only velocity that matters to a target is the speed of impact.

I have never measured bullet speed at the target. I do not want the chrono to be hit my shrapnel. When testing ammo I check the velocity 10ft from the muzzle and then use ballistic tables to calculate the bullets velocity at the target.

 

So the 3200 fps is the muzzle velocity, correct?

 

No. 3'200 is the impact velocity. A target does not care about the speed at which a bullet leaves the barrel.