Why I Hate Federal XM193PD and Love My ACOG.


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Bartholomew Roberts
July 4, 2006, 10:44 AM
I was shooting this rifle (http://www.ont.com/users/kolya/AR15/midLilja.jpg) off the bench at 100yds using the Grippod and the rifle case to support it and made a couple of modest discoveries.

First discovery (which I pretty well already knew) is that you can be very precise with the donut reticle on the ACOG if you take your time. Combined with the 75gr OTM Moly and the Lilja barrel, I did a pretty nice group for using a 3.5x scope with a round reticle.

Second finding (which I definitely already knew) is that Federal XM193PD is basically floor sweepings. I had one round fail to penetrate the target backing and a second round drop about 6-7" low

http://www.ont.com/users/kolya/target.jpg

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taliv
July 4, 2006, 11:15 AM
bart, first, our taste in ar15 accessories is remarkably similar. :) second, you put a lilja barrel on your AR?? interesting. what chamber and twist did you ask for? third, what happened to the BH group on the right?

Coronach
July 4, 2006, 11:54 AM
I had one round fail to penetrate the target backing and a second round drop about 6-7" low:scrutiny:

Daaaaang. Is it possible to squib-load a rifle? As in, will the M-16 action cycle if the bullet passes the gas port but fails to exit the barrel? I don't even want to contemplate the practical repercussions of this for the shooter- or the rifle.

I just note that if you're getting that much fluctuation in powder charge, it is probably only a little further out on the tails of the distribution to get to the point where lead completely fails to fly. That's sobering.

Mike

Bartholomew Roberts
July 4, 2006, 12:02 PM
first, our taste in ar15 accessories is remarkably similar.

Yes; but is it a case of "Great minds think alike" or "Fools seldom differ"? ;)

second, you put a lilja barrel on your AR?? interesting. what chamber and twist did you ask for?

Yes, I've been very pleased with it so far. It is an absolutely great barrel and is holding up to hard use better than I expected. I went with the Wylde chamber and a 1/8 twist. The 1/8 seems to handle anything that will feed from a magazine well. Haven't had a chance to try it with M856 tracer or the VLD 90gr that are single-loaded. I will qualify it by saying I've seen several barrels that can do 90% of what the Lilja does for about 1/3 the cost. Since *I* can't do 90% of what the Lilja can do, I probably overspent on the barrel.

third, what happened to the BH group on the right?

Crummy shooter mostly :) Partially it was just me being sloppy and the other part was we were shooting with big scattered thunderclouds in the area, so I would have a nice reticle with optimum lighting for one shot and then the clouds would move and I would get full sun where the reticle "bloomed" brighter. It made it kind of difficult to hold a consistent point of aim (which is why some ACOG shooters run a piece of inner tube over the fiber optic to control brightness).

I had nice steady light for that last group on the left and was shooting better to boot. I imagine the Hornady 55gr TAP and Federal 55gr TBBC are also capable of better groups than what that target shows. I've shot enough XM193PD by now to know that the group there is pretty typical.

Bartholomew Roberts
July 4, 2006, 12:09 PM
Daaaaang. Is it possible to squib-load a rifle? As in, will the M-16 action cycle if the bullet passes the gas port but fails to exit the barrel? I don't even want to contemplate the practical repercussions of this for the shooter- or the rifle.

:eek: Well, I don't want to find out with that barrel. I'll tell you that much right now. So far all of the loads have exited the barrel; but I am running a very high rate of underpowered loads that fail to cycle the action (about one per mag this last time out).

I make it a practice to break open the action and check for squibs if the round doesn't cycle or cycles weakly and I do not hear or see the impact. One thing I have been noticing is that the XM193PD rounds that do this often leave a trail of unburnt powder in the bottom of the barrel.

I just note that if you're getting that much fluctuation in powder charge, it is probably only a little further out on the tails of the distribution to get to the point where lead completely fails to fly. That's sobering.

I think the powder charge is probably consistent; but for some reason it doesn't seem to be igniting reliably. It is definitely sobering and as it is now I am building up some bad stoppage habits in order to safely shoot this stuff. It will definitely be the last XM193PD I buy.

Coronach
July 4, 2006, 12:25 PM
How many rounds of it did you get?

Mike

Bartholomew Roberts
July 4, 2006, 01:12 PM
2,000 :(

I had a friend shoot up several thousand rounds of it with no problems, so I figured I would just jump right in and buy it when I saw a good price on some. Really regretting that decision about now...

swingset
July 5, 2006, 04:03 AM
Interesting thread about the PD:

http://www.ar15.com/forums/topic.html?b=3&f=16&t=271471

I shot 200 rounds and had 3 duds, shot over 15,000 rounds of Wolf without a single failure. You do the math on PD.

goon
July 5, 2006, 04:18 AM
FYI, yes you apparently can get a round stuck in an AR between the muzzle and the gas port.
I was warned about this in the Army by a friend who was a unit armorer. It apparently doesn't happen very often though.

Master Blaster
July 5, 2006, 08:22 AM
PD = Probably Defective.

Stay away from it, its factory rejects, seconds the government wont take, ok for range blasting ammo if your not too concerned about hitting anything.

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