I finally got around to doing a POI shift test in my A2 20"er.  I probably should've been more anal and used a new target each time, but you will probably get the picture.  

Needless to say I'm not happy with it.  I always knew it did this, but I wasn't sure how bad it was.  If I used even more loads of more varying size / weight bullets, it would show even larger spreads.  At least I'm going by past experience.  

This time I used (4) 55 grain loads and M855.  The 55 grain were at least mostly on windage wise.  A little bit.  But then the M855 was shifted 3" to the left from the center of most of the 55 grain loads.  Another thing to note is that Q3131 sucks balls in that gun.  And XM193 shot super well.  Wolf wasn't all that bad.  

All shots were taken at 50 yards.

The waters get kind of muddied in the picture but you can at least see the disparity between the M855.  That would be 6" at 100.  I'm not sure I can really live with that.  Both my M4gery and my Recce don't do this at all.  And they're also more accurate.  Actually the A2 can be real accurate, but it's more picky about what it will be accurate with than other guns.  Personally, I've had this experience with another Colt I owned. I'm sure some will blame me, but my other two AR's don't do this.  I shoot NTCH for repeatability.

Anyways......  I really want to my old alpha duece to play SHTF / bedside gun, but I just don't like how it does this.  If I had crap load of xm193, I'd be set.  But I don't.  I have a good amount of Q3131A, Q3131, XM193, M855, AND some .223 ,black hills and such. I guess I just have to save this gun for 1 load.   I wish I would've just bought XM193 for a while now.  Oh well.  







It's probably a moot point anyways because even at 50 yards my eyes struggle with the irons.   It's better with the 20"er but optics are easier.

I think expecting your rifle to have the same POI with different ammo from different manufacturers is a little unrealistic. Also, whats your twist rate on that barrel?

You saying your other 2 ARs have no POI shift between different ammos? If that's true its a lucky fluke.

Also throwing it out there, since you have trouble seeing the sights, how sure are you you had the same point of aim when shooting each group.

Not trying to talk trash or anything, just saying.

Pretty normal in my experience.

This.  It's great that you have two rifles that shoot all ammo into the same group, but I always expect different loads to shoot to different POI.

Think your mad? Imagine that being your issued rifle, and you zero with "A1" ammo (aka M193), and then get issued shiny new "A2" ammo (aka M855) when you deploy.. Was a common problem at one time.

Indeed, not to mention that in my personal opinion that American Eagle ammo is plinking ammo at best.

Yes you will see inconsistency with factory ammo, and that factor increases with the quality of it.

The most repeatable accuracy I have out of my AR's has come from my reloads that I meticulously measure the load for every single round.

I've thought this might be a problem and I'd be shitting bricks if I were in that situation and actually had a clue.  If all shots were within 25 meters, no big deal.  But something tells me that's not really always going to be the case.  If you were in that situation, my hats off to you.  And thank you for serving in general.

It's funny.  I've talked about this before over in regular AR discussions and most people say their AR's don't shift that much.  At least that's what I feel like the overall feedback has been.  

But you guys might be right.  I know I always stuck with one kind of ammo when going hunting with my lever actions because of this.  Maybe I just need to be mindful of it.  I fricking love that A2.  I could just keep trying to get XM193.   Because it seemed to shoot it very well.  

Whoever asked about twist, I don't think that has anything to do with it.  And the other guy about American Eagle, yes, it's not that great of ammo.  Neither is wolf.  But as I said, my other two AR's don't shift as much as this one when changing ammo, regardless of what it is.  They are both HBar's though.  And that probably has something to do with it.

As far as the eyeball thing goes, I'm pretty sure my sight picture was consistent.  But it's possible I'm part of the problem.   If you were to believe that I had those groupings correct, look how well the XM193 shot.  I could mount a scope on it and redo the test to make sure.  But this gun has always done this, and I've had it a long time.  Before my eyes were old.  

I'm bumping this cuz I don't want to lose it.

OP, yes you will see POI shift between bullet weight.  As a former Marine Corps marksmanship instructor I've tried both M193 and M855 back to back out of several AR and M-16 rifles and experienced POI shift.  I'd suggest keeping a DOPE book on your rifle with windage and elevation for each particular load or factory ammo choice.  Remember some ammo can vary between lots and a little tweaking may need to be done.

I hope this helps.

Old Marine

^ I use similar techniques.  I know that there will be a POI change from different ammo.  So I will sight in and shoot 1 type of ammo until I am out and then have to sight in again if I change.  I learned while deployed in 2012 while shooting at the on base range.  We had orange tracer, red tracer, M855 and M855A1.  We knew the M855A1 was the new round.  Had to look up on the internet which tracer was used for which round.  Shooting at 25m with M855 A1 shifted POI 3 inches high and left.  I had been loading mags with a mix of tracers, M855 and A1.  After I learned that I spent a couple hours reloading mags with all the same ammo and tracer.  Crazy thing is I seemed to be the only guy on base who knew this.  Luckily it never effected anything OTW.  I only used my radio.

ETA; Luckily it never effected anything OTW FOR ME.  Can't speak for others.
ETA 2;  M4 with an Elcan Specter DR 1-4X.

3" shift at 25 meters would bug the ever living freaking SH*& out of me.   But I guess you adapt and overcome.  What other choice do you have?     But I have noticed that kind of shift in my A2 also.  

It's annoying.  I guess the real moral to the story is to try and run the same type of ammo if you can.  Buy in bulk once you find what your rifle likes or the one you want.  But there's no way I'm doing that with  self defense ammo.  So one round for practice and SHTF, like M193 and then know your dope for more serious rounds, like 77 grainers and I guess you're good to go.   But the more shift between the 2, the harder that makes it.  I mean like 1 or 2 MOA at 100 yarrds, no biggy.  3" at 25.....  I mean you're totally dialing in some changes.   And at longer distances, could make it interesting.  Would be nice to just set and forget.

Why don't you just use XM193 for everything?

I should.  My problem is I typically don't have a bunch of money to buy a lot at once, so I cherry pick.   Last time I bought XM193 I bought it from PSA when they ran free shipping deal for over 4 boxes or something. I think I bought 10 boxes.  OR maybe that's what it was.  Free shipping for 10 boxes.  

And another thing, I think M855 performs better at longer distances.  Probably won't ever matter much but my range does go to 600 yards.  And it's always windy over there.  It's right off lake Michigan.  I've seen M193 start getting pushed even at 200 yards on a windy day.  

Now, will I ever NEED to shoot past 200 for anything serious?  Of course not.  But when you do, even for fun, you want to hit your target  And of course 68/69 - 75/77's will perform better than any either one of those.  And it's nice to have that option.  

It would be best if I could settle on two loads.  A blasting one, and an accuracy one, and then just know the dope.   I haven't quite got there with that particular gun.  I have 2 other AR's that get shot too.  But both of them are HBAR and shift waaaaay less.  In fact I can't even tell that they shift with all different kinds of ammo at 100 and under.  I'm sure there is some, but not enough to speak of.  

But there again, even if you settle on a particular accuracy load, it's not always available.  M193 is a bit easier to get the same ones.  But even that........  it's more available if you buy in bulk.  Sometimes it's harder to fine in smaller amounts.  

Seems like Federal XM193 is the  most accurate lately in my guns.  And has always been pretty consistent.  I have a pretty good amount of Q3131A made in Israel though because that stuff was awesome.  It won't last forever though.  Booooooooo......  I wonder if IMI is pretty much the same stuff.

I see.  Personally I just buy Federal XM193:  it's cheap, I buy in bulk, I use it for home defense, and I never shoot beyond 300 yards.

I kinda thought everyone understood they had to rezero their rifle when changing to a different load.

Simple is good.

I guess I'm spoiled with my 2 that I don't have to do that with.  It's not that I don't understand that, it's that the shift is pretty extreme, moreso than the test I did here showed (I've shot more varying weights through it in the past to see).   And as I said, I don't have just 1 type of ammo laying around.