Sorry, I wasn't thinking ahead enough to grab pictures at the range, but I was out shooting my 34 for the first time other than just function checking.  I was shooting at the bottom of an 8" shoot n see, while I was hitting dead center with my 21.  

I had the largest back strap on the pistol at the time if that might have anything to do with it.

I'm planning on taking it out again, but curious if I may need to get a higher front sight due to grip, or just something add with the rear sight from the factory.

Is the sight all the way up?   A taller front will make it shoot lower.

What you seek

It's the Indian not the arrow.

Recommend more trigger finger.

Most likely this .... did you have someone else shoot it?
Stock trigger can be kind of stagey, gritty, and not smoothed out at first till you put some mileage on it

It absolutely could be me.  But I shot some pretty damn consistent low groups with it.  Slow was 6'o clock and even when it was me pulling and jerking it was 7-4 on the target.

Try dry firing or have someone blind load some snap caps in your magazine.  Focus on the front sight and watch for a dip as you break the striker.

Having a number of glocks, including the g17, I recently added a g34 to my collection. It's my favorite, and the frame is the same as the g17, but it does shoot a little different in terms of balance and sighting.

If you're used to the g17 you may not shoot the g34 as well. I personally didn't find that a problem, but when I swapped out the stock barrel for a lwd ported I did notice a big jump in accuracy with the lwd barrel. If it's not your grip or your trigger placement, I'd swap out the barrel as I've found some aftermarket barrels to be more accurate that the factory glock. Fwiw

I shot low with one of my g19s so when I replaced the sights I just used a lower front sight.

THIS

With modern manufacturing the relationship between the bore axis and sights will be monotonously consistent from one G34 to the next.

Any deviations are much more likely due to the shooter than the sights.

Be certain of your sight picture. Are the tops of the front and rear sights truly and properly aligned? Is this front sight centered?

Do you have an anticipatory flinch? There are two kinds of shooters, those who worked their way out of a flinch and those who haven't yet.

Personal example:

My G22 has aftermarket Trijicon night sights, whereas my G35 has the stock sights.

I recently put the G22 upper on my G35 lower to see how I liked the Trijicons in USPSA. Lo and behold I was suddenly terrible on the plate rack, constantly shooting high. Further exploration confirmed the sights were fine, but for some unknown, subconscious reason, just that day I'd developed a new bad habit of not bringing the front sight all the way down into the U-notch. My bad. Identified the problem, corrected it and the plates began falling reliably again.

All the variations of POA and POI described in this thread are more likely variations in shooter techniques than variations in the weapons.

IMHO.

If the indian keeps putting the arrow in the same fucking place, its the god damned arrow.

Barrel change to fix shooting low.....? That seems greatly excessive.  Many accuracy test over the years shows Glock barrels are not slouch in the accuracy department and many times more accurate than some\many aftermarket barrels.  LWD barrels are not known for the amazing accuracy the two I have are not better than stock and many test have shown this as well.  Maybe you got a good barrel and it is more accurate but unless you are removing the human influence I doubt you can see a significant increase in accuracy.

Or the indians technique or sight alignment.

If you consistently group, change the gun to match the fundamentally correct shooting.

"Just shot my rifle.  Groups low and to the left.  Whats the answer?  I know.  Completely change how I shoot!"

If you are not zeroing the pistol from a rest, then you're doing it wrong.

We do not know that he is following fundamentals.  This is where dry fire or snap caps randomly mixed in a magazine could quickly diagnose.  What then as distance increases if you change the gun and fundamentals are the issue?  

Your premise is that he is practicing correct fundamentals and the pistol is the problem my premise is that the pistol is the unknown factor here and the human is the problem which in my experience usually is problem to address first.  Start with the most likely the problem and work forward to the pistol.  If he spends $200 on trigger parts and barrel but still hits low that did him no good.  I hear all the time I shoot low left and I am a righty or low right and devil handed.  98% of the time that it human error and fixing human error is cheaper than throwing parts at something that may not be the problem.  For all we know OP could be misaligning his sights or his front sight may be too tall who knows I consider that an unknown unless OP gives us that info.

Sometimes that is the right answer. With glocks it generally is the shooter. Not always though.

Sometimes the way people shoot is just wrong. Even if they've been doing for years.

I do that sometimes especially if I have been shooting a CZ all day or 1911 then pick up a Glock the first few rounds I might be thrown off until I switch my brain that I am shooting a Glock now.  Or vise versa if I shoot my G17 then switch over to my P-09 I have to switch my mind to not press as hard on the SA.

I consider myself an above average shooter (don't we all) and I've noticed out of the box Glocks shoot *slightly* different from one another, usually not more than 1-2" tops at 10-15yd or so. Whatsmore this difference is always exclusively vertical, I've never had one shoot off horizontally at all from the factory to any degree I've ever perceived. This is benched and with an at least decent shooter behind the trigger.

Anything more than that, especially orders of magnitude more, is a clue that it likely isn't the hardware. It being low and left on a Glock is also a *big* clue. If I had a nickel for every time a shooter complained their Glock shot low-left.

As long as groups are consistent, I always defer to adjusting the weapon to the shooter.

I know glocks have a tendency to shoot low left.  Just adjust the sights.  Trying to change how you shoot to adjust to different weapons is a fools errand.  Also G34 sight radius does weird things because most irons are for the G17.  I had a 34 and needed a special tall front sight to match the adjustable rear.

So you have them destroy muscle memory with shooting a pistol because adjusting the sights is "wrong"

why?

My muscle memory is different for my 1911 vs CZ vs Glock vs Sig pistols.  Although the muscle memory is similar between the Sig and CZ but still differs some.  

It is like comparing how you drive a sports car vs an SUV or front drive vs all wheel vs rear wheel.  In a straight line you can basically mass the gas and go but when you brake and turn they are very different.  You will have different racing lines, different speeds at which to take a corner, and braking will be different as the sports car you can drive deeper into the corner before applying brake.  Pistols and rifles are the same thing no one particular model pistol will have the same muscle memory as another with a few exceptions.

I don't race my SUV, either.  there is a tactical feel to driving that doesn't happen with shooting.

This desire to change the shooter to the weapon seems unique to pistol shooting.  No one would tell a rifle shooter who groups well to not adjust their sights.

whatever.

Not all driving is racing but physics still apply to cornering, braking, and acceleration but every vehicle handles different.

Never said not to change or adjust the sights but I have seen people adjust and as they become accustomed the sight shift back because they are shooting the pistol correctly.  Usually better to fix the problem instead of treating symptoms.

There can be quite a bit if coaching to proper rifle shooting with body alignment, trigger finger, grip, cheek weld, sling pressure, etc

Failures with any of those will generally manifest itself in poor grouping.

I don't think getting an experienced shooter to change how they shoot to move a tight group is smart.  Just my opinion.

Where does the OP ever say "tight" group.  OP has not even posted pictures of groupings or targets he seems to have disappeared and left us to argue over something we have very little information to go on.  We could both be wrong and he has a damaged crown on his barrel causing his shots to go low.

if he is declaring all his bullets are going in one area, I assume he is grouping well.

maybe you and I have different definitions of "group"

Say his crown is off and causing all his bullets to deflect consistently.  Changing his sights fixes this problem.  changing how he shoots is fucktarded.

Changing the sights will fix possibly close range but may have a dramatic effect at longer ranges 20-50m.  I would say it needs to go back to Glock at that point.  Again we are both speculating working on what ifs which we could go back and forth on forever.  We both need more info to give OP an informed recommendations.  We could both we right or both be wrong.

Or as is attributed to Winston Churchill:

"I could agree with you, but the we would both be wrong."

If you are using the glock factory front sight try blacking out the white dot on the front. I have seen MANY people focus on the dot which results in sights not truly aligned ( equal height equal light with the rear notch)

Take all the backstraps off and shoot it without any.

The "perfect jerk" is a very common phenomenon. While it's possible it's the gun, chances are it isn't.

Dot Torture with random snap caps helps tremendously. Isolate that trigger press and I would put my money on it fixing with no change to the gun.

Have you had someone else who is "better" than you shoot it and do they get the same results? I am not saying you aren't good, I'm a firearms instructor and have seen this play out literally hundreds of times. Particularly when someone switches guns. You may shoot lights out with one gun and struggle with another. Go back to focusing on the fundamentals instead of expecting same results with a different gun. While a 21 is similar to a 34 with a large backstrap, there are still differences. Crawl, walk, run every time you switch guns.

Pretty much every time I switch guns it happens to me as well. I must force myself to focus on the fundamentals and retrain myself to shoot that gun. In fact I was in the exact same situation. I switched from a 21 to a 17 for duty and a 34 for competetion. I had the exact same issue. I knew it wasn't the gun because both the 17 and 34 did the same. Low left solid groups.

Happy shooting and don't get discouraged. Just train and focus on isolating that trigger press.

ETA: having someone else press the trigger for you is my favorite technique and I love watching them go "holy shit it really is me!"

Chances are you are doing the "pull the trigger right NOW!" And jerking the shot. Let the sights wobble cause you can't stop that. Straight press to the rear and you'll be golden.

I believe it was the new trigger effect.  I spent last week dry firing the gun while I watched tv, and took it out again this weekend with my 21.  Shot them side by side and got similar (not great) grouping, but the groups came up and was closer to what I expected.  

Used it for 3-gun once I was confident I wouldn't have to aim six inches high each time and it worked well.  I need more time behind the trigger (of pistols in general) and then I'll look at some upgrades to help smooth the gun.