Red Dot & Barrel Length re: Accuracy

[socalbeachbum]

I've been told several times that once an optical sight is in play, barrel length does not affect accuracy. My question is this, would a Glock 19 4" really have the same accuracy results as a Glock 34 5.3" if they have same shooter, same red dot, same ammo etc?

Do competitors in a class where red dots are used choose the G34 because followup shots are quicker than with a shorter barrel?

And does geometry come into effect, how a longer barrel is supported front and rear vs a short barrel? I do not have a Glock at the moment and do not know if when in battery the barrel is supported at the front or not. I simply picked Glock as an example, but I have the same question about 1911's, or any semi-auto with a tilt barrel modified Browning type of action.

 

[Dragonfly]

Certainly the accuracy advantage a longer sight radius provides is negated by a red dot, so the remaining differences would be the mechanical accuracy difference (which I would say would be very small between a 4" and 5" or 6" pistol), and the handling and recoil differences between a shorter and longer pistol affecting follow-up shots. In my experience, a longer-barelled semi-auto handgun does not always provide less recoil due to the heavier reciprocating mass of the bigger slide, although the G34 you mention actually has a cut-out in the slide to reduce its mass. I do find that a 5" 1911 does seem to buck a bit more than a Commander-length one.

 

[Havok7416]

Barrel length is not connected to accuracy assuming the twist rate for the bullet is correct. Sight radius on the other hand is very much connected to accuracy. In handguns barrel length and aight radius are often interconnected out of necessity. A red dot or similar alternative reduces everything to mechanical accuracy (minus shooter input of course).

 

[socalbeachbum]

so with a Red Dot would a Glock 26 3.5" show similar results as a Glock 34 5.3" ?

 

[Havok7416]

Yes

ETA: The limiting factor between those 2 guns may come down to the limited grip area on the G26. The accuracy will still be there though.

 

[JTQ]

so with a Red Dot would a Glock 26 3.5" show similar results as a Glock 34 5.3" ?

Massad Ayoob on the accuracy of "baby Glock's", though not a red dot specific article.

https://www.personaldefenseworld.com/2012/11/baby-glock-26/

What was most surprising with these little guns was that, off the bench, they “outshot” their big brothers. The primary Glock 17 I had at that time would group 3.5 to 4 inches at 25 yards with most loads, better than that with its favorite Winchester 115-grain ammunition…but my little Glock 26 delivered 2.5-inch groups at the same distance, with regularity.

 

[Walt Sherrill]

When talking about handguns, accuracy is primarily dependent on the consistency of barrel/slide lockup -- if the sights are mounted on the slide (and the barrel is a competent barrel.) With a frame mounted sighting systgem, slide/frame fit is also important.

• Barrel length alone doesn't really affect accuracy. Some guns with 3" barrels can be as accurate as guns with 4" or 5" (or longer) barrels.

• The main benefit of a longer barrel is slightly improved round performance -- because the round is moving faster, it spends less time getting there, it drops slightly less and the extra velocity due to a longer barrel will generally let the bullet penetrate a bit more -- which could be important in some applications. The performance differences between a barrel and another 1" or 2" longer (all other things being equal) typically won't be that great.

• A longer sight radius makes it EASIER for the shooter to shoot the gun accurately, but that's human engineering, not mechanical engineering.

• Red Dot sights can also make it easier for the shooter to shoot the gun accurately, but unless the gun locks up consistently (and the sighting systems is linked to that locked-up assembly), where the bullet goes (accuracy) will depend as much (or more) on the randomness of the lockup than the barrel length.

• The same is true of a good trigger: it doesn't make the gun more accurate, but does make it easier for the shooter to shoot the gun accurately.