Ok, I'm interested in getting an upper. I'm leaning toward  19.5" How much accuracy will I lose beyond 300 yds. by not going 24"? Thanks 1911roben.

Accuracy is not related to barrel length.

Visit www.65Grendel.com if you have not.  

FWIW, I have been shooting a 24" overwatch for about a year now, about 750 rounds in total, and it has been very accurate.  

Today, I was shooting Arne's 20" A2 and it was very accurate as well.  It functioned perfectly with the 16 round mags, and we were getting pretty good velocities.  Looks like we will be @ 2700-2750 with Norma 120 FMJs when done with load development, again out of a 20" barrel.  

With a Hornady 95 VMax I was getting about 2950...  

As an uneducated guesstimate.... roughly 4.3636" drop per 1" reduction in barrel length @ 1000 yds....    or 19.63" drop compared to a 24" bbl. if it held the zero at 1000 yds.  An 18.5" bbl should have about a 24" drop at 1000 yds. compared to the 24" bbl.  
Guessing that the 19.5" bbl should be about perfect for a 4 moa size dot sight for up close and personal.  

Thanks walker, so this cal. is no different than others in that respect. So why are people using 24" and longer? most of the pics I see show optics not irons 1911roben.

I picked the 24" for hunting (where the 19.5 would probably be fine, maybe better) and long range paper punching.  Where I live we have a 1000 yard range that I haven't used yet.

Quoted: Thanks walker, so this cal. is no different than others in that respect. So why are people using 24" and longer? most of the pics I see show optics not irons 1911roben.

Yep, no different concerning accuracy.  People go with longer barrels to increase velocity, aiding in long range shooting.  Less drop & less drift with greater velocity.  When talking strictly about accuracy, look to the BR community.  They are using 20" barrels at 200 yards, 26-28" @ 1000 simply to aid the velocity.  

In talking with Arne, orders for the 24" uppers have slowed.  As it was the only initial offering, it was 24" or nothing.  Now people have options and they are buying based on what they will use the upper specifically for, and no longer have to compromise.  

In CGs case above, it is a good compormise.  He wants both to hunt and to punch paper with the upper, the 24" is the way to go.  

Thsnks walker, It's starting to make sense. I have no use for a 24" bbl. I'm not a BR shooter. I shoot on BLM land 100-900 yds. prone off a ruck. Shooting across 2 canyons to the 900 yd. cut bank I looking for good wind bucking but still want a handy bbl. lenght. 1911roben.