Hello guys, I am planning on building a AR 15 flat top upper in the near future, and was curious if it should  have a 16" or 20"bbl. I will be shooting between 75 and 200 yards. My bullet choice  will be between 55 and 70 gr. hollow points. Please keep in mind I would like to keep this rifle as light as possible ? what do you think? Do I have any other options?

At your ranges, there is no reason (other than personal preference or the dreaded, unavoidable "maximum fragmentation range" arguement) to go with the longer 20" barrel.

Although a couple of friends and I have successfully engaged (read "hit" ) a steel sillouette at 500 yards with both 14.5" and 16" rifles, I'd start leaning towards the 20" after 350 yards or so.

I also can't let this post go by without a plug for my FAVORITE rifle of all... the 16" lightweight Mid-length!  I know that because of your bullet weight stipulations, you'd have to wait for that 1:7 "group buy" or some other source, but I just REALLY like the Middie for looks, extra forend length, less gas impulse, and did I mention looks?  I think they're really worth the extra effort.


*edited to add plug for mid-length

The short course is that a 16" gives you a lot more "handiness" for close-in (house distance) work whereas the 20" gains you a softer recoil and, load for load, approximately 50 more yards of effective killing distance.

The barrel contour you choose will affect the weight more than barrel length will. That is; an HBAR 16" will be a lot heavier than a pencil-profile 20".

My best advice to you is to beg/borrow/steal examples of each and shoot them. Then and only then make your decision.

Luck,

SD

Another option would be to get one lower receiver, and an upper receiver of each length.  

For the distances you want 14.5 is plenty of rifle,light and handy too.16" is overated,a happy medium but over rated . if you want a self defense AR chances are better than 90% that if you ever have to use it it will be well under 100 yds.If you plan on shooting longer like an SPR or match rifle go 20" but in that respect I would go to .308 for distances longer than 1 to 2 hundred yards.16" has a little better velocity and fragmentation range but be that as it may probable ranges encountered would be better served in having the shortest rifle legaly possible.An 11.5 is also relevant at real world ranges but seeing us civies have to have the 5.5 supressor you might as well go 14.5 as compactness is the 11.5s real strong point in its true 11.5 form.

I have a 16" M4 profile barreled upper, and a 20" hbar barreled upper, so I'm gonna go ahead and say what hasn't been said yet and sooner or later will.  GET BOTH!!!!

Thanks to all of you for your replies. I think I'll go on Model 1 Sales web page and see what they have in 16" varmint uppers. I am probably pushing my luck by asking for one of these 16" varmint uppers with a 1and 7 twist, so I guess I'll have to settle for a 1 in 8 twist. I hope I am making the right choice.

Get a 20.  Before I owned one I thought it would be too long; however, it is the exact same length as my 870 with an 18.5" BBL.  No big deal. You have a FH on your 16 and the difference between the 20 is seriously negligible.

Oh yah, DON'T GO MODEL 1 SALES!!!!!!!!!!!!!!!!!!!

They treated a member hear like shit and they gave contradictory statements on their BBL steel.  I don't trust them.  The money you supposedly "save" with them can easily be compensated for by shopping the EE.  You buy from the dealers that support this site and you will get quality shit.  Trust me, I have learned the hard way.

I'd go 16" midlength.

Quoted: Get a 20.  Before I owned one I thought it would be too long; however, it is the exact same length as my 870 with an 18.5" BBL.  No big deal. You have a FH on your 16 and the difference between the 20 is seriously negligible. Oh yah, DON'T GO MODEL 1 SALES!!!!!!!!!!!!!!!!!!! They treated a member hear like shit and they gave contradictory statements on their BBL steel.  I don't trust them.  The money you supposedly "save" with them can easily be compensated for by shopping the EE.  You buy from the dealers that support this site and you will get quality shit.  Trust me, I have learned the hard way.

Chewbacca, Whats wrong with Model 1 Sales? Why do you dislike them so much?

16 in CAR hbar bbl

1-7 twist probably

Seriously, either 16 or 20 is fine.  Build what you like the looks of, then build another