AR15: 20 inch vs 16 inch 223 bbl

[Tarvis]

I'm going to buy a kit for my lower, but I can't decide if the weight of a 16" is worth the loss of MV over a 20". The rifle will be used for a prarie dog trip in 2 weeks, but will also be used for jack rabbits (lots of freehand and moving), possibly squirrels and possibly 3 gun matches.

The load I plan on using is W748 pushing a 55 gr vmax, which should be around 2900 fps (max load) in a 20". If anyone has an idea on what the loss could possible be, please post.

These are the 2 kits I'm trying to decide between:
http://m-aparts.com/productsDetail.asp?id=14
http://m-aparts.com/productsDetail.asp?id=16

Please, only posts about choosing between the two for the stated uses and fps information.

Thanks

 

[RockyMtnTactical]

You'll probably lose 100fps in a 16", give or take.

 

[browningguy]

Just an opinion, no facts to back it up. I think my 16" AR does really well out to 300, beyond that I would want to get every bit of velocity possible so personally would go with a 20" or even a 24". In target shooting I currently shoot my 16" AR out to 300, and a 26" barrelled .243 for everything longer.

 

[dawgtraxx]

from the little exp i have, and with what i have read, you dont need anything longer than a 20"

 

[Snipe315]

Depending on what you want to do with it, I'd go with a compromise.

18" would get you decent velocity and keep the rifle fairly handy.

Of course, I've got a 24" barrel upper (Armalite M15A4T) that I love and have no trouble manuvering around.

 

[rangerruck]

a 16 inch bbl, gives about 2700 fps, depending on ammo; this is not good for distance shooting, as the speed drop off, will start to make the bullet tumble proly at 300 yds, or a bit more. A 20 inch bbl is going to put you at about 3000 fps, which is fine for both trajectory issues, and getting further out. Since the 223 is a hi speed cartridge/ I would say you lose 50fps or more per inch of bbl.

 

[skinewmexico]

I shoot steel plates @ 500 with my 16" all the time, the problem is my optics, not the barrel length. Big difference in a PD and a 12" steel plate though.

 

[RockyMtnTactical]

a 16 inch bbl, gives about 2700 fps, depending on ammo

No, they average better than that with a 55gr bullet, closer to 2800-2900fps in .223.

 

[Tarvis]

It depends on the powder, but the faster loads stated in my reloading book are up to 3100 with max loads in a 20", anywhere from 100-200 fps loss in 4 inches (guess) puts you at 2900-3000 in a 16" bbl.

Semi conclusion: I just got done helping my buddy put his 20" kit together and I do believe it is way to heavy (with the bbl it came with) to hunt rabbits with. I may try and find a lighter bbl than what is in the kit, but will most likely do the 16" either way.

 

[RockyMtnTactical]

I do all of my coyote hunting with a 16" superlight or M4 profile. No problems for me.

 

[jrfoxx]

If its for stationary (or mostly stationary) hunting, as opposed to HD/SD, I dont think the weight difference will be noticed in a 20", and since it sounds like youre goal is longer range accuracy for hunting, and not short and handy for SD/HD/CQB type stuff, the 16" looses MV, without you gaining anything since weight and handiness arent really going to effect you for what you are using it for.I'd probly get the 20" if it was for a dedicated, or primarilly hunting or longe(er) range shooting gun.Just me though, as it sounds like people with more experiance have no problems doing what you want with thier 16" guns, so if you went that way, it would still be a short, handy gun for SD/HD/CQB if you decide to use it for that too.I guess it boils down to whether or not you wnat it to daouble for that, or just be for hunting IMHO.

 

[Bartholomew Roberts]

a 16 inch bbl, gives about 2700 fps, depending on ammo; this is not good for distance shooting, as the speed drop off, will start to make the bullet tumble proly at 300 yds, or a bit more.

I have fired 16" barreled ARs with 55gr M193 out to 600yds with no tumbling. They certainly will not tumble at 300yds with any commerical ammunition (just for future reference).

At 300yds, drop for a 55gr M193 round will be around 9" and wind drift will be about 6" for a 5mph crosswind from 90 degrees.

 

[Tarvis]

Well I bought the 16" today. My main reason was that my buddy got the 20" put together last night and it's pretty heavy for shooting freehand. Of course, it is a bull barrel, probably around .960" near straight profile so it's not the 20" in general, just in the configuration I got this rifle in. For the next build I will most certainly get a 20" and post some data for each using some different ammo.