View Full Version : Before I order my upper...
Does the 4" difference between a rifle and carbine length barrel really make much of a difference?
I'm leaning towards 16" mid-lenght, but I wonder if I should look at 20" uppers at all...
This is for an all around general use AR. So far, I have been striving for quality, so I'm not cheaping out on the upper half either.
It depends on what you want to do with it. There are three things I would consider. (1) sight radius if you plan on using iron sights. (2) the velocity difference if you plan on shooting long range. (3) the increase in perceived recoil associated with shorted gas systems.
If you plan on using any type of optic for most of your shooting then #1 isn't an issue.
If you don't plan on shooting long distance (and have access to a long distance range) then #2 isn't an issue either.
A 20" upper with a rifle length gas system should have less perceived recoil than a 16" mid-length gas system, which should have less perceived recoil than a 14.5" or 16" carbine length gas system.
Personally, for general use, I would look at the BCM mid-length lightweight uppers in stock at G&R Tactical.
For a general use AR a 16'' can do everything a 20'' could. Personally the longest I would go is 18'' but ive always considered 16'' to do just fine. As far as gas systems go yes a carbine system has more recoil than a mid-length and same for rifle. But to me I can hardly tell a difference.
It depends on what you want to do with it. There are three things I would consider. (1) sight radius if you plan on using iron sights. (2) the velocity difference if you plan on shooting long range. (3) the increase in perceived recoil associated with shorted gas systems.
If you plan on using any type of optic for most of your shooting then #1 isn't an issue.
If you don't plan on shooting long distance (and have access to a long distance range) then #2 isn't an issue either.
A 20" upper with a rifle length gas system should have less perceived recoil than a 16" mid-length gas system, which should have less perceived recoil than a 14.5" or 16" carbine length gas system.
Personally, for general use, I would look at the BCM mid-length lightweight uppers in stock at G&R Tactical.
Thanks. I have been looking at BCM regardless. Their 16" mid upper and their 20" upper cost the same currently, so price is not an issue.
I'm leaning towards the 16" but I'm just wondering if I should look over the 20" again.
More questions:
When it comes to dynamic shooting, is the difference in that case really significant at all?
At what distance does the barrel length-accuracy-and-velocity factor actually start to matter?
Is there any accuracy difference between the two using standard ammo at say 100 or 200 yds?
ETA: I see now that post #3 says that a 16" can do everything a 20" can. I guess that answers my question.
How far out can one shoot with a 16"?
Thanks. I have been looking at BCM regardless. Their 16" mid upper and their 20" upper cost the same currently, so price is not an issue.
I'm leaning towards the 16" but I'm just wondering if I should look over the 20" again.
More questions:
When it comes to dynamic shooting, is the difference in that case really significant at all?
It may not sound like a lot but that extra 4'' can really become cumbersome especially in CQB environments.
At what distance does the barrel length-accuracy-and-velocity factor actually start to matter? Start stretching out to 500-600 then the extra length in barrel comes in handy.
Is there any accuracy difference between the two using standard ammo at say 100 or 200 yds?No, choice of ammo is going to have the greatest impact.
ETA: I see now that post #3 says that a 16" can do everything a 20" can. I guess that answers my question.
How far out can one shoot with a 16"?
With a 16'' 500-600. Once you start stretching out to that length than the extra length in barrel can start coming into the factor.
See red
If effective range is workable out to 500-600 yds with the 16, but is handier in closer quarters, that's it.
16 it is.
Thanks gents.
I had no idea a 16" bbl could even go that far; I thought it would only be good up to like 400m.
And just out of pure curiosity, what is the difference in velocity between a 16" and a 20" using m855?
Guessing offhand, around ~200 feet per second.
Actually if I'm not badly mistaken, velocity loss is closer to 20-30 fps per inch.
And yes, there is huge differences in cqb type spaces when you start trying to move with a longer barrel. Same goes for thick woods.
JBecker 72
10-23-12, 19:44
M855 is 3120 fps or so out of a 20" and 2950 fps or so out of a 16" IIRC.
Just a follow up question:
When you unbox the upper before slapping on to the lower, are you supposed to liberally grease it normally? Or does this factory dry film lube come into play?
Just wipe off the factory lube, relube it with your preferred brand of lube and start shooting. I personally like Froglube and Slip.
I did exactly as nubs suggested. Wipe down, lube, and have fun!
I was thinking of ordering one of the BFG 16" mid-length gas uppers myself. Did you go with the "Light Weight" or standard barrel? Personally i'm leaning towards the lighter, but havent made up my mind yet. I see a forum seach on barrel profiles in my future.
Let us know what you think when it arrives!
I haven't ordered yet. I actually a different BCM upper, a 20" arrive at my house for a buddy (for logistical reasons and convenience).
https://dl.dropbox.com/u/69962118/ARs%20001.JPG
The only thing that belongs to me there is the bottom lower with the STR stock. Both uppers belong to my buddy, and he is selling the M&P one to help finance the BCM.
When my gun is done, since I'm sticking with the 16", it will or or less look like 95% of this
https://secure.flickr.com/photos/stickgunner/6482746943/
I don't have any experience with dynamic shooting, so I wonder if the VFG is necessary?
So I have had my upper for a few months (I've posted pics elsewhere on this board).
How do I determine what kind of optic is right for me (eg RDS or optic).
I have no idea. I thought I wanted to get an RDS, but I keep learning about how much you can wring out of a 16" tube with a good twist rate, so I wonder what benefit a scope could bring me.
So I have had my upper for a few months (I've posted pics elsewhere on this board).
How do I determine what kind of optic is right for me (eg RDS or optic).
I have no idea. I thought I wanted to get an RDS, but I keep learning about how much you can wring out of a 16" tube with a good twist rate, so I wonder what benefit a scope could bring me.
Depends on what you're wanting to do and how far you want to shoot.
I only have a 200 yard range here at home so my long range scoped ar's don't come out very often unless I just decide to see how close I can get holes on paper. I end up shooting the ones with 1-4's and aimpoints more often.
I wasn't thinking of anything like super long range. I think I'd like to make mine semi-SPR ish just to get it to shoot a little better.
That being said, where can I learn more about the purpose and application of these 1-4x scopes that many of you seem to have?
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