Do They Make Such An Upper??

Greetings Smitty03 - Welcome to the Forum.

My first question is this: Do you want to build one? Or outright purchase one?

When you say you are looking for just an upper, and you want a target crown, but you only want a 16" barrel - what will the application be for the platform?

Normally the 16" barrels all come with either a flash hider or the famous "barrel shroud".

Target crowns are very comon, but more on varmint, long range shooting applications. Thus, you see them commonly on longer 20" or so barrels.

Here is my first build, it features an A4 upper, a 17 inch GI Chrome Lined barrel with target crown and a Yankee Hill Machine free floated fore-end.

Is this kind of the application that you are looking at adding?

JD

JD-
I oughta just let you ask for me

I think his search to meet the criteria would go high and low, specifically the mid length one. I wasn't quite sure if it was mid length handguard or gas system being sought. I have seen a lot of hype about the mid length gas system improving function over the standard CAR length sytem. I am positively and firmly convinced that the CAR system is fine IF it is properly assembled. Save serious heavy full auto, I've never seen a properly assembled CAR system have problems due to the inherent design in the shorter system. It's usually been a component of the system. Loose carrier keys and damaged or mis-aligned gas tubes primarily. Chased a feeding problem for months only to find the gas tube roll pin was the wrong size. 13 cents later it was fine.

I assumed that the quest for a "ban compliant" upper meant probably no F/A.

So, I would second your comment about putting what he wants on it later. I have a YHM mid length f/f tube on my patrol rifle and love it.

Another plug for Model 1 Sales: they offer all of their uppers in "ban compliant" configuration with a recessed crown. Because God (and leftist fruit loops) know that flash hiders are deadly in their own right!

Jeep - Awesome post. +1

There is too much BS out there about this AR or that AR and why anything else is just going to get you killed. The Mid Length CAR Gas System is just another example of that mythos.

ANY properly assembled and tuned AR is going to get the job done. Period.

There are "Tier 1" and "Tier 2" parts, from manufacturing and from "name association" but they can ALL be made to run like a "custom" if the person doing the assembly knows what they are doing, and what they are tuning for.

I actually did some searching on my own this morning, about building an AR and things to "look out for" through Google. There are a ton of forums out there with people just posting opinion of their buddies' experiences and what went wrong, with their "opinion" as to why. If this website condoned forum raids, I could put some funny posts up here for a laugh.

Bottom line - There is too much myth and not enough fact about the AR platform and what it can be made to do.

Luckily we have some very good guys here that are willing to take some time and help folks get some real education instead of playing Grand Wizard of the Black Rifle.

JD

No problem Smitty - We have several members here that are willing to help, not just myself.

The gas recoil system is based on the gas "power" generated by the cartridge, in most cases the 5.56NATO round.

Now, if you look at it base numbers to base numbers, if you fire the same round through both a long barrel, long tube/gas system & a short barrel, short barrel/gas system - you are obviously going to get more gas, per cubic, in the shorter barrel than in the longer barrel.

This could be construed as "lighter" recoil in the long barrel version, or "more aggressive" recoil in the short barrel version, but that is where your gunsmith, or parts, play a key factor.

If you want a smoother recoil, and you want smoother bolt stroke, you just have to ****** the gas system a bit in a short, versus a mid length, versus a long barrel configuration.

Your barrel length should give you an ideal configuration for either a long, mid, or short fore end grip when you buy it - but that doesn't mean it has to stay the same as when you purchase it. There is an extensive aftermarket for just such "wants".

JD

Essentially, the gas block is merely a valve, at the end of the barrel, to re-direct some of the gas, back down a return line, into the chamber to cycle the bolt. This will eject the spent round and load the next round from the magazine.

If you think about it like a straws for a Super Big Gulp - if you have a decent size straw, like the one that comes with it, you get a lot of soda per sip. If you use the kind of mini straws used for mixed drinks in bars, you get a lot less per sip.

The gas recoil system is the same way. You ****** the system, for a shorter barrel version, and get the same amount of pressure in the chamber per shot. Use a full lenth gas block system, for a less than full length barrel system, you get too much gas coming back into the chamber and get a more aggressive recoil. Tailor it to the length of barrel for the weapon you are building, you get exactly what you are looking for.

JD

"If you want a smoother recoil, and you want smoother bolt stroke, you just have to ****** the gas system a bit in a short, versus a mid length, versus a long barrel configuration."

Above is something that should be taken to heart. I have seen guys throw ridiculous amounts of money at AR's to fix something that is simple and 99 times out of 100 the only problem: gas system.

If your goal is smoother bolt cycling and and the benefits offered by a longer gas system, do not try to affect that system by mechanical means. I wouldn't add heavier buffers or extra power buffer springs as some recommend. This does work in an F/A rifle to reduce cyclic rate, but that is because the carrier and hammer interact (doesn't seem like the right word) differently during cycling.

Go with JD's words and TUNE the gas system with an adjustable block to your needs, don't try to add resistance here and lessen it there to speed up or slow down your dwell and cycling. After tearing your hair out and spending money you don't need to, you'll get frustrated enough to put everything stock again and start from scratch.

I had a table somewhere with figures showing the distance of gas tube holes to muzzle between the rifle and carbine. It also had pressure levels for each. Basically, if I can remember this right, the distance to the muzzle once the gas has exited the gas tube hole into the gas tube determines dwell time. By shortening this with a CAR barrel (less distance from hole to muzzle) the gas pressure increases. I think the pressure in a standard CAR system is twice that of a rifle length system. Anyhow, that accounts for "more aggressive" recoil. This has been engineered by guys with more brains and a lot more money than I have, and counter acted accordingly with proper weight buffers and correct buffer spring rate in relation to gas tube and barrel length. So by changing these, we end up back to where we were in my third paragraph. The gas pressure needs to be regulated, not the forces opposing that pressure.

In short, the mid length gas system is a solution to a problem that wasn't really a problem. It is basically an in between for rifle and carbine systems. And finally, the aggressiveness of the recoil and the smoothness of bolt cycling between the two is barely noticeable anyhow, making the mid length nothing more than an in between. Like owning three fast cars with only a two horsepower difference in power from the most to least powerful. I am not good with analogies, but you get my drift.

I have both a shorty and a mid length. But, the shorty has a long flash suppressor front end to make it to minimum length under the law, so there is addtional front end weight.

I don't consider the 5.56NATO round to be that much of a recoil concern, especially in an 8 pound gun, which is about what my 17" variant weighs in at with optics.

As far as function, both my weapons perform fine, cycling exactly as they are supposed to.

Now, part of that could be argued that I work part time in a gun shop and have access to a gunsmith that others might not. However, if you are going to purchase a gun, you should be buying one that was built with these same thoughts in mind.

Quite frankly I would say you need to shoot both a CAR length and a mid length for yourself and see what you like.

At the end of the day, it's going to be your money. You need to buy what you think is the best weapon for you, and your needs, and not what the folks here, or the guys from the range, think is the best choice, regardless of how well intentioned the advice that was given.

JD