14.5" AR Upper question...

[Big Frank]

If you shorten a 16" barrel I think you should get one that's not chrome lined.

[TAB]

hmmmmm....there's a thought, I know a good lathe guy, cheers TAB   - he can braze too and I'm sure we can figure the 'pinning' thing between us,

MP

pinning is pretty simple.

its just a matter of using a mic to measure the  pin, then drill a hole a thousand smaller( larger pins, larger diffrence in size).  then using a drift to push the pin in.

I've done it many, many times.

[twyacht]

The chrome-lined debate, but your right jumbo to a point, however even the FN SCAR full auto barrel is cold-forged steel, yet still chrome lined.

For every give there's a take, the SS barrels are heavier. May not be a factor for some, but maybe for others, seeking a light weight carbine.

Thanks Ichiban for the link.

http://forums.officer.com/forums/showthread.php?81462-So-you-want-to-buy-an-AR-15-huh

THE BARREL

The heart of the rifle is the barrel. The barrel is the part of the rifle that directly touches the bullet in its path towards the target, and will be the single most expensive part in your rifle. It is also the one part of an AR-15 rifle that is prone to deteriorating (due to rust, erosion, or being shot-out.) The barrel is what determines the service-life of the rifle, so it should not be the part we scrimp on in order to save a few clams.

So, what kind of barrel SHOULD a fighting rifle have? We have two choices: Stainless Steel (expensive), and Chrome-Lined 4150 steel. 4140 is what most commercial barrels are made of, and is not altogether a horrible choice (as long as it is chrome-lined), but 4150 is still preferable.

H&K, Noveske, and now LWRC are offering Cold Hammer Forged barrels, which are MUCH more durable than standard barrels. These have a service life far surpassing what is currently available, but still need to be chrome-lined. CHF barrels are more expensive and should be regarded as highly desirable.

While SS barrels are VERY accurate, are VERY durable, and are definitely 'en vogue', they are also usually heavier, as they are most commonly made for "match" rifles. In addition to weighing more, they are also more expensive. This can range from moderately more expensive, to outlandishly more expensive! You will also have to be sure the chamber is meant for a fighting rifle, and not a match rifle. We'll talk about that in a minute...

So now that we know what material it should be made of, what about the other aspects? Here is the list of characteristics you should look for:
1- Gov't profile
2- Chrome lined chamber and bore
3- 5.56 NATO chamber
4- 1/7 twist
5- Parkerizing under front sight base
6- M4 feed ramps
7- Magnetic particle tested

If this is what we SHOULD look for, what else could we see? We'll take it spec by spec...

[Big Frank]

I don't know if there's a problem re-crowning a chrome lined barrel. I don't know anyone that's done it.

[tombogan03884]

Chrome is great in barrels,but it is applied after the machining has been finished.  Will it "Peel" away from the bore when its being machined, (cut and recrowned ) any burrs in the bore will destroy accuracy.
It would be much better to get the barrel already at the length you want and eliminate the risk of wrecking it.

[Sponsor]

[bafsu92]

Check out Rainer Arms for barrels of different lengths and the different flash hiders and comps. A good example, if you run a Noveske flaming pig flash hider you can use a 13.7" barrel to start to get an overall length of 16". They stock a very nice White Oak Armory barrel in 13.7" just for this combo. I've got a setup I had machined by Adco. I started with a 18" Daniel Defense mid-length barrel (I wanted a mid-length gas system and got the best deal on a 18" barrel) They cut it down to 14.5", opened up the gas port to the correct size for the barrel length, re-crowned and threaded it and turned it to pencil profile (.650) all for around $100 including return shipping. They are in my opinion the best there is for AR related machine work.

This is a super-light rifle, it's technically my son's AR but I usually commandeer it for my woods walks since I don't even notice I'm carrying it. I'll try to post some pics of the setup in the next few days. As far as pinning a flash hider I've got a little trick I do that's passed ATF inspection. Drill your hole in the collar of the flash hider then screw it onto your barrel and tighten it down. Take a punch that will fit inside the hole and tap it hard enough to put a detent into the barrel. Remove the flash hider and get a pin that will fit that's slightly longer than the depth of the hole and detent. Re-install your flash hider with red (permanent) locktite. Fill your hole nearly full with JB Weld and then insert your pin into the middle of the JB Weld. Allow to set for the instructed time, usually 24 hours. Grind and finish with a dremel tool to your desired look and cover with a flat black touch up pen if you wish. This meets ATF requirements of "pinned and welded" since the combination of the permanent locktite and JB Weld can't be removed without the use of a torch and/or cutting tool. You could actually just drill out the JB Weld then heat the flash hider with a torch to loosen the locktite but nobody is going to inspect it that closely. I have a friend who works for BATFE and he said as long as it looks like a welded pin and they can't break it loose with standard tools and a vice you have nothing to worry about on the actual method you used.

[fightingquaker13]

So, what kind of barrel SHOULD a fighting rifle have? [/i]We have two choices: Stainless Steel (expensive), and Chrome-Lined 4150 steel. 4140 is what most commercial barrels are made of, and is not altogether a horrible choice (as long as it is chrome-lined), but 4150 is still preferable.

H&K, Noveske, and now LWRC are offering Cold Hammer Forged barrels, which are MUCH more durable than standard barrels. These have a service life far surpassing what is currently available, but still need to be chrome-lined. CHF barrels are more expensive and should be regarded as highly desirable.

2- Chrome lined chamber and bore

4- 1/7 twist

TW I have heard folks disagree with both of those specs.
First the chrome lined bore. Yes, it is more corrosion resistant. But, it is also, acording to some, less accurate. Further, unless you are going on an extended swamp hike, do you need it? Most rifles don't have one and do just fine. Does your AR need one?
Second 1/7 twist. Why not 1/9? 1/7 seems (from admittedly limited knowledge) to favor heavier ammo. But for standard 55 gr as opposed to 62 gr and up, what does 1/7 buy you? Does it really matter unless you go above the 62gr mark?
Just curious.
FQ13

[Bic]

Terrific info bafsu, thanks a mill.

I too await with much interest replies to FQ's query.



where else could I get this much great info in such a short time?

MP

[bafsu92]

TW I have heard folks disagree with both of those specs.
First the chrome lined bore. Yes, it is more corrosion resistant. But, it is also, acording to some, less accurate. Further, unless you are going on an extended swamp hike, do you need it? Most rifles don't have one and do just fine. Does your AR need one?
Second 1/7 twist. Why not 1/9? 1/7 seems (from admittedly limited knowledge) to favor heavier ammo. But for standard 55 gr as opposed to 62 gr and up, what does 1/7 buy you? Does it really matter unless you go above the 62gr mark?
Just curious.
FQ13

I agree with you on your chrome lined theory. Unless you can't/won't keep your rifle clean (see Vietnam) a chrome lined barrel gives no real advantage over a QUALITY hammer forged barrel. If you can take the time to run a patch down the barrel every couple months of storage then you don't need chrome lined. That is assuming you clean your rifle after shooting sessions. I own about 8 AR variants currently and only 1 or 2 are lined and 2, soon to be 3 are stainless barrels. Lining does inhibit accuracy but this should only be an issue in match rifles, not every day defensive carbines. I personally have started using more SS barrels myself which sort of gives the best of both worlds. I really like the White Oak Armory stainless barrels and they are priced decently.

On twist the basic rule of thumb is "whatcha shootin?" If you want to shoot mil-spec/surplus or factory cheapie or even high end varmint ammo from 55gr (or less) to 62gr then 1-9 is the right choice. If you want to shoot heavier stuff and match stuff 72gr and higher then 1-7 is needed there. If you want to do it all well but nothing great run a 1-8. They're a little harder to find, although the most common 5.56/.223 wylde chambered stainless barrel, but they will handle anything from 40gr - 80gr with "acceptable defensive carbine accuracy". 1-8 is also a good choice for your 10.5"-14.5" barrels. My personal duty type rifle has a 14.5" M4 profile 1-8 stainless barrel that's been cerakoted matte black. I normally carry 62gr PMC X-Tac in it but keep a couple mags of specialty stuff in the 72-77gr range handy.

[twyacht]

According to another gun guru, here at our DRTV resources, the original M-16 rifles were 1 in 12, with 20" barrels, as the bullet weight increased from 55-62, 67-69, 72-77, the round would tumble. So the evolution between 1-7, 1-9 seems the most popular.

Tumbling rounds are a bad thing.

 My Sig556, is a cold hammer forged SS barrel, not lined, and between that and the gas tube, is more fwd. heavy than some pencil thin AR barrels, but scary accurate, albeit were limited to 100-120yds. Those little Tannerite tupperware containers at 100yds, are awfully small...But a lot of fun...

Accuracy is also relative to application. Especially for a 14-16" carbine.  I am not building a minute of playing card at 400yd. 5.56. Just a lightweight, iron sight, well-built, durable, reliable, and combat accurate AR for ranges less than 150yds.

I do expect combat accuracy to 100-150yds. that's it, with very little recoil. For longer ranges,... I pull out something else...

If I can get to a range with longer ranges other than 100-120yds, I have several rifles I'd love to try.

Since my POF lower is multi caliber compatible, a different 20" upper, or 6.5 or 6.8 upper may provide the minute of playing card option.