11.5" or 14.5" SR-15? First AR

[Five_Point_Five_Six]

Do you have a porsche GT2 already?


That's the equivalent of a sr-15.

There's absolutely ZERO reason why a new shooter needs one. You'd be just as well served with ANY manufacuers rifle.

Besides just bragging to your friends that its a legit SR-15, you wont notice the differnce from a Colt or BCM or even PSA as a new shooter.

Attachment 55010

[Wake27]

Do you have a porsche GT2 already?


That's the equivalent of a sr-15.

There's absolutely ZERO reason why a new shooter needs one. You'd be just as well served with ANY manufacuers rifle.

Besides just bragging to your friends that its a legit SR-15, you wont notice the differnce from a Colt or BCM or even PSA as a new shooter.

There's also zero reason why anyone needs any AR-15, right?

[Outlander Systems]

OP,

Get the SR-15. Go with a 16” and forget the NFA headache.

Add ammo.

theend.wav

[amac]

Op, congrats on your purchase! You can't go wrong with a KAC lower. As a civilian shooter myself, I was lured by the name brand and bought a KAC. I sold the upper, SBR'd the lower and eight years later couldn't be happier! It's bad ass, rock solid and erased any need to search for something better. Buy once, cry once. I will add, if this is your first AR, it won't be your last!

As for the 11.5" vs 14.5" or 16" question... As everyone has advised, if you want an SBR, register your new lower as a pistol and then consider if you want to proceed with the NFA process. Which length is ideal? If you've shot AR's, then you know the 14.5 and longer run on a mid-length gas system. The benefits of a longer platform are increased long range accuracy, slightly reduced felt recoil and more rail space to mount "stuff". Benefits of the shorter barrel are weight and maneuverability. A shorter barrel means you have a carbine length gas system and as a result, have a bit more felt recoil, less space for accessories and may feel cramped for hand space. YMMV. I don't find the noise to be a factor until you mount a muzzle break instead of a flash hider. The port design of the breaks make for a loud bark and your shooting neighbors eat the blowout! I don't like pinning because that limits future decisions on changes you may want to make. Consider carefully. Definitely add a can!

Personally, I'd consider what type optic I want to run as a major consideration to barrel length. If you prefer a red dot, then shorter makes more sense to me. Red dots are quick and SBR's swing side to side more smoothly, in my opinion. The combo can't be beat! If you prefer an optic like a 1-6, then the longer barrel makes sense. There are lots of great magnified optics that give you true 1 power for CQB application and can zoom out to give you 300 yard accuracy. A 14.5" barrel with a 1-6 scope is a great all around rifle.

Another consideration is a 12.5" barrel. I have a 12.5 on my KAC lower with a 1-4 optic on top and feel this does everything an AR needs to do. I've done everything with the setup from CQB training to 3-gun competition and easily reached 300+ yard targets. My research showed this to be the shortest barrel length to maintain effective ballistic performance. Other, more experienced shooters may differ, but it has done everything I need it to do. Just another length to consider if you plan to go short.

You inquired about swapping uppers on lowers. Yes, uppers can be dropped on lowers, but in my experience, reliability may be an issue. My 10.5" upper will not run reliably on my 12.5" setups lower. The reverse is also true. You may find the need to tune your lower to handle the gas pressure created by your upper. For me, this has created dedicated lower/upper combo's. YMMV.

Good luck on your quest. Read up before you buy and be sure to check the EE for the rest of your build. Everyone here started where you are and through trial and error have decided to sell an upper, lower, trigger, optic, hand rail, etc... You can find like new AR parts and accessories for a fraction of the cost of new. I buy and sell all my AR stuff on the EE here for that very reason.

amac

[DocMaynard]

Thanks for the advice! I appreciate it!

I sold the upper, SBR'd the lower and eight years later couldn't be happier! It's bad ass, rock solid and erased any need to search for something better. Buy once, cry once. I will add, if this is your first AR, it won't be your last!

What motivated you to sell the upper? Or I should ask, what did you end up selling and replacing it with?

As for the 11.5" vs 14.5" or 16" question... As everyone has advised, if you want an SBR, register your new lower as a pistol and then consider if you want to proceed with the NFA process. Which length is ideal? If you've shot AR's, then you know the 14.5 and longer run on a mid-length gas system. The benefits of a longer platform are increased long range accuracy, slightly reduced felt recoil and more rail space to mount "stuff". Benefits of the shorter barrel are weight and maneuverability. A shorter barrel means you have a carbine length gas system and as a result, have a bit more felt recoil, less space for accessories and may feel cramped for hand space. YMMV. I don't find the noise to be a factor until you mount a muzzle break instead of a flash hider. The port design of the breaks make for a loud bark and your shooting neighbors eat the blowout! I don't like pinning because that limits future decisions on changes you may want to make. Consider carefully. Definitely add a can!

Thanks, I certainly plan on registering it as a pistol lower and then considering carefully of going through with the NFA process. It'll be in a gun trust anyways since it makes passing guns on down to the next generation much easier as my state requires some stringent requirements for transfer

Personally, I'd consider what type optic I want to run as a major consideration to barrel length. If you prefer a red dot, then shorter makes more sense to me. Red dots are quick and SBR's swing side to side more smoothly, in my opinion. The combo can't be beat! If you prefer an optic like a 1-6, then the longer barrel makes sense. There are lots of great magnified optics that give you true 1 power for CQB application and can zoom out to give you 300 yard accuracy. A 14.5" barrel with a 1-6 scope is a great all around rifle.

I'm debating this myself. I like the quick sight acquisition that the red dot gives. I'm still researching and debating the red dot vs LPVO. I've been realizing that there's so much you can do with ARs it's hardly fair to have one gun to do it all. But for a SHTF gun, I do wonder the distance where most engagements occur. Shooting at a 400yd target seems extremely unlikely since it's hard to get a target id at that distance.

You inquired about swapping uppers on lowers. Yes, uppers can be dropped on lowers, but in my experience, reliability may be an issue. My 10.5" upper will not run reliably on my 12.5" setups lower. The reverse is also true. You may find the need to tune your lower to handle the gas pressure created by your upper. For me, this has created dedicated lower/upper combo's. YMMV.

This is a very newbie question but what exactly needs to be tuned on the lower? I know the buffer weights need to be replaced depending on the gas length of the system but does anything else need to be tuned? Which if it's a pain in the ass to tune, it begs the question of what's a good ambi lower I can get other than another SR-15 lower...?

[oldbrowndog]

I'm new here, but I've read this entire thread with some interest because it sounds like me 6 or 7 years ago.

I started with the standard advice. Bought a BCM lower, slapped a 16" FSB upper on it. I was a poor student at the time and even the BCM was a stretch. KAC prices were otherworldly. Eventually hated the FSB and got a BCM 14.5" ELW upper with a pinned A2X. It was fine, but scoped it and wanted better accuracy, and went down the rabbit hole of building/buying ARs.
Long story short, I ended up with an assortment of 5.56 guns in 10.3 - 16" and 2 SBR lowers.

For any serious use, everything but my 300 BO has now been replaced by a SBR'd KAC lower and a pair of KAC uppers - a 14.5" with a 1-8 LPVO and an 11.5" with an Aimpoint RDS. By my math, if I had saved up money and bought KAC from the start instead of churning through a pile of guns/parts, I'd have $8000 extra in my pocket for ammo/optics/training, etc. If you know that you want a serious-use AR and you're willing to wait, save and get what you really want - it'll be cheaper in the long run.

PS. I bought the KAC lower separately and it started as a pistol, so I revert back to a pistol with an SBA3 as necessary for travel/etc.

[OldState]

If you are already down the KAC path I would say continue if you can afford it.

It’s important to keep in mind though that the concept of “working your way up” to KAC isn’t really the best way to think about it in my opinion. There are MANY serious shooters who can afford the best of the best and still run Colts, BCM, etc. It’s not like people are telling you to buy a cheap pair of skis and if you like skiing get something better. Functionally speaking BCM, Colt, etc are universality considered top tier products in the SME community.

There is “nice to have” and “need to have” and then “very very nice but certainly not need to have” stuff.

By all accounts KAC is extremely nice and durable stuff.

I guess what I’m hoping you understand is that you can quickly reach the point of diminishing returns. The difference between a $500 consumer grade AR and a $900-1000 BCM, Colt, etc set up is pretty big. After that it’s more about the accessories.

[RobertTheTexan]

I'm debating this myself. I like the quick sight acquisition that the red dot gives. I'm still researching and debating the red dot vs LPVO. I've been realizing that there's so much you can do with ARs it's hardly fair to have one gun to do it all. But for a SHTF gun, I do wonder the distance where most engagements occur. Shooting at a 400yd target seems extremely unlikely since it's hard to get a target id at that distance.

Somehow I have a missing post. The number one thing that drives EVERYTHING.
- barrel length
- optic
- buis
- trigger
- stock
- weapon light
- rail
- and more....

All of the above can be driven by purpose

In other words “mission drives the gear.” This is the truest of true statements.

I suppose if someone is building or buying a range toy or a “Hey buddy, look and see what I have!!”

I’m not saying this is you, I’m outlining a couple of examples where I can see all Tactical/purpose-driven sense being discarded.

I believe before a part for a build gets purchased the ol’ mission statement needs to be defined and adhered to. Whenever I’ve bought things without paying attention to that, I ended up with parts I had no use for and ended up selling it giving away. Purpose drives everything!

Of course it’s ok for you to buy whatever, I’m just sharing what I’ve learned building many AR’s. Mistakes and all. Do I see a really good buy and buy a part even though I may not have a project going on? Sure, but it’s usually something. I know I will use or have already used. So the lost I can’t find said.basically: let the purpose drive your build. Especially barrel length and optic since those are two of your questions.

This is a very newbie question but what exactly needs to be tuned on the lower? I know the buffer weights need to be replaced depending on the gas length of the system but does anything else need to be tuned? Which if it's a pain in the ass to tune, it begs the question of what's a good ambi lower I can get other than another SR-15 lower...?

Tuning only happens with your buffer weights and buffer spring and an adjustable gas. Lock if you have.

Some comp triggers are tunable but that’s it.



Sent from my iPhone using Tapatalk

[prepare]

For civilian self defense, purpose/mission is pretty clear. Its not like civilians have that many differing rolls. Civilians aren't involved in conducting raids or any type of offensive op or overwatch. You hear a bump in the night and you grab your AR. Or you detect a threat at distance via your security system. Pretty simple. Covers 99.9% of your mission.

[oldbrowndog]

...
It’s important to keep in mind though that the concept of “working your way up” to KAC isn’t really the best way to think about it in my opinion. There are MANY serious shooters who can afford the best of the best and still run Colts, BCM, etc. It’s not like people are telling you to buy a cheap pair of skis and if you like skiing get something better. Functionally speaking BCM, Colt, etc are universality considered top tier products in the SME community.
...

I guess what I’m hoping you understand is that you can quickly reach the point of diminishing returns. The difference between a $500 consumer grade AR and a $900-1000 BCM, Colt, etc set up is pretty big. After that it’s more about the accessories.

I would 100% agree with this. The bigger point of my post was get what you want the first time, even if you have to wait and save. I drooled over KACs when shopping for my first AR, but they were over my immediately-available price range. Being patient and saving up would've saved me a ton of money over time.