OK, so i built my first AR just a few months ago and let me say; it was great. Great learning experience and definitely fun. trying to fulfill a CQ/SPR role is annoying so I want one CQ and one SPR. 
 
I will be using my current AR as the CQ rifle, pinning the stock fully closed, removing the bi pod, switching to a Geissele SDC trigger, and maybe switching to a NiB BCG. i will take the Spikes BCG for the new build.
 
As for the SPR build i have acquired another Spikes lower receiver. Plan on putting my SSA on it at some point. Pretty sure i want the Luth-AR stock, will a standard A2 buffer kit work with this? This build will take a bit longer as i want to save a few bucks on parts (unlike my last build). If anyone has any used parts they want to get rid of, let me know.
 
ETA: This is what I have spec'd out so far:
 
Lower - 

• Spikes lower receiver 
• Luth-AR 
• A2 stock kit 
• Geissele SSA
• Battle Arms pin set 
• CAA grip 
• Standard LPK for the rest 

Upper - 

• Odin Works 3-gun barrel 
• PSW FSC556
• Diamomdhead VRS-T 13.5"
• MidwestPX upper 
• WMD NiB BCG 
• Spikes CH

Optics 

• Bushnell Elite 3200 3-10x40 
• Rings 

 

 
 

Almost forgot....

Yep, the Luth uses a standard riflelength extension.

If I plan to use the Luth-AR I know I need a rifle length buffer set up. But can I use that with a mid-length gas system?

I ran across this chart.

 

I was planning on going 18" plus a muzzle device 2-3". Not sure what length gas system I should be using.

 

I would like to keep recoil down obviously, and not put unnecessary pressure on my internals.

Rifle or intermediate length.

If I plan to use the Luth-AR I know I need a rifle length buffer set up. But can I use that with a mid-length gas system?

I ran across this chart.

 

I was planning on going 18" plus a muzzle device 2-3". Not sure what length gas system I should be using.

 

I would like to keep recoil down obviously, and not put unnecessary pressure on my internals.

You can.  I've built a couple 18" midlength guns that use A2 extensions without issue.

Rifle or intermediate length.

You can. I've built a couple 18" midlength guns that use A2 extensions without issue.

 

Is there a benefit to one over the other?

 

Is there a benefit to one over the other?

The longer the gas system, the softer the perceived recoil as the rifle isn't cycling as fast/violently.

The longer the gas system, the softer the perceived recoil as the rifle isn't cycling as fast/violently.

I have a mid length has with carbine buffer. How is the midlenth with rifle in comparison? Same amount of perceived recoil. It's not a lot.

I'm thinking the midlength might be easier to find parts for..

I have a mid length has with carbine buffer. How is the midlenth with rifle in comparison? Same amount of perceived recoil. It's not a lot.

I'm thinking the midlength might be easier to find parts for..

Likely harsher though dependent gas port sizing.  My 18" midlength with an A2 recoils harsher than my 16" midlength with an H buffer.

Likely harsher though dependent gas port sizing. My 18" midlength with an A2 recoils harsher than my 16" midlength with an H buffer.

is this same thing that a heavier buffer/spring, brake, or adjustable gas block can mitigate?

 

Reason being, I have a spare carbine buffer assembly that I could use if I go with mid length. Spare lpk partsm allowing me to temporarily finish the lower a lot faster and move on to the upper while watching for deals. I want a match grade barrel as I want this gun to be pretty accurate. But I want to make the right choice on barrel and gas system so I don't have to buy twice.

is this same thing that a heavier buffer/spring, brake, or adjustable gas block can mitigate?

 

Reason being, I have a spare carbine buffer assembly that I could use if I go with mid length. Spare lpk partsm allowing me to temporarily finish the lower a lot faster and move on to the upper while watching for deals. I want a match grade barrel as I want this gun to be pretty accurate. But I want to make the right choice on barrel and gas system so I don't have to buy twice.

Yes but it may ultimately cost you more money.  A quality A2 extension kit can be had for $35 and is more or less guaranteed to work without further tweaking regardless of gas system (mid or rifle).  Most heavier buffers are $25 to $35 and may or may not achieve your objective.  Some adjustable gas blocks are even more than that.  See what I'm getting at?  

Yes but it may ultimately cost you more money. A quality A2 extension kit can be had for $35 and is more or less guaranteed to work without further tweaking regardless of gas system (mid or rifle). Most heavier buffers are $25 to $35 and may or may not achieve your objective. Some adjustable gas blocks are even more than that. See what I'm getting at?

I understand completely. I just don't know what recoil to expect with the 18" mid length. If it's close to or the same as my 14.5 mid with stand and buffer then I have no problem.

 

Is there a noticeable difference?

I understand completely. I just don't know what recoil to expect with the 18" mid length. If it's close to or the same as my 14.5 mid with stand and buffer then I have no problem.

 

Is there a noticeable difference?

With 3.5" more barrel and the same gas and recoil systems, yes, you will notice it's a good bit sharper in recoil.

Any recommendations on a barrel, 18" rifle length?

Any recommendations on a barrel, 18" rifle length?

 

Not any with personal experience, no.  I do like the Odin 3-Gun barrels as they're guaranteed to be sub-MOA (mine certainly is as is one I sold to a close friend), come with a gas block and gas tube for under $300.  They aren't a rifle length gas system though and use an intermediate gas system which is about 1" shorter than rifle. They weigh a little under 2.2lbs and are extremely well balanced.

 

There's also White Oak Armament and Rainier Arms who have 18" SPR-type barrels with rifle length gas systems.

I have the Odin barrel from Ty (Midwestpx) and I really like it. True, it is an intermediate length, but I find no significant difference between it and my NM Colt.  I took the NM upper and put it on the SPR lower for S&G, and found no appreciable difference in perceived recoil.  I then reversed it and put the SPR on the Colt lower, same results.  I am now in the process of finding out which load maximizes the effectiveness of both barrels.  As all my rounds are on a 100 yard range, I try to keep the charge as low as possible.  Early results still find the old recipe the best 55FMJ over 25.0 W748.  Have a little CFE223 to try next.

Not any with personal experience, no.  I do like the Odin 3-Gun barrels as they're guaranteed to be sub-MOA (mine certainly is as is one I sold to a close friend), come with a gas block and gas tube for under $300.  They aren't a rifle length gas system though and use an intermediate gas system which is about 1" shorter than rifle. They weigh a little under 2.2lbs and are extremely well balanced.

 

There's also White Oak Armament and Rainier Arms who have 18" SPR-type barrels with rifle length gas systems.

 

 

I have the Odin barrel from Ty (Midwestpx) and I really like it. True, it is an intermediate length, but I find no significant difference between it and my NM Colt.  I took the NM upper and put it on the SPR lower for S&G, and found no appreciable difference in perceived recoil.  I then reversed it and put the SPR on the Colt lower, same results.  I am now in the process of finding out which load maximizes the effectiveness of both barrels.  As all my rounds are on a 100 yard range, I try to keep the charge as low as possible.  Early results still find the old recipe the best 55FMJ over 25.0 W748.  Have a little CFE223 to try next.

It's funny, i was looking at that barrel last night when posting this thread. I'll have to keep my eye on it.

 

I'm trying to get everything spec'd out before I really get into the build. I Spec'd it out a little in the OP, let me know what i'm missing please, my last build i bought a complete upper.

It's funny, i was looking at that barrel last night when posting this thread. I'll have to keep my eye on it.

 

I'm trying to get everything spec'd out before I really get into the build. I Spec'd it out a little in the OP, let me know what i'm missing please, my last build i bought a complete upper.

I could do some shameless self-promotion

I could do some shameless self-promotion

i'd rather buy from a forum sponsor than Brownells or Midway.. Haven't seen one bad post about either..

i'd rather buy from a forum sponsor than Brownells or Midway.. Haven't seen one bad post about either..

So this is how I built my SPR upper. Keep in mind that while this serves as a company demo for local customers, I wouldn't keep it like this if I didn't like it personally. I'm doing some copying/pasting from the pic thread.

 

 

Upper

 

Receiver: Complete PX Forged Upper Receiver

Barrel: ODIN Works 18" 3-Gun Stainless

BCG: WMD Guns Full-Auto Profile NiB-X

Handguard: 14" Centurion Arms CMR w/ bipod stud

Charging handle: Rainier Arms Raptor 

 

The only thing I wouldn't be able to provide is a pinned/welded muzzle device. While I stock brakes, I'm not setup to do the work.

 

So why do I like this build?

 

1. It's accurate. ODIN guarantees these barrels to be sub-MOA and they are. I've sold quite a few and haven't heard a single grumble about their capabilities.

2. The balance is perfect. Even with a longer handguard and a longer barrel, the rifle balances at the magwell. This makes for easy off-hand shooting as well as fast transitions. Lightweight handguards and properly profiled barrels are key to managing the distribution of the weight. You don't want something front heavy if you intend to shoot it off-hand.

3. While these are premium quality components, nothing is really over-the-top cost-wise. The CMR is the most expensive part at around $300 but if you think about it, you're building what is essentially a match grade upper that can double as a CQ upper for under $1K.

So this is how I built my SPR upper. Keep in mind that while this serves as a company demo for local customers, I wouldn't keep it like this if I didn't like it personally. I'm doing some copying/pasting from the pic thread.

 

 

Upper

 

Receiver: Complete PX Forged Upper Receiver

Barrel: ODIN Works 18" 3-Gun Stainless

BCG: WMD Guns Full-Auto Profile NiB-X

Handguard: 14" Centurion Arms CMR w/ bipod stud

Charging handle: Rainier Arms Raptor 

 

The only thing I wouldn't be able to provide is a pinned/welded muzzle device. While I stock brakes, I'm not setup to do the work.

 

So why do I like this build?

 

1. It's accurate. ODIN guarantees these barrels to be sub-MOA and they are. I've sold quite a few and haven't heard a single grumble about their capabilities.

2. The balance is perfect. Even with a longer handguard and a longer barrel, the rifle balances at the magwell. This makes for easy off-hand shooting as well as fast transitions. Lightweight handguards and properly profiled barrels are key to managing the distribution of the weight. You don't want something front heavy if you intend to shoot it off-hand.

3. While these are premium quality components, nothing is really over-the-top cost-wise. The CMR is the most expensive part at around $300 but if you think about it, you're building what is essentially a match grade upper that can double as a CQ upper for under $1K.

 Not sure about that rail or the raptor. I have a spare spikes CH. I do not plan to shoot this off hand either so  i wasn't looking for anything ambidextrous. But my CQ AR is ambi. It is also front heavy, and that's with a light weight upper.. maybe i should evaluate that.

 

That upper, BCG and barrel good to go for me. I'm gonna need to eventually get 2 Nib BCGs, one for each AR. And that Luth... Running any sales soon? lol

Boejoula, my SPR has the 18" Ranier Arms Ultramatch barrel. They also come in Intermediate length. I wanted the Intermediate but it went out of stock before I ordered.

 

I have the Magpul PRS on mine with a rifle buffer.

 

If you'd like to try it out at CJ one day, let me know.

Boejoula, my SPR has the 18" Ranier Arms Ultramatch barrel. They also come in Intermediate length. I wanted the Intermediate but it went out of stock before I ordered.

 

I have the Magpul PRS on mine with a rifle buffer.

 

If you'd like to try it out at CJ one day, let me know.

Thank you but those are both way out of my price range. lol

anyone use the Fortis RED comp?

anyone use the Fortis RED comp?

I don't have any personal experience with it however I've heard it does a good job of keeping the muzzle flat with some redirected sideblast though not as bad as the FSC from PWS. My problem with muzzle devices is most demo guns are fitted with either an AAC flash hider or muzzle brake since those are the suppressors I sell to local customers and they want to hear the cans on the demo guns typically.

Thank you but those are both way out of my price range. lol

Actually was offering you the opportunity to see what a rifle length gas in an 18" barrel with a rifle buffer felt like.

Actually was offering you the opportunity to see what a rifle length gas in an 18" barrel with a rifle buffer felt like.

Sorry, that sounds great. I appreciate it. Sundays are my only available days.

I don't have any personal experience with it however I've heard it does a good job of keeping the muzzle flat with some redirected sideblast though not as bad as the FSC from PWS. My problem with muzzle devices is most demo guns are fitted with either an AAC flash hider or muzzle brake since those are the suppressors I sell to local customers and they want to hear the cans on the demo guns typically.

I have been doing a bunch of reading on brakes and it seems the PWS FSC556 is the choice of most people.

Sorry, that sounds great. I appreciate it. Sundays are my only available days.

Yep. We can head out on a Sunday that's convenient for you.

 

Maybe in the next couple of weeks.