Tossing around (very tentatively) the idea of a SPR build with an 18" Barrel with either a mid-length or rifle length gas system; leaning towards the rifle system.
Anyone have any pics of this setup?
Thanks,
Greg
Check out the Centurion Arms SPR Sticky.
Lots of good pics of the Mk12 Mod 1 and Monty’s clones.
Here’s a pic from the thread-
Oooo, cool.
I have looked at their site; guess I just brain-farted it.
I would like to see more samples if anyone has more.
Maybe one with a fixed sight base.
That one from Centurion is kewl.
Not mine, I found this a couple of pages down.
A pic of a 18" White Oak SPR barrel with rifle length gas system. Built it 2005. Used it for a couple years and sold it.
Run and gun rifle match targets from 0 to 425 yards:
The SPR profile barrel was heavier than what I would have prefered.
S/F,
Jeff
My 3gun rifle as current as of today 7/20/2009, it’s a work in progress.
18" WOA SPR 1-7 twist .223 Wylde chamber barrel turned down to .650" under the rail (courtesy of W.A.R. Rifles). JP adjustable gas block LMOS carrier and close range sight, BCM bolt, KAC Triple Tap comp, VLTOR MUR upper, DD RIS II M4A1 rail, Bobro forward grip and 30mm scope mount, Burris XTR 1-4x 30mm scope, Charles Drissel ‘cat-tail’, Troy FDE flip up sights, PRI gas buster charging handle, Tactical Innovations lower, Geissele trigger, LMT SOPMOD stock in FDE, Magpul XTM covers, MOE grip and MS2 sling and PMAGs, Arrendondo mag button. Assembled by me ‘gotm4’.
I too am toying with building a new upper based on some parts I have lying around…
I am wondering if anyone has a 16 inch barrel on a rifle gas system? Bruce Piatt seems to like them as I read on the Enos forums…all the talk about different recoil etc…
What about harshness on the parts? How will it recoil differently than my 16 inch midlength?
I have a Colt 20 inch Govt 1/7 barrel that I am considering having cut and thread to 16 inches and having a Colt “F” sight base installed on so to be correct with a Colt M16A4 upper. The BCG would also be Colt and to top it off I have a LT 12.0 rail.
I like the long handguard length the way I like to shoot the longer guns and want a fixed front sight base and the long sight radius (older eyes) but do not have much use for 20 inch barrels.
Besides, I have all the parts, just need the barrel work done.
Just like mine… I wish. 
My 18inch LMOS upper is on its way, what weight buffer do you run? The real LMOS buffer is rifle length so it won’t run in a carbine reciever extension like in your set up. (I’m going to run an UBR).
I’m using a CAR buffer (the lightest one I have, 2.9oz). A normal CAR buffer and JP LMOS rifle buffer both weigh 3.0oz. I was using a 1.8oz that I took some weights out and replaced with Delrin but it proved to be not quite reliable enough. I use a standard rate chrome silicon spring from Brownells. The UBR uses carbine length buffers and springs so you’ll be able to use a CAR weight buffer. Eventually I may use a UBR stock in FDE on this gun.
Wow, resurrection…
That looks like a 12" rail. You need slightly longer to cover the gas tube (around 12.3"), or a bit beyond 13.2" to cover the gas block.
I had this barrel on an upper build for a couple of years…White Oak Armament
http://www.whiteoakarmament.com/xcart/product.php?productid=17518&cat=250&page=2
It shot anything, cycling wise and shot small groups. It was heavy and sold it to someone who had money and an urge for it.
It had a Troy VTAC Extreme 13" handguard and Phantom FH. It was pinned to a collapsible stock lower and ST-2 buffer, (before I learned better).
You are correct, this is a rifle length gas system with a 14" rail. Should work out just fine for me. 
Gas block will sit back just about an inch or so from the end of the rail. I will try to find the end view. These are not my pictures, but provided from a member here on M4C. The rag is where the barrel will be cut to length.
Found it.
This is what I am working on.
I ended up buying a MEGA 16", should be here next Friday. hope to have it installed next weekend. Break it in and be happy once again.
Do any of you have tips for balancing medium weight contour 18" barrels? I have been considering doing a build like USMC03’s and I want to-
a. keep weight down
b. create the best possible weight balance
To keep costs low I was hoping to just go with an A2 stock so the main variables would be handguard, barrel, and optic.
Use an A1 stock and you’re there.
Yep, A1. You can always have a barrel turned to just about what ever shape/custom contour you want to help cut weight. But then again, you can add weight to the stock if needed to balance. It will depend a lot on what you call heavy, and what you call keeping the cost low. Is this going to be a BR gun? Weight would be your friend then. What is the specific use for this weapon? I would find similar ones, ask what the weight/balance is to get a good direction on the set up you want to most mimic.
I am envisioning a “long carbine” such that the barrel is cmv chrome lined 18"-20", an A1 or A2 stock for looks and personal preference, a handguard to be determined (a 15" kmr would be great), and a low power scope or aimpoint. This may sound similar to a 3 gun setup and I guess it could fit that role as well. I have looked at builds that have a moe rifle stock and medium weight contour 18" barrel with fairly lightweight handguard and the balance was just not how I liked it. Balance comes first, then weight (for me).
If you are set on that build, then it’s “shooters choice”. The weight if the barrel with a A2 would be close, a light hand guard will help. Depending on the eye relief of what you end up with will determine where it will sit on the upper as you may know. I know this is not what you were talking about, but this is how my SPR started out.
It’s was a 16" Rainier Amrs Ultra Match, the rest is pretty easy to see what it is. As you can see the weight is low and pretty much centered. If I was to throw a RDS on it on the upper it would still stay low on weight and weight front to back would be the same. A little weight forward will help for actual shooting. There are several different views on this but it get’s back to what I call shooters choice. Everyone is different, bottom line.