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SR-25 build - First 308 AR

J

jamesbern

Sergeant
Full Member
Minuteman
Jan 12, 2012
202
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40
CT
So i got very lucky and scored a pre-ban Knights SR-25 receiver set yesterday. Here in CT we're kinda screwed on the AR front. Trying to read up and learn all I can so I make the right decisions off the bat. After hours of research this is where i'm at.

Upper:
Barrel: 16" rifle length gas...no idea what brand
Gas Block: depends on barrel
Brake: AAC 51T Blackout 7.62 (Ordered)
BCG: DPMS 308 (on sale at $190) (Ordered)
Rail: Knights URX 3.1 SR-25 rail (Ordered)
Charging handle: stock Knights for now, BCM eventually


Lower:
Stock: B5 Sopmod (Ordered)
Buffer tube: VLTOR RE-10 (Ordered)
Buffer: Damage Industries H3 (Ordered)
Spring:Armalite EA1095 (Ordered)
LPK: Armalite AR10 LPK (Ordered)


Now I really wanted to replicate a SR-25 ECC. The problem is I'm having a hard time finding a manufacturer that makes a 16" barrel with a rifle length gas system. It has to be rifle length gas and I'd much prefer a 16" over an 18". Criterion Barrels has an Ultra light 16" Rifle gassed barrel, but Fulton Armory isn't returning my email and I have no idea if they will ever get them again. I emailed Criterion about availability, but have heard nothing.

CMMG has a 16" rifle gassed barrel, but what can I expect quality wise? I've read some stuff that makes me nervous to grab it. Quality wise. Due to the proprietary barrel nut on the URX rail I need to have a shop (boltcarrier.com) put the upper together for me. So I don't want to settle on a barrel only to have to replace it soon after.

I'm also hope to not have to wait months for a barrel. Any ideas? The barrel decision is the only thing holding me up right now.

171FB3E3-7257-4F41-B1F8-BEFA6CA20253_zpsm44avve8.jpg
 
If it were me, I would steer away from a rifle length gas system on a 16" parts build. There is awful little gas time (12" gas port on a 16" barrel) to know it will be reliable out of the box. If you buy one pre-built, that is one thing as they will have tuned the gas already, if you build it that is another. With varying springs, BCGs, buffers and gas ports, I would plan to have to mess with the gas system a little on such a setup. You may not, but I always like to plan for the worst and hope for the best.

It would be a cool replica, but if it were me, I would go with a mid-length setup for the gas.

My opinion is worth what you paid for it... $0.02 max! So take it for what you will
 
yeah, middy on a 16" is better, you can run rifle gas on a 18"
 
I'll be watching this thread. I'm in CT too, and got my name on a list with Greyson's Guns. Hoping for a call soon.
 
TheJ said:
If it were me, I would steer away from a rifle length gas system on a 16" parts build. There is awful little gas time (12" gas port on a 16" barrel) to know it will be reliable out of the box. If you buy one pre-built, that is one thing as they will have tuned the gas already, if you build it that is another. With varying springs, BCGs, buffers and gas ports, I would plan to have to mess with the gas system a little on such a setup. You may not, but I always like to plan for the worst and hope for the best.

It would be a cool replica, but if it were me, I would go with a mid-length setup for the gas.

My opinion is worth what you paid for it... $0.02 max! So take it for what you will
Click to expand...

I tend to agree with you. I can order a Black Hole Weaponry 18" rifle length barrel and it will be about a 3 month wait for it to arrive. I've heard they are really nice barrels.

Here is the 16" with the URX 3.1 rail.

2012_ECC_Right1.jpg


Here is a 20" with the URX 3.1 rail.

2012_ECR_Right1.jpg


With the 18" being an in-between I think it would actually look pretty good. 20" is too long IMO.

marc308 said:
I'll be watching this thread. I'm in CT too, and got my name on a list with Greyson's Guns. Hoping for a call soon.
Click to expand...

That's where I got mine....Mike and Ivan are good people.
 
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I shoot a 24" BHW bull on my 6.5 grendel. Its an awesome stick. It did take a little playing, needed a bit more gas than it gave originally. But it shoots lights out for sure.
 
Lilja Precision barrels are favorites of the armorers in Little Creek. Lilja offers a nice rifle length gas 18". You could always chop 2" off if your heart is set on a rifle length gas 16".
 
Lilja Are top notch for sure. If you chop off a few inches, expect to open up the gas port too. Not a huge deal... But something to plan for.

But an 18" RL lilja will do it's job if you can do yours... No question about it.
 
MSTN said:
Lilja Precision barrels are favorites of the armorers in Little Creek. Lilja offers a nice rifle length gas 18". You could always chop 2" off if your heart is set on a rifle length gas 16".
Click to expand...

TheJ said:
Lilja Are top notch for sure. If you chop off a few inches, expect to open up the gas port too. Not a huge deal... But something to plan for.

But an 18" RL lilja will do it's job if you can do yours... No question about it.
Click to expand...

That's really odd that you guys just posted this. I just sent Dan an email about lead times and finish on an 18". I don't mind paying more for a quality barrel, but I was at least set on a black barrel for the build.
 
MSTN said:
If you're set on a custom build, getting the barrel coated is the least of the challenges that lie before you.
Click to expand...

Yeah, that's a valid point. I actually decided I liked the look with the stainless barrel after looking at a few other builds. Think it would look pretty good. Now just to wait and hear back how long the wait is.
 
Waiting is almost easier than getting a barrel coated. You just have to sit there. Even I can do it.

Dan makes awesome barrels. I have thirty on order from him. You won't be disappointed.

Yep, I've been waiting, too. Three months almost. Dan's faster than most.
 
If you don't mind paying more for a quality barrel why not have George over at GA do you up with a Bartlien and you can pick our gas system length?
 
I don't think you will have any issues with a rifle-gas 16". 308 AR's don't suffer from port-pressure/timing issues with this configuration like 223 AR's do. MAYBE you will need to open the gas port, but most 308's are overgassed anyways so this is more than likely not an issue.

IMO - either a Lilja or a Criterion would be a great barrel. I personally have one the 20" Criterion barrels from FA, and it shoots great. Have you considered getting their 18.5" cut down? The barrel has a finish that would be amenable to coating.

This looks like an awesome build, keep us updated!
 
Sweet!! Just waiting to hear back from them to find out lead time...as long as it isn't crazy, i'll be placing my order.
 
There is a guy at Arfcom that hangs out in KAC's industry section, I think his name is boltripper. He does awesome work along with a guy named Marvin Pitts. Inthinknthose two are the ones that come recommended by the knight employees. With that said there is nothing hard at all about running a 16 inch rifle length gas system in .308, it has a softer recoil impulse too. I would only get a top notch barrel for your project if I were you.

ETA Marvin does barrel dimpling and has turned many SRs into EMC etc... Boltripper and Marvin seems to be able to find alot of the hard to find correct KAC parts too.
 
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Heard back from Dan. Happy to say I'm going with a Lilja 18" stainless barrel. Should be sweet and the lead time is actually pretty fast.
 
Been acquiring parts slowly. Been trying to figure out what optic to go with. I want a battle rifle type setup that allows it to be effective both near and far. Settled on an SWFA 1-6x24. I actually finalized the parts list which i've posted below. The optic/mount and back up sights will be the last bits to be taken care of.

Then I need to start figuring what ammo to run.

 
I dont see a trigger on your parts list. Go with an SSA-E. You won't be disappointed.
 
padom said:
I dont see a trigger on your parts list. Go with an SSA-E. You won't be disappointed.
Click to expand...

Yeah, for now i'm just going with the basic trigger in the LPK. I do plan to swap out to something like that once the build is functioning.
 
Your gonna want a high quality trigger if accuracy is your goal. Trust me, going to SSA-E made a huge difference in tightening up my groups.
 
Thoughts? PSA AR-15 on left and Armalite AR-10 on right.

I can't cycle the DMPS BCG with the Armalite catch in. Angle is too steep. Options:

1. Grind/sand it down so it isn't as tall (the "ramp" would end up being slightly round)
2. Install AR-15 catch
3. Order and install DPMS LR-308 catch and hope it works.

 
I would check ar15.Com forum. They have a page under the ar-10 section about parts in/compatibility . Best of luck wit build
 
Jamesbern, did you look at/consider a JP Enterprises bolt and barrel assembly before going with the Lilja setup? Just curious.
I should be getting my KAC receiver set next week.
 
Wow. Seeing that price tag I think ill just order a socom which is still level in Ct as long as it doesn't have a flash hider.
 
marc308 said:
Jamesbern, did you look at/consider a JP Enterprises bolt and barrel assembly before going with the Lilja setup? Just curious.
I should be getting my KAC receiver set next week.
Click to expand...

I looked at a bunch of barrel options. Settled on the Lilja due to quality, gas length, and fast emails back from the owner of the company Dan, when I inquired about their barrels. Also seemed to be the shortest lead time. They are headspaced for DPMS bolts so when I send the upper to be assembled I'm going to see if Ayan @ bolt carrier.com can check that for me.

anthonylapoint said:
Wow. Seeing that price tag I think ill just order a socom which is still level in Ct as long as it doesn't have a flash hider.
Click to expand...

By socom do you mean M1A Socom? I owned a SA M1A Socom II. It was fun, but I'd prefer an AR even if it is more expensive.

997/2man said:
Going to be nice.

Where did you get the URX 3.1?


GL.
Click to expand...

Ayan at boltcarrier.com. Not sure if he actually got it yet and if it shipped, but it's going back to him once I get the barrel and rail in. He offers free installation of the rail if the rail is bought from him. Considering the KAC tool is $280 and I can't find one he is the one to go with for installation!
 
jamesbern said:
I looked at a bunch of barrel options. Settled on the Lilja due to quality, gas length, and fast emails back from the owner of the company Dan, when I inquired about their barrels. Also seemed to be the shortest lead time. They are headspaced for DPMS bolts so when I send the upper to be assembled I'm going to see if Ayan @ bolt carrier.com can check that for me.



By socom do you mean M1A Socom? I owned a SA M1A Socom II. It was fun, but I'd prefer an AR even if it is more expensive.



Ayan at boltcarrier.com. Not sure if he actually got it yet and if it shipped, but it's going back to him once I get the barrel and rail in. He offers free installation of the rail if the rail is bought from him. Considering the KAC tool is $280 and I can't find one he is the one to go with for installation!
Click to expand...

If he has the rail, I've got the money. The 3.1 rail is sweet. Like it BETTER than the key mod. Thanks, man.
 
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Yeah. The socom 16's are legal and they are certainly beautiful. I have an AR so I guess to me, a socom would just fit another slot of types of firearms that hasn't been filled yet.
 
Just got the barrel in tonight...beautiful!!! Sending everything out tomorrow to Ayan so he can put the upper together.

 
jamesbern said:
Nice dude! What are your specs? Love to hear what your parts list is.
Click to expand...

Magpul STR stock
Vltor RE-2 buffer tube
Magpul ASAP QD
JP captured buffer spring
JP low mass bolt carrier group
Geissele SSA trigger
Magpul MIAD type 2 grip
Magpul Enhanced trigger guard
Rainier Arms 16" Ultramatch barrel
Syrac adjustable gas block
Samson Star 10 13.2" rail
AAC Brakeout

Don't know what to do for iron sights and optics yet.
 
Very nice. Looking forward to my upper coming back to me when it's done. Then I just have to buy optic and iron sights.
 
Did you get your trigger in yet? I got my Geissele SSA today, and could not get it to work. I got everything in, but the trigger would not release the hammer. I'm pretty sure the part of the trigger well with the pencil lines needs to be machined out to allow the trigger travel needed to release the hammer.
 

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I didn't. I just used a standard trigger for now. I'm wondering if anyone else tried dropping in a SSA with the same issue.
 
marc308 said:
Did you get your trigger in yet? I got my Geissele SSA today, and could not get it to work. I got everything in, but the trigger would not release the hammer. I'm pretty sure the part of the trigger well with the pencil lines needs to be machined out to allow the trigger travel needed to release the hammer.
Click to expand...

Had the same issue … I installed a Mil Spec trigger and it worked fine. At first I thought the hole locations were off … was pissed. These old receivers are not nearly as "build friendly" as a new one but in CT it's all we can get!

FYI … Mine is an SSA-E but same difference.
 
I got it to work. I filed/polished about .035 off the front of the hammer, and made a groove for the spring. Works great!
 

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This picture is a little better. I cut it as close to the trigger as I could. I started the groove with a triangle shaped file, and got to the final depth with, believe it or not, a hacksaw blade. The groove is just deep enough to keep the spring flush with where I cut the front of the trigger. I polished everything up with 320 then 600 grit sandpaper.

Not that the trigger was cheap, but I figured it was better to screw up a $200 trigger instead of a $1600 receiver.
 

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Just ordered the Leupold Mark 6 1-6 w/ 7.62 reticle from Eurooptic and it was the best price I could fine....and their last one in stock. I was planning on a USO SR-8S, but heard too many negatives about quality control and customer service.
 
jamesbern said:
Just ordered the Leupold Mark 6 1-6 w/ 7.62 reticle from Eurooptic and it was the best price I could fine....and their last one in stock. I was planning on a USO SR-8S, but heard too many negatives about quality control and customer service.
Click to expand...

Nice, I'm assuming your upper isn't complete yet?
 
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