High end SPR build list help. Please pick it apart

[Sogan]

PLEASE pick this apart if I'm not on the right track. Need some help in 4 main areas (barrel, receiver, Bolt carrier and buffer) for a new SPR type build. I live in IL so for now NO suppressors, if that matters for buffer type etc.

Main Use:
-I really want to be able to shoot 53gr Vmax for coyotes and 77gr loads for 600-700ish. Goal is to upgrade to a thermal with range finder so the 53gr option could possibly go away but it does seem to wreck coyotes so I've liked using them for that so far.

Receiver set w/ handguard: SLR Rifleworks B15 Ambi builders set. Is this stiff enough or would you recommend a different upper? I know MEGA used to be popular for their rigidity.

Barrel - Going with CLE for the barrel work and am between a few options:

-Brand: Krieger or Bartlein 4 groove? Really any option, but I dont mind spending the price for those two if it makes a difference

-Profile: Any real accuracy different between these two if all else is equal?
1. Tactical 18.1"
2. Varmint 20" - Obviously heavier as its 1" under the handguard. Will this fit under normal handguards like the SLR ones?
Flute: Should I flute either? If the Varmint barrel is better, can/should I flute it to save weight or does that defeat the purpose of the barrel profile?

-Chamber: CLE vs Wylde? One better than the other for what I'm wanting to shoot out of it (53gr and 77gr)?

-Twist: 1/7.7 to hopefully help shoot the 53gr if possible?

Buffer: I see a lot of people going the JP silent spring option. Since I cant use a suppressor will I still see a benefit? I will be using a SLR adjustable gas block. If not, do I just go normal buffer?

Bolt Carrier: Getting a matched bolt from CLE. Any carrier recommendations?

--------------------------------------------------------------------------------------------------------------------------------
Other build info:

Upper:
-SLR adjustable gas block. Some say clamp on effects the barrel less than the set screw/dimple option. Always used dimpled but ill do whatever is best.
-I plan to lap and bed the upper if needed.

Lower:
-PRS lite stock or XLR tactical stock
-MKM Vertical Crossover grip
-Buffer tube depends on the buffer question above
-Trigger: TT diamond or Elfmann most likely

 

[nn8734]

My thoughts:

Mk12 profile if running the AWM5, otherwise pick the one that best suits your needs

5.56 Nato chamber, 1/7 or 1/8 (i prefer 1/7 but either will work for your bullets)

Another Barrel considerstion: Douglas SS Mk12 SPR if going w/ the SPR profile

 

[Sogan]

My thoughts:

Mk12 profile if running the AWM5, otherwise pick the one that best suits your needs

5.56 Nato chamber, 1/7 or 1/8 (i prefer 1/7 but either will work for your bullets)

Another Barrel considerstion: Douglas SS Mk12 SPR if going w/ the SPR profile

Good catch. I edited the post. thanks! I do not need the true SPR profile as I wont be running the collar and that can etc

 

[padom]

Short answer...

Build list looks good

I'd go with Rubber City BCG with adjustable gas key and use a geissele super low .750 fixed gas block... ill never use AGB again. The RCA adjustable gas key BCG's are fucking awesome. Been running them for over 16 months now.

Standard Mass 5.56 x 45(223) M16 BCG Complete w/ Adjustable Gas Key – Welcome to Rubber City Armory

Bartlein/Krieger barrel is great. 1/7 shoots lighter bullets also...I shot 53smk per Frank White that shot great out of my 4 groove Bartlein. 5R shoot great too. I like 223 Wylde. But CLE chamber shot good too...

SLR makes great stuff, I'm sure it's g2g but I love MEGA.

 

[Steel head]

Don’t sweat the barrel between those two choices, whatever is in stock and your GTG
1-8, 1-7.7, can’t go wrong with either.
SLR gas block is nice but exercise it occasionally or it will seize.

Any good BCG will do, rubber city, rainier and BCM are my favorite s but plenty of other solid choices.

I really like the 18” SPR profile, mine is a rainier UM.

I use a vltor A5a2 buffer, tuned to run in the cold with PMC bronze(about ye weakest ammo you’ll encounter)

CLE I think has a bit less freebore than wylde
Both excellent chambers.

 

[padom]

Don’t sweat the barrel between those two choices, whatever is in stock and your GTG
1-8, 1-7.7, can’t go wrong with either.
SLR gas block is nice but exercise it occasionally or it will seize.

Any good BCG will do, rubber city, rainier and BCM are my favorite s but plenty of other solid choices.

I really like the 18” SPR profile, mine is a rainier UM.

I use a vltor A5a2 buffer, tuned to run in the cold with PMC bronze(about ye weakest ammo you’ll encounter)

CLE I think has a bit less freebore than wylde
Both excellent chambers.

Yes cle does have a less freebore to get your 77's closer to lands at mag length.. I haven't had a problem with 223 wylde...77smk like to jump...

I'm a JP SCS fan, supressed or not. So nice to be able to tune and is super soft shooting. But I also run JP buffer springs and Geisele buffers with excellent results

 

[Steel head]

Yes cle does have a less freebore to get your 77's closer to lands at mag length.. I haven't had a problem with 223 wylde...77smk like to jump...

I'm a JP SCS fan, supressed or not. So nice to be able to tune and is super soft shooting. But I also run JP buffer springs and Geisele buffers with excellent results

Yea
The wylde does fantastic with 69SMK as well.

When I built my SPR none of that fancy JP or BCG stuff was around yet.

 

[padom]

From what I've been told ZEV/MEGA makes these for JSE and are the same as a MEGA billet receiver set. They look the same...

JSE AR15 Billet Stripped Upper Receiver

Please view details for more information.

www.jsesurplus.com

 

[JBoomhauer]

My opinion is that you may want to go for two uppers, one lightweight for the thermal and one for the 77s out to 700.

Scanning with a thermal scope will get pretty old with an 18-20” heavyish barreled upper. Especially considering a 300yd shot is a long way out for thermal on a coyote.

 

[Sogan]

My opinion is that you may want to go for two uppers, one lightweight for the thermal and one for the 77s out to 700.

Scanning with a thermal scope will get pretty old with an 18-20” heavyish barreled upper. Especially considering a 300yd shot is a long way out for thermal on a coyote.

I do have a thermal spotter than I use and the gun stays mounted in the RRS tripod for shots only. 300 is my max at night especially with a 223.

 

[JBoomhauer]

I do have a thermal spotter than I use and the gun stays mounted in the RRS tripod for shots only. 300 is my max at night especially with a 223.

Ok that’s much better with the scanner also!

 

[Sogan]

Short answer...

Build list looks good

I'd go with Rubber City BCG with adjustable gas key and use a geissele super low .750 fixed gas block... ill never use AGB again. The RCA adjustable gas key BCG's are fucking awesome. Been running them for over 16 months now.

Standard Mass 5.56 x 45(223) M16 BCG Complete w/ Adjustable Gas Key – Welcome to Rubber City Armory

Bartlein/Krieger barrel is great. 1/7 shoots lighter bullets also...I shot 53smk per Frank White that shot great out of my 4 groove Bartlein. 5R shoot great too. I like 223 Wylde. But CLE chamber shot good too...

SLR makes great stuff, I'm sure it's g2g but I love MEGA.

I knew you were a big fan of MEGA and I didn’t know they were back to being made by ZEV again.

Do most handguards work with them or what do you use most often?

 

[padom]

I knew you were a big fan of MEGA and I didn’t know they were back to being made by ZEV again.

Do most handguards work with them or what do you use most often?

All handguards work with them.. my favorites I use with Mega are slr, bcm, seekins and jp...

 

[Sogan]

All handguards work with them.. my favorites I use with Mega are slr, bcm, seekins and jp...

I love SLR rails so ill probably go that route. Any bipod induced flex issues on their "lites" if I keep it around 15"?

 

[padom]

I love SLR rails so ill probably go that route. Any bipod induced flex issues on their "lites" if I keep it around 15"?

I haven't had any bipod flex issues with Ion and Solo....another reason I use Geissele fixed low profile gas blocks....leaves more clearance around the block vs AGB

 

[roostercogburn98]

I have almost the build you talk about now minus a few small details. It shoots very well, all I have shot from it is 77g thus far. I think you’ll have good results with your build list. Build deets are below for mine

-Mega ambi upper and matched lower
-Bartlein 18in 1:7.7 custom contoured and built by a guy I know at GAP, WOA competition barrel extension, headspaced to a Seekins bolt and carrier. Wylde chamber, 5/8-24 muzzle threads
-SLR adjustable GB, rifle length gas
-TriggerTech trigger
-Magpul PRS Gen 3 stock, heavy weight wolf spring and standard buffer
-JP cantilever mount and an HDMRii pro 3.5-21 scope
-typically sits on GG&G bipods

 

[Molon]

Main Use:
-I really want to be able to shoot 53gr Vmax

-Brand: Krieger or Bartlein 4 groove?

The 53 grain V-MAX was specifically "optimized" for the 223 Remington chamber. It shoots extremely well from my Krieger barreled AR-15s. The 5-shot group pictured below was fired from one of my Krieger barreled AR-15s with a 223 Remington chamber and a 1:9 " twist. The group has an extreme spread of 0.317 MOA.

The 10-shot group pictured below was fired from the same AR-15. The group has an extreme spread of 0.533 MOA.

....

 

[MontanaMan]

Your build is fine, all top shelf parts...................much of it just really boils down to personal preference.

As for the barrels, any of the 4 major SS barrels that CLE uses are excellent, & you probably can't shoot the difference between them...........but Bartlien get a slight edge IMO, if you can shoot the difference. Wylde over CLE chamber.

I'd also not overlook Craddock Precision on the barrel..........................every single barrel I've gotten from Paul has been fantastic & I like their Rock Creek blanks, but he also has Bartliens. And he will do it however you want it.

I like SLR AGB's & haven't had any issues with them but I don't allow them to freeze up & they are easy to take apart & clean; the RCA adjustable gas key is nice & there are no better people to deal with than RCA on anything they sell.

Except for shooting suppressed you likely really don't need the AGB unless you are going superlight on the BCG / buffer weight.

SLR & Geiselle rails are by far my favorites; Viltor MUR upper, Aero lowers have worked well, also SanTan is a favorite along with Cross Machine Tool uppers & lowers.

There's really lots of good stuff that all performs well, as I said before mostly just personal preference within that top tier of products.

MM

 

[RickyRodney]

A rail rangefinder and a good reticle in your thermal or a clip-on and know your dope. 300 is NBD.

Maybe build a .22 creedmoor AR-10 upper for night-time hammering if you reload. The flat trajectory can compensate for range errors.

 

[WindstormSCR]

I'd recommend a 1:7 5R for 77gr high BC bullets (SMK, TMK, etc) bartlein, krieger, or douglas are hard to go wrong with there.

Also definitely recommend against fluting unless you want to minimize weight and are strictly doing cold bore shots, at which point I'd say go with a lightweight profile, carbon fiber handguard, and build it on a KP15 polymer lower to maximize your weight savings.

Since you're shooting from a tripod, heavy is good, heavy is accurate.

 

[Shawn1492]

The geiselle super 42 buffer spring is worth the price.

 

[Longshot85]

I am a nobody and have never built an MK12.

I did build a rifle based on the MK12 concept though.

Barrel = WOA SPR profile in .223 wylde 18 inches 1:7 twist

This rifle shoots 77grain stuff AMAZING. It shoots the factory IMI 77 grain Razorcore sub MOA 10 shot groups all day. With handloads I'm seeing results like the groups Molon posted above (yes I know he's showing 53 vmax results) just to give you an idea with 77grain TMK's and XBR 8208.

Trigger is an SSA-E and I love it.

The guys above know MK12 stuff FAR better than I do.....and I've never had the chance to get any barrels from all the top tier manufacturers above. I know they shoot great. @padom is THE man when it comes to AR's.

You will end up with an amazing rifle.

The first time I took my SPR inspired build to the range.....I had an epiphany. It was my first semi that was accurate at distance.......as soon as I smacked the 500 yard piece of steel 5 times in a row shooting at a relatively fast rate.....I IMMEDIATELY thought......"So THIS is why people build large frame AR's!!!"

Today I am finishing up a 16 inch 6.5CM AR10 built off mostly Aero parts.......it also has a Law Gen3 folder and a 6 inch suppressor. This is my new night hunting coyote rig......will have NV and my Luna Elir3 IR Laser on it SOON......trying to plan some night hunting ASAP

I rambled I know....good luck with the build and you will enjoy it. My SPR inspired build is currently my favorite rifle in the safe (I haven't shot 16 in AR10 6.5CM yet though....)

 

[r.tenorio671]

PLEASE pick this apart if I'm not on the right track. Need some help in 4 main areas (barrel, receiver, Bolt carrier and buffer) for a new SPR type build. I live in IL so for now NO suppressors, if that matters for buffer type etc.

Main Use:
-I really want to be able to shoot 53gr Vmax for coyotes and 77gr loads for 600-700ish. Goal is to upgrade to a thermal with range finder so the 53gr option could possibly go away but it does seem to wreck coyotes so I've liked using them for that so far.

Receiver set w/ handguard: SLR Rifleworks B15 Ambi builders set. Is this stiff enough or would you recommend a different upper? I know MEGA used to be popular for their rigidity.

Barrel - Going with CLE for the barrel work and am between a few options:

-Brand: Krieger or Bartlein 4 groove? Really any option, but I dont mind spending the price for those two if it makes a difference

-Profile: Any real accuracy different between these two if all else is equal?
1. Tactical 18.1"
2. Varmint 20" - Obviously heavier as its 1" under the handguard. Will this fit under normal handguards like the SLR ones?
Flute: Should I flute either? If the Varmint barrel is better, can/should I flute it to save weight or does that defeat the purpose of the barrel profile?

-Chamber: CLE vs Wylde? One better than the other for what I'm wanting to shoot out of it (53gr and 77gr)?

-Twist: 1/7.7 to hopefully help shoot the 53gr if possible?

Buffer: I see a lot of people going the JP silent spring option. Since I cant use a suppressor will I still see a benefit? I will be using a SLR adjustable gas block. If not, do I just go normal buffer?

Bolt Carrier: Getting a matched bolt from CLE. Any carrier recommendations?

--------------------------------------------------------------------------------------------------------------------------------
Other build info:

Upper:
-SLR adjustable gas block. Some say clamp on effects the barrel less than the set screw/dimple option. Always used dimpled but ill do whatever is best.
-I plan to lap and bed the upper if needed.

Lower:
-PRS lite stock or XLR tactical stock
-MKM Vertical Crossover grip
-Buffer tube depends on the buffer question above
-Trigger: TT diamond or Elfmann most likely

..........to be honest, by time you purchase all of those individual pieces you will most likely exceed the cost of just buying a complete rifle from one of the recognized and established companies/smiths/barrel makers with a reputation for accurate builds. If you were going to assemble all of those pieces on your own, the cost of the proper tools and gauges to ensure the accuracy potential is extracted from that collection of premium parts is not an insignificant amount either, i.e., a reaction rod is the proper tool to install a barrel and muzzle devices, prices range from ~$50-$150.

...just my $0.02

 

[Sogan]

..........to be honest, by time you purchase all of those individual pieces you will most likely exceed the cost of just buying a complete rifle from one of the recognized and established companies/smiths/barrel makers with a reputation for accurate builds. If you were going to assemble all of those pieces on your own, the cost of the proper tools and gauges to ensure the accuracy potential is extracted from that collection of premium parts is not an insignificant amount either, i.e., a reaction rod is the proper tool to install a barrel and muzzle devices, prices range from ~$50-$150.

...just my $0.02

You arnt wrong on both accounts. You can certainly get precision rifles cheaper. However, no offerings offer EXACTLY what you want down to the individual part 99% of the time. Plus I enjoy searching for the parts and the actual building part, so its enjoyable for me.

As far as the tools go, I've been building ARs for awhile so I have everything there but its amounted to hundreds of money in tools over the years.

What companies are you thinking for full builds though? Ill certainly take a look!

 

[Gustav7]

I'd go with Rubber City BCG with adjustable gas key and use a geissele super low .750 fixed gas block... ill never use AGB again. The RCA adjustable gas key BCG's are fucking awesome. Been running them for over 16 months now.

Standard Mass 5.56 x 45(223) M16 BCG Complete w/ Adjustable Gas Key – Welcome to Rubber City Armory

Have you used Bootleg's adjustable BCG? And if yes, how does it compare to the RCA adjustable one?

I have an adjustable SLR on my SPR and I'd rather just go the Buffer/Spring/Adjustable BCG route in the future.

 

[r.tenorio671]

...based on your list:

---buffer & bolt carrier can be standard M4/M16/AR15, no need for more Gucci and expensive ones as you will as you will be using a SLR adjustable gas block that allows you to tune the timing to either load you plan to shoot.

---gas block, the clamp type gives a better seal around the circumference of the gas journal, just make sure you get the SOLO Series based handguard with the 1.315" ID. The set screw type will work with the ION/HELIX based handguards that have a 1.305" ID.

---barrel, your choice between a Kreiger or Bartlein will basically come down to cost differences as both are high performers. 4 -vs-6 groove is moot in regards to accuracy, although 4 groove impart less engraving resistance to the bullets.

---bolt, good choice to get it from CLE along with the barrel as it implies it has been headspaced to the barrel so no issues should be encountered and has the implied warranty from CLE as well. Same with getting the BCG from CLE.

---fluting, while some weight savings can be gained commensurate to the size, depth and quantity of flutes, empirical data supporting claims it makes for a more rigid barrel is less than absolute. The claim that the increased surface area sheds heat faster has been widely supported by testing, but those same tests have also indicated that the fluted barrels heat up faster and affect accuracy sooner as opposed to unfluted barrels of the same diameter. Rate of fire is a factor as well regarding heat build up and associated effects on accuracy.

----profile, depends on how frequently and how far you will be carrying the rifle and once there if used in a supported or unsupported method.

---chamber, the CLE will give more flexibility to shoot the lightweight varmint projectiles which are typically loaded at a shorter OAL. The Wylde chamber is better suited for the longer & heavier bullets you mentioned, primarily due the leade length and angle. If anything, speak with CLE and let them know the intended bullets you plan to use.

 

[jLorenzo]

I see no reason why a 1:7 wouldnt shoot the 53. As far as I know thats a long bullet for its weight anyway. I have a 1:7 that shoots 50gr hollow points very well.

 

[Sogan]

Thanks for everyones feedback so far!

Does a "matching set" from MEGA or SLR etc mean anything besides you are buying both products at the same time? I cant imagine they try and find the two that go together the tightest etc? And if I do want to mismatch upper/lower should I just look for two that fit together tightly, IE: mega upper and ADM lower since I love their ambi controls?

 

[r.tenorio671]

...going with both upper & lower from same maker increases probability that all dimensions (pin holes, etc) are compatible and decrease fitment issues. If you like the specific features of the ADM lower, just get the upper too.

 

[Sogan]

...going with both upper & lower from same maker increases probability that all dimensions (pin holes, etc) are compatible and decrease fitment issues. If you like the specific features of the ADM lower, just get the upper too.

Truthfully the MEGA upper seems to have more meat behind the threads than the ADM. ADM is pretty thin all the way up to the ejection port. I think that matters?

 

[r.tenorio671]

Truthfully the MEGA upper seems to have more meat behind the threads than the ADM. ADM is pretty thin all the way up to the ejection port. I think that matters?

...no personal experience with ADM or MEGA, but my advise remains the same, upper and lower from the same manufacturer to avoid fitment issues. The fitment isn't just between the receivers, it's also all of the other components that the receivers house.

 

[JMcQ]

I just put together my new setup that’s pretty close to what your looking at OP
It’s a Mega MML upper with a CLE Bartlien 18in barrel 1-7.7 with CLE chamber rifle gas . SA gas block
CLE headspace bolt. The lower is a old Mega I already had with a TT diamond trigger. I have a new lower I just need to get a build kit and another TT diamond to throw in.
I’ve only put 18rds through it since I assembled the upper last night. I did that today to start a barrel break in.
The Meopta/ Sphur combo came off another rifle and was near zeroed when I swapped.
I didn’t save photos but all groups touched using some federal .223

 

[Rougarou504]

I just put together my new setup that’s pretty close to what your looking at OP
It’s a Mega MML upper with a CLE Bartlien 18in barrel 1-7.7 with CLE chamber rifle gas . SA gas block
CLE headspace bolt. The lower is a old Mega I already had with a TT diamond trigger. I have a new lower I just need to get a build kit and another TT diamond to throw in.
I’ve only put 18rds through it since I assembled the upper last night. I did that today to start a barrel break in.
The Meopta/ Sphur combo came off another rifle and was near zeroed when I swapped.
I didn’t save photos but all groups touched using some federal .223
View attachment 7806182

That's really nice. I just bought a DD V-7 PRO 18" barrel that I'm using to build my first rifle, which apparently is a SPR. I have the rifle and I'm lurking here waiting on a NX8 4-32 in FDE with mil knobs and a mil-xt reticle to come up. I was wondering what stock/cheek piece you were using? I've been looking for one with some kind of intergrated cheek riser that is also collapsible and light and yours looks great, even if it doesn't appear to be collapsible.

 

[bigjake83]

Thanks for everyones feedback so far!

Does a "matching set" from MEGA or SLR etc mean anything besides you are buying both products at the same time? I cant imagine they try and find the two that go together the tightest etc? And if I do want to mismatch upper/lower should I just look for two that fit together tightly, IE: mega upper and ADM lower since I love their ambi controls?

Looks like just about everything has been covered here, but I will recommend the Seekins IRMT-3 V3 or the LaRue Stealth 2.0 Receiver and Handguard over the conventional upper handguard combo that secures to the barrel nut for more of a true free-floating set up.

Also keep in mind in regards to Barrel contour that the heavier the barrel the easier it will be for you to drive because the weight over the front of the bipod will keep the rifle planted and not hop around on you as much as a lightweight barrel will.

 

[TonyTheTiger]

I was wondering what stock/cheek piece you were using?

That's an XLR. Tacmod makes a similar one also.

 

[blbennett1288]

Tagging for future followup

 

[Sogan]

Build is complete. Sometimes I get these groups but not always. I’m sure I am probably the issue but they are rarely over 3/4 moa. Still testing to see if the groups open up after fouling or if I’m just tired at the end of each session. Ammo is 75gr FGMM 2” dots

 

[Obi-WanKannoli]

Regarding a carrier, I'd highly recommend either an RCA or Scionics NP3.