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18" MK12 vs 20" Service Rifle/SDM

C

Chrazy-Chris

Private
Minuteman
Mar 17, 2018
56
25
I'm looking to upgrade the barrel on my AR. This rifle currently has an 18" MK12 barrel and is mostly just a project gun that I've been slowly upgrading into a premium component rifle. I use it for steel out as far as I can go (usually 700yrds on the 1000yrd range), and an occasional coyote hunt. I'd like to shoot a local small frame AR-specific PRS style match with it and have a dream of someday using it as the carbine guy for the Team Safari match. Right now I'm using my Hornady 75BTHP reloads and they shoot MOA through it but I'm ready to upgrade from this tired old DPMS barrel to a top of the line WOA or CLE. I'd like to stick with a .750 gas block but could be talked out of it (that was my latest part upgrade- a .750 adjustable block).

What are your thoughts on going with a 20" service rifle profile for a build like this? Is that length/profile noticeably heavier than the MK12 profile? The SDM looks like another option with some fluting.

1114191911 by Chrazy-Chris, on Flickr
 
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57741DDC-5271-4099-9C00-14E54403C271.jpeg


a fluted SDM is an option but as far as I’m concerned the 18” MK12 is AR perfection.
Woa
Cle
Rainier UM
Keystone accuracy.
Are where I’d look.
 
Rainier Arms or Faxon.
both have match grade barrels that shoot lights out
 
Kickin45 said:
Rainier Arms or Faxon.
both have match grade barrels that shoot lights out
Click to expand...

WOA makes a fantastic barrel. I have the 18" SPR profile and it shoots crazy good groups. My 40 yr old eyes and massive caffeine intake have hurt my group sizes but the barrel itself will shoot 1/2 MOA if the shooter is capable.
 
If taking it to a grand I’d run the 20” tube to get the most velocity you possibly can. As others mentioned, WOA, CLE or Centurian Arms make great barrels. My 6.8 SpC WOA stainless holds 1 - 1.25 MOA at 500 (3/4 at 100) and I’m an average shooter.
 
I’ve got CLE Bartlein 18”SPR and 20”Service rifle barrels, both with CLE Match chambers.
BH 5.56 77gr, and IMI Razorcore 77gr both loads, 2850 fps suppressed out of the 18”, and 2900 fps suppressed out of the 20”. All easy sub MOA.
 
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Laseredge said:
I’ve got CLE Bartlein 18”SPR and 20”Service rifle barrels, both with CLE Match chambers.
BH 5.56 77gr, and IMI Razorcore 77gr both loads, 2850 fps suppressed out of the 18”, and 2900 fps suppressed out of the 20”. All easy sub MOA.
Click to expand...

Your experience is exactly what I'm after.

In terms of weight and maneuverability, how does the 20" feel compared to the 18"?

I was having a hard time deciding between the two chambers. I assumed the CLE chamber was more suitable for folks single loading 80s, but you chose it for 77s. This rifle will see 75-77gr exclusively. Is the CLE a clear winner over the wylde?

Edit: I looked up the specs again and now see where I had the chamber types mixed up and I've answered my own question on chambers: CLE's shorter throat would be better for my intended use. Sorry bout that.
 
The CLE 20” Service Match barrel is 1” diameter to the gas block, so it is a lot heavier than the 18” SPR.
If you are going to have to carry it, the 50fps may not be worth it, or you could have CLE do a custom lighter contour.
I have had the 18” out to 850yds, and it works well with hot 77gr ammo, but with 8-10 mph gusts it is a lot harder to hit 1.5 to 2 MOA at that distance. I’ve never hit 1K yds with 5.56, but of course it can be done.
 
Laseredge said:
The CLE 20” Service Match barrel is 1” diameter to the gas block, so it is a lot heavier than the 18” SPR.
If you are going to have to carry it, the 50fps may not be worth it, or you could have CLE do a custom lighter contour.
I have had the 18” out to 850yds, and it works well with hot 77gr ammo, but with 8-10 mph gusts it is a lot harder to hit 1.5 to 2 MOA at that distance. I’ve never hit 1K yds with 5.56, but of course it can be done.
Click to expand...
I’ve shot my SPR build to 1000 a couple of times on very calm days.
Wind will hammer you.
That 50 fps won’t make 223 a consistent 1000 contender or even noticeably better at 700 yard so I feel it’s better to have the great balance and handling of the 18”
 
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Chrazy-Chris said:
I'm looking to upgrade the barrel on my AR. This rifle currently has an 18" MK12 barrel and is mostly just a project gun that I've been slowly upgrading into a premium component rifle. I use it for steel out as far as I can go (usually 700yrds on the 1000yrd range), and an occasional coyote hunt. I'd like to shoot a local small frame AR-specific PRS style match with it and have a dream of someday using it as the carbine guy for the Team Safari match. Right now I'm using my Hornady 75BTHP reloads and they shoot MOA through it but I'm ready to upgrade from this tired old DPMS barrel to a top of the line WOA or CLE. I'd like to stick with a .750 gas block but could be talked out of it (that was my latest part upgrade- a .750 adjustable block).

What are your thoughts on going with a 20" service rifle profile for a build like this? Is that length/profile noticeably heavier than the MK12 profile? The SDM looks like another option with some fluting.

1114191911 by Chrazy-Chris, on Flickr
Click to expand...


Looks like someone went to Seekins. What are you shooting out of yours? I shoot IMI Razorcor but I have seen that the rifle like speeds in the 2,660 range. The IMI shoots at 2,760.
 
shax2lex said:
Looks like someone went to Seekins. What are you shooting out of yours? I shoot IMI Razorcor but I have seen that the rifle like speeds in the 2,660 range. The IMI shoots at 2,760.
Click to expand...

Yeah I won a few certs at some matches and have always appreciated their customer service and warranty. This build started out with PSA parts and the DPMS MK12 barrel about 7 years ago. I've slowly been upgrading it piece by piece with the goal of eventually having a 100% premium AR. It has a Geissele NM trigger, JP SCS buffer, Young NM BCG. The handguard, stock, and a seekins select adjustable gas block were my latest upgrades. I have the seekins billet upper that turns this handguard into a more monolithic setup sitting in a box waiting for the new barrel. I'm currently using a SiCo Specwar762 can on it (super heavy) but have a Tbac on order. Final parts on the list will be the matching seekins lower, the MDT Ckyepod, and maybe a JP carrier (still researching whether the low mass would make sense for long range use). I have my progressive setup to pump out some dialed-in 75gr loads (volume charge) so it's nice to have a rifle I can shoot mag after mag through without thinking of how much time I'll need to spend at the reloading bench to catch back up. Not to mention those 75s are pretty cheap.

Edit- to answer your question I'm shooting 75gr Hornady BTHPs over 23.1gr 8208XBR using SSA brass and CCI400s. They're only 2620fps but since these are off a progressive and I'm not individually weighing the charges I keep them mild for safety purposes. And that is where I saw the tightest groups with this combo.
 
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Steel head said:
but as far as I’m concerned the 18” MK12 is AR perfection.
Click to expand...

Agreed.

Right now WOA is offering $85 off their SPR barrels; that makes their fluted 18" SPR barrel $250 & that's a great price if you want a WOA barrel.

They are backordered, but they replenish constantly, so probably only 3 weeks or so to get one & they are very nice people to deal with.

It's not a Bartlien, but it's very good, also a Rock Creek or a Bartlein from Craddock is hard to beat as is CLE, as already mentioned above.

MM
 
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I ended up buying a Seekins cert and buying the rifle out right. I thought about building it but the finished rifle had almost everything I wanted. Cert definitely helped. I think the things I want to upgrade as needed are the BCG and spring. I want a JP silent capture spring and BCG. Eventually the barrel.

If you are looking at another lower, check out the American Defense. I say that because they have a truly ambidextrous lower. You can release the mag, lock the bolt back, and release it on both sides. Seekins AR-10 does that and I like that.
 
I have a 20" Rainier UM that is a great shooter. I shoot IMI 77gr Razorcore most of the time. Since you are asking opinions, I would not go below 20 and give up any velocity if you are going to compete with it. If it was just for fun then yeah maybe 18.
 
Just a heads up, White Oak is doing $80 off SPR barrels for black friday. The sale starts tomorrow and put them at $195 + $10 shipping. The 18" rifle gas is currently out of stock but the lady I spoke to said they were allowing backorders on the sale price and the lead time for that barrel was 4-6 weeks. Almost did it but I ended up ordering a Proof for $390 instead because cut rifled is better.

As to 18" vs 20", they're both a good compromise for weight/manuverabiity and performance. IMO 18" is better with rifle gas and for 20" I really prefer +1 gas.

If it's a range/match rifle and you're serious about comps I'd go longer. Like 22" with a rifle +2 gas. And I'd also spring for something hella good like a Craddock cut rifled Bartlein or Rock Creek. I'd also dump that mil spec receiver for something thick walled.
 
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Chrazy-Chris said:
Yeah I won a few certs at some matches and have always appreciated their customer service and warranty. This build started out with PSA parts and the DPMS MK12 barrel about 7 years ago. I've slowly been upgrading it piece by piece with the goal of eventually having a 100% premium AR. It has a Geissele NM trigger, JP SCS buffer, Young NM BCG. The handguard, stock, and a seekins select adjustable gas block were my latest upgrades. I have the seekins billet upper that turns this handguard into a more monolithic setup sitting in a box waiting for the new barrel. I'm currently using a SiCo Specwar762 can on it (super heavy) but have a Tbac on order. Final parts on the list will be the matching seekins lower, the MDT Ckyepod, and maybe a JP carrier (still researching whether the low mass would make sense for long range use). I have my progressive setup to pump out some dialed-in 75gr loads (volume charge) so it's nice to have a rifle I can shoot mag after mag through without thinking of how much time I'll need to spend at the reloading bench to catch back up. Not to mention those 75s are pretty cheap.

Edit- to answer your question I'm shooting 75gr Hornady BTHPs over 23.1gr 8208XBR using SSA brass and CCI400s. They're only 2620fps but since these are off a progressive and I'm not individually weighing the charges I keep them mild for safety purposes. And that is where I saw the tightest groups with this combo.
Click to expand...
How did the dpms barrel shoot?
 
So I ended up going with the WOA SPR non fluted black Friday special...

And a 22" .875 Rock Creek .224 Valk from Craddock. I have a problem.
 
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Chrazy-Chris said:
So I ended up going with the WOA SPR non fluted black Friday special...

And a 22" .875 Rock Creek .224 Valk from Craddock. I have a problem.
Click to expand...

I ended up buying a Geissele SSA-E trigger, MK14 Rail, SuperCharging Handle, Reaction Rod, 5 Axis Trigger Guard, Super 42 Buffer Spring, 2 Maritime Bolt Catches (Why call them Maritime LOL), a Superlative Arms Gas Block, 2 AXTS Talon Safeties. The Geissele sale was just too good to pass up. Bought a lot more from them than I planned. Course other companies like V-Seven and BCM missed out on getting my money because they either didn't want to run a sale or their sale sucked big time considering the time of year it is.

I think I have the same problem. Good thing I'm no longer married. :sneaky:
 
Chrazy-Chris said:
So I ended up going with the WOA SPR non fluted black Friday special...

And a 22" .875 Rock Creek .224 Valk from Craddock. I have a problem.
Click to expand...

I’d say you did well. I had that exact same 224V barrel from Craddock in the 6.7T flavor and it was wicked accurate, like benchrest bolt gun accurate. It loved 95gr SMK’s with Varget.
 
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