[willyj]

I have a DPMS upper and lower. It is a 20 in bbl (6.8 1:11)
Its a standard A4 set up with a ACE skeleton stock on the back and a flat top upper.

Since I added a KAC rail (M5 Rifle RAS PN 98065) it has become kinda front heavy with the rail set up and the heavy barrel.

What I want to do is have it turned down and shortened to 18in. Like an SPR. How well will this work? Will the gas system work ok? Thats my biggest worry is reliability.

I have looked at new barrels and It will cost as much to swap a barrel as it is to work this one down. I am looking at having http://www.ar15barrels.com do the work.

Please let me know your opinions.

 

[paulosantos]

Don't cut it to 18" as it will not cycle properly. I'd just lighten it up. The lightest I would go is .700" under the handguards and .600" in the front. I don't know if AR15Barrels is still doing that kind of work, but ADCO will also do it.

 

[JesseJames]

Sell the barrel and buy a new one.

It's not worth the $$ or time to do all of that work to a 1-10 twist DPMS barrel.

 

[willyj]

Don't cut it to 18" as it will not cycle properly. I'd just lighten it up. The lightest I would go is .700" under the handguards and .600" in the front. I don't know if AR15Barrels is still doing that kind of work, but ADCO will also do it.

Adco huh...

got this

http://www.adcofirearms.com/shopservices/

back around 4:30ish EST
Steve

 

[paulosantos]

Adco huh...

got this

http://www.adcofirearms.com/shopservices/

back around 4:30ish EST
Steve

I've used them for a ton of stuff and they do great work. Send [email protected] an E-Mail and he can help with any questions.

 

[zoomie]

That is odd on their site - I had them turn down a .223 barrel and was very pleased. Good turn around time, smooth transaction. I wouldn't hesitate to send them more work.

 

[jdgilbert]

Don't cut it to 18" as it will not cycle properly. I'd just lighten it up. The lightest I would go is .700" under the handguards and .600" in the front. I don't know if AR15Barrels is still doing that kind of work, but ADCO will also do it.

This is probably a stupid question, but trying to learn as much as possible:
AR15Barrels' diagrams show 18" SPR designs with both rifle & carbine-length gas ports, isn't that the same as just cutting 2 inches off the 20"? Does that mean that there would likely be operational issues with an 18" with rifle-length gas system? I'm not looking at doing either right now, but if building an 18" I assume an intermediate gas port is ideal.

 

[paulosantos]

This is probably a stupid question, but trying to learn as much as possible:
AR15Barrels' diagrams show 18" SPR designs with both rifle & carbine-length gas ports, isn't that the same as just cutting 2 inches off the 20"? Does that mean that there would likely be operational issues with an 18" with rifle-length gas system? I'm not looking at doing either right now, but if building an 18" I assume an intermediate gas port is ideal.

The SPC uses faster powders so the rifle length or intermediate gas system with an 18" barrel will cause short stroking with a lot of powders.

 

[jdgilbert]

Thanks for clearing that up paulo. I had seen that mentioned but wasn't sure what barrel lengths/gas port lengths it applied to.

 

[nemohunter]

16" needs a mid location
18" is either mid or intermediate with most being mid
20" is either intermediate or rifle.

 

[willyj]

Thanks for all the input!

Now where can I get a 16 or 18 in barrel with the intermediate gas block and still keep my front site base in the standard 20 in location where I can keep using my KAC rails that I already have.

All for 250 or less?

 

[OC455]

The last I looked, CMMG had 6.8SPC stripped barrels listed, that & I believe they are now running 1:11 twist rates too. I would check with Garson, with their tech support to see if they can set you up, or check with H at ARPerformance too.

 

[willyj]

Sell the barrel and buy a new one.

It's not worth the $$ or time to do all of that work to a 1-10 twist DPMS barrel.

Turns out its a 1-11.
Makes it worth it. Ream the chamber and its a good barrel.

After looking it over a little more it has a staked gas key, M4 cuts on the barrel and upper.
The history of this rifle is funny. I traded an Bushmaster M4 that started out as a post ban 20 in bbl. I did some horse trading and turned it into the M-4. Friend of mine was going back to his dept and needed a patrol rifle. He bought my BM M4 for some coin. I went to a local gun shop and bought the DPMS that day. Almost broke even. It was a consignment gun so it was used.

Looked like a standard A2 with a flat top. Plus it had a worked over trigger and came with a set of dies for reloading. I got two C products mags and a no name 10-15 round mag.
All I did was add my ACE stock and put on the KAC rails. I had an M68 (Aimpoint) on there and it was a sweet set up. I dont have the optic anymore so I am looking at a Trijicon TR21. Only thing I dont like is how heavy and off balance the weight of the rifle is.

Ben with Bison Armory were the best to respond so far. They could do an 18 in bbl with a dissipator type set up to run the full length KAC rails I allready have on the rifle.
Did the picture work? I can see it on there at work but not at home.

 

[willyj]

double posted.

 

[Test_User]

The DPMS barrels if you fix the few things tend to be accurate shooters.