Posted: 11/23/2007 12:34:03 PM
[Last Edit: 2/14/2013 11:44:46 AM by DPMS]
In the past, we at DPMS have received numerous inquiries into materials, procedures, and features of our rifles. There is much outdated and/or incorrect information floating around AR15.com. This post will hopefully clear things up a little.
Barrels – We make our own, all machining and button rifling. We make them from 3 materials, 416 stainless steel 4140 and 4150 chrome-moly. We make the following calibers;
In our A-15 rifles - 5.56 NATO, .223 Rem, .204 Ruger, 6.8SPC, 300BLK and 7.62x39 (discontinued)
In our LR rifles – 308 win, .260 Rem, .243 Win, 6.5 Creedmoor, .338 Federal, 7.62 NATO and 300 RSAUM (discontinued)
The barrel markings themselves, not the lower receiver, will indicate what chambering is in the barrel. All 5.56, 223, 6.8, 7.62x39, and .204 Ruger threaded barrels use 1/2x28 threads for flash hiders or comps. The LR series rifles use a 5/8x24 thread also the 300BLK.
Our 5.56 NATO 16” or 20” barrels can be chrome-lined (bore and chamber) at the customers request for an additional $32. All AP4 barrels are 4150 chrome-lined standard..
All 7.5”, 11.5” and 14.5” barrels are 4150 chrome-lined. They are available in 1x9 or 1x7 twist.
Our 5.56 NATO barrels are available in 1x7 or 1x9 twist. The barrel markings should indicate whether it is chrome-lined or not.
Our .223 barrels are all 416 stainless, typically found on our bull barrel rifles or DCM rifles. The shorter throat of the .223 chamber, with quality .223 ammunition typically produces better accuracy. They are available in 1x9 or 1x8 twist.
Currently we have only one .204 Ruger barrel, a 24” stainless fluted target barrel. It has a 1x12 twist and it optimized with the light, 32-34gr bullets.
Our 6.8 SPCII barrels are currently available in either a 16” “M4” contour or 20” “HBAR” Both have a 1x11 twist. They are not chrome-lined.
We do not chrome-line any of our LR rifle barrels. All 308, .338 Federal, and 243 rifles have a 1x10 twist. The 260 and 6.5 Creedmoor rifles are 1x7.5.
We correctly stake our gas keys on all rifles, barrel assemblies, and complete carriers as pictured.
We use forged front sight bases.
Our A-15 lower receivers are all forged 7075-T aluminum, anodized to mil-spec and Teflon coated. DPMS has also produced stainless steel lowers and cast lower receivers in the past. DPMS has not produced a cast lower receiver since 2004. A forged lower should begin with the letter “F”. Any receiver with the serial number ending in “K” left the factory as a stripped lower, or lower assembly.
All A1, A2, and A3/A4 upper receivers are forged 7075-T6 aluminum, Lo-pro, Hi-rider, and extended rail receivers are extruded 6066-T6. All upper receivers are anodized per mil-spec and Teflon coated.
We use correct mil-spec height A3/A4 receivers.
Our LR series lower receivers are machined from a solid billet of 6061-T6 aluminum, hard coat anodized per mil-spec and black Teflon coated.
Our LR series uppers are made from extruded 6066-T6 aluminum.
We have 4 different carbine buffers for different applications. Standard, heavy (H), double tungsten (H2), and counterweight.
We offer both mil-spec and commercial carbine buffer tubes at the customer’s request.
Barrels and bolts are lot tested by high pressure and MPI.
We use only mil-spec fire control group pins.
All rifles and complete upper barrel assemblies are test fired and function checked at the factory.