Finish/Wear FAQ

In a nutshell, all firearms finishes– even Armor-Tuff– will show wear over time. Metal-on-metal contact will eventually cause wear to moving parts and ejected brass will leave impact marks on the ejection port area. This is common and expected.  Brass marks can be influenced by shooter, ammunition choice, recoil spring weight and lubrication. Most brass marks can be removed with copper solvent on a patch.  Our finishes are designed to prevent corrosion, add lubrication, and reduce the firearm’s visual signature, but will show wear from metal on metal contact as soon as you use the firearm.

AR Platform FAQ

To break in your new AR use a lot of light oil and hand cycle or fire the weapon several hundred times.  For best reliability it is important that your bolt and carrier rails be run “wet.”

New USGI, Lancer or Magpul magazines are recommended for best function.

Barrel Break In

Your barrel has been polished internally before it left our shop. We recommend that you initially clean the barrel with a patch and light solvent before you shoot for the first time to remove any debris it may have collected during storage. Surgically cleaning your rifle barrel is not advised. For best accuracy remove heavy carbon fouling every few hundred rounds and remove copper fouling only when accuracy starts to degrade.

To remove Carbon buildup use our Carbon remover.


For Copper removal use our Bore Cleaner/Copper remover.


Finish your bore cleaning job with Bore Polish.


After a complete cleaning, you will need to fire a few rounds to foul your bore before you see accuracy back at peak levels.

Designed by Bill Wilson and the Wilson Combat design team as the base for the ultimate precision tactical AR-15 rifle, the BILLet-AR matched upper and lower receiver is 100% machined in our Berryville, Arkansas, facility.

The Wilson Combat BILLet-AR receiver was engineered from the ground up to address structural design weaknesses in standard USGI receivers and enhance overall tolerances. The BILLet-AR upper receiver has a precise bolt raceway for smoother chambering, more rigid receiver walls to reduce firing flex, an oversize magazine well for quick reloads, an integrated trigger guard for gloved use, and added lower receiver strength. Our extensive experience as a premier custom builder of AR-15 rifles will ensure your satisfaction with this next generation precision tactical shooting platform.

  • CNC machined from 7075-T6 aerospace aluminum billet stock
  • Picatinny top rail
  • Shell deflector
  • M4-style extended feedramps for excellent reliability with a wide variety of calibers
  • Undersize bolt raceway for smoother chambering, improved feeding and enhanced recoil dynamics
  • Smooth side profile without forward assist for maximum accuracy potential
  • Oversize, EDM-cut magazine well
  • Precision threaded receiver and reamed pin holes
  • Hand prepped for a flawless surface finish
  • Mil-Spec hard anodized prior to final finishing

We recommend a quality lubricant for the bolt and carrier rails of your rifle.

Best results will be had from domestic, brass-cased ammunition.

We suggest new USGI, Lancer, or Magpul magazines in 5.56X45 caliber.

Read our manual on Operations and Maintenance for some helpful tips.

Wilson Combat® Rifle/Rifle Barrel Accuracy

Wilson Combat® custom AR rifle accuracy is well known throughout the firearms community.  We take great pride in our precision button-rifled barrels and the care we put into the testing, manufacturing and gunsmith assembly of our world class firearms.

We certify our custom AR rifles in supersonic, 5.56/.223/6.8 SPC/.308 calibers to shoot 3-shot, sub 1” groups at 100 yards as verified by our test shooters using match-grade ammunition.  We provide a test target with every complete rifle we build to verify the capability of our guns, and we will not ship a rifle in the above calibers that will not consistently shoot a 3-shot, sub 1” group at that distance.  This is no easy feat for a semi-auto rifle and is a testament to our stringent assembly and parts quality.  When you consider that most rack-grade USGI, chrome-lined AR pattern rifle barrels shoot groups 3-4 times that size in testing, a consistent sub 1” AR carbine is a very accurate rifle indeed.

We also expect our Wilson Combat® Match-Grade barrels as sold separately in the above calibers to shoot 3-shot, 1” or less groups at 100 yards when properly assembled by a gunsmith and targeted by experienced shooters with match-grade ammunition.

Wilson Combat AR Barrel Service Policy
Because of the nature of the AR parts business and varying pressures of commercially available ammunition, Wilson Combat cannot guarantee function in customer built AR rifles. We recommend all components be installed by a competent rifle-smith.

If you assemble a firearm with Wilson Combat components and it fails to function, you first need to check the fit of the barrel to the gas block and the overall condition of your rifle’s gas system/bolt carrier group to ensure your system isn’t leaking gas. As buffers and springs play a role in overall reliability, the use of an aftermarket style buffer system is not recommended. When using an adjustable gas block, reliability is best achieved at the fully open setting without any gas port restriction.

Wilson Combat will not troubleshoot customer built firearms/uppers.

If you feel a Wilson Combat component is defective, please return the component only to us using our Return Form. Shipping to Wilson Combat is the responsibility of the consumer.

We recommend the following ammunition/reloads for accuracy verification:

  • Federal Gold Medal 69 gr. BTHP Match
  • Federal Premium 55 gr. BTHP Match
  • Black Hills 52 gr. BTHP Match
  • Black Hills 68 gr. BTHP Match
  • Wilson Combat Match Ammunition (any weight)


  • 24.5 gr. AA2460, 69 gr. Sierra BTHP Match
  • 24.4 gr. Win 748, 69 gr. Sierra BTHP Match
  • 26 gr. Win 748, 52 gr. Hornady BTHP Match

AR Barrel Installation FAQ

Prior to installing your barrel check compatibility with your rail, gas system and muzzle device.

Our AR barrels are individually headspaced to a master USGI bolt to .002-003” tolerance.  They will work with any quality USGI “Mil-Spec” parkerized bolt without headspacing. Plating or other finishes may add tolerances that decrease headspace.  To check headspace properly you must follow the manufacturers recommendations on gauge use. With a clean chamber remove the ejector and extractor from your bolt. Do not slam headspace gauges in your chamber using spring tension or excessive force. Use only gravity or hand pressure to gauge check your chambers.

All of our rifles are set up to use a standard carbine spring or buffer except for heavy calibers like .458 SOCOM. You can use heavier buffers than standard to reduce cyclic rate in short-barreled and suppressed rifles. Adjustable gas blocks are not recommended in subsonic calibers like 300 Blackout.

7.62 X 40 WT  Information

Designed for tactical/defense applications as well as hunting for medium sized game such as deer and feral hogs. The 7.62×40 WT (Wilson Tactical) has very useful tactical applications with soft point and hollow point bullets providing reliable terminal performance on soft tissue while the Barnes TTSX will easily penetrate tough barriers. For hunting the 7.62×40 WT vastly out performs the 5.56 and is on par with the 6.8SPC at ranges out to 175-200 yards. The VERY mild recoil of the 7.62×40 WT also makes it ideal for female and younger shooters as well as anyone that’s recoil sensitive.

Cartridge Specifics
The 7.62×40 WT is based on the inexpensive and readily available 5.56×45 Nato cartridge case. The 5.56 case is shortened to 1.560” and then re-sized (single operation) in a standard 7.62×40 WT sizing die which results in a formed 7.62×40 WT case with a finished overall case length of 1.565”. The cartridge is designed for 110-150gr .308” diameter bullets loaded to supersonic velocities, but if chambered in a 1-8 twist barrel is also suitable for heavy bullet subsonic use also.

Ballistic Performance Comparison

7.62×40 WT (16” barrel)

110gr: 2534FPS Muzzle Velocity and 1569 Foot Pounds of Energy

125gr: 2463FPS Muzzle Velocity and 1684 Foot Pounds of Energy


5.56 Nato (16” barrel)

55gr: 3150FPS Muzzle Velocity and 1212 Foot Pounds of Energy

62gr: 3000FPS Muzzle Velocity and 1239 Foot Pounds of Energy

77gr: 2750FPS Muzzle Velocity and 1293 Foot Pounds of Energy

7.62×39 (16” barrel)

123gr: 2320FPS Muzzle Velocity and 1470 Foot Pounds of Energy


6.8 SPC (16” barrel)

110gr: 2550FPS Muzzle Velocity and 1594 Foot Pounds of Energy

300 BLACKOUT (16” barrel)

125gr: 2275FPS Muzzle Velocity and 1436 Foot Pounds of Energy


NOTE for Handloaders: Once a 7.62×40 WT case has been fired once it will be fire-formed and provide approx 1gr additional powder capacity and the potential for approx 25-50FPS more velocity at comparable pressure levels.


Trajectory and Remaining Velocity

125gr Nosler Ballistic Hunter, 2375FPS MV, Zero range 175 yards

100yds +1.7” 2156FPS

150yds +1.1” 2052FPS

200yds -1.6” 1951FPS

250yds –6.6” 1854FPS

Based on extensive testing of numerous barrels with 1-10, 1-11 and 1-12 twist rates in which thousands of rounds were fired we have settled on an optimum twist rate of 1-11 to 1-12 depending on rifling type and manufacturer. All of our barrels are premium stainless steel.

Accuracy Potential

We have found the 7.62×40 WT to be consistently accurate with the following bullets, routinely producing groups in the .75”-1.5” range at 100 yards.


110 gr. Barnes TTSX

110 gr. Sierra HP

110 gr. Hornady V-Max

125 gr. Sierra Pro Hunter SBT

125 gr. Speer TNT HP

125 gr. Nosler Ballistic Hunter
The 7.62×40 WT was designed around an optimal overall cartridge length of 2.250” which is a perfect fit in the new Lancer L5 AWM magazine and allows for proper case neck to bullet fit. Therefore the barrel throat was optimized for this overall length and the 7.62×40 WT does not suffer from the same inconsistent accuracy issues in the AR platform often seen with the 300 Whisper and 300 BLACKOUT.

Real World Terminal Performance

A LOT of Texas feral hogs, whitetail deer and predators lost their lives testing the terminal performance of this cartridge! The 7.62×40 WT has proven to be a VERY efficient killer on medium sized game with the 110gr Barnes TTSX, 125gr Nosler Ballistic Hunter and the 125gr Sierra Pro Hunter. Any of these three bullets perform admirably on deer and hogs under 150# or so, but we recommend the 110gr Barnes TTSX for large hogs. The 110gr Sierra HP is a great bullet in the 7.62×40 WT for varmints and predators, and has proven to be one of the most accurate bullets.


Unique Components

The 7.62×40 WT only requires one unique component, the barrel to build. All other standard AR platform 5.56 caliber components are compatible. The 7.62×40 WT will function reliably with standard unmodified Lancer L5 magazines if downloaded to 17 or 24 rounds or Wilson Combat has modified Lancer L5 AWM magazines with 18/19 or 28/29 round capacity available that function ultra reliable.

Wilson Combat would like to express our gratitude to Kurt Buchert for all his early development work on this cartridge.

What twist rate should I get for this bullet type/weight?

1-7: Match or hunting bullets in the 68gr – 80gr range
1-8: Match or hunting bullets in the 50gr – 77gr range (best all around choice)
1-9: Match or hunting bullets in the 45gr – 69gr range 

1-10: Match bullets in the 168gr – 190gr range (best choice for long range match use)
1-11.25: Match or hunting bullets in the 110gr – 168gr range (best all around choice)
1-12: Hunting bullets in the 150gr – 168gr range (optimal accuracy with common hunting ammo/bullets)

1-14: Bullets in the 300gr – 500gr range (best choice for heavy bullet sub-sonic use)
1-22: Bullets in the 250gr – 350gr range (optimal accuracy for bullets in the recommended range)