May 24 2013
We have a very limited quantity of Mega forged AR-15 upper receivers in stock. These are stripped receivers, which do not include the port door or forward assist. The receivers do have M4 feed ramp cuts. Get them while they last in our web store, just follow this link.
May 21 2013
It seems that when we update the release date for new Bison Armory lower receiver orders a message is sent to existing customers indicating a changed release date. We apologize for the confusion as this information is inaccurate.
The updated release date only applies to orders placed after the update to the release date. We are still on track to meet the release date posted when you placed your order.
May 13 2013
We’re finally getting new 6.8 and .223 bolts from Stag that will be sufficient to cover all back orders and a certain number of new orders. Bolts and carriers are the primary hold up at the moment. We’re still working on carrier supply but it is coming back slowly.
Standard .223 and 6.8 bolts are back in stock.
Match carriers are in stock now, but black and chrome are out of stock with no ETA yet.
May 10 2013
Our new line of shirts is here just in time for summer – available in sizes Large, Extra Large, and Extra-Extra Large! These are olive green “Hanes Beefy Tee” cotton shirts, with the Bison Armory logo in white on the front, and a 4 color graphic on the back – with the bullets done in proper bullet colors! Here’s a link to the product page: http://bisonarmory.com/bison-armored-shirt/
Perfect for Cougar watch in the driveway… seriously, we had a cougar in the driveway a few months ago!
Back graphic detail
Front graphic detail
Apr 26 2013
We just got our lower receivers back from CNC!
Big box of receivers.
We then drill and tap for the tension screw that ensures a nice tight fit between upper and lower receiver.
Tapping for tension screw
Notice that we simply hand tap in a lower receiver vice block. Typically, precision tapping is done in a machine fixture using a tail stock in a lathe or the milling head for exact alignment, but the tension screw has no need for this sort of precision, so we just tap by hand to get the job done.
Tension screw in place
After this process the lower receivers are sent for anodizing which is the last step in the manufacturing process. Once we get them back form anodizing they are inspected, hit with light mist of gun oil, and then shipped to customers or used in builds. This batch of receivers should be sufficient to fill orders placed through March 2013. I expect anodizing to add another 3 to 4 weeks, including return shipping, and then we’ll start shipping to customers.
For orders placed in April 2013 or later we expect our next batch to come back from CNC in June 2013.
Almost there!
Apr 18 2013
We have new items in stock now, ready to ship:
Stripped Mega Forged AR-15 upper receivers with M4 feed ramp cuts
Mega Billet GTR-3H non-ambi lower receivers
First come first serve, get them while they last!
Apr 14 2013
Bison Armory is now selling our great shooting .223 Wylde barrels on our web store here. These barrels are made from 416 stainless steel, button rifled with 1:7 twist 6-groove rifling, and have .223 Wylde chambers, which means they handle .223 Remington and 5.56 NATO ammo equally well.
Our current offering is a 16″ Recon profile barrel that is capable of MOA performance. Starting at $160, these barrels can’t be beat on price for performance. These barrels are in stock now and ready to ship.
Apr 10 2013
Anyone who’s ever put built an AR-15 upper assembly knows the pain of installing a barrel only to find out their barrel nut will not time properly within correct torque specifications. In a big shop the solution is simple, just keep trying different barrel nuts till you find one that times properly within torque specs. Not so easy when you have one barrel, one upper receiver, and one barrel nut.
The real-world solution to this problem is to use one or more shims to correctly time the barrel nut while getting the torque just right. To this end, Bison Armory is now offering barrel nut shim sets for $10 including shipping. The set includes instructions and 3 shims, which are all that is needed to get it right the first time. Shim sets can be purchased through our we store here.
AR-15 shim sets are available now, AR-10 / LR-308 shim sets are coming soon.
Apr 10 2013
The latest grudge match in the tactical and sporting rifle world is heating up between two relatively new calibers: 6.8 SPC and the .300 AAC Blackout (“BLK”). We here at Bison Armory evaluated the BLK to see how it stacks up against the 6.8 SPC cartridge. We considered (1) what the BLK offers to the tactical rifle market and (2) whether it does anything better than the 6.8 SPC. Based on these criteria, we came to the conclusion that the BLK underperforms the 6.8 SPC where it really counts. And here’s why:
1. Parts Compatibility with .223 AR-15
Winner: 300 BLK
The 6.8 SPC and BLK both share good parts compatibility with .223 Rem / 5.56 NATO AR-15 rifles. Conversion to 6.8 SPC only requires the install of a caliber specific barrel, bolt, and magazine. BLK conversion, on the other hand, simply requires the install of a caliber specific barrel. Not only does this save a few bucks, but it means BLK rifles are PMag compatible. So the BLK takes this round.
2. Subsonic Rifle Operation
Winner: 6.8 SPC
Unlike the BLK, 6.8 SPC subsonic ammunition does not require both the use of a pistol length gas system and a silencer for your rifle to operate reliably with a 16″ barrel. With a 16″ barrel, 6.8 SPC subsonic ammunition loaded with 200 grain bullets will cycle and lockback the action with a carbine length gas system without a silencer. In high stress situations you want your rig to run whether or not you have a silencer attached. If something happens to your can, or for some other reason you cannot run suppressed, do you really want to be hand cycling your rifle in the heat of the moment? This is clearly an important win for the 6.8 SPC subsonic.
3. Subsonic Ammo Performance
Winner: 300 BLK
The 220 grain and 240 grain 300 BLK subsonics have 10% to 20% more muzzle energy, respectively, than the 200 grain 6.8 SPC subsonic at the muzzle. This is not a huge difference, but the BLK has the advantage.
4. Supersonic Ammo Performance
Winner: 6.8 SPC
Performance in this category is measured in terms of bullet velocity, energy, and drop as functions of range. We will compare the Sierra 115 grain Match King .277 for the 6.8 SPC with the Sierra 125 grain Match King .308 for the 300 BLK for an apples to apples comparison. Bullets are available for both rounds with higher BC’s and so forth, but to keep things simple we’ll work with the Sierra MK bullets. Ballistic coefficients are available directly from Sierra here. These are G1 ballistic coefficients and we’ll stick with that for sake of simplicity.
To start, the 115 SMK .277 has a ballistic coefficient of 0.317 for velocities between 1800 and 2400 fps, and the muzzle velocity of the round is assumed to be a relatively tame 2500 fps. The 6.8 SPC can be driven harder than this but, to be conservative, we’ll stick with 2500 fps out of a 16″ barrel.
The 125 SMK .308 has a ballistic coefficient of 0.338 between 2000 and 2650 fps and 0.330 below 2000 fps. For this comparison the higher BC will be used to give the BLK as much advantage as possible. The muzzle velocity from a 16″ barrel of 2215 fps direct from AAC will be used as well for this comparison.
The following chart shows the muzzle velocity from 0 to 500 yards using the Hornady Ballistics Calculator. 
Muzzle velocity by itself doesn’t say much about the performance of a cartridge, except that higher muzzle velocities tend to equate with flatter shooting. So next we will look at bullet drop vs range:
Both rounds are set to 100 yard zeros for comparison. There is not much difference between the trajectory of the two rounds until about 200 yards, at which point the difference in drop is only 2 inches. At 300 yards the difference is 6 inches, and at 400 yards the difference opens up to almost 13 inches. At 500 yards the difference is approximately 2 feet. The 6.8 SPC and 300 BLK are very similar to 300 yards, but past that the 6.8 is clearly superior in terms of bullet trajectory.
Bullet energy is the best performance comparison of the three metrics considered here. The 6.8 SPC starts at the muzzle with 8.5% more energy than the 300 BLK. This advantage is maintained downrange to 300 yards, and the 6.8 SPC still has 3% more energy than the 300 BLK at 500 yards. Combined with the flatter shooting of the previous figure, which round are you going to want for 3-gun, hunting, or combat/tactical use?
The 6.8 SPC is the clear winner in this category. Who says you can trust my analysis? Apparently AAC does as they quoted my work on page 27 of this document.
5. Ammo Cost and Availability
Winner: Tie
Cost is more or less the same, and there are more varieties of 6.8 SPC available than 300 BLK on Midway USA. However, there is no commercially loaded 6.8 200 grain subsonic yet available, but there will be in the near future. So I call it a tie.
Overall Winner: The 6.8 SPC takes it.
While the 6.8 SPC and 300 BLK each win two of five categories with one category resulting in a tie, the 6.8 SPC won the title for best supersonic ammo performance. Supersonic ammo performance is, in my opinion, a more important category than the others, and where the 300 BLK had victories, the margins were narrow. Therefore the 6.8 SPC wins the grudge match in my opinion. Does this mean that the 300 BLK is a bad round, or that it isn’t an effective round for hunting, competition, or defense? Of course not. Both the 6.8 SPC and the 300 BLK outclass the 5.56 NATO in most categories, and both will serve their users well. Our goal is simply to cut through the hype.
Apr 3 2013
We are very pleased to introduce our line of Bison Armory low profile gas blocks for use with any AR platform rifle barrel 0.75” in diameter. These blocks were designed and manufactured to our exact specifications by Black River Tactical. All our gas blocks are finished in hard wearing black phosphate with our logo laser engraved on the left side.
Each gas block costs $55 and is available HERE in our store.
Unlike all other gas blocks on the market, these are available in two sizes specifically designed to accommodate the variation in the outside diameter of coated and uncoated rifle barrels. The ‘Small’ block is for use on barrels with a gas block journal diameter of 0.749”. The ‘Big’ block is for use on barrels with a gas block journal diameter of 0.750”.
The slightly larger diameter opening in the Big block means that it can be installed without marring the finish on a Bison Armory coated barrel and without having to hand fit the block first.
Another advantage of these blocks is that they come with a small flat pre-machined into the right side to assist with the pinning process. Anyone who has ever tried to drill a hole at a precise angle through a curved surface will appreciate the time and effort this tiny feature saves.
Rugged and reliable, we guarantee that you will be happy with the fit, finish and performance of Bison Armory gas blocks.
Left Side
Right Side