Iron Ridge IRA‐X THOR AR 10
Finding the Limits for this Fine Precision Rifle
When my close friend Andrew Carroll told me, due to work requirements, he needed someone to replace him for a long range rifle course, I assumed this would be one of those walk‐in‐the‐park, cookie cutter, baby‐sitting civilian rifle classes. I was in for one of the best surprises of my life.
What I didn’t know was that Andy had signed up for the Precision Rifle Works (www.Precisionrifleworkshop.com) three day Extreme Long Range Rifle (Sniper) Course at the ANG base in Guernsey WY. He told me we would be shooting out to 1000 yards with .308. I told him he was nuts as I had only shot .308 to 400 meters in my Military days with iron sights and with an FN FAL (C1), wood stock and steel butt plate. Not a pleasant experience for my shoulder back then.
Andy had arranged for the rental (also supplied by PRW) of a bolt action M24/Remington 700 platform with 10.5 twist and 20 inch barrel. Optic was a Nightforce 5.5-22 X 56. We were also required to purchase 1200 rounds of ammunition. Specifically suggested was the Federal .308 Sierra Matchking BTHP, product code GM308M2. Prior to this course I had always been a CorBon precision ammunition customer, but more on that later.
With the course coming in two weeks, I put the screws to Oliver at Iron Ridge Arms (www.ironridgeguns.com). I had ordered a custom IRA-X AR-10 THOR platform over a year ago and was still waiting delivery. (See Special Weapons April, 2012 review on the AR‐10 Sniper IRA - X THOR) Due to the backorder for some of the precision parts (e.g. barrel) and backlog of orders, I was a little down the food chain when it came to delivery.
When Oliver heard the course details he was kind enough to put in the overtime to complete the THOR so I could take to the course and shoot both bolt and semi‐auto platforms side by side. Oliver's IRA‐X THOR is known for long range precision and accuracy in a semi‐auto format, previously held for bolt action rifles. I would be the first of Oliver's customers to shoot out this far, so a great data gathering opportunity.
On the drive to Guernsey, I stopped in at Iron Ridge to pick up the THOR. Oliver had not had the chance to sight in the optics (Nightforce 10-2 X 56) (I went with the 10 - 32 so I could spot my own shots and be a spotter for others on the team) or even work the action beyond a few shots into the test can. This was going to be a true test to work in the rifle and the SRT Shadow XL Titanium can (Suppressor) punching out 800 rounds over the next three days 
Day One
The AM consisted of meeting the exceptional and highly experienced instructor team from PRW (Neal Ash, George Delena and Aaron Riccio) and going thru the math class all morning….ugh (Optics selection, Dope charts, Density Altitude, ammo selection and so much more). With three instructors and five participants this was going to be a great course with lots of exceptional instruction.
For the afternoon it was off to the range to chrono the ammo and sight in the rifles at 100 yards. Typical Wyoming, it was hot and windy as hell but we got things set up at 100 yards then moved back 100 yards at a time to 500 yards. Unfortunately the ANG base shuts down the range at 5:00 PM so just when the fun started it was time to go home.
We chronoed the ammo for the two firearms platforms and two ammunition manufactures. To keep the data profile short I have only supplied the Average Speed (AS) and Standard Deviation (SD).
NOTE: Yes, we chronoed the ammo twice and the Federal was far superior. CorBon has been contacted with the data and we are awaiting a response. (CorBon did indicate they had an issue with a powder supplier so lot numbers are being explored but there internal test data does not match any of our numbers in the field)
Day Two
Once again, this was going to be typical Wyoming. Off to the range in 10 - 35 MPH gusts and solid rain. Laying out the ground sheet and watching a puddle form reminded me of my SCUBA days. It will only be cold till I warm the growing puddle of water I would become good friends with for the rest of the day.
Gloved fingers quickly become numb with wind, rain and hail. I had to pull off the THOR and switch to the M24. The Nightforce optic needed adjustment for a better eye relief and fine adjustments were not possible with the current weather. Unfortunately the THOR would need to rest till we got back to the barracks for adjustment.
For the remainder of the day I punched out 400+ rounds on the M24... 200, 300, 500, 750, 1150 yards! Elevation without a spotter was a breeze with the Nightforce scope. The skill of the instructors came as they made the wind calls through the winding valley. Watching as the vapor trail moved left and right through the valley until the round hit the target at 1150 yards was an incredible experience!
As the day was ending, one of the Law Enforcement snipers from Wyoming provided the team with the opportunity to shoot his Sako .338 Lapua. As I confirmed the sight picture, focused my breathing and slowly pressed the trigger, I saw the impact on the 6 X 6 steel targets... 1950 yards! Over a mile! I chambered two more rounds and both also hit the target. Even with a superb muzzle break my shoulder was done from the 400+ prior rounds on the bolt action M24 and I passed on further attempts.
Back to the barracks and after sufficient hydration to feel my fingers again, I was able to complete the fine adjustments required to reposition the Nightforce scope. Day three was coming and I would have little time to mess around to complete the rest of the course with the THOR.
Day Three
The weather was the same as day two, windy rainy and cold. I was not looking forward to spending more intimate time with my cold puddle. Due to the weather conditions three previous attendees decided to call it quits, leaving three of us with three instructors. Today was going to be even better with one on one instruction, so I readied myself for a long wet day.
When we got to the third range I was in for a pleasant surprise. This time we would be spending the day behind a concrete machine gun bunker engaging targets from 100 yards to well over several miles. Obviously “miles” was beyond the limit of the .308 caliber we were all shooting but what a range. The targets were ½ man size “green zombies” on solar panel powered resets. Once shot they fall, and then pop up again.
I quickly sighted in the THOR at 100 yards, dead on. Mounted the suppressor and shot again. The second shot followed the first, both dead on target. I had prepared my shoulder for the recoil and was again very pleasantly surprised from the prior day of the .338 and bolt M24. Now it was going to be a great day.
As we all worked our scopes, determining distance and wind adjustments, the instructors must have been impressed...time for the final day shoot off.
Each of us was to call a target, hit the target and the next shooter had to hit the same target. If they hit they called the next shot. If they missed, that counted as one point against the shooter, five points and you were out. I was the last in line of four shooters, two with the M24, the .338 Lapua, and then my suppressed THOR. The THOR was so quiet the sound signature was similar to shooting airsoft. Calling ranges, following the prior shooter, adjusting the scopes was great, but keeping up with the .338 beside me calling 1000, 1150, 1200 yards was an awesome challenge the THOR was up to.
After several hours and several hundred rounds later, we had to call it quits as it was taking too long to break the tie. So, the instructors set up an exploding zombie head at 550 yards. First to hit would be the winner. We all had no issues with elevation but the increasing velocity of wind gusts (20 - 35 MPH) through the valley were making that small target tough. My friend with the .338 Lapua nailed the zombie in the cheek and the Zombie head disappeared in a red mess. Time to police brass, debrief and hit the road.
I can’t praise the course and instructors more highly than by saying I am coming back to take more of their courses!
The THOR function was flawless both dry and wet (lubed up) with not a single malfunction or jam after over 600 rounds, and that was straight from the factory. With the suppressor, you could see the back pressure did blacken the brass significantly, but with and without the suppressor and the heavy AR 10 buffer the THOR was very pleasant to shoot. In fact, recoil on the .308 was almost non‐existent.
The biggest issue I had was with ammunition. Shooting long range with the semi auto THOR versus bolt, you can go through hundreds of round very quickly so bring lots of ammo!
This article was written by Peter Haug of Spartacus Combatives and Spartacus Combatives Firearms Academy