Sunday GunDay: 6mm Rem AI Runs 3675 FPS in LR Varmint Rifle

Spring varmint season is well underway, and we just showcased six groundhog hunting videos. So here’s a very accurate Half-Mile ‘Hog rifle, that can drill a groundhog at long range. While just about any cartridge from a 22 Magnum on up will do the job on a groundhog at close range, when you want to “reach out and touch” your prey at very long distance, it takes a case capable of tossing a heavier, wind-bucking projectile at ultra-high speeds. This week we feature a 6mm Remington Ackley Improved (6mm AI) belonging to our friend John Seibel, who ran the Varmints for Fun website for many years.

John’s handsome BAT-actioned rifle sends the 87gr V-Max at a blistering 3675 fps. With its 1/4-MOA accuracy and flat-shooting ballistics, this gun is a varmint’s worst nightmare, a rig that regularly nails groundhogs at a half-mile (880 yards) and beyond.

Quarter-MOA Accuracy For Long-Distance Varminting

GunDay Report by John Seibel
John reports: “So far this gun has been an awesome long-distance varmint rig, with enough velocity to smack those critters hard at 800 yards and beyond. I have some more testing to do, but it seems that the 87gr V-Max (molyed) pushed by 52 grains of N160 or 51.5 grains of RL-19 shoots very well indeed. Velocity runs around 3675 fps. I shot consistent 1″ groups at 500 yards with both of these loads. Warning: These are max loads that work in my rifle, so start at least 10% lower and work up.

My fire-forming procedure is just jam and shoot. I start with a powder (such as H414) that works for the parent case, fire a few cases as I work up the load to where I get a well-formed case, then shoot them at varmints. Then I work my load up with the newly-formed cases over a chrono. If a load looks good at 100 yards, I will go straight for 200 yards. I’ve seen that some loads which grouped well at 100 won’t shoot well at 200. If it is consistent at 200, then I’ll shoot it a steel plate at 500 yards. Then the truth will be told.

Man I love that BAT action! I have tried some Berger 88gr Lo-Drag bullets as well. They have the same BC as the V-Maxs but offer excellent accuracy. The action is BAT’s Model B round action configured Right Bolt, Left Port, with a fluted .308-faced bolt. The port is 3.0 inches wide — perfect for the 6mm Rem Improved cartridge’s OAL. I use a NightForce 8-32x56mm NXS scope mounted to BAT’s 20-MOA aluminum Weaver-style base. I use Burris Signature Zee rings because they are self-aligning and easy on scope tubes, plus you have the option of adding more MOA if needed.

Krieger with Harrell Brake The barrel is a stainless Krieger 1:12″ twist Heavy Varmint contour, finished at 26″. I installed a Harrell’s muzzle brake because I hate recoil and I like to be able to spot my hits when target shooting and hunting–especially hunting. When hunting I am usually by myself so when I eyeball a varmint I want to see my shot flatten him … and I hardly ever miss (heh-heh). Make sure you have your earplugs in though — that muzzle brake is loud!

Easy-Steering Thumbhole Varminter
The stock is Richard’s Custom Rifles Model 005 Thumbhole Varminter. This is a big stock that rides the sand bags very well. Took me a while to get used to this stock as I had never shot a thumbhole before. It is very comfortable and easy to control when you are shooting a moving target. In fact, my first kill with this rifle was a coyote at a little over 200 yards, she was moving along at a slow clip and I had to give her the ole’ Texas heart shot before she disappeared over a hill! (It’s pretty rare for me to shoot moving varmints though — at long-range, I want my cross-hairs steady on the target.)

Regarding the stock selection, I like Richard Franklin’s stocks [now out of production] because they are well-suited to my kind of shooting. I prefer a stock that is flat most of the way back towards the action because when I’m shooting out of my truck window it has to balance around mid-point. Also his stocks seem to track very well on the bench. I guess the stocks I like the most are his Model 001 and Model 008 F-Class. [Editor’s note: John often shoots from the driver’s seat of his truck because he is partially paralyzed. He also has a hoist in his truck bed for his wheelchair. Even with his mobility challenges, John tags more varmints in a season than most of us ever will.]

Choice of Caliber — A 6mm with More Punch for Long Distance
I picked the 6mm Rem Improved mainly because it has that long neck for holding long bullets and it doesn’t burn the throats out as fast as a .243 AI would. I don’t use Remington brass; it splits when fire-forming and seems to work-harden fast. Another reason I picked the 6mm Improved was what I saw in the field–it seemed to be a perfect long-range groundhog getter. I saw my stocker, Richard Franklin, flat smack groundhogs out to 900+ yards with regularity. The OAL of a 6mm Improved does make it hard to remove a loaded round from a standard Remington 700 action. That’s why I went with the BAT Model B, with its longer 3.0″ port. For a standard action, a .243 AI might function better.

As for the 6 Dasher, from what I have read, I think it is a fine round. I’m a hunter though and a lot of case-forming isn’t worth it to me. Forming the Ackleyized cases is bad enough. The 6-250 is a real screamer and very accurate but it doesn’t have the capacity to drive the heavier bullets as well as the 6mm Improved. I have tried a .243 WSSM, also with a Richard’s stock (#008) and a BAT action. It may not shoot as well as the 6mm Rem Improved, but I like those short fat cases.

John’s Views on the Great Moly Debate
Editor: John started with moly-coated bullets for this 6mm Rem AI rifle, but he has moved away from that. He does have considerable experience with coated bullets, and now, at least with custom, hand-lapped barrels, he normally uses uncoated bullets. He now favors coated bullets only for the small .17 caliber.

Moly or no moly… hmm? I have used moly and Danzac for several years, mainly Danzac. In my experience, both moly and Danzac can work well for somebody who shoots a lot of rounds before cleaning. A barrel has to be broken-in correctly whether you use moly or not. I have done break-in with naked bullets, using the conventional method of shooting and cleaning till the copper stops sticking. I have also gone through the break-in process using molyed bullets from the start. It seems to me the barrels broke-in more readily with moly bullets than with naked bullets. I think if there are any rough or sharp places in the barrel the slick molyed bullet doesn’t grab it as badly and the moly will “iron” the flaw out without leaving copper behind.

The main mistake I think most people make with moly is improper cleaning. By that I mean they don’t get the bore clean from the beginning. Some people will scoff at me for this but I use JB bore paste for most all my cleaning, hardly ever use a brush. Just JB and Montana Extreme or Butch’s Bore Shine. It works for me! Now shooting molyed bullets works fine to say 500 yards, but any further and you really need a lot of tension on the bullet. If not you will get bad flyers.

Personally, I use coated bullets only with .17 cal rounds now. I did use them initially in my 6mm Rem AI but I am starting to move away from that. With proper break-in, the fine custom barrels we have now will not copper if you clean correctly and don’t push those bullets too fast! And remember that powder-fouling build-up is an accuracy-killer too. That is another reason I use a lot of JB paste.

John lives and works on a farm in Virginia. Getting rid of intrusive varmints is part of the job of running the farm. Here is one of John’s bolt-action pistols, which is very handy when shooting from a vehicle.

The Guru of Varmints For Fun
For many years John Seibel ran the popular Varmints For Fun website (now offline). This site offered excellent advice for hunters and reloaders. John covered a wide variety of varmint chamberings, from big 6mm wildcats, to the popular 6BR, 22BR and .22-250 caliber varmint rounds, and even the micro-caliber wildcats such as the 20 Vartarg and 20 PPC. Shown below is one of his favorite rifles, a 20 PPC with a special short version of Richard Franklin’s Model 008 stock.

John tells us: “I guess one reason I started my web site is that I was getting a lot of inquiries about hunting groundhogs, custom rifles and reloading. Plus I thought it was a fine way to get young people interested in the shooting sports. Lord knows hunting and firearms aren’t taught any more. I get a lot of young hunters and shooters asking what’s the best caliber for hunting varmints, and they’ll ask for reloading help too. It’s a shame, but many of them have no one to teach them. I do my best to help.

Showing others that a person can still shoot, even with a disability, is another reason I started my web site. I am a C 6-7 Quadraplegic, which means I have no grip in my hands. Imagine shooting those 1.5 oz Jewels that way! I had a therapist tell me I wouldn’t be able to shoot or reload once I got out of the hospital…shows you how much he knows! First time I got home from the hospital it was deer season and I had Pops park me at the edge of some woods. Well I had a 7-point buck on the ground in thirty minutes! Being raised on a farm didn’t hurt none either–it helped me figger ways to jury-rig stuff. Of course I couldn’t have done much if it wasn’t for my family and my lovely wife Cathy[.]”

John’s Favorite 20 PPC Varmint Rifle

Cartridge History Lesson — the Original .244 Remington
Here’s bit of cartridge history. The 6mm Remington, parent of John’s 6mm AI, actually started its life with a different name, the “.244 Remington”. What we now know as the “6mm Remington” was originally called the .244 Remington. The cartridge was renamed because it was not a commercial success initially, being eclipsed by the .243 Winchester. The .244 Remington and the 6mm Remington are identical — only the name was changed.