Big-bore bolt: the Brockman .450 Marlin bolt action is just the ticket for dangerous game

Guns Magazine, March, 2006 by Dave Anderson

Big-bore rifles have a devoted following and are popular in wilderness country where the chance of encountering big bears is a real possibility from the northwest US to Canada and especially Alaska.

The Marlin .45-70 is popular with lever action fans, but factory loads are limited to modest pressures in deference to the many old .45-70 rifles. In the modern Marlin it can be handloaded to considerably greater power levels. Since not everyone handloads, Marlin introduced the .450 Marlin. Where industry standards for the .45-70 are limited to 28,000 pounds per square inch, maximum average pressure for the .450 Marlin is 43,500 psi. The case has a wide belt so it can't be inadvertently loaded in a .45-70.

Jim Brockman of Gooding, Idaho, makes a number of components (front and rear sights, large-loop levers, scope mounts) for big bore Marlins as well as full-house custom rifles. The quality of his workmanship is simply superb.

Not every big-bore enthusiast is a lever action fan. Brockman began getting requests from Alaskan guides, hunters, and other outdoorsman for a bolt-action big bore. The result is about the slickest, handiest, neatest big-bore rifle I've ever used.

Brockman built the rifle on a Montana 1999 action. This excellent controlled-round-feed action combines the best features of the pre-'64 Winchester Model 70 and the Mauser 98. The short action is just the right size to fit the .450 Marlin round. The actions are beautifully made, precise, smooth and reliable.

Premium Parts

The 20"-barrel is by Lothar Walther with a 1-18" twist. It is fitted with Brockman's custom front sight, a square post, adjustable for elevation, and protected from accidental blows by sight wings. The Talley scope base on the receiver bridge carries another Brockman custom component, a spring loaded, pop-up peep sight. When a scope is fitted the sight is pressed down, allowing the scope to fit as low as possible. Remove the scope and the sight pops up ready for use. It comes with a small diameter insert, useful for sighting in or other precision shooting. Removing the insert leaves an extremely fast large diameter "ghost ring" peep.

The tough, rust-resistant, nonreflective finish is Cerakote by Fit 4 Duty. The strong, laminated wood stock is further reinforced with two stock bolts and carries no checkering. Instead, Brockman finished it with epoxy paint in which tine grit is mixed. The result is a non-slip surface over the entire stock except the cheekpiece, which is finished smooth and won't abrade your face.

The front sling swivel stud is fitted on the front of the forearm rather than the bottom, recommended on hard-kicking rifles. Unlike barrel band slings, this won't cause point-of-impact shifts when shooting with a tight sling.

The test rifle came with a Leupold 2.5x20 FX-II Ultralight scope in Talley quick-detachable rings, allowing the scope to be detached or replaced in seconds with no perceptible change in point of impact. The scope is light at 6.5 ounces, strong and durable, with 4.9" eye relief, a welcome feature on any heavy recoiling rifle.

Hornady loads the .450 Marlin with a 350-grain flatpoint bullet at 2,100 fps. Brockman provided some ammunition for the bolt-action rifle loaded a bit hotter--a 300-grain Barnes XFB bullet at 2,360 fps, a 350-grain Barnes at 2,250 and a 400-grain Swift A-Frame at 2,150. These are chronographed velocities from the 20"-barrel, presumably in summer. Over my chronograph, at 20 degrees F they averaged 40-50 fps slower.

For general use Brockman favors the 350-grain load. Sighted 3" high at 100 yards, it doesn't drop 3" below point of aim until 225 yards. Even at 250 yards it is just over 6" low.

The .450 Marlin produces respectable velocities with relatively modest powder charges, which in turn reduce recoil and muzzle blast. Nonetheless there is a price to pay for launching a 400-grain bullet at 2,150 fps in a rifle weighing seven pounds, two ounces. Recoil is comparable to the .458 Win in a 10-pound rifle.

Shooting from the bench isn't exactly fun, but with the excellent stock design, efficient Pachmayr pad and a PAST shoulder protector, recoil is tolerable. Accuracy of the Brockman rifle was startling. As with any heavy-recoiling rifle even minor inconsistencies in hold result in vertical stringing. I had several three-shot groups with two rounds touching, the third 1" to 1 1/2" high or low. However when I did my part, concentrating on a consistent hold, the rifle would print clover leafs. One five-shot group measured just over an inch, outside edge to outside edge.

Shooting was made easier by a superb trigger pull, just over 2 1/2 pounds, breaking clean and crisp as an Alaskan icicle. Personally, on a rifle which might be shot with cold-numbed fingers I'd have Brockman tune it to 3 1/2 or 4 pounds.

Big-Bore Fun

The best fun I had with Brockman's "Little Big Gun" was simulated field shooting on steel targets, engaging targets in succession as fast as the action could be cycled and sight alignment reacquired. Feeding, chambering, extraction and ejection of the .450 rounds was smooth and absolutely reliable. Whacking steel is always fun, but never more so than with big, heavy bullets.