The Barrel Block System
My 6.5 Mystic currently has two complete barreled actions, each with its own barrel block. The idea was to make a "switch rifle" (with two barrels) by just changing complete barreled actions, block attached. Just unfasten two bolts (that connect block to stock) and swap one barreled action for the other. The blocks remain fastened to the barrels. Of course you could also swap barreled actions by unbolting the upper and lower sections of the block. Unbolting the unitized block/barrel assembly from the stock is faster and simpler, however. You don't have to remove the scope and you don't have struggle to get the barrel aligned just right.

The original block (shown in most of the photos) was made from two slabs of aluminum bolted together, sides milled, with a hole bored for the barrel. For simplicity, the bottom slab is thicker than the top. This way you can put the barrel hole off-center without a lot of machining. The bottom is high enough so that the action clears the stock when installed. This free-floats the entire action. I recently added a second barrel block made from mild steel with stainless bolts. The new block is very similar in size and bolts into the original stock just like the aluminum block. The new steel block is much heavier than the first aluminum block. Also, the barrel shank diameter for the new steel block has been reduced to 1.240" (orig was 1.25"). The only reason for the change is that the new block-maker has a slightly smaller-diameter boring tool.

The barrel blocks are mated to the stock using two 1/4" diameter machine bolts (pillar-bedded of course). All of the recoil forces are actually handled by the stock. If you look at the photos, you will see that the block butts up against the stock. Bedding compound ensures they touch. Bracing the block against the stock makes for an extremely rigid set-up as the top of the stock would have to shear off or crush for the block to move.

The barrel blocks are removable, so you can swap in a different barreled action, block and all. And I'm not limited to Stevens/Savage actions. Since the action floats above a cut-out in the stock, you can use most actions, so long as the barrel diameter (contour) fits the block. Since the block supports the barrel above the fore-end, there is cooling airflow around the whole barrel. This barrel heats up evenly over its entire length and circumference. Moreover, the block acts as an enormous heat sink, helping cool the barrel in rapid fire.

Key Design Features Removable Barrel Block--Barrel block designs are not uncommon, particularly in long-range Heavy Guns. However, in most cases the block is designed to remain fixed in the stock. The block may even be permanently mounted in the stock with epoxy and/or bolts. In Jerry's rifle, by contrast, the block is easily removed by loosening two bolts. Then the block-fitted barreled action can be lifted out and replaced with another block holding a second barreled action. This allows a rapid barrel/caliber change with just an allen wrench--no need for a barrel vise. (Yes, you could simply keep the block in place, remove the top half, and drop in another barreled action, but this would require removing the scope. Moreover, getting the barrel aligned just right in the block is tricky and time consuming.) In practice, an F-Class competitor could shoot Open Class with a 6.5mm or 7mm chambering, then switch out the block-fitted barrel action with a .223 or .308 unit, and proceed to shoot F-TR class with the same stock. You can do the change in less time than it would take to adjust a three-way buttstock. Wide Buttstock Flat--According to Jerry: "Canadian F-Class rules do not restrict the width of the buttstock. I wanted maximum stability so I went with a 2"-wide flat on the toe (underside) of the stock. Using a Protektor front-type bag (for a narrow fore-end rifle), in the rear, this fits the 2" flat very well, and the gun tracks like it's on rails. Editor's Note: You'll see wide flats like this in long-range benchrest Heavy Guns, but thus far, American F-Class shooters haven't gone that route. At the U.S. F-Class Nationals, we saw no stock with a rear buttstock flat wider than about 3/4". It is unclear whether this dimension will be regulated in the future either in the U.S.A. or internationally. Universal Action Compatibility--The barrel block holds the barrel and action as a rigid unit which floats free above the stock. While Jerry has used inexpensive Stevens (Savage) actions, other actions can be used as well. Jerry explains: "Any action will work so long as the trigger fits in the slot. This means you can have a variety of block-equipped barreled actions and shoot them all in the same stock. The shooter can use different calibers without having to adjust to different stock designs." Barrel Cooling--The barrel is held quite high above the forearm. This allows cooling air to circulate completely around the barrel. On most guns, even if the barrel is free-floated (in an open barrel channel), the forearm restricts airflow and holds in some heat. Jerry's design allows maximum air flow around the barrel. In addition, the barrel block serves as a giant heat sink that absorbs and radiates much of the heat produced in long strings of fire. Jerry explains: "With all the effort spent on tweaking the rifle and ammo, it always surprises me that something as simple as barrel heat management wouldn't get more attention. With relays requiring upwards of 20 rounds fired, barrels are going to get very hot. All common stock fore-ends 'insulate' the bottom half of the barrel (venting slots don't actually help that much). This will create a temperature gradient across and along the barrel. Shots could be fired very quickly not allowing the barrel time to equalize. Many top-quality match barrels are quite resistant to [heat problems] but any change will show up on the target. It doesn't take much. In testing this rifle, I shot 16 rounds over a 12 minute span. Ambient temp was 75-80° F. The barrel in front of the block got very warm, the block just starting to heat up. All shots continued to fall into one small group at 200 yards."

Faux Carbon Fiber for Looks, Tracking, and Paint Protection Many benchresters put Teflon tape or similar types of adhesive coatings on stocks to reduce friction and aid tracking. On this rifle, the parts that look like carbon fiber are actually covered with vinyl adhesive accent material used for auto and motorcycle customizing. You can find this stuff at any Pep Boys or similar car parts store, and it comes in many colors and textures. This is an easy way to dress up a stock, action, scope, or even barrel. But the adhesive panels aren't just for looks. The vinyl helps to protect the paint where it would wear thin from rubbing on the bags. The stick-on vinyl also reduces friction substantially, helping the gun to track smoothly in the bags. The adhesives provide a smooth and very durable surface to aid in recoil tracking/consistency on the stock. So far, my faux carbon fiber has worked very well. The thin adhesive panels are very easy to put on and will come off without a lot of residue or tearing off paint. This material works well on curved surfaces too as can be seen on the action and trigger guard.