View Full Version : Tube gun

Brush Okie
03-11-2017, 11:38
Anyone used one. Thoughts? For those of you not familiar here is an article. A few years ago they were being experimented with in competition. Basicly you epoxy a bolt action such as Remington 700 action into an AR type chassis to strengthen it and it uses AR furniture for adaptability.


Eliseo R5 6mmBR Repeater
State of the Art Kit Gun for the Highpower XTC Game
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Attend a Highpower match on the West Coast and you're likely to see Gary Eliseo's handsome, high-tech kit rifles used by many of the top shooters. After many long nights and much hard work, Gary has perfected a new repeater rifle for prone and across-the-course competition. From the ground up, it is built around the 6mm BR cartridge. Gary explains: "The 6BR is a proven winner. It is a step up from what you can shoot in an AR15-based spacegun. The 6BR is hard to beat for pure accuracy and loads are easy to tune. It offers low recoil, and with the R5 we now have a platform with reliable mag-feeding. With a 6BR you also have extremely high-quality factory ammo available." Using proprietary CNC-machined aluminum magazines, the gun will rip through a rapid-fire stage as fast as you can work the bolt--and it will feed the stubby 6BR cartridges flawlessly. Click the screen-shot at right to see a Rapid-Fire VIDEO showing Gary shooting 10 rounds through the R5, including a mag change. More VIDEO.

Gary recently demonstrated his new R5 repeater for us, and explained the features of this impressive new rifle. It combines mag-fed cycling speed, superb accuracy, and excellent ergonomics in a kit that retails for just $875.00 (subject to change). Add barrel, Rem 700 short action, sights, and trigger, and you have a rig that can win matches for under $2000.00 complete. BIG Photo.

Design Principles of the R5--Beyond the AR In creating the R5, Gary wanted to preserve the ergonomics and rapid-fire functionality of the AR15 (and its spacegun variants). However he wanted a gun that had superior accuracy and that could shoot the high-BC 6mm bullets. Gary felt the heavier 6mm bullets offered a definite performance edge over even the best 22-caliber projectiles, and he wanted to shoot the 6BR cartridge because of its great inherent accuracy. The challenge was to make the 6BR function in a bolt gun that had the feel and balance of an AR spacegun. And it also had to have a magazine that would work flawlessly in rapid fire.

Gary explained: "I have a background in Service Rifle competition. I cut my teeth on an AR15 and later an AR15-based space gun. That's really the reason my stocks look the way they do. The AR-style configuration feels natural to me. To those accustomed to an AR-type spacegun, the R5 will feel very familiar. The weight and more importantly the balance of the rifle feel just right. By contrast, I always found the Highpower bolt guns I've tried in the past to be a bit muzzle-heavy. I prefer the way my spaceguns handle offhand, with the mass sort of centered at my chest.

A 'tube' stock has another major advantage over a conventional stock, namely how the tube stock helps the shooter maintain his sight picture. In the rapids, with a conventional stock, you are forced to lift your head off the stock to keep from getting hit in the nose by the bolt as it comes back. This in turn forces you to re-acquire the sight picture after each shot. That slows you down and won't help your score. On the other hand, with a tube gun, the bolt runs under your face so you can keep your face planted and keep your sight picture during the entire rapid string. Furthermore, with my R5, being chambered in 6BR, recoil is so light you hardly need to move your head at all. Watch the rapid fire video clip and you can see for yourself.

One other little feature that really helps during the rapids is the thumb stud I put on the side of the lower unit, I've found that operating the bolt is made much easier if I keep my thumb on the right side of the pistol grip and rest it on the thumb stud, this gives me a 'jacking point' that I can leverage my thumb against giving me much more power to open the bolt with, with a little practice it's really easy to learn, and works great!"

Cartridge Selection--Why the 6BR for
Across the Course (XTC) Competition?
We asked Gary why he chose the 6mm BR for his R5 rifle. First he noted: "There's not much point in engineering a new rifle to shoot the .223 Rem--you can shoot that from an AR15 platform, and I think some kind of 6mm is a much better choice for Highpower and XTC anyway." Gary explained: "I chose the 6BR cartridge for many reasons. First is its extraordinary accuracy--those who know this cartridge know what I mean, and those who try it for the first time are quickly converted. Half-moa (or better) is almost a certainty with this cartridge if you have a decent barrel. But for Highpower competition this cartridge offers other very important benefits such as the ability to propel high-BC 6mm bullets at good velocity, outstanding barrel life, low recoil, good availability of high-quality brass at reasonable price, and a cartridge that's easy to load for and not finicky. I don't think there's another XTC cartridge that can boast all of those qualities. Sure some bigger cases may offer a more velocity, but there's usually a trade-off. You will give up useful barrel life, or you may have to spend time forming brass from other parent cases. I've explored most of the popular XTC cartridges. On balance I think the 6BR is close to perfection in achieving all the necessary qualities you want in an XTC cartridge. The only major argument against the 6BR cartrridge for XTC was that it was hard to feed from a magazine. Well, with the R5, and our new single-stack magazine design, that issue is a thing of the past." Check out the photo to see the magazine and how it work

Accuracy and Reloading
Gary tells us his R5 "holds half-MOA with ease." He employs no exotic reloading methods, instead using a moderate load of Varget with Lapua brass right out of the box. For his Slow Fire, single-round loads, he seats his bullets long so they engage the lands. However, in order to ensure reliable magazine feeding, he loads his mag-fed rounds off the lands, keeping the C.O.A.L. under 2.385". [Editor's note, the 6BR Lapua 105-grain loaded ammo measures about 2.330" overall so it fits perfectly within Gary's recommended cartridge length guidelines.]

Gary tells us: "I take full advantage of the beautiful Lapua brass--I take them right from the box, prime them with CCI BR4 primers, measure 29.5 to 30.0 grains of Varget (dependant upon which bullet I use) and top them off with a Sierra 107, Berger 105 VLD or a Berger 90 BT. The 90-grainer is used for short stages. The only thing that needs to be done is to set my magazine ammo to fit in the 'slot length' of 2.275"-2.385". If the ammo is too short, the bullet tip won't be started in the chamber when released from the magazine. If the ammo is too long, the bullet tip may drag on the inside of the mag well. By the way my rifle shoots under 1/2 MOA without any fuss. That's why I love this cartridge so much."

R5 Adjustments--A Myriad of Options
The R5 is fully adjustable, stem to stern, with all the user-configurable features you'd expect to find on a high-grade match rifle used for position shooting. The buttstock/buttplate assembly adjusts for length of pull, drop, cant and cast-off. The minimum length of pull is a tight 12". This is important to many shooters who prefer a very short LOP for use in the offhand position. Two 8-ounce weights can be fitted to the bottom of the buttstock. These are most helpful when standing, but Gary usually leaves them in place in all positions.

A thumbwheel-type, vertically-adjustable cheekpiece is fitted to the main arm of the buttstock assembly. (See Large photo below). The cheekpiece can be raised and lowered for individual preference but Gary likes to keep it pretty low as that helps him stay "glued" to the stock during rapid-fire. Gary says that R5 recoils pretty much straight back with very little vertical pulse. This allows the shooter to stay right down on the stock, with minimal head movement in the rapids.

As you'd expect, the handstop adjusts fore and aft via a slot cut in the underside of the fore-end/handguard. The entire handguard itself can be rotated about 20 degrees left or right around the bore axis, allowing the handstop to be placed off-center without canting the rifle. This is a slick feature one not found on conventional target rifle stocks (or most tube guns for that matter). Gary notes: "I prefer to rotate the handguard as this places the handstop into the web of my sling hand. I find that much more comfortable, especially after spending many minutes in the sling during the slow prone event."