Engineers’ perspective on the Remington 700 VTR triangular barrel
CR Riddell, PE posted a comment about the Remington 700 VTR triangular barrel and I thought it deserved its own blog post:
I am a professional structural engineer. In 1977, I was granted a patent on a structural system that uses triangular cross-section members with a circular cross-section hole down the middle. Remington’s VTR barrel is identical to that shape. The objective of this shape is to maximize structural force transmission with a minimum of mass.
Remington Model 700 VTR barrel and integral muzzle brake.
During development of the concept, I established that the triangular cross-section provides the maximum surface area for a given enclosed volume. This accounts for the Remington heat dissipation claim/feature. Removing the mass along the central axis leaves the mass in the three corners at a maximum distance from the central axis. This maximizes the axial compression rigidity and the torsional rigidity, also a Remington claim/feature. The torsional rigidity promotes stability under the influence of the rifling twist, a special benefit in a rifle barrel. Flexural stiffness is optimal for downward bending of the muzzle end in the orientation Remington uses in the stock; one corner up and two corners down. That puts the top corner in tension and the bottom corners in compression, where buckling concerns reduce the allowable load-carrying capacity.
From Riddell’s Structural Member and System patent (#4007574)
All this techno-mumb-jumbo counts for doodly, unless the holes in the target get chummy and cuddle up together. As with all accuracy discussions, the teamwork between barrel, bedding, and ammo gives a unique performance result. This must be where Remington spent its advertised years in development.
Obviously, the manufacturer cannot control the customer’s choice of rounds, so they have to shoot for a statistical middle, so to speak. But the bedding is another story. Remington advertises a multi-point mount, not free-floating or glass bedding. This would be crucial for taming the harmonics in concert with the unique tension-vs-compression qualities of the barrel shape.
Thoretically, this barrel should be better than round, but the industrial wisdom and inertia is all compiled for round. Some tuning is required.
Very interesting. Thanks CR for the information.
Oh I’m getting one of these probably later this year or next in .223 version.
Just found out that Bubgunshop has it below $700.
http://www.budsgunshop.com/catalog/advanced_search_result.php?keywords=VTR&osCsid=8fb5f6a911d8f044df32392e4aa3343b&x=21&y=3
jdun1911, I also want one. Everytime I see one in a gun shop I can help but want one. It is a very sexy rifle.
This year they will have the new Remington adjustable trigger and butt plate inserts to adjust length of pull.
Yeah it’s very sexy and you don’t see triangular barrel often.
I didn’t even know it existed until now.
jdun1911, thats what you get for not keeping up with the blog
Thanks for that info on the VTR.
I have had my VTR in 308 since December last year and i think its a great rifle, handles well and shoots excellent. Only wish it came with a free floating barrel.
Like the Remingtons but this engineer’s analysis is a bunch of silly nonsense.
I designed exactly this kind of barrel in the mid ’90’s and nobody would buy the idea. the barrel is just about as ridged as a round barrel the same diameter as the points of the triangle but the weight is reduced greatly. The key is that the three strongest points on the barrel are exactly opposite the three weakest points so the strength is not compromised. I just wish I was getting paid for them.
“During development of the concept, I established that the triangular cross-section provides the maximum surface area for a given enclosed volume.”
Ahhh, no. More surface for a given enclosed volume can be generated by a very narrow rectangle. A star shaped cross section will also provide more surface area for a given volume. This is not the only error in this. He mentions that this particular cross section “maximizes the axial compression rigidity and the torsional rigidity”. The axial loads are dependent only on the amount of material and a triangle is not a good shape for torsional rigidity; torsion bars are round for a reason. He mentions buckling; if you’re barrel is buckling it would be a very strange occurence to have happen when the barrel is in tension which is what happens when the bullet is squeezing down the barrel. Bucking happens under compression.
I don’t think there’s any harm from making a barrel with a triangular cross section but I would doubt there’s any real benefit from it.
Interesting insight from the original patent holder. Clearly someone at the patent office deemed his idea legitimate enough to grant him a patent. I noticed also that he is a licensed engineer. I would be curious to know about the credentials of those individuals attempting to counter the information he provided. If they would come forward with their credentials it would be a great help for a lay person such as myself to make a better purchasing decision.
Regards,
DDearborn
I’m a retired P. Eng. I appreciate Mr. Riddell’s comments, both the analysis and particularly his observation regarding Remington’s “multi-point” stock being designed to tame harmonics. It would certainly have been simple enough to provide a free floated barrel otherwise. I would offer the observation that the design of the muzzle brake likely plays a role in the harmonics equation also.
The internal design of the forward portion of the stock reminds me of the recent Smith and Wesson “i-bolt”.
Also, I have seen a triangular barrel before, but where? I think I’m trying to remember a pistol barrel. Help me out somebody?
Desert Eagle
I just got one of the rem. vtr 700 with a all black stock in 308. i love this rifle.i can shoot around a 1in group at 100yd with 150gr corelock.and i got a good deal on it $500 new.i cant wait to to it hunting.
I got a rem. vtr 700 in 308 cal. this is a great rifle.i can shoot around 1in groups at 100yds with cheap bullets.and i only paid 500 for rifle.and i love the look of the rifle.
just a touch off subject. the remington 700 target tactical rifle has the 26″ vtr barrel with the 5r rifling. is this barrel free-floated and is the 5r rifling in the target tactical the same as the 700 ss 5r milspec. also, is the ss 5r milspec barrel free-floated. trying to decide on a new rifle but cant find thi info out there. anyone know of any websites i can get that info. tried the remington website and e-mailed them, no response. thanks in advance