Barrel Choice

[Jim Kidwell]

You need one, Colt.............

[Coltsmoke]

I might.

[Dennis Armistead]

Dennis please explain why a heavy round barrel is better than a heavy octagon barrel.

Colt, the biggest advantage that a heavy round barrel has for extended strings of fire is they have more surface area for cooling. Round or half round also seem to position better when shooting off of sticks. A matte finished barrel also cools better because of surface area and a stainless steel barrel cools the best because of the alloy.
Dennis

[Coltsmoke]

I would think the octagon barrel has more surface area. I do remember Dan T. talking about the SS cooling faster than CM.

[Michael Johnson]

I think that the choice of barrel contour depends upon what you want to do with the rifle. My first BPCR was a Shiloh No1 45-70 with a 30 inch heavy octagon barrel. It is still my favorite Silhouette rifle. I think that has more to do with the 45-70 chambering than anything else. The rifle is heavy enough that it does not beat me up. My second BPCR is a 45-2.6 in a 34 inch heavy octagon barrel LRE. This rifle does really well with the 600-1000 yard tasks. The chambering and the 13.5 pound rifle weight help but it can still beat you up over shooting it for 3-4 days (especially if you do not pay attention to how you hold it. It does shoot accurately. Twice on one of our Poulsbo money shoots I managed to hit a two inch chicken offhand at 200 yards with it Every once in a great while the stars line up. I was shooting this gun because my oldest son was shooting my 45-70 and my youngest was shooting my 40-65. My third BPCR is a 40-65 Hiwall with a half octagon half round 30 inch barrel. It is superbly accurate out to the turkeys but on a day without perfect conditions starts to fall apart on Rams (typically getting 6-8). It is also the only rifle that I have shot 6 chickens with. The rifle balances very well when shooting offhand.It has a 1/16 twist so maybe the twist should be a little tighter. My last BPCR is my hunting rifle. Dave Higginbotham built me a 50-90 28 inch heavy straight 1 1/8 octagon 28 inch barrel on a Rolling Block action. The gun weighs 10.5 pounds. I have shot game out to 260 yards with this gun. It is easy to carry and the Dave Manson tight no freebore custom chamber shoots 550 grain slugs accurately out of the 1/24 twist Green Mountain barrel. With all of that meager BPCR experience Kirk is now building me my "retirement rifle" a 40-90 SBN with a 32 inch heavy round barrel with a 1/14 twist barrel for shooting long range paper patch slugs. My only experience with BN cartridges has been shooting the 1871 Mauser bolt action BPCR with paper patch. This rifle will be for prone long range. It will probably be frustrating but in 18 months I will be retired and could use another challenge.

[Dennis Armistead]

I would think the octagon barrel has more surface area. I do remember Dan T. talking about the SS cooling faster than CM.

Sorry Colt, round has more surface area

[bruce m]

and sand blasted has more again.
bruce.

[Aviator]

I guess it depends on how you define an octagon barrel size.

I have always thought of the size of an octagon barrel as being defined by the dimension across the flats.

However, I guess some may think of it as being defined by the dimension across the points.

Assume a 1 inch diameter round cylindrical barrel. The circumference is 2*Pi*0.5= 3.14159 inches

Assume a 1 inch octagon barrel (across the flats). The circumference is 16*0.5*tan(22.5)= 3.31371 inches

Assume a 1 inch octagon barrel (across the points). The circumference is 16*0.5*sin(22.5)= 3.06147 inches

If you have an octagon barrel that you made by starting with a 1 inch diameter round barrel, and ending up with an octagon which is 1 inch across the points, then it will have less surface area than the 1 inch round barrel.

If you have an octagon barrel that is 1 inch across the flats, it will have more surface area than the 1 inch round barrel.

I would venture a guess that if you ordered a "1 inch octagon barrel", it would measure 1 inch across the flats, unless you specifically stated that you wanted it measured across the points.

[BFD]

Aviator, I'll disagree.

[Kurt]

Oh Boy for a math challenged guy like me this going to be interesting

[charlie young]

Kurt, don't worry buddy, I'll back you up with any prognosis you want to throw into the mix...after all I did pass College Algebra in 1971!!!!!!!!!!

[BFD]

Charlie. Its geometry that counts here. Not algebra.

I think Aviator may have forgotten some geometry and trigonometry.

[Don McDowell]

Having heavy half , heavy round and heavy octagon, about the only differences I notice is the octagon lays better in cross ticks. Using a wrist rest there's virtually no difference.

[Aviator]

Charlie. Its geometry that counts here. Not algebra.

I think Aviator may have forgotten some geometry and trigonometry.

Maybe.... Maybe not....
Waiting to see your calculation for the length of the perimeters of 1) 1 inch diameter circle, 2) the cross section of an octagon 1 inch across the flats, and 3) the cross section of an octagon 1 inch across the points...

[desert deuce]

Dang, given the circumstances and history?

Seems like waiting 30 minutes for a reply is unusually long.