I am in the process of ordering a 280AI and Im stumped on what barrel profile to get. I am leaning towards either a .60 or .625 at the muzzle. They call it a number 2 and number 3 profile. However that doesn't mean much as all companies seem to have a different contour per number. Like I said, one is a .60 and the other is a .625. What would be your preference for a 280AI do it all rifle? Also does anyone know what the muzzle diameter is of a Kimber Montana in 280Ai or a Remington cdl sf? If I had these two measurements, it may make things a little clearer. Thanks
Trying to decide contour and barrel diameter for 280AI
- Thread starter Elkwonder
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J E Custom
Well-Known Member
All I can do is make a recommendation based on building many 280 AI's.
Go with a 1 in 9 twist Barrel 26" long in a #4 or #5 contour. That will allow you to shoot any Bullet weight and if later you want to install a muzzle brake the barrel will be heavy enough.
Keep the muzzle diameter around .750 minimum to .820 for best accuracy and forgivingness.
Just My recommendations.
J E CUSTOM
I went with a PacNor #3 contour (0.625). 24" long with 1:8 twist. I built it to be a hunting/carry rifle, and it feels very nicely weighted. Not too heavy to pack. Heavy enough for good field accuracy.
I went with the 1:8 because I wanted to use the 168 grain Barns LRX. Also some of the 175 grain bullets may benefit from faster then 1:9. Just depends on what you want to shoot. Probably most go with the 1:9
Good luck!
I went with the 1:8 because I wanted to use the 168 grain Barns LRX. Also some of the 175 grain bullets may benefit from faster then 1:9. Just depends on what you want to shoot. Probably most go with the 1:9
Good luck!
Last edited:
WildRose
Well-Known Member
There's a lot of wisdom and common sense here. Whippy barrels are never as accurate as a barrel of the same quality that has some meat to it.
The weight difference between a barrel that finishes at
.600 vs .750 is less than a couple of ounces.
I've messed with a lot of barrels for calibers from .17Rem to .204ruger, 7mm STW to 300WM and 300Rm to 45-70.
I find the Sendero contour or larger to be a bit more of a pain than I want in a rifle I'm going to have to carry so I tend towards the .750 finished diameter.
Chris at Benchmark says what I need is roughly a #3.5 contour and I'll be well pleased.
To that end I bought one that was originally chambered for .300H&H that I'll be rechambering and putting on my latest 300wm project. If I can find the right guy here locally I'll hopefully have it ready to go by November. We shall See. If I like it as much as I expect I'll have the 27" Version on the 300wm and then I'll have Chris do me two more, a 28" version for one of my 300Rum's and another for the 375 in either 28 or 29". Planning on 1:9 twists for the 30 calibers and probably 1:10 for the 375 unless someone can talk me into going another route with good hard data.
If I get all that done I suspect I'll be about done building rifles for the rest of my life.
Your math is off. The physical appearance of barrels sized that much different is huge. The difference in the weight is about a pound, 16 ounces.
scottishkat
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My 700 CDL SF has a muzzle diameter of .642. I don't own the Kimber Montana but its lighter than the CDLSF. In 260 Remington .642 is sufficient and light enough to carry. .625 would be a little light for my tastes with a .284 bore. I don't think I would go with .750 that would be more than enough.
My Accumark 6 lugs are .720 and not a great burden to carry on long hikes. The same thing in a 26" can become a bit heavy. All that said there is a lot of personal preferences involved. IMO .684 would be my minimum on the .284 bore .200 on both sides will give you good accuracy and not real heavy.
I am in agreement with JE though and generally speaking the heavier the barrel the better they shoot.
Good luck with your new acquisition in any case.
Shoot straight
Bob
My Accumark 6 lugs are .720 and not a great burden to carry on long hikes. The same thing in a 26" can become a bit heavy. All that said there is a lot of personal preferences involved. IMO .684 would be my minimum on the .284 bore .200 on both sides will give you good accuracy and not real heavy.
I am in agreement with JE though and generally speaking the heavier the barrel the better they shoot.
Good luck with your new acquisition in any case.
Shoot straight
Bob
WildRose
Well-Known Member
J E Custom
Well-Known Member
+1
Just a side note to this post.
9 to 16 oz is less than the difference in weight of many scopes. The range in weight of premium scopes range from 22.0 OZ to 40.0 OZ, so put the weight where it counts the most. The barrel is the heart of any accurate rifle. A very light barrel can be made to shoot well but I Personally have not seen any #1 or #2 contoured barrels shoot sub 10th MOA but plenty heavier barrels do it.
Most lightweight barreled rifles could use a muzzle brake, but many are to small to safely install
one unless it is a clamp on. also if a person doesn't like brakes, the bigger contour is a large benefit
as far as recoil.
I stopped building/using light weight rifles for long-range hunting/shooting many years ago because accuracy was more important than weight/carry ability. Also I found that the lightweight rifles were very picky about the ammo used and the limited distance ruled them out many times.
There does seem to be a happy medium between carry ability and accuracy, #4.5, #5,#5.5s and #6 contours fit this in weight and portability based on bore diameter.
Just an opinion
J E CUSTOM
