Barrel Profile/Contour

[lsuTigers]

I wanna pick the Hive Mind’s brain if you will. I’m looking at ordering a ”heavy” barrel in .223 for my Model 14. I’m not entirely sure what profile and twist rate I’d like to get. I think varmint contour will probably be too big and heavy for what I want. Maybe magnum or is there a standard target profile out there? As far as twist goes I was thinking 1:7” or 1:8” because I’d be shooting anywhere from 55-77 grain bullets. What say ye?

[Dave Hoback]

Are you concerned with weight? Is this a hunting rifle? If not, what is your intended use? I use a Shilen Varmint profile right now. On next rebarrel, I’m going to a full bull barrel, basically no profile. But my rifle is strictly a Bench Gun.
Savage offers 4 barrel profiles: Sporter, Magnum, Varmint & Bull. But different manufacturers offer different profiles for their Savage Pre-fits. Here is X-Caliber’s list, which is fairly extensive. http://www.x-caliber.net/contours


In 223, using 55-77, you’ll do just fine with 1:8. No reason to go 1:7, unless you are planning on the heaviest & longest bullets.

[lsuTigers]

Are you concerned with weight? Is this a hunting rifle? If not, what is your intended use? I use a Shilen Varmint profile right now. On next rebarrel, I’m going to a full bull barrel, basically no profile. But my rifle is strictly a Bench Gun.

In 223, using 55-77, you’ll do just fine with 1:8. No reason to go 1:7, unless you are planning on the heaviest & longest bullets.

The rifle would mostly be used on a bench punching holes in paper or maybe steel at ranges greater than 100 yards, so I’m not super concerned about weight. However I don’t wanna lug around a real heavy F-class type of gun around if that makes sense. Length I’m thinking either 20” or 22”.

[charlie b]

For that short a barrel a varmint contour would not weigh much. My Axis had a 22" 1:9 varmint barrel and easily managed 77gn bullets. But, 1:8 would be better, especially if you go to a 20". If you want to go to >77gn and 20" I'd go with a 1:7.

https://www.6mmbr.com/223Rem.html

Twist Rates
The .223 Rem shoots a wide range of bullets very effectively, from 35gr flat-based varmint bullets, to ultra-long 90gr VLDs. However, you'll need the right twist rate for your choice of bullet. For max velocity and accuracy with the lightest bullets, a 1:14" twist may be ideal. More versatile is a 1:12" twist that will allow you to shoot the popular 60-64 grain match bullets. (However, a 1:9" twist is needed for the steel-core 62gr bullet used in the M855 military loads, because that bullet is as long as most 70-grainers.) For normal lead-core jacketed bullets, a 1:9" twist will let you shoot up to 73gr bullets. Since most .223 Rem shooters prefer bullets in the 50-73gr range, a good "do-it-all" solution is a 9-twist, unless you're a Highpower competitor.
For long-range match purposes, long, high-BC bullets are favored for their ability to buck the wind. You'll want at least a 1:8" twist to shoot the 77gr and 80gr MatchKings and 80gr Bergers. To shoot the new 90gr pills, a 1:6.5" is recommended, though a true 1:7" will work in most conditions.
Overall, what twist rate is best? For varminting we like a 12-twist. The slower twist will give you a bit more velocity, and minimize the risk of jacket failure at high rpms. For general use, an 8-twist barrel will let you shoot the excellent 77gr and 80gr Sierra MatchKings and nearly all varieties of non-tracer milsurp ammo. We'd only select a 1:7" or faster twist barrel if we had a need to shoot the 90gr VLDs.


Barrel Twist Rate
1:14"
1:12"
1:9"
1:8"
1:7" or 1:6.5"


Max Bullet Weight
55gr FB
65gr FB
73gr BT
80gr BT
90gr BT VLD

[Revoliver]

The above guideline are good guidelines, but not the whole picture, bullet shape (and construction) are also factors involved with how well your barrel will shoot certain bullets.

That being said, 1/8 should cover everything nicely IMO in regards to twist.

As far as profile, how much or fast you plan to shoot is also a factor. 1 to 3 rounds and then a good break for awhile? Thin profile will be fine. I've got a 20" faxon gunner profile 6.5g that'll stack holes if I shoot a round a minute. I don't know if it'd still do that if a ripped through a 15rd magazine (because I've never tried and have no desire to) but I sure don't expect it to.

[Whynot]

Another thing to keep in mind... those contours are the same along all the calibers-- so a varmint profile in 223 has a lot more material than the same profile in .338- simply because the hole in the center is much smaller. Also- a 223 doesn't burn much powder so barrel heating is much less. Magnum and varmint would both be good selections- but I never noticed if you mentioned the stock/chassis? Make sure you don't get more barrel than will fit in the channel- unless you need an excuse for more purchases.

[Fuj']

Two factors you need to be concerned about the most....Length of bullet and the speed
at the muzzle. I shoot a 1:8 and have won match's with the Sierra 77 HPBT's. I can push
them higher, but my match accuracy node is at 2880 fps.....The longer the bullet the more
it will want to swap ends and keyhole as speed drops. So Yes, a 1:8 is the best ball park as
long as you know what range you'll be shooting. I'm good to 400 yards, and marginal out
to 600, and beyond, probably most are going sideways.....I'll always tell people to go to JBM's
free online stability calculator. and plug in what you have, then change speeds up and down
and make your range card for a given load you create.

[charlie b]

FWIW, .223 Axis, 22" varmint barrel, 1:9 twist, 77gn SMK, 2850fps (23.5gn Varget), Lapua brass, Rem BR primers.

1000yd, 18" group, 10 rounds. Nice round holes. No yawing. I only shot the .223 at 1000yd a few times. One 5 round group was 15in. Had to be a really calm day and on the cold side (lower speed of sound). But, it is not a 1000yd cartridge. Long range stability really depends on how far above the speed of sound the bullet is near the target.

It is pretty solid at 600yd. Reading wind is key.

[lsuTigers]

Another thing to keep in mind... those contours are the same along all the calibers-- so a varmint profile in 223 has a lot more material than the same profile in .338- simply because the hole in the center is much smaller. Also- a 223 doesn't burn much powder so barrel heating is much less. Magnum and varmint would both be good selections- but I never noticed if you mentioned the stock/chassis? Make sure you don't get more barrel than will fit in the channel- unless you need an excuse for more purchases.

I’m going to stick with a wood stock. Either a new one or if I have enough wood on the factory stock to open up.

[Dave Hoback]

I find it odd you wish to handicap yourself so. You are saying punching holes in paper at greater than 100yds. That sounds like a target rifle to me. How much greater than 100 are you planning; 200yds? If so, than sure.. not a big deal. But if you are going to the further 223 ranges.. 500, 600yds & beyond, a wood stock can become a severe handicap. Not to mention, although we clearly know it can be & proven by both Fuj’ & Charlie that it IS done with a 20-22” barrels, I doubt either would argue it would be just a little easier with a 26” barrel. I get it completely if you were planning to hunt with this rifle even once a year, besides the paper/steel punching. But if that’s all it’s doing, not sure where the difficulty is. I mean, a 20lb rifle.. yeah, I get it. But a 12lb rifle? Just it’s sounding like you are shooting for a 7lb rifle! And the weight reduction, shorter barrel & using a wood stock, add up to reducing distance & accuracy.

[Whynot]

Two factors you need to be concerned about the most....Length of bullet and the speed
at the muzzle. I shoot a 1:8 and have won match's with the Sierra 77 HPBT's. I can push
them higher, but my match accuracy node is at 2880 fps.....The longer the bullet the more
it will want to swap ends and keyhole as speed drops. So Yes, a 1:8 is the best ball park as
long as you know what range you'll be shooting. I'm good to 400 yards, and marginal out
to 600, and beyond, probably most are going sideways.....I'll always tell people to go to JBM's
free online stability calculator. and plug in what you have, then change speeds up and down
and make your range card for a given load you create.

That seems really odd that you would be losing stability.... in my experience once a bullet is stable it remains stable- at least until transonic. If anything the bullet should be spinning faster compared to velocity down range because velocity decreases faster than spin- so if a bullet has gyroscopic stability it should maintain it.

[lsuTigers]

I find it odd you wish to handicap yourself so. You are saying punching holes in paper at greater than 100yds. That sounds like a target rifle to me. How much greater than 100 are you planning; 200yds? If so, than sure.. not a big deal. But if you are going to the further 223 ranges.. 500, 600yds & beyond, a wood stock can become a severe handicap. Not to mention, although we clearly know it can be & proven by both Fuj’ & Charlie that it IS done with a 20-22” barrels, I doubt either would argue it would be just a little easier with a 26” barrel. I get it completely if you were planning to hunt with this rifle even once a year, besides the paper/steel punching. But if that’s all it’s doing, not sure where the difficulty is. I mean, a 20lb rifle.. yeah, I get it. But a 12lb rifle? Just it’s sounding like you are shooting for a 7lb rifle! And the weight reduction, shorter barrel & using a wood stock, add up to reducing distance & accuracy.

I’ve always liked the look of the old school Winchester and similar target/varmint/sniping rifles and want to make something similar in a Savage platform. For now I’m limited to 100 yds but I’m looking into local gun clubs for extended range opportunities. If I end up getting a different stock, I’d free float and bed the action. The more digging I’ve done has me leaning more towards 22” or 24” probably in a ER Shaw “savage heavy magnum” profile. I should’ve provided more details in the OP.

[charlie b]

I am another who likes laminated wood stocks. 12BVSS has the original stock. Axis has a Boyd's (Pro Varmint). I did bed and pillar the Boyd's stock. One of these days I will get around to a skim bed of the BVSS (it comes with pillars from the factory).

Yes, a chassis is stiffer and more adjustable.

[Dave Hoback]

Ahh, I gotchya. Hey I get that man! Those who claim all they care about is performance, yadda, yadda is not only likely lying to everyone else, but also maybe to themselves! Part of the human condition is having things which are aesthetically pleasing to our eyes. So I understand completely if you are simply attracted to the look of wood. I’m on the other side of the token: I’m an Aluminum Chassis guy & prefer synthetics.

[Robinhood]

That seems really odd that you would be losing stability.... in my experience once a bullet is stable it remains stable- at least until transonic. If anything the bullet should be spinning faster compared to velocity down range because velocity decreases faster than spin- so if a bullet has gyroscopic stability it should maintain it.

This could turn into a great, maybe even contentious discussion. Distance directly correlating to spin. I better go get my calculator. :tea:

[Robinhood]

I find it odd you wish to handicap yourself so. You are saying punching holes in paper at greater than 100yds. That sounds like a target rifle to me. How much greater than 100 are you planning; 200yds? If so, than sure.. not a big deal. But if you are going to the further 223 ranges.. 500, 600yds & beyond, a wood stock can become a severe handicap.[/SIZE] Not to mention, although we clearly know it can be & proven by both Fuj’ & Charlie that it IS done with a 20-22” barrels, I doubt either would argue it would be just a little easier with a 26” barrel. I get it completely if you were planning to hunt with this rifle even once a year, besides the paper/steel punching. But if that’s all it’s doing, not sure where the difficulty is. I mean, a 20lb rifle.. yeah, I get it. But a 12lb rifle? Just it’s sounding like you are shooting for a 7lb rifle! And the weight reduction, shorter barrel & using a wood stock, add up to reducing distance & accuracy.

Tell that to all of the Fclass and benchrest shooters where most of them are using wood.
https://www.6mmbr.com/i/Reader%20Photos/Richards_008Maple.jpg

[Revoliver]

This could turn into a great, maybe even contentious discussion. Distance directly correlating to spin. I better go get my calculator. :tea:

It would be eye opening for sure.

[charlie b]

The rate of spin of the bullet does not degrade much over the path of the bullet. If the rate of spin makes the bullet stable at the muzzle, it will be stable downrange.

But, the aerodynamics of the bullet changes dramatically when the bullet goes through the transonic range. The center of pressure can move such that the bullet stability is compromised. Some bullet shapes do really well, others do not. This has more of an effect on bullets that are marginally stable to start with.

Note that most of the simplified stability calculators are using aerodynamic constants corresponding to a velocity 2700fps and a bullet shape that is kind of like a football. The velocity input does not change those constants, it is simply used to calculate the rate of spin of the bullet.

[Dave Hoback]

Charlie is absolutely correct. The bullet spin directly correlates to bullet speed within the barrel rifling. Once the bullet leaves the barrel, the velocity declines at a much, much higher rate than the bullet RPM. The formula for bullet spin is MV x (12 / Twist Rate Inches) x 60. Or use the online calculator, LOL! https://www.findnchoose.net/bullet_rpm_calculator.html

Heres a great real world example we can see with our eyes. Anyone who watches football, you’ve seen the slow mo footage of the ball in flight. Look at the spin from just after release to being caught. No discernible RPM is lost during the flight.

[Dave Hoback]

Tell that to all of the Fclass and benchrest shooters where most of them are using wood.

I disagree. Most serious shooters are using either Composite (Fiberglass/Carbon Fiber), or Wood Laminate.(which is actually also a composite.. half anyway.) Also see many that are Hybrids. Of course, it comes down to weight, which is why Chassis aren’t used. Isn’t it like 18-22lbs Max. or something, depending on Class? And I’d assume professionals are using the stock by whoever will sponsor them.