Barrel contour vs. long range accuracy

358Scout

358Scout

Regular
Rating - 100%
72   0   0
Location
Saskatoon
I'm ordering myself a Gaillard barrel to be chambered in a 243 Winchester. My main purpose for the rifle is Varmints off a bipod at long distances about 800yds +.

I can't decide if I should go with the Sendero style contour finishing at .820 at 26" or the bull barrel at .900 at 26" I'm assuming the additional steel/ barrel will allow for more shots before heating up. Your comments appreciated.
 
Typically, a heavy barrel has two distinct advantages: Heat "resistance" and harmonic rigidity.

Varminters typically shoot enough rounds in a short period of time that heating is an issue. 243's burn lots of powder and get hot quickly.

Heavy barrels are more rigid and resist the effects of heat warping and harmonics better than thin barrels. Ted's barrels are button rifled, so bigger is better.

There is not an appreciable difference velocity wise with a short vs. long barrel (26" is fine), and longer does NOT equal more accurate, particularly if the barrel is proportionally thinner.
 
I'd be curious as to the velocity difference between 26 and say 30 inch in a 243?

FWIW I understand a 6mm Rem has significantly better barrel life than the 243?
Perhaps a 6.5-284 for real 800 plus yard varmints?
 
X-fan said:
I'd be curious as to the velocity difference between 26 and say 30 inch in a 243?

FWIW I understand a 6mm Rem has significantly better barrel life than the 243?
Perhaps a 6.5-284 for real 800 plus yard varmints?
Click to expand...

The 6 Rem has a worse barrel life than the 243, being based on a 57mm case versus the 243 wich is a 51mm case. It has greater case capacity and a higher overbore index.
 
358Scout,
I did a little research on using a 6mm 80gr Berger(BC - .31) as opposed to a 6.5mm 123gr Scenar(BC - .54). All calculations assume 800 yards. The Berger has stats that list the elevation from 100 yards at 23", the initial velocity at 3400 fps, the windage is 72" per 10 mph of wind, and terminal velocity is 1390 fps. The 6.5mm 123 gr Scenar has an intitial velocity of 3000 fps, the elevation at 100 yards is 18.5", the windage is 40" per 10 mph of wind, and the terminal velocity is 1800 fps. It would appear that BC is very important. The wind is not your friend. Look at getting a 6.5 caliber for 800 yard varmint shooting, or maybe even a 7mm.
 
Obtunded said:
Typically, a heavy barrel has two distinct advantages: Heat "resistance" and harmonic rigidity.

Varminters typically shoot enough rounds in a short period of time that heating is an issue. 243's burn lots of powder and get hot quickly.

Heavy barrels are more rigid and resist the effects of heat warping and harmonics better than thin barrels. Ted's barrels are button rifled, so bigger is better.

There is not an appreciable difference velocity wise with a short vs. long barrel (26" is fine), and longer does NOT equal more accurate, particularly if the barrel is proportionally thinner.
Click to expand...

Thank you!!! You took the words right out of my mouth.

I don't know how long it is going to take to get the "longer is better" mentality out of peoples heads. A longer barrel will give you marginally better velocity, but won't necessarily shoot more accurately. A fat 20-22" barrel will shoot just as well as something longer in a thinner contour. As long as a shorter barrel has enough rigidity it will shoot just fine. A good factory example is the Remington LTR in .308. No benchrest rifle by any means, but there are lots of guys shooting it out the 1000yds without issues.

Shorter barrels are obviously better with smaller cartridges as you get most of the powder burnt before the bullet exits, hence the marginal loss in velocity. I would imagine, and someone will surely jump in here and correct me if I am wrong, that a larger calibre would suffer a bit more in the velocity department with a shorter barrel as there would be much more unburnt powder exiting the end of the barrel. More powder, less burnt time, less pressure, less velocity.
 
I don't know how long it is going to take to get the "longer is better" mentality out of peoples heads. A longer barrel will give you marginally better velocity,
Click to expand...

i remember reading an article done by TAC Op's and they cut down the barrel of a 308 rifle in 1" increments form 26" to 18" they found 20" barrel produced the maximum velocity and would produce a full burn with factory federal Gold metal match ammo. they did the same with a 300 win mag and 22" was all that was needed using factory federal ammo. you will of course need a longer barrel if you are hand loading heavy bullets with a slower burning power. something along those lines the article can be found at http://ww w.tacticaloperations.com/ then articles then SWAT Dec 2000 in the top right hand side
 
Gopher Slayer said:
i remember reading an article done by TAC Op's and they cut down the barrel of a 308 rifle in 1" increments form 26" to 18" they found 20" barrel produced the maximum velocity and would produce a full burn with factory federal Gold metal match ammo. they did the same with a 300 win mag and 22" was all that was needed using factory federal ammo. you will of course need a longer barrel if you are hand loading heavy bullets with a slower burning power. something along those lines the article can be found at http://ww w.tacticaloperations.com/ then articles then SWAT Dec 2000 in the top right hand side
Click to expand...

You are right. I should have added to the above that once you have a full burn, you are done accelerating.
 
To the original post, either will do the job just fine. If you have to pack it around and are concerned about the weight, go with 0.820". Will also be easier to shoot offhand or in other field positions should the need arise.

In general when a case has decent case capacity (overbore index quite high) vs the bore and barrel length, you can gain 20 to 25fps per inch of barrel to 30". After that velocity gains are small unless you a pushing some serious amounts of powder down the bore.

As long as a barrel is properly supported and the action bedded, long barrels can shoot as well as shorter barrels. That is why most F class shooters go with barrels out to 30". Why not? It's like free horsepower.

I am sure that you have noted the 243 is not the easiest on barrels especially at elevated pressures but it does work great from any mag. If single shooting is part of the plan, why not the 6BR? Double the barrel life and superbly accurate. The difference in velocity will also not be that great.

A 6XC would be a very nice middle ground and will equal the 243 in a 26" barrel.

Good luck with your project...

Jerry
 
It took me alot of trial and error to find a powder and load that would produce a complete burn in my .308 with the 20" barrel and still hit needed speeds for longer ranges.
 
X2 on Mysticplayer

I shoot a 6BR with 105's (107's) ground hogs would be an easy target at 6-800 and double the barrell life.

My BR has a heavy barrell at 31" 1-8 tw.

From what i've heard the .243 isn't as accurate as the BR and it's harder on barrells and eats more powder to do it.

Mike.
 
dune said:
You should think about adding some length to the barrel if you are shooting 800+
Click to expand...

The short vs long barrel thing has been flogged to death a hundred thousand times.
Refer to the 'other' sniper sites to get more info on that...

There has been numerous tests done with factory 700 (.308) 20" barrels, which actually turned out being as or more accurate out to 1000 yds than longer barrels.

Not to mention my factory .700 LTR (in .308) has had NO issues hitting the gong at 1300 yds ;)
Having said that, my next barrel will probably be a 22" Krieger or similar.
 
In the past 5 years I have run several custom 308's with long, short, fat and thin barrels. Also flutted and non flutted. Other than a very minor velocity loss (we are talking 35 to 50fps, the best of both worlds has been 22" heavy contour non flutted (thats just the were I decided to go), and no appreciable differences other than the thinner contour barrels obviously heat up faster, thus suffering more. And, as Obtunded mentioned, likely suffer way more harmonics than a fatter, stiffer barrel.

As for barrel life, by Krieger and Rock Creek have been doing the best.

Just my .2C
 
You must log in or register to reply here.
Back
Top Bottom