Why is the 6.5-284 such a barrel burner

[tammons]

I am new into long distance shooting and considering buying a 6.5-284 barrel for my 22-220 12vss and maybe giving a competition a go sometime.

At around 3000 fps I would expect more barrel life than 1000 rounds, but I assume it has to do with the load of powder pushing a long bullet, but its certainly no worse on barrels than a 270 mag/7mm mag/300mag is it ??

Actually a plain old 270 has more powder charge and with a 140 grain bullet produces a similar velocity to the 6.5-284.

Just trying to understand.


Thanks in advance.

 

[Forum Boss]

Many of the 6.5-284 guys are running pretty high pressures for a variety of reasons. Part is to reach high velocities, and also some of the powders are just most accurate when burning hot.

The deal with the 6.5-284, and also 6.5-06 is you typically have a LONG bullet with a lot of bearing surface running through a pretty narrow bore. That creates a lot of friction. By contrast, a typical 150 grain .308 match bullet has a relatively short bearing surface and the bore is much larger by comparison.

 

[rhino]

A .260 AI or 6.5x55 SE will get you to 3000 FPS in a 28-30 inch tube. This means less charge similiar velocity. This should translate into extended bore life.

Maybe 1500 rounds of match accucracy?

Don't think you need to go 6.5x.284 to get 3k fps velocity. I tried it and diddn't like it and I am going back to 6.5x55 SE with a tight chamber 30 inch tube.

I am going to be using 48-49.5 grains of VIN N560...which is a slower powder than 4350 which along with moly should extend my barrel's life. Well at least I hope even though Dan and Alan seem to think otherwise.

RHINOUT!

 

[WayneShaw]

I agree with Rhino, I think you can get the velocity with something other than the 284 case. I'm going to see what I can get out of a plain old Swede using Lapua brass, bet I can get close!

 

[AlanPF]

I think its just become fashionable to say the 6.5x284 is a barrel burner. There are worse chamberings for barrel wear, and many commonly used ones that aren't much better. If you load to about 2900 to 2950 fps using slower cooler powders such as H4831SC and H1000, you can get up to 1800 rounds, possibly more with waxed moly. And at these velocities, brass life is excellent, and much better than some of the lower capacity cases pushed to limit to reach 2950fps. I shouldn't be telling you this - the less 6.5x284s out there, the better my chances because I have one !

Alan

 

[tenring]

Its called "overbore capacity"; i.e. the bullet diameter is small compared to the case capacity. I loaded a mild 48.0 grs H4831sc with the 142 gr. SMK exclusively in my 6.5-284 28" bbl., and the throat eroded in 1,200 rounds.

 

[mysticplayer]

My 6.5 Mystic which is my version of the 260AI has been getting excellent barrel life. Burning H4831SC, the first 900rds has moved my throat no more then 20thou. At this present rate of erosion, the barrel might make it another 2000rds before needing a set back. This assumes that erosion is linear with use. That I don't know for sure. Pressures are certainly not mild.

I can get close to 3000fps in my 30" Gaillard barrel and 139gr Lapuas no moly. I find best accuracy in the 2900 to 2950fps range.

I think excessive bore erosion is due in large part by using a 'fast' powder relative to the case and velocity. I do not shoot a 6.5-284 but hear H4350 is a common powder.

In that large of a case, 4350 would be considered 'fast' and would likely be consumed closer to the throat. Load density is very low.

A better powder would be the H1000, maybe even Retumbo or Re25. At near 100% or even slightly compressed, these slow powders will burn over a much longer time concentrating less total heat in the throat area.

Downside may be that the bullet is now going faster then it likes to. I would expect a 6.5-284 to push a 139/142gr bullet to at least 3100, more likely 3200fps given the extra case capacity. However, many of these bullets prefer to shoot at 2950fps.

Using a slow powder will likely show the same dividends that 243AI shooters are seeing using H1000.

There are a few threads on the 6CM which is getting very long real world throat life. A case like that should be a 'barrel burner' but isn't due in large part by the powder choice.

Many shooters shooting 260AI and similar sized cases would lean towards the h4350 for a powder. I think for longer throat life, H4831SC is the better choice IF you can make it shoot in your rifle. Nothing slower will fit in the case and still give adequate performance.

I have just started shooting a 223 with 75gr Amax. The powder of choice here is Varget but I am finding it too 'fast'. I am now testing H4350 after the initial testing was very promising.

Jerry

 

[Spotcheck_Billy]

I really think that the answer to your question mostly depends on what kind of accuracy you're talking about. The 6.5-284 is primarily a competition cartridge, and competitors using this cartridge commonly throw away a barrel long before it's through giving the kind of accuracy that would be perfectly acceptable to hunters shooting some of the other cartridges that you've mentioned.

The top competitors using cartridges like the 6.5-284 view barrels as a renewable commodity. Those that seek longer barrel life most often go to "lesser" cartridges, with no disrespect implied or intended. You might want to check out the "Gun of the Week" archives for a good idea of what many of the top shooters are using for long range competition. You'll get a good idea of loads, barrel life, etc.

 

[chrisj]

I think its just become fashionable to say the 6.5x284 is a barrel burner. There are worse chamberings for barrel wear, and many commonly used ones that aren't much better. If you load to about 2900 to 2950 fps using slower cooler powders such as H4831SC and H1000, you can get up to 1800 rounds, possibly more with waxed moly. And at these velocities, brass life is excellent, and much better than some of the lower capacity cases pushed to limit to reach 2950fps. I shouldn't be telling you this - the less 6.5x284s out there, the better my chances because I have one !

Alan

It isn't just fashionable..it's true. I agree that some shooters who have never shot a 6.5-284 are calling it a bbl burner. I know of many HP shooters who have toasted their bbls @ 1200 rounds or less. Some have only gone 800-900 rounds. When shooting 1000 yds..You can't have a 1.5 moa rifle or a rifle that shoots 8 shots into 1 moa and the next 2 shots which opens the group to 3 moa. 6.5-284 is a bbl burner if you consider 1200 rounds bbl life a bbl burner.

Chris

 

[rcw3]

Don't fret over whether a cartridge is a barrel burner. Look at it this way - the quicker it burns out, the sooner you have an excuse to rebarrel and try another "toy". I have to say, when I have a great barrel that shoots very very well, I hate to see it die. It's all compromises, you want the performance, you have to pay the price somewhere - you can fiddle with moly or different powders and maybe get some more life, but ultimately if you push things hard, it costs.

Robert Whitley

 

[chrisj]

Don't fret over whether a cartridge is a barrel burner. Look at it this way - the quicker it burns out, the sooner you have an excuse to rebarrel and try another "toy". I have to say, when I have a great barrel that shoots very very well, I hate to see it die. It's all compromises, you want the performance, you have to pay the price somewhere - you can fiddle with moly or different powders and maybe get some more life, but ultimately if you push things hard, it costs.

Robert Whitley

LOL Robert...You try a new caliber? NO....LOL
BTW Robert...of all the 6mm's that you are experimenting with; which one is working out best for you and which is giving the best barrel life?

Chris

 

[2644ever]

Right on, Chris!
If we look at the bucks we dump into our passion, the aggravation and the frustration of not having our hardware not behaving as it should or would, the price of a good barrel is very low indeed... I don't mean it shouldn't be considered, of course, but I'd rather see a barrel as a part you gotta replace someday. Just as you gotta replace your brass from time to time... as well as your bullets

 

[Spotcheck_Billy]

I don't see why the 6.5-284 is being singled out. I've toasted my share of .22-250's and .243's in sometimes less than 1200 rounds shooting varmints. You either accept the price that you have to pay for using a high performance round or you learn to live with the .223 and the .308

Not that there's anything wrong with those two cartridges. I use and own more rifles in those calibers that any others. I'm presently experimenting with a .243 and 115 DTAC bullets while I'm waiting for a 6.5x47 barrel for one project and a new 6.5-284 barreled action for another. The .243/DTAC combo is showing some excellent performance, but I'd be kidding myself if I thought it would exhibit significantly better barrel life than a 6.5-284.

I witnessed a fellow shooter at our club range try to equal 6.5-284 performance with better barrel life by going to a 6.5x55 Swede last summer. The very slow powder approach didn't work,'cause he couldn't get enough of it crammed into the case to produce decent velocities. At this point it's looking like a 100-200fps slower 6.5-284 with perhaps 200 rds better barrel life. Not really worth it, IMO!

 

[rcw3]

LOL Robert...You try a new caliber? NO....LOL
BTW Robert...of all the 6mm's that you are experimenting with; which one is working out best for you and which is giving the best barrel life?

Chris

Chris

It's hard to say since winter weather in my area is putting quite a damper on things. For the upcoming season I am looking forward to trying out a number of 6mm's in bolt guns,6CM, 6mm Super X, 6mm Rem) as well as my continuing work with the 6mmAR in the AR-15. In addition Lapua just sent me some of their new 6.5 x47 Lapua factory ammo. I will be testing it out as well,beautiful stuff). So many options - so little time.

Robert Whitley

 

[AlanPF]

Regarding the 6.5x284, perhaps the next question should be, why is it so successful and popular when its such a barrel burner? My answer would be that this chambering is a good compromise between running costs and performance, particularly in F-Class. Its recoil is as high as most like to go with an unbraked 10Kg rifle, and it shoots high BC bullets at their optimum velocity with moderate pressure and good accuracy. One of the prices you pay for this excellent cartridge is a shortish barrel life. But barrel life should be treated as just another running cost. In my case the difference between a 1500 shot and 3000 shot barrel life is about 7% of my total shooting running costs. Its worth it.

Alan

 

[chrisj]

I agree with Alan on most points here. Here is the downside of a "bbl burner" caliber like the 6.5-284...

I used to shoot the 6.5-284, and I practiced about twice a week. I fired approximately 40-50 rounds each time.
I started in March, and by the middle of the summer,between practice and matches) the bbl was shooting like crap. I had to rebarrel in the middle of the summer...wait 2 weeks to have the work done, and work up a whole new load for the new bbl.
A caliber that gets 2000 rounds or so would at least do for 1 whole season for me and others like me.
The 260 Rem AI, 6.5x55, 6 Dasher, 284 Win and a host of others will go 2K rounds and will give similar performance in my experience.
If someone shoots enough to burn a bbl out before seasons end..you may want to chamber 2 bbls at the same time, then you can screw on the other bbl and have the same manufacture bbbl and same chamber. Loads should be very close.

Chris

 

[AlanPF]

Chris,

For what you do, the 6.5x284 is probably not ideal, particularly if you're firing 40 or 50 rounds relatively quickly. I use a few strategies to save barrel life e.g. using slower powders, moly bullets,jury still out on that!), buy 2 barrels at a time and run different loads,for short and long range) in each, thus reducing load development time as a percentage of each barrel's life. And I only "machine-gun" when conditions dictate - otherwise I take my time between shots. And strings are never more than 13 shots,in about 10 to 15 minutes). Most experts agree that a very hot barrel will erode faster.

But one of the main reasons I prefer the 6.5x284 to for example a 260, is that I get to do some marking of targets most weeks, and every time I see a shot very close to the line at 3 or 9 o'clock,which is quite often on our Australian targets), I wonder if the difference between touching the line and not, is about 50 or 100fps muzzle velocity!

Alan