6.5x284 Throat Burner

[swpc629]

I keep seeing where some people refer to the 6.5x284 as a throat burner. Why is this? Most loads for it are around 3000 fps. Usually when you refer to a caliber as a throat burner it is pushing 4000 fps and above.

 

[steeltraps]

I have had several 6.5x284s over the years. Expect 800- 1400 rds out of barrell. I had one HART barrell i shot out in 900 rds. Its depends on who much and how fast you shoot iT. In mathes with 20 shots per string of 20 minutes, it doesnt take long to burn the throat out of one! I had a bartlein that shot 1/4 moa till 1000 rds then went to 1/2 moa. Buy the time it hit 1400 rds it wad 3/4 moa. I have shot 140 vld bergers out to 1500 yards and the 6.5 bergers do very well at distance!

 

[MudRunner2005]

Once you get past 3K fps, barrel life will show a sharper decline...Regardless of what caliber it is. Which is partially why the .308 Win lasts ****-near forever. That, and it has large bore with a small case capacity.

The smaller the bore, with the larger the case, the faster the bullet...Usually tends to burn out barrels faster than a big bore with a large case.

For example 2 calibers with the same case... 7mm RUM and .338 RUM. The .338 RUM will get significantly better barrel life over the 7mm RUM because it is #1 slower, and #2 has a larger bore diameter for the gasses to pressurize in and push the bullet down, so they're not quite as concentrated.

Yes, the 6.5-284 is a throat burner. You're talking about necking down a .284 WinMag to a smaller diameter bullet, that is faster and a smaller diameter bore for more powder to burn in... Which will equal a longer and more concentrated flame (hotter) coming out of the case onto the throat, propelling the bullet at higher speeds. No matter what caliber, if this is the scenario, it's gonna burn throats.

If you want a 6.5 caliber that's not such a bad throat burner, but gets good velocity, look into the .260 Rem Ackley Improved.

 

[steeltraps]

Correct. The 260 is a great choice. I jave a tight neck 260 with a bartlein 1-8 palma thats getting 2980 fps with 43.5 gr of rl-17. My friend has a custom 6.5x47 that also shoots 140 bergers 2900 fps. This gun has 2100 rds threw it and the gun still shoots 1/2 moa.

 

[Trickymissfit]

I wouldn't call it a barrel burner like many other well thought of calibers often mentioned on the board. It's better than a .243, but that's nothing to be bragging about. I've known guys that got 1000 rounds out of C/M barrels, and I've also known a couple that saw less than 500 rounds out of a couple gold plated king of the hill barrels that are often regarded as the best money could buy. I Think a lot of it is how you load the rounds and the powder burn rates. Certainly it won't last nearly as long as a 6.5-06 or even sorta close to the 6.5/.257AI. Still it's a .264 bore, and just how many thousand rounds do you plan on shooting?

The 6.5-284 like the 6.5-06 is starting to get into overbore, and of course barrels suffer. The 6.5/257 is about perfect capacity wise and the 2900fps with a 140 grain bullet shows this. My only complaint is that I've seen cases dry up to un-obtanium twice in my lifetime, so I would not go for it. Still I've long felt the 6.5-284 tobe 150% better than all the 6-284's ever built.
gary

 

[johnnyk]

"a .284 WinMag" stated in an earlier post should have read "284 Win". JohnnyK.

 

[Mateo]

It's not speed that kills, it's pressure. That being said, to get more speed it takes more pressure, most of the time. There are some powders that will get the same speed with lower pressures. This will extend barrel life. A good example of this is the 6.5 SAUM or the 6.5 SS. These are wildcats designed to use low pressure powders (H1000/Retumbo) and still get decent velocity. 3200 fps with 130/140 gr bullets. Round count for the 6.5 SAUM is up there at 3000+. I don't think the 6.5 SS has been around long enough to have burned out a barrel yet.

 

[Trickymissfit]

It's not speed that kills, it's pressure. That being said, to get more speed it takes more pressure, most of the time. There are some powders that will get the same speed with lower pressures. This will extend barrel life. A good example of this is the 6.5 SAUM or the 6.5 SS. These are wildcats designed to use low pressure powders (H1000/Retumbo) and still get decent velocity. 3200 fps with 130/140 gr bullets. Round count for the 6.5 SAUM is up there at 3000+. I don't think the 6.5 SS has been around long enough to have burned out a barrel yet.

agree with you yes, but also disagree with you somewhat. Heat is what erodes the throat, and not basic pressures by themselves. Low pressure does tend to avoid the issue of blasting the throat and barrel with unburnt powder, or hot burning gases with intensity. The basic shape of the case and neck also have a good part of this equation. Forty degree and beyond shoulders with at least a caliber and a quarter neck length seem to give far better throat lives. The 6.5/284 has a 35 degree shoulder, and this is a big plus for that particular cartridge. Yet the neck length is barely adequate. Had it been another .06" to .093", I think we're looking at a spectacular cartridge. 3200fps with a 140 grain bullet and H1000 powder powders seems like 75K psi pressures to me. Maybe I'm wrong, but a look in several manuals doesn't even come close to that. The Hornaday manual is 500fps slower, but also can see that load to be a little light. A heavy load of Magpro in that case and using the 140 grain bullet will get you a little over 3000fps @ 61K psi. That looks right as the case capacity is slightly less than a 6.5-06, and that's close for max safe load in it. Yet the 6.5/.257AI will do an honest 2900fps with the same bullets and using less powder. Perhaps Kirby will chime in here as his case design off the .270 improved design might add some better light to the subject.
gary

 

[Mateo]

agree with you yes, but also disagree with you somewhat. Heat is what erodes the throat, and not basic pressures by themselves. Low pressure does tend to avoid the issue of blasting the throat and barrel with unburnt powder, or hot burning gases with intensity. The basic shape of the case and neck also have a good part of this equation. Forty degree and beyond shoulders with at least a caliber and a quarter neck length seem to give far better throat lives. The 6.5/284 has a 35 degree shoulder, and this is a big plus for that particular cartridge. Yet the neck length is barely adequate. Had it been another .06" to .093", I think we're looking at a spectacular cartridge. 3200fps with a 140 grain bullet and H1000 powder powders seems like 75K psi pressures to me. Maybe I'm wrong, but a look in several manuals doesn't even come close to that. The Hornaday manual is 500fps slower, but also can see that load to be a little light. A heavy load of Magpro in that case and using the 140 grain bullet will get you a little over 3000fps @ 61K psi. That looks right as the case capacity is slightly less than a 6.5-06, and that's close for max safe load in it. Yet the 6.5/.257AI will do an honest 2900fps with the same bullets and using less powder. Perhaps Kirby will chime in here as his case design off the .270 improved design might add some better light to the subject.
gary

You are absolutely right. It is heat that eroded the throat. Pressures go with heat , but heat is more of an accurate term. Real world testing can show different results than what computer models would predict. The guys at snipers hide tested the 6.5 SAUM and came up with numbers that seem too good to be true. 61.5 gr. of H1000
gave 3200 fps/130 gr bullet with less than 60,000 chamber pressure. At a glance this is impossible. But their barrel life is proving this true. These are exciting times to be a shooter with access to reamers and gunsmiths.