6.5x55 vs 6.5x284

[rhino]

For a brand new shooter...I wouldn't hestitate to point them towards the new Savage Target 6.5x.284 norma.

You can always learn what you want and keep and or change to another caliber on a Savage quite easily.

6.5 140 berger going 2950 either from a 6.5x.284 or 6.5x55se or .260 AI is going to perform the same in the wind regardless.

Now ES, SD and how good your rifle is put together and smithed comes into play.

Now for me I like the Swede, others swear by the 6.5x.284, others the .260 AI.

If all of us are getting good results then can you really say one is better than the other?

I am by no means an expert and still learning. Whatever you choose good luck and keep shooting!

RHINOUT!

 

[ConnorExum]

The information that needs to be read about this, was covered some years ago in PS magazine by articles written by a rocket scientist. Among the factors covered was the reflective nature of the inside of the ctg and how it factored in the burn.

One thing to keep in mind about powder in the bore is just this, it is not "unburned powder", it in fact is burning powder that is traveling down the bore in a fluid mass.

The series of articles by the rocket guy and another fellow brought to some vary interesting conclusions about the shape a ctg should be. They were never able to produce such cases for a number of mechanical reasons. The entire effort was because of bore erosion problems. You might change some of your understanding if you were to read this material. Often we find good information outside the normal sources when we read what the thoughts and conclusion from people with different disciplines.

The rocket scientist started from the point that the erosion in rifle bores reminded him of similar problems he had had with rocket motors and exhaust nozzles. His methods of correction for his problems in his field.

I have no interest in any arguments with you,or anyone). My wish is, to only provide my understanding on the subject.

You see I don't think we are disagreeing as much as it might appear. We have a lot of variables to consider here and each one is going to affect the barrel in a specific manner. I don't discredit any effects of burning powder in the bore. However, I'm curious as to if that is the true destroyer of accuracy. If that effect was so detrimental to barrel life; I don't think cutting a barrel back and re-chambering it would be a solution to accuracy loss. It appears that throat wear is the most problematic factor in accuracy, and it would appear that temperature is the biggest factor in that sort of region as to wear. The ejection of a fluid-mass of particles in the bore would appear to be a function of particle density and the velocity of the gas. So yeah you increase this effect by spewing more powder into the bore at higher temperatures and velocities. Yet, I think this sort of wear would show up as pits or holes in the bore, perhaps even micro grooves where hot particles are pushed along the axial plane of the bore. I'm sure there are signs of it. But how does this take to really affect accuracy? Still I think we cannot underestimate the effects of pressure on gas temperature at the throat. That scaling effect is usually do to high temperatures, and accuracy does seem to improve from cutting back and re-chambering, so that's curious. We would need to model it more.

So what designs of cartridges did they develop? Spherical looking ones? That would seem to be the type of cartridge that would avoid this problem with probably a flash-tube type ignition system.

 

[ConnorExum]

For a brand new shooter...I wouldn't hestitate to point them towards the new Savage Target 6.5x.284 norma.

You can always learn what you want and keep and or change to another caliber on a Savage quite easily.

6.5 140 berger going 2950 either from a 6.5x.284 or 6.5x55se or .260 AI is going to perform the same in the wind regardless.

Now ES, SD and how good your rifle is put together and smithed comes into play.

Now for me I like the Swede, others swear by the 6.5x.284, others the .260 AI.

If all of us are getting good results then can you really say one is better than the other?

I am by no means an expert and still learning. Whatever you choose good luck and keep shooting!

RHINOUT!

are you shooting a basic 6.5x55 or are you improving the case some?

 

[rhino]

Currently shooting a straight 6.5x55se. Custom reamer .294 neck .112 free bore all SAMI min specs. I have to turn necks, but hell it don't bother me.

Proteus-x is also shooting same reamer and is doing a more in-depth analysis of the caliber. He is comming off a .260 AI.

RHINOUT!

 

[ConnorExum]

Currently shooting a straight 6.5x55se. Custom reamer .294 neck .112 free bore all SAMI min specs. I have to turn necks, but hell it don't bother me.

Proteus-x is also shooting same reamer and is doing a more in-depth analysis of the caliber. He is comming off a .260 AI.

RHINOUT!

I like the 6.5x47mm myself... I think that it has some potential. But the 6.5x55mm has some alluring appeal to me too. But I think the 6.5x47mm will provide a better platform for my rifle... A 600yard across the course rifle... I'm think Grunig & Elmiger actually.

 

[rhino]

600 yards then ya a 6.5x47 lapua would make sense. No sense of lighting more powder when you don't have too.

I do have my doubts about that caliber pushing a 140 class bullet to 2950 without serious brass life issues and pressure.

However if you're pushing a 120-130 class to 2950 fps then I can foresee it.

RHINOUT!

 

[ConnorExum]

600 yards then ya a 6.5x47 lapua would make sense. No sense of lighting more powder when you don't have too.

I do have my doubts about that caliber pushing a 140 class bullet to 2950 without serious brass life issues and pressure.

However if you're pushing a 120-130 class to 2950 fps then I can foresee it.

RHINOUT!

2800-2890fps with 139-147grain bullets should be do able with 6.5x47mm and that should get me out 600yards and even beyond without too much trouble.

 

[Spotcheck_Billy]

I started playing with the 6.5x47 Lapua this summer. My best load uses the 123 Scenar over a reasonably hot charge of Re15 for a MV of 2990 out of my 28" barrel and yields superb accuracy. Case life has been great, with absolutely no stretching and primer pockets have remained as tight as new,so far) after 5 reloads and counting. Working up to this load was very easy by using the data that Robert Whitley provided in his 6mmhot website. It's rapidly becoming my favorite cartridge!

Because I also shoot a 6.5-284 Norma I haven't yet tried the heavier bullets in the Lapua, but I'd like to see if any of you guys have been able to get decent velocities with them without pushing the pressure limit. I'm thinking that the 130 Berger VLD might be optimum for the Lapua and intend to try them in the spring. I'll post my results then.

 

[ConnorExum]

I started playing with the 6.5x47 Lapua this summer. My best load uses the 123 Scenar over a reasonably hot charge of Re15 for a MV of 2990 out of my 28" barrel and yields superb accuracy. Case life has been great, with absolutely no stretching and primer pockets have remained as tight as new,so far) after 5 reloads and counting. Working up to this load was very easy by using the data that Robert Whitley provided in his 6mmhot website. It's rapidly becoming my favorite cartridge!

Because I also shoot a 6.5-284 Norma I haven't yet tried the heavier bullets in the Lapua, but I'd like to see if any of you guys have been able to get decent velocities with them without pushing the pressure limit. I'm thinking that the 130 Berger VLD might be optimum for the Lapua and intend to try them in the spring. I'll post my results then.

Supposedly you can get the 120-130 class bullets up to nearly 3200fps... are you saying that is impossible without pressure issues and excessive case wear?

 

[Spotcheck_Billy]

Supposedly you can get the 120-130 class bullets up to nearly 3200fps... are you saying that is impossible without pressure issues and excessive case wear?

I haven't tried pushing the 120-130 class bullets from my 6.5x47 that fast, so I can't answer your question from my personal experience. I tend to think that "supposedly" is the key word here. Personally, I'm sceptical. There are too many internet velocity claims out there that are easily posted but not so easily backed up. My gut feeling is that there's just not enough space in the boiler room of this small cartridge.

Considering that the Lapua case was designed with a very strong web featuring the use of a small rifle primer it's conceivable that pressures could be pushed past reasonably safe limits without expanding the primer pockets so I wouldn't necessarily use that as an indicator. Perhaps sticky bolt lift, excessive case head expansion, and case stretching could serve as guidelines. It would be interesting to find out for sure.

 

[ConnorExum]

Supposedly you can get the 120-130 class bullets up to nearly 3200fps... are you saying that is impossible without pressure issues and excessive case wear?

I haven't tried pushing the 120-130 class bullets from my 6.5x47 that fast, so I can't answer your question from my personal experience. I tend to think that "supposedly" is the key word here. Personally, I'm sceptical. There are too many internet velocity claims out there that are easily posted but not so easily backed up. My gut feeling is that there's just not enough space in the boiler room of this small cartridge.

Considering that the Lapua case was designed with a very strong web featuring the use of a small rifle primer it's conceivable that pressures could be pushed past reasonably safe limits without expanding the primer pockets so I wouldn't necessarily use that as an indicator. Perhaps sticky bolt lift, excessive case head expansion, and case stretching could serve as guidelines. It would be interesting to find out for sure.

http://www.6mmbr.com/gunweek072.html

I figured this guy wouldn't be lying especially since it is in guns of the week selection here.

I don't know I think that 30 inches is the perfect barrel length the cartridge however. Perhaps the 2 extra inches over the 28 will help?

 

[Spotcheck_Billy]

Supposedly you can get the 120-130 class bullets up to nearly 3200fps... are you saying that is impossible without pressure issues and excessive case wear?

I haven't tried pushing the 120-130 class bullets from my 6.5x47 that fast, so I can't answer your question from my personal experience. I tend to think that "supposedly" is the key word here. Personally, I'm sceptical. There are too many internet velocity claims out there that are easily posted but not so easily backed up. My gut feeling is that there's just not enough space in the boiler room of this small cartridge.

Considering that the Lapua case was designed with a very strong web featuring the use of a small rifle primer it's conceivable that pressures could be pushed past reasonably safe limits without expanding the primer pockets so I wouldn't necessarily use that as an indicator. Perhaps sticky bolt lift, excessive case head expansion, and case stretching could serve as guidelines. It would be interesting to find out for sure.

http://www.6mmbr.com/gunweek072.html

I figured this guy wouldn't be lying especially since it is in guns of the week selection here.

I don't know I think that 30 inches is the perfect barrel length the cartridge however. Perhaps the 2 extra inches over the 28 will help?

Darrell's not lying!

You were initially talking about the 3200 MV range! Darrell tried pushing 120 SMK's at 3198 but it ruined his brass.

His competition load goes at 3068 MV with 120 SMK's. That's more within reason IMO. I noticed that he's getting great accuracy pushing 120gr. Cauterico bullets @ 3054 MV with 39.0gr. of Re15. He reports an ES of 22 and SD of 11. I'm getting 2990 MV over my Oehler 35 with 123 Scenar's with 37.5gr of Re15, seeing an ES of 11 with a SD of 4 and my groups are every bit as good as Darrell's. That's 64 fps less velocity using 1.5 grs. less powder. Not saying that there's a damned thing wrong with Darrell's load, but mine works for me I think that the differences in individual barrels,mine's a 1/8.5 twist 5R Border) could go a long way in explaining the different results.

In any case, after reading the article I'm even more convinced that 3200 MV is unrealistic from a 6.5x47 with 120gr+ bullets.

I don't believe that there would be very much to gain by going to a 30",over a 28") barrel with this cartridge. I think that 28" is all that's required to burn between 37-39.5 grs of powders like Re15 in a 6.5mm bore.

 

[ConnorExum]

Supposedly you can get the 120-130 class bullets up to nearly 3200fps... are you saying that is impossible without pressure issues and excessive case wear?

I haven't tried pushing the 120-130 class bullets from my 6.5x47 that fast, so I can't answer your question from my personal experience. I tend to think that "supposedly" is the key word here. Personally, I'm sceptical. There are too many internet velocity claims out there that are easily posted but not so easily backed up. My gut feeling is that there's just not enough space in the boiler room of this small cartridge.

Considering that the Lapua case was designed with a very strong web featuring the use of a small rifle primer it's conceivable that pressures could be pushed past reasonably safe limits without expanding the primer pockets so I wouldn't necessarily use that as an indicator. Perhaps sticky bolt lift, excessive case head expansion, and case stretching could serve as guidelines. It would be interesting to find out for sure.

http://www.6mmbr.com/gunweek072.html

I figured this guy wouldn't be lying especially since it is in guns of the week selection here.

I don't know I think that 30 inches is the perfect barrel length the cartridge however. Perhaps the 2 extra inches over the 28 will help?

Darrell's not lying!

You were initially talking about the 3200 MV range! Darrell tried pushing 120 SMK's at 3198 but it ruined his brass.

His competition load goes at 3068 MV with 120 SMK's. That's more within reason IMO. I noticed that he's getting great accuracy pushing 120gr. Cauterico bullets @ 3054 MV with 39.0gr. of Re15. He reports an ES of 22 and SD of 11. I'm getting 2990 MV over my Oehler 35 with 123 Scenar's with 37.5gr of Re15, seeing an ES of 11 with a SD of 4 and my groups are every bit as good as Darrell's. That's 64 fps less velocity using 1.5 grs. less powder. Not saying that there's a damned thing wrong with Darrell's load, but mine works for me I think that the differences in individual barrels,mine's a 1/8.5 twist 5R Border) could go a long way in explaining the different results.

In any case, after reading the article I'm even more convinced that 3200 MV is unrealistic from a 6.5x47 with 120gr+ bullets.

I don't believe that there would be very much to gain by going to a 30",over a 28") barrel with this cartridge. I think that 28" is all that's required to burn between 37-39.5 grs of powders like Re15 in a 6.5mm bore.

I wasn't saying the source was lying, I just trying to say that source seems pretty reliable. And not just internet ramblings.

To get the 3198 with 120's Darrell had to use 42.5grains of powder. Which was excessive, I figure backing down to 42.0-42.1grains of powder and increasing the barrel length by 2 inches might make up the difference. Clearly, with loads in the lower end of the range the velocity difference will be marginal with a 30 inch barrel over that of a 28 inch barrel. Where I'm trying to get better results is at the extreme end of the spectrum where the pressures are higher already just increase the time that this pressure can affect the built's velocity.

 

[rhino]

6.5x47 lapua looks very interesting. I just wonder if your shooting at lets say 65,000 psi with less powder compared to 56,000 psi and more powder what the difference is bore life would be.

I have my Savage Platform I have for a test rifle, perhaps she is in need of something new to screw onto her in the future I'll think over the 6.5x47 lapua.

I was thinking the .280 AI...but you never know.

RHINOUT!

 

[ConnorExum]

6.5x47 lapua looks very interesting. I just wonder if your shooting at lets say 65,000 psi with less powder compared to 56,000 psi and more powder what the difference is bore life would be.

I have my Savage Platform I have for a test rifle, perhaps she is in need of something new to screw onto her in the future I'll think over the 6.5x47 lapua.

I was thinking the .280 AI...but you never know.

RHINOUT!

Well competition barrels are meant to be used! And used hard!

 

[rhino]

no doubt. no doubt.

If your a serious competition shooter...this excludes me...you'll burn 2 barrels or so a year. I'll burn one barrel every 2-3 years.

Hopefully things will free up more in the future for more load development and testing.

I really would like to shoot more...just no time.

RHINOUT!

 

[Spotcheck_Billy]

Rhino,
You make an excellent point about barrel life vs. pressure in the 6.5x47 Lapua. I have no way of measuring the pressure of my 37.5 gr Re15/ 123 Scenar load but it sure would be interesting to find out. Pressures in the 60k range are certainly possible.

So far, I've not heard of anybody who's shot enough rounds down the tube of his 6.5x47 to know just what the barrel life will be and I'd rather not be the first to find out

 

[rhino]

Whats interesting is that you lighting around 10 grains less powder per charge than I am.

I shoot 47.6 grains of VIN N560 to drive the 140 class bullets to 2950. 4 shots and your up a case on me

I am going to try H4350 and H4831 sc again this year and see what happens. Tighter custom chamber and a more consistant chronograph OEHLER 35, should help a little.

My intial testings were done 4-5 years ago in my Tikka MS with a factory chamber and 23.5 inch barrel.

RHINOUT!

 

[mysticplayer]

I enjoyed reading the last few pages of tech on barrel erosion et al.

One thing that I feel must be said is all of this is being done WITHOUT a way of measuring chamber pressure.

With zero tolerance, super strong actions with tight firing pin holes, sumo brass, etc, all of the traditional pressures signs are hindered.

We see that with both the 6PPC and 6BR. The 6BR is casually run at 243 performance which IS held to pressure standards.

Can we run at higher then the normal SAAMI 50,000ish PSI? Of course, I routinely run at magnum pressures. This is considered 62 to 65000psi. But much higher and we are into proof loads.

To get these very small cases to push a bullet to such high velocities, I feel we are treading dangerously close to/even exceeding proof load pressures.

Will your custom action bolt open with one finger? You bet. The actions are that well made. However, pressure is pressure as is fatigue. At some point, a rifle fails and someone,s) may get hurt.

From a liability standpoint, if nothing else, we should have disclaimers on load data. A load in a Nesika that shows no pressure signs, might just do some damage to a Rem.

Like car racing, you can get a 1.6L 4 cyc engine to make as much power as a stock 5L V8. Which is more likely to fail during a race?

I know, I know...being quite the mother hen especially on the dawn of a new year.

I just think that someone should put a strain guage on some of these very hot loads. Might give you pause for thought. Also, I have found that all of my match barrels and brass, don't like shooting at excessive pressures.

If I need more speed, I go to the next larger case. Barrels are consumables.

To all, have a most wonderful New Years, be safe and shoot even smaller groups.

Jerry

 

[ConnorExum]

I enjoyed reading the last few pages of tech on barrel erosion et al.

One thing that I feel must be said is all of this is being done WITHOUT a way of measuring chamber pressure.

With zero tolerance, super strong actions with tight firing pin holes, sumo brass, etc, all of the traditional pressures signs are hindered.

We see that with both the 6PPC and 6BR. The 6BR is casually run at 243 performance which IS held to pressure standards.

Can we run at higher then the normal SAAMI 50,000ish PSI? Of course, I routinely run at magnum pressures. This is considered 62 to 65000psi. But much higher and we are into proof loads.

To get these very small cases to push a bullet to such high velocities, I feel we are treading dangerously close to/even exceeding proof load pressures.

Will your custom action bolt open with one finger? You bet. The actions are that well made. However, pressure is pressure as is fatigue. At some point, a rifle fails and someone,s) may get hurt.

From a liability standpoint, if nothing else, we should have disclaimers on load data. A load in a Nesika that shows no pressure signs, might just do some damage to a Rem.

Like car racing, you can get a 1.6L 4 cyc engine to make as much power as a stock 5L V8. Which is more likely to fail during a race?

I know, I know...being quite the mother hen especially on the dawn of a new year.

I just think that someone should put a strain guage on some of these very hot loads. Might give you pause for thought. Also, I have found that all of my match barrels and brass, don't like shooting at excessive pressures.

If I need more speed, I go to the next larger case. Barrels are consumables.

To all, have a most wonderful New Years, be safe and shoot even smaller groups.

Jerry

NO, you're absolute correct, that we need to put disclaimers on all loading data. Not all actions are create equal, nor are all cases... I agree completely in this respect and I would never claim pushing a cartridge to unsafe limits in pressure is an advisable solution.