New Bullet Needed For 6.5 Cal!

[ThunderDownUnder]

6.5mm cal rifles are sweet shooting guns, they are not too big and not too small. You dont need Goldilocks to tell you just how right this caliber is but just as she had bears to contend with, we have bullets.

The bullet selection is almost good for long range target shooting but it isn't there yet. The 140gr VLDs with their best being a JLK with a G7 BC of 0.327 is almost right but when shot at competitive velocities out of a 6.5-284 the barrel life is short.

The 6.5x47L, 260 Rem, Grendal, Creedmoor, Swede, etc, dont burn barrels but dont have the horsepower to mix it with the big boys. The big boys being the 300WSM, 284W, 30 Boo Boo, etc, these calibers get the big heavy bullets with the high BCs but also suffer from increased recoil.

I would like to have low recoil and high BC, high enough to compete with say a 7mm, 180gr Berger VLD with a its G7 BC of 0.337. I think bullet manufacturers can make a 130gr VLD with a high G7 BC of around 0.330. Most of the 6.5 cal rifles could launch the 130gr bullets at 3000+fps and without the recoil of the bigger cals, this would be a match winner. The 130gr bullets would be easier on barrels than the current 140gr VLDs when shot at similar velocities from smaller cases. The need for barrel replacement after 600 shots would be overcome and shooting the 6.5 cal at high velocities would be common place.

What manufacturer will step up to the plate to be the first to produce a 130gr VLD bullet with a G7 BC of 0.330 or better? A ballistic tipped bullet could be made to achieve this request and that limits the manufacturers who could do it and do it well. Hornady stands out as a bullet maker that could do it and has considerable interest in the 6.5mm cal cartridge. It seems a no brainer, the first manufacturer to produce a truly high BC 130 gr bullet, stands to make a considerable return on the development of the product. We target shooters have a need for this just right caliber to gain a just right bullet.

What do you think?

Ian

 

[ChrisNZ]

I wouldn't complain Ian if someone pulled it off. I certainly don't need the barrel life of a 6.5-284, that's why I chose the Lapua. My main gunsmith/clubmate assures me 1000rnds is max for a 6.5-284 and he's replaced many at 800rnds.

Was talking to another gunsmith the other day and he related a very recent experience of a friend of his. This guy had been chasing max vel using RL17 in his 6.5-284. The thing started off well but went off the boil. They discovered with his bore scope the throat was toast at -285- rounds. Apparently the flame temp of RL17 is very high.

ChrisNZ

 

[ThunderDownUnder]

A smaller more efficient case than the necked down 284W is what we now have in abundance, 6.5x47L, creedmoor, etc, etc, we just need a light 130gr high BC bullet. I really think these new 6.5mm cases are the start of something big, a bit like the revolution that the 6mm BR and it variants got going.

We need the bullet makers to come up with a design that will give us what we want. Hey Bryan Litz, if your reading this can Berger Bullets do this or does it require the ballistic tip to enable the design. Have we got a manufacturer reading this thread that would like to comment?

Ian

 

[ThunderDownUnder]

Was talking to another gunsmith the other day and he related a very recent experience of a friend of his. This guy had been chasing max vel using RL17 in his 6.5-284. The thing started off well but went off the boil. They discovered with his bore scope the throat was toast at -285- rounds. Apparently the flame temp of RL17 is very high.

ChrisNZ

Thats very interesting Chris, I always wondered if there was a price to pay for the increased velocity of RL17

Ian

 

[cliffe]

so if the throat is going at 285 on a 6.5x284, when does the throat go on the 6.5x47 lapua about 600?????????? all of these barrel toast threads are always a guy i know, knows a guy that did......... sorry for hijacking this thread.
the first bullet mfg. that makes a 130 with a .330 bc will have a very optimistic computer program. cliffe

 

[Bryan Litz Ballistics]

Ian,

I'm with you on the analysis of recoil and ballistics of the 6.5 and 7mm's. You loose me with the notion that a 130 grain 6.5mm at higher velocity would not burn a barrel as fast as a slower 140 grain.

A 6.5mm 130 grain bullet with a G7 BC of .330 would have to have a G7 form factor of 0.81. It's not 'impossible', but the lowest form factor I've ever measured was in the .88 range. Most VLD's are around .92/.93'ish. It sound's like you want your lunch and to eat it too!!

Your on the right track, that if you want better ballistic performance with lower recoil, the only way to get there is with lower drag projectiles, but there is a practical lower limit. I don't see how shooting a 6.5mm 130 grain VLD faster than a 140 VLD will result in better barrel life. The bearing surface might be shorter, but with higher velocity I think the barrel life would be comparable.

There's no free lunch with physics. Ballistic performance is proportional to recoil. Better ballistic performance is usually obtained by high recoiling barrel burners. Think of it this way: if it was possible to make a 130 grain 6.5mm VLD with a form factor of .8 it might be able to outshoot a 140 VLD with a higher form factor. But wait, why couldn't you make the 140 VLD with the same .8 form factor? If that's possible, the 7mm 180 grain class bullets with form factors around .8 will blow you out of the water.

I like playing the 'what-if' games, but when you look at all aspects, it becomes clear that there's no free lunch. If you apply the same thinking that can make the smaller lighter bullet beat the bigger heavier bullet TO the bigger heavier bullet, then the bigger heavier bullet will always be the better ballistic performer.

Clear as mud, right

-Bryan

 

[ChrisNZ]

so if the throat is going at 285 on a 6.5x284, when does the throat go on the 6.5x47 lapua about 600?????????? all of these barrel toast threads are always a guy i know, knows a guy that did......... sorry for hijacking this thread.
the first bullet mfg. that makes a 130 with a .330 bc will have a very optimistic computer program. cliffe

The point is Cliffe that 285 rounds is pretty pathetic in terms of practical shooting, not just the cost but the fact that you're barely underway before you have to restart.

I'll try to get a borescope photo of the barrel mentioned. The guy that told me is a serious rifle builder and not prone to even a hint of BS. He has nothing against big bangers- his 7/.338L Imp drives 180s at 3445.. Now I hate to think how bad that barrel life is.

ChrisNZ

 

[ThunderDownUnder]

Bryan, thanks for taking the time to answer the question!

My reasoning for thinking high BC 130gr bullets traveling at 3000+fps would not burn barrels like the 140s at the same velocity is based on a smaller powder charge in a more efficient case launching it. I wasn't thinking of the friction aspect of the bullets in the barrel, just the thermal blast of hot gas being less and therefore less throat erosion resulting. Physics makes it clear that launching a 130gr bullet at 3000fps takes less energy than launching a 140gr bullet at the same velocity and at equal BC for both bullets I would rather shoot the low recoiling 130 grainer.

Its a shame I now have to face the fact that the high BC 130 VLD is nothing more than a dream. I am already shooting 139gr bullets in my 6.5x47L at 2920fps and am competitive with the big cals until the wind picks up velocity. It looks like I will have to develop great wind reading skills or get a 7mm barrel to be competive on those windy days at long range.

Ian

 

[cliffe]

chris, the point i am making is if the throat is going south with 285 rounds in a 6.5x284 case because it is a hotter burning powder, wouldn't the throat of a smaller case capacity be affected sooner as well. a barrel shot with a hot load should wear out faster than the same barrel with a slower load, right. if you shoot 50 grains in a 284 case and 41 in a 6.5x47 lapua, i can't see how one the throat is going at 285 and the other is shooting for 3000. cliffe

 

[expiper]

what brand bbl.

was it cut or button....some brands and types wear out kwiker....Roger

 

[CanusLatransSnpr]

From what I understand, throat life is dependent on two variables! The first being the charges of powder that are behind the bullet, and second, the bullet itself. A hot charge will take the throat faster than a mild charge. With bullets, lighter, shorter, low B.C. bullets will be easier on throats than heavier, longer, high B.C. bullets. Heavy VLDs seem to "wash" the throat out of a barrel. Think about it, a hot powder charge then a long, heavy bullet with alot of bearing surface traveling across this hot throat is going to take its toll sooner, rather than later.

Mike

 

[ChrisNZ]

chris, the point i am making is if the throat is going south with 285 rounds in a 6.5x284 case because it is a hotter burning powder, wouldn't the throat of a smaller case capacity be affected sooner as well. a barrel shot with a hot load should wear out faster than the same barrel with a slower load, right. if you shoot 50 grains in a 284 case and 41 in a 6.5x47 lapua, i can't see how one the throat is going at 285 and the other is shooting for 3000. cliffe

Cliffe- it largely comes down to a combination of the total amount of powder burned times the bore diameter. 50grs is going to hammer the throat far more than 41grs, the pressures held constant. Flame temp is an aggravating factor and no doubt fairly proportional to the energy density of the powder.
Projectile deisgn is a minor variable it seems

ChrisNZ

 

[ThunderDownUnder]

Maybe I gave up a bit too early on this concept of a high BC 6.5mm bullet. It seems CNC lathed turned bronze projectiles at the same price as current bullets will soon be available. I was reading the latest Feb Target Shooter Ezine and came across the article complete with pictures of various caliber bullets. Could be the start of the biggest BC improvement in bullets for some time.

Look here on page 9: http://www.targetshooter.co.uk/

Ian

 

[OKIE2]

From what I understand, throat life is dependent on two variables! The first being the charges of powder that are behind the bullet, and second, the bullet itself. A hot charge will take the throat faster than a mild charge. With bullets, lighter, shorter, low B.C. bullets will be easier on throats than heavier, longer, high B.C. bullets. Heavy VLDs seem to "wash" the throat out of a barrel. Think about it, a hot powder charge then a long, heavy bullet with alot of bearing surface traveling across this hot throat is going to take its toll sooner, rather than later.

Mike

If your bullet is set at the lands it seems to me the bullet would go through the throat first ahead of the hot gas. Am I wrong?

 

[Laurie]

Maybe I gave up a bit too early on this concept of a high BC 6.5mm bullet. It seems CNC lathed turned bronze projectiles at the same price as current bullets will soon be available. I was reading the latest Feb Target Shooter Ezine and came across the article complete with pictures of various caliber bullets. Could be the start of the biggest BC improvement in bullets for some time.

Look here on page 9: http://www.targetshooter.co.uk/

Ian

I should get some 0.308" samples to have a look at shortly in which case there will be a photo or two in the March issue of Targetshooter.co.uk in my look at .308 Win.

Machined mono-metal bullets are not necessarily unalloyed (pun!) good news however. As well as their increased length for any given weight and different load-pressure characteristics, many shooting and range authorities don't allow them. A few years ago, the UK's top 'Match Rifle' (.308W at 1,000-1,200yd with 5.5lb barrel weight restriction) competitors started using them successfully, but they're now banned by the UK NRA at Bisley and on all MoD military ranges on the basis of alleged ricochets from the backstops, likewise stories of jump-back from the sand into the butts pits endangering the markers. Also, the MoD looked at their BCs and said the increased potential range put them outside their firing-range danger area templates.

However ............... 'some people' said these problems either don't exist or were exaggerated in order to remove what was seen as a threat to their competiveness, and/or a likely source of cost escalation. I honestly don't know as I wasn't involved in any way. all I can say definitely was that the NRA and MoD looked at the use of these bullets and didn't like what they saw, hence the ban.


One competitive rifle-shooting discipline I've heard of their being used with great success is long-range, unknown distance sniper rifle competition, mostly loaded in .338 Lapua. They shoot so flat that the effect of range estimation errors are reduced substantially. I don't know if the new Berger long-range 338s will erode this advantage.

(See Lutz Moeller's English language website if interested

http://www.saxtech.eu/English/index.html

and click on the words 7th Annual Lapua Sniper Competition below the picture of the bullet.

Moeller is a German who machines solid copper banded bullets for both match and sporting shooting. His 338s were used in 2005 by the winner of the prestigious international Lapua Sniper competition held in Finland each year. He claims a BC of 0.93 for the LM-105 338


Laurie,
York, England

 

[ThunderDownUnder]

Laurie, I look forward to reading about how you get on shooting the machined mono-metal projectiles in 308W. You always have something interesting to say and your above contribution to this thread gave me an insight into some problems that may arise during the transition to new type projectile acceptance.

Ian

 

[aJR]

If the product lists are not telling lie's ,all of the bullets used to win 600/1000yd benchrest matchs in both the US and in Australia have been std jacketed lead core bullets .. This is over the last 5 years mind you as the 600yd match is a relatively new one ..The only arena that the CNC projectiles have any inroads is at 1000yds with the 50 cals ..Also at 1000 yds in the H/G class the world group record/ IBS group record/ the NBRSA group record and the Australian group record all belong to one projectile ,that is the 187 BIB 30 cal flat base bullet .. This bullet on any given Sunday is the bluntest tool in the chest on any range anywhere at a real world BC of .525, doesn't seem to be holding it back any and i know i'm not changing to .900 bc Mono bullets any time soon as i like things just the way they are now,,JR..Jeff Rogers

 

[Laurie]

Jeff,

I suspect that it's no coincidence that the two areas I know of where mono-metal bullets have done well, plus your mention of 50-cal shooting all provide major benefits to shooters with bullets whose BCs are exceptional. Match Rifle at 1,200yd is really pushing 308W's ballistic envelope and ultra long-range unknown range sniping matches also offer big potential benefits to somebody with a really flat shooting bullet that needs less elevation change for different stages and ranges. I can think of some F/TR shooters who might get excited too at the thought of a big reduction in wind deflection at 1,000yd - if it could drop .308W deflections to the same level as a good 6mm or the smaller 6.5s like 6.5X47L, such a user would have a huge competitive advantage ................ providing accuracy is as good as with a top-notch lead core bullet.

As you say, that's the question. The interesting scenario would be if accuracy is 'good enough'. Not everybody needs BR grouping capability, and the question might be how much trade-off in long-range group size a shooter would accept for a noticeable reduction in wind drift. Worth looking at!

Laurie

 

[mikecr]

You can get better barrel life, or better performance. It's a mystery to me how you can expect both.
The 6.5x47L nearly copies the 6XC. 50.9grH20cap[6.5x47] -vs- 51.4[6xc], and same case design except primer size.
Tubb did a great deal of testing(and winning) with the 6XC to conclude the best primer size before having brass made. He found that small primers were inferior w/greater than 35gr of powder.
The 6.5x47L has 4gr less H20 capacity than a standard .260, which get's good barrel life but is accepted as underpowered for 1Kyd competition(compared to the field).

So, on the surface the 6.5x47 appears to me an under capacity, under primered cartridge in 26cal. This of course is why so many are going 6-6.5x47L. As such, I predict it'll do well only at medium ranges, or on easy 1Kyd courses -on good days.

So how do you get more for less?
-Burn hotter/quicker powder for extreme pressures? You think you can run any pressure you like without a price? Or that you will be rewarded with better barrel life from this?
-Invent magic bullets? Please do, but your edge would be short lived. Solids(like Barnes & Lost River) have never shown to be as accurate as jacketed bullets though. And twist/stability requirements come with a price as well.

There must be basis for use of the 6.5x47L beyond it's intended -medium ranges. But I'm missing it.
Why couldn't anyone do what you WANT to do, with a 260, 6.5wssm, or 6.5-284? How is a small primer qualifying this cartridge as something better?

 

[ThunderDownUnder]

There must be basis for use of the 6.5x47L beyond it's intended -medium ranges. But I'm missing it.
Why couldn't anyone do what you WANT to do, with a 260, 6.5wssm, or 6.5-284? How is a small primer qualifying this cartridge as something better?

Hey Mike, good points you raise! I'm not recommending that anyone shoot a 6.5x47L at all ranges and expect it to be competitive with the 7mm/30 cals on the longs and in the wind.

I like the concept of getting the job done without the need to super size beyond what works well. The 6.5 cal in my opinion is a great caliber to shoot. If really high 6.5mm, 140gr, BC bullets were available like they are now in 180gr, 7mm and the 220gr, 30 cal bullets, then that would be a better way to go. I realise that at the moment that is not the case and that the 140gr, 6.5mm are a little behind in the BC stakes but if you dont ask you dont get!

I'm just asking the question of bullet makers can they do it? Bryan Litz rates it as not impossible and from reading about these new CNC bullets it may in fact happen in the near future. If I'm shooting a 6.5mm bullet with a higher BC than the big cals and at the same velocity, then the 260s and the 6.5x47Ls etc will rule. Not there yet, so your statement holds water and is the reason why the 6.5-284 is the pick of these cals for long range work.

Ian