6.5x47L 123 grainers vs 139's at 1000

[stubbicatt]

Reading the other thread on velocities with the 139-140 grain bullets, and not having chrono'd any loads in my rifle yet, I was prompted to use JBM Ballistics website, using data from Vihtavouri for the 123 and 139 Scenar bullets, and I find that using that data, the 123 grain Scenar has less drift and drop than the 139. It also stays supersonic a bit longer. Mind you the VV load data has the 139's at about 100 fps slower than what is posted here, something like 2744 fps.

VV data: http://www.lapua.com/en/products/reloading/vihtavuori-reloading-data/relodata/5/54

Then I changed velocities at the JBM calculator to 2850, which some say they are getting with the 139's, and the differences were negligible between drift with the 123 and 139, making the assumption that I can obtain 2850 in my rifle. I should have kept the pages open so I could post the results here. But the JBM page is www.jbmballistics.com

So I wonder, then, if I shouldn't concentrate on building a 123 grain load for F Open? At least initially... Heck in the Bulletin this morning there is a story about an Australian gentleman, Mr. Peter Varley, shooting this combo and getting a heck of a small group (something like 2.6 inches) at 1000 yards there in Australia. Per the Bulletin, wind conditions were calm, something I don't recall seeing at Colorado Rifle Club but maybe one time when I used to shoot there 14+ years ago. Even so, drift differences between 123 and 139 Scenar, even at the (what seems to me) optimistic 2850 for the 139 grainer, are negligible.

There is much work to be done yet in load development of course, before taking a decision, but assuming similar grouping, and similar ES, I already have a bunch of RL15, (and assuming I can get 2976 fps from a RL 15 load) and not a whole bunch of RL 17 or N550, perhaps I would do well to focus my attention on the smaller bullets?

If I am able to go, the first match is the 17th of May.

 

[ShootDots]

Stubbi, have you thought of the Berger 130VLD's? I can get mine going to 2920 with either 37.7gr of RL-15 OR 37.4grs of Varget.. No pressure whatsoever in either of those loads.. The VLD's "pointed" get in the vicinity of a 585B.C. which is nothing to sneeze at when traveling in excess of 2900f.p.s.! I have used BOTH the 123 Scenars and SMK's and they like'em with 38.0grs of RL-15... That pushes them to around 2970f.p.s.

 

[stubbicatt]

Shootdots, I have indeed considered the 130 Berger. I was able to obtain a sample pack from Sinclair, but to find those bullets in any quantity seems to be a very challenging task. I already have a few hundred of the 123's. I figured I would work with the 130's later in the year, but two weeks away is the first match I would like to shoot in.

I have less than 25 rounds thru the barrel for break in, and no load yet, as it was my goal to find a working maximum load for the 123's using RL 15, and the 139's using RL 17 and N550, whilst breaking in the barrel. (As an aside, it sure seems to build up copper!)

Initially then I have only 120 Scenar L, 123 Scenars, 136 Scenar L, and 139 Scenars. A lot of choices I suppose to start with. Of these, I am tempted to work with the 123's initially because if they work, I have components readily available for the short term.

From what I have read, the Scenar L is supposed to be more consistent in aerodynamic shape, so while it doesn't post the same BC as the 139er, I intend to test it to see if it does indeed provide better inherent accuracy. I sure don't know.

 

[Erik Cortina]

Chase accuracy, not BC.

The 123's will do well for you.

 

[ShootDots]

Stubbi, from what I understand the ONLY difference betwixt the 123Scenar's and the "L" version is the idea that the "L's" are held to tighter tolerances.. If this be the case, and you can get excellent accuracy from the "regular" Scenars, then simply switch to the "L's", using the exact same load data you found your accuracy with "regular" Scenars and go to competition with those... Try this: Load the Scenars "set" into the lands about 7-8K in.. Then run between from 36.8grs of RL-15 to 38.0grs (obviously watching for pressure) using CCI 450's for primers... Once you find a really good accuracy node, switch to the "L's" and go to your match.. You can always "tweak" it later when you have more time to devote to finding THEE LOAD!

 

[krktractor]

my brother shoots 136 scenars at 2900 and it does well. the bullets are very consistent in lenght, weight and bearing surface. though they are a little on the pricey side. I shoot 140hybrid bergers at 2900 out of a 28 inch barrel with H4350 and it's a 1 hole shooter at 400. pick your bullet I think the wind drift is minimum between all of them. buy light bullets give it some gas and watch your wind and any of these will be very competitive. I looked at ballistics tables between all of the bullets and I saw no more than a couple of inches at a 1000, making a bad wind call will put you much more than couple inchs off so I went with what my gun shoots well. have fun and good luck.

 

[krktractor]

this my take on the scenars. from what I gathered they are more on the lines of a hybrid. if you compare a regular scenar against a scenar L you will see they a lot longer taper. the L bullets look more like a berger than a scenar.

 

[Erik Cortina]

Stubbi, from what I understand the ONLY difference betwixt the 123Scenar's and the "L" version is the idea that the "L's" are held to tighter tolerances.. If this be the case, and you can get excellent accuracy from the "regular" Scenars, then simply switch to the "L's", using the exact same load data you found your accuracy with "regular" Scenars and go to competition with those... Try this: Load the Scenars "set" into the lands about 7-8K in.. Then run between from 36.8grs of RL-15 to 38.0grs (obviously watching for pressure) using CCI 450's for primers... Once you find a really good accuracy node, switch to the "L's" and go to your match.. You can always "tweak" it later when you have more time to devote to finding THEE LOAD!

Ben, this is horrible advise. Would you work up a load with a certain lot of bullets and then load a different lot of bullets the same way and assume they will work identically? The answer is no, so, why would you assume that a different line of bullets will perform the exact same way?

OP: Work up a load with the bullet you intend to shoot and be done with it. If you change anything, verify before you go shoot a match.

 

[Laurie]

There are three issues here, two amenable to analysis, the third more open to personal opinion and preference. The third is whether the small 6.5s, especially the '47 Lapua are 'suited' to heavier bullets defined as greater than 130gn. My purely personal opinion is that the three smaller 6.5s (260 Rem, 6.5mm Hornady Creedmoor, and especially the 6.5X47 Lapua) are ideally suited to a high-BC 123gn bullet. However, many others disagree and if you've had a rifle built with a chamber whose freebore suits the heavier bullets, results are often very good. The debate is more about which is marginally better at mid to long range. I have a gut feeling that a lot of LR shooters simply can't get their heads and hearts around the concept of a 123gn projectile being ballistically adequate never mind optimised for 1,000 yard distances. I know that I did after shooting 90s in 223 Rem, 155s to 210s in 308 and 180s in .284 Win.

The other two issues - bullet choice / ballistic specification and performance; comparable velocities for different weight bullets in any cartridge / rifle combination. The latter is easily sorted for desktop exercises if you have chronographed MVs for one bullet - calculate the ME this produces then work back from there to the MVs that produce that value with other bullet weights. It's not infallible as there is the freebore issue, and tuning the load may vary the MV you end up with, but it's good enough to do reasonably valid comparisons.

As an example, my 6.5X47L rifle produces just over 3,000 fps with the 123gn Lapua Scenar in my usual match load. If I round the figure down to 3,000, that's 2,459 ft/lb ME. The velocities that produce this energy level with heavier bullets are:

130gn .... 2,918 fps
136gn .... 2,853 fps
140gn .... 2,812 fps

(The easy way to obtain these values is to find an online ME calculator, a simple three box spreadsheet. Input the base bullet weight and MV to get the load's ME, then leaving that alone replace the bullet weight with the new value and clear the MV box before redoing the calculation. I use Airhog, an airgun website's facility: http://www.americanairrifle.com/convert.htm) but there are lots around.)

You've not chrono'd your current load, but you can still do such an exercise with an estimated figure as it's the relationships between bullet performance you're comparing.

The other issue is bullet design and aerodynamic efficiency, and the key value here is the 'form factor', a numeric comparison of the bullet's drag coefficient to the standard G-whatever 'reference projectile', the latter always given a value of 1.000. As this is a drag related factor, a high value is bad, a low one good. So a form factor of 0.900 has that bullet produce 10% less drag than the reference projectile, 1.100 sees it produce 10% more.

There is a considerable range of 'form factor' values for 6.5mm match bullets using Bryan Litz's G7 based data. Lapua has a strange habit of designing one or two really aerodynamically efficient models in each calibre, but the other weights being average or even poor in this respect, so it may make a great deal of sense to choose one particular bullet weight for 1,000 yard shooting, but not the others if the cartridge's ballistics are marginal for long-range applications. Let's look at the four Lapua 6.5mm bullet form factors against the G7 reference (i7 is the moniker ballisticians use for this particular metric):

120gn .... 1.000
123gn .... 0.950
136gn .... 1.018
139gn .... 1.002

By the standards of most calibres / bullets the trio with i7 values of 1 to 1.018 would be regarded as very good, but this calibre has some of the lowest drag bullets designed by man. Here are the values from the better competitors:

Berger 130gn VLD ............. 0.944
Berger 140gn VLD ............. 0.918
Berger 140gn LRBT ........... 0.946
Berger 140gn Hybrid .......... 0.905
Sierra 107gn MK ................ 0.954
Sierra 123gn MK ................ 0.970
Sierra 142gn MK ................ 0.968
JLK 140gn VLD .................. 0.895
Cauterucio 131gn VLD ........ 0.907
Norma 130gn Black Diamond 0.905

(Source: Bryan Litz, Applied Ballistics for Long Range Shooting 2nd edition)

These low drag values feed straight through to higher BCs for any given weight.

So ............... starting with the 123gn Lapua at 3,000 fps and looking at the equivalent ballistic performance for the 139gn Scenar, 130gn Berger VLD, 140gn Berger VLD, and 140gn Berger Hybrid, we get:


123 Scenar / 3,000 fps MV .................. 0.265 G7 BC ......... 1,451 fps / 77.3"

130gn Berger VLD / 2,920 fps MV ........ 0.282 G7 BC ......... 1,473 fps / 74.0"

136gn Scenar / 2,850 fps MV ............... 0.274 G7 BC ......... 1,389 fps / 80.3"

139gn Scenar / 2,815 fps MV ............... 0.285 G7 BC ......... 1,411 fps / 77.5"

140gn Berger VLD / 2,810 fps MV ......... 0.321 G7 BC ......... 1,542 fps / 66.0"

140gn Berger Hybrid / 2,1810 fps MV .... 0.355 G7 BC ......... 1,647 fps / 57.8"

The final columns are predicted retained velocity and wind drift in a 90-deg 10 mph crosswind at 1,000 yards in 'standard ballistic conditions' (59-deg F, 29.92 inches Hg pressure, 0% humidity).

So on purely ballistic factors, there is no benefit from trading up from Lapua's 123gn Scenar to a heavier bullet in that product range, hardly any in switching to the 130gn Berger VLD (4% wind effect reduction), but there are good arguments for adopting a top performing 140gn VLD or the new Hybrid, the latter calculated to reduce the effect of any given wind change between shots by a full quarter.

However, this is desktop ballistics. These results only provide usable results on the range if two other and non-predictable conditions are also met:

1) that the 'comparable MV' is actually attainable

2) that every bullet provides similar precision (grouping) and velocity spreads at these ballistically equivalent velocities.

There are other factors too that only experience and trial and error will show up. How well does a particular bullet design given a whatever rotational speed from the chosen barrel rifling twist rate with a whatever Stability coefficient that imparts, at a whatever speed, actually perform at 1,000 yards in terms of 'holding elevation'. I've found the 123gn Scenar at ~3.000 fps from two very different 1-8" twist barrels to provide exceptional 'elevations' at 800 yards and up - often a near horizontal line on the plot diagram from 2+20 shot F-Class matches shot alternately with a partner in two-to-a-mound shooting on a range that is well known for wind angle changes to cause elevation effects.

 

[ShootDots]

Stubbi, from what I understand the ONLY difference betwixt the 123Scenar's and the "L" version is the idea that the "L's" are held to tighter tolerances.. If this be the case, and you can get excellent accuracy from the "regular" Scenars, then simply switch to the "L's", using the exact same load data you found your accuracy with "regular" Scenars and go to competition with those... Try this: Load the Scenars "set" into the lands about 7-8K in.. Then run between from 36.8grs of RL-15 to 38.0grs (obviously watching for pressure) using CCI 450's for primers... Once you find a really good accuracy node, switch to the "L's" and go to your match.. You can always "tweak" it later when you have more time to devote to finding THEE LOAD!

Ben, this is horrible advise. Would you work up a load with a certain lot of bullets and then load a different lot of bullets the same way and assume they will work identically? The answer is no, so, why would you assume that a different line of bullets will perform the exact same way?

OP: Work up a load with the bullet you intend to shoot and be done with it. If you change anything, verify before you go shoot a match.

Erik, according to the information I have read and heard, the "L" Scenars are exactly the same as the regular Scenars. AND according to the same sources, the "L" version will have such tight tolerances that from one lot to the next you will have a plus or minus of no more that 1 thousanths variations. That was the whole reason behind the "L" concept in the first place.. If they are that far different from one lot to the next, WHY would anyone want to buy them? They were specifically made to be of the tightest tolerances in the industry AND their prices reflect that..

 

[Erik Cortina]

Stubbi, from what I understand the ONLY difference betwixt the 123Scenar's and the "L" version is the idea that the "L's" are held to tighter tolerances.. If this be the case, and you can get excellent accuracy from the "regular" Scenars, then simply switch to the "L's", using the exact same load data you found your accuracy with "regular" Scenars and go to competition with those... Try this: Load the Scenars "set" into the lands about 7-8K in.. Then run between from 36.8grs of RL-15 to 38.0grs (obviously watching for pressure) using CCI 450's for primers... Once you find a really good accuracy node, switch to the "L's" and go to your match.. You can always "tweak" it later when you have more time to devote to finding THEE LOAD!

Ben, this is horrible advise. Would you work up a load with a certain lot of bullets and then load a different lot of bullets the same way and assume they will work identically? The answer is no, so, why would you assume that a different line of bullets will perform the exact same way?

OP: Work up a load with the bullet you intend to shoot and be done with it. If you change anything, verify before you go shoot a match.

Erik, according to the information I have read and heard, the "L" Scenars are exactly the same as the regular Scenars. AND according to the same sources, the "L" version will have such tight tolerances that from one lot to the next you will have a plus or minus of no more that 1 thousanths variations. That was the whole reason behind the "L" concept in the first place.. If they are that far different from one lot to the next, WHY would anyone want to buy them? They were specifically made to be of the tightest tolerances in the industry AND their prices reflect that..

Ben, you make too many assumptions. The consistency between lots is in the "L" line, but you are proposing that he switch from Scenar to Scenar L's and make the same assumptions.

Regardless of how consistent they are, they are a different bullet line, therefore shooter must confirm.

 

[stubbicatt]

So, from what I just read, if I try heavier bullets, the only advantage to me to be gained is to use a Berger Hybrid were I to shoot the heavier bullet?

Too from the little I have been able to glean, the Scenar L line has 120s and 136s, while the Scenar line is 123 and 139ers. The little tables at Lapua website suggest markedly different BCs between comparable bullets suggesting to me that these bullets are not the same.

 

[Erik Cortina]

So, from what I just read, if I try heavier bullets, the only advantage to me to be gained is to use a Berger Hybrid were I to shoot the heavier bullet?

Too from the little I have been able to glean, the Scenar L line has 120s and 136s, while the Scenar line is 123 and 139ers. The little tables at Lapua website suggest markedly different BCs between comparable bullets suggesting to me that these bullets are not the same.

That is correct, bullets are not the same, which as been my point this entire thread.

My other point has also been that you should chase accuracy and not BC. There is advantage using a heavier bullet only if they are as accurate as the lighter bullets, if they are not, no advantage has been gained.

 

[stubbicatt]

So, from what I just read, if I try heavier bullets, the only advantage to me to be gained is to use a Berger Hybrid were I to shoot the heavier bullet?

Too from the little I have been able to glean, the Scenar L line has 120s and 136s, while the Scenar line is 123 and 139ers. The little tables at Lapua website suggest markedly different BCs between comparable bullets suggesting to me that these bullets are not the same.

That is correct, bullets are not the same, which as been my point this entire thread.

My other point has also been that you should chase accuracy and not BC. There is advantage using a heavier bullet only if they are as accurate as the lighter bullets, if they are not, no advantage has been gained.

This advice makes sense to me. In the spirit of "run what you brung" I guess I'll use the 123s initially, and work the "heavies" in as time permits, perhaps later in the year, again, assuming that I am able to obtain an accurate load with the 123s.

 

[ShootDots]

Stubbi, as Erik stated, you do need to confirm your loads.. You said you had a very short time to "get ready" for the first match, which you would like to attend. If you have a decent load, go to the match and enjoy yourself. Then take the time you need to tweak the load so that you can wring out all the accuracy you can using 1 line of bullet. I have had 3 / 6.5 x 47 barrels and 2 of them ate the 123 / 130 weights up like candy. Only 1 shot the heavies very well. Since you are short on time, go with the 123's for the time being and later you can try the 139's or Hybrids or whatever "heavy' you want. But put the odds in your favor at this juncture and give the light bullets a try. You may find that you have no need for the heavies! But give them all a run for their money and see which shoots the best.

It has also been my experience that RL-15 will give you UNDER 10ft. e.s.'s which makes for a great "waterline" load, if you have an accurate load..

Stubbi, the last statement on your last posting was exactly what I was saying..

 

[stubbicatt]

Stubbi, as Erik stated, you do need to confirm your loads.. You said you had a very short time to "get ready" for the first match, which you would like to attend. If you have a decent load, go to the match and enjoy yourself. Then take the time you need to tweak the load so that you can wring out all the accuracy you can using 1 line of bullet. I have had 3 / 6.5 x 47 barrels and 2 of them ate the 123 / 130 weights up like candy. Only 1 shot the heavies very well. Since you are short on time, go with the 123's for the time being and later you can try the 139's or Hybrids or whatever "heavy' you want. But put the odds in your favor at this juncture and give the light bullets a try. You may find that you have no need for the heavies! But give them all a run for their money and see which shoots the best.

It has also been my experience that RL-15 will give you UNDER 10ft. e.s.'s which makes for a great "waterline" load, if you have an accurate load..

Stubbi, the last statement on your last posting was exactly what I was saying..

Thanks Shoot Dots. Man, I have been following you here for a year, lapping up your wisdom, Erik's wisdom, Laurie's and some others. It is difficult for me to express the gratitude I have for you gents, and your generous willingness to help. Actually, the 6.5x47L choice was due to you gents. Laurie had a great essay in the main website that piqued my interest, and ShootDots, Erik Cortina and others are like bedrock foundation... I have found no cracks in you gents' advice, so I went with this chambering.

Anyways, maybe the day will come when I have something of value to share with you fellas. Until then, keep it coming!~

 

[ShootDots]

Thanks Stubbi.. However, we are ALL fallible! All of us say things on here that leaves someone else "scratching their heads", as it were.. Having said that, I believe we ALL try and do our very best to help others out by letting them benefit from our successes as well as our failures>>>of which I have A LOT OF!! About a year ago I REALLY had a HUGE potential failure. I was developing loads for my first Dasher>>> WOW! What a learning curve that was... The GREAT people on here helped me out of that "situation" in relatively short order! Having learned from that "escapade" if you will, I am able, at least to some degree, help other too.. On the 6.5 x 47, I have quite a bit of experience and can help most people out and get them rolling "in relatively short order"..

Thanks Again Stubbi! Oh and do not think that you can not contribute on this project in a short time span too! We ALL have A LOT of room to learn! I started a post about "Preliminary Results on my .284 Shehane">> I wish everyone would do something similar so we can see the progression! Hint, Hint..

 

[schumi]

I believe we ALL try and do our very best to help others out by letting them benefit from our successes as well as our failures. The GREAT people on here helped me out of that "situation" in relatively short order!

+1 to ShootDots. His experience and advice on forum, along with a few others, has been invaluable to me on several occasions.