Is there now a case for 6.5-284 in LR F-Class?

[Steve Blair]

Another thread in this forum brought up the point about low vertical dispersion with 6.5-284 rifles. I started shooting F-T/R in December 2010 and F-Open in November 2011. By then, most shooters had moved to 7mm rifles. I saw several shooters with .284 Shehanes post excellent scores and built my rifle in that caliber. It has done very well for me and I still shoot it. I ordered a BAT magnum action about a year ago and now have a .300 WSM that I will shoot in matches, over the next two weeks, for the first time. The load is pushing 230 Hybrids at 2947 from 34" and the gun weighs 21.75 lbs. Even at that weight, it still has a lot of recoil. I've only shot it at 300 yards but will say that it moves around a lot. Barrel torque is especially noticeable. [br]
The first two barrels on my Shehane tuned 180 Hybrids around 2930-2940. I had excellent vertical even while I saw 7mm Mag shooters cursing their guns. The latest barrel tuned with slightly less powder at ~2965. The ES figures and short range accuracy are exactly the same and all components are as before. But now I see more vertical at 1000. [br]
When the 6.5-284 was abandoned, the 140 VLD was still the bullet of choice. There is now a 140 Hybrid available and the B.C. is about the same as 7mm VLD's. Here are some comparative numbers in a 10 mph crosswind at 1000. [br]
6.5-284 - 140 Hybrid @ 3100: ~4.98 MOA
.284 Shehane - 180 Hybrid @ 2940: ~4.62 MOA
7mm Mag - 180 Hybrid @ 3000: ~4.48 MOA
.300 WSM - 230 Hybrid @ 2950: ~4.14 MOA [br]
In the recent Berger Nationals, I finished 11 points behind Shiraz, who shot his .300 WSM/215 Hybrid combo extremely well. But I didn't lose to ballistics. I dropped 23 points on Saturday and that was purely my failure. The Shehane was doing its part, I wasn't.

So, my questions are: [br]
How much of the vertical we are seeing with 7mm magnums is cartridge and how much is gun handling?
If you have to concentrate more on gun handling, does that detract from wind evaluation?
Is it worth trading the occasional 10 from decreased wind deflection for the occasional 9 from elevation?
Is it possible to overcome increased wind deflection disadvantage with better elevation control? (keep in mind that better elevation means a wider target)
Are we too focused on ballistics and ignoring handling as a factor?

 

[Immike]

I have to vote for the handling. I dropped at least (5) points at Raton last year because I wasn't handling my rifle properly as it was a new caliber for me (284 win ) and didn't have the pull length adjusted long enough to keep the scope off me. I was having to give it thumb pressure and that was too dependent on me. All Points lost where straight up above the 10 ring. After I returned from the match I went straight to work on these issues and tightened up the ship. There is achievable accuracy in magnum cartridges that can compare to the lower recoil cases but this requires a great effort on the shooters part.

 

[mysticplayer]

I had a chance to shoot Raton last year. Big Air.

This reinforced what I was dreading cause I HATE recoil, no matter the paper ballistics, in a place that can have strong gusts and switches (what I call bumpy air), SIZE MATTERS.

Small and light can be as accurate/more accurate but when the air comes and bumps the bullet, the larger/heavier slug stays on course better. This is not the main wind condition but a localised gust or switch. And it is intermittent and unpredictable.

For LR matches (800 to 1000yds), bullet inertia truly matters and smaller/lighter bullets can get tossed around even when launched well.

The heavies are harder to shoot vs a small light set up (223 or 6BR) but will make it to target with a "truer" flight in bumpy air.

The difference.... inside 10 or outside 9.

Unfortunately, this trend will be a serious negative to the sport in the long run. Cost, recoil is affecting interest up in Canada. More and more shooters are considering FTR or 2 gun (mid and long range guns) solutions.

I fear that this arms race will soon cause our attendance to collaspe (sure hope I am wrong). Or we may consider putting some caps on the race???? (ouch, that is a can of worms)

Jerry

 

[Steve Blair]

As far as the ability to buck wind, only ballistic coefficient matters. A round nose 220 in caliber .30 would be handily beaten by a 6mm 105. So, while size and sectional density are related to ballistic coefficient, form is more important. [br]
Regarding Raton at the 2012 Nationals: I thought the conditions were pretty good. When wind was up, it was fairly predictable and readable. We routinely have more wind at Camp Pendleton. Thankfully, not like Phoenix during Berger this year, but strong and switching.

 

[ShootDots]

I have been shooting a 6.5 x 284 for 2 years now. I shoot F-Open.. Accuracy, ease of handling (less recoil), extremely flat trajectory, time of flight and HIGH B.C.s make the 6.5 x 284 VERY hard to beat in the right hands. I shoot 1000 yards with mine and I do "ok" at best>>>Not the gun's fault>>MINE! I often wonder what my gun would do if Mark Walker or Matt Davis or some other EXCELLENT 1000 yard shooter would do, IF they shot my rifle instead of me! On paper, it is almost impossible to beat>>>add REAL life shooting into it and I can not think of a better caliber! The only 2 things I would change on a 6.5 x 284 case would be: 1.) Lengthen the neck (shorten the case a small degree and flare out the shoulder to 40 degrees); and 2.) make small primer pockets with the case to add strength to the web. Thereby keeping tight primer pockets... If these 2 things were done, there would be no end to the sales of that caliber! That is my humble opinion.. Remember, accuracy, tight shot strings and B.C. will keep vertical to a minimum!

 

[DBailey]

Hey Steve,

I have tested the 140g Hybrid, and it's a very good bullet in the wind but I don't believe it's enough to beat the 7mm on a regular basis.
To be honest, the velocity number that you have listed for the 6.5 is a little to high. It will run 3100 fps but it's sweet spot is in the 2950 to 3000 fps range.

Just out of curiosity, have you ran the ballistics with a 2mph variable? What I'm trying to get at is most shooters will not miss a 10 mph change in conditions but most have missed a 2 mph change. So the real advantage of one cartridge over the next is the difference in windage from a 10 mph wind to an 8 or 12 mph wind.
I'm not sure what the outcome will be, but I think the gap between calibers will actually be smaller.

 

[Steve Blair]

Deflection is linear with wind speed. So, 2 mph would be 1/5 of the values above.Between .8 and 1 MOA for the cited cartridges. That's not much difference.

 

[DBailey]

Thanks Steve that's about the way I thought it would be, although it sure seems like a lot more under match conditions.

Benjamin,
Mark and Matt are way up on my Hero list. I would love to see them with a 6.5 also.

 

[mysticplayer]

As far as the ability to buck wind, only ballistic coefficient matters. A round nose 220 in caliber .30 would be handily beaten by a 6mm 105. So, while size and sectional density are related to ballistic coefficient, form is more important. [br]

Consider the 223/90 vs the 308/185 jaggernaut.

90gr VLD G7 0.281
185gr jaggernaut 0.283. Let's call these two equal

200gr hybrid 0.320

I ran my 223/90 at 2850fps. Seems the 185gr has a sweet spot at 2750fps. 200gr around 2600fps (maybe some are running faster, I don't know)

On paper, the 223/90 should be better ballistically vs the 308/185. Or at least in the same ballpark with the 200.

I can tell you that shooting with other 308's on the same relay on neighbouring targets, when a condition was missed, I got moved further then the 308's.

Same direction... just further.

Not much but I am a 9, they stay a 10. See this happen time and again over several days with random shooters beside you, you have to call it a trend.

One US shooter I was squadded with even me called "very brave" to shoot a 223 at Raton. He was using a 308 with something a wee bit heavier.

I will be taking a 308/heavy combo to Raton this summer.... wish I was still shooting my 223.


If bullet mass didn't matter all that much in the first place, why are we even having this discussion?

Why not just shoot 6Dashers and call it a day? There is no denying how wonderfully accurate this chambering can be.

I really wish that is all we needed......But there really is only 1 way to prove this. Build a 6.5 and start competing.

Jerry

 

[Laurie]

Steve,

I was much intrigued too by those references to how low 6.5-284's verticals are in the other topics. I hadn't realised there was such a difference between them and the sevens. I have a 260 Rem mind you that I shot in horrible conditions one day at 900 using the piddling little 123gn Lapua Scenar in dreadful wind conditions - a day when most people were blown out of the black sometime or other, or went straight from one side of it to the other, and the visibility was so poor it was a hard job seeing the far wind flags never mind reading them. I'd been struck by how good the verticals had been for the relatively light .264 bullet - a few had been out vertically, but three-quarters had really hung into a small band despite this being on a range where wind often comes with a major vertical component. So, I shouldn't be too surprised that the much superior 6.5-284 / 140 combination does well in this respect. It also begs the question - is there something special about 6.5mm calibre in this particular aspect of the long range F game?


Moving on to your questions

If you have to concentrate more on gun handling, does that detract from wind evaluation?

Yes, I'm convinced of it. Shooting should be like driving a car where you do the basic mechanical jobs on auto-pilot and concentrate on the road conditions and other vehicles. I'm testing Seb Lambang's prototype Joy-Pod in F/TR (one of them anyway, as there will ultimately be at least three prototypes on the go before he gets artound to production) and allied to a much heavier and stiffer rear bag (no squeezing needed) means I spend much less time getting the rifle and sight aligned with the aiming mark and more on reading the wind and taking the shot. It has definitely improved my scores. I shoot quicker too, which was always one of my deficiencies in comparison to many of my fellow F/TR competitors who seemed able to squeeze shots off really quickly.

Is it worth trading the occasional 10 from decreased wind deflection for the occasional 9 from elevation?

Maybe. As you know, this is a big issue in F/TR. Our experience in the UK is that over the course of a season, neither 155s or 210s give their users any overwhelming advantage. We have one 230gn Hybrid user who had a very good 2012 GB league season ..... but he also threw away a match and a league round overall win with its 20 championship points through a cross-shot. Heavy bullet users seem to be much more prone to this failing which says something about their rifles' handling characteristics to me. At the end of our 2012 season, the league F/TR champion shot 210s, the runner-up 155.5s and the latter also set a new 1,000yd 20-shot match score record in the process.

Is it possible to overcome increased wind deflection disadvantage with better elevation control? (keep in mind that better elevation means a wider target)

In theory yes, in practice it doesn't seem to work out that way. It's something I keep reminding people of - that you lose a point if you misread the wind by a half-MOA +, but only if your elevation is spot-on. If it's a half-MOA high or low, almost any windage misread loses you the point.

Are we too focused on ballistics and ignoring handling as a factor?

Yes - a purely personal view and a minority one probably. I've tried the heavies and gone back to lighter bullets. The 168gn Hybrid has worked out to provide a very good compromise for me. Even going up to 185 makes my life harder - but apparently not for many others.


Moving on to the BC + MV issue:

Consider the 223/90 vs the 308/185 Juggernaut.

90gr VLD G7 0.281
185gr Juggernaut 0.283. Let's call these two equal

200gr hybrid 0.320

I ran my 223/90 at 2850fps. Seems the 185gr has a sweet spot at 2750fps. 200gr around 2600fps (maybe some are running faster, I don't know)

On paper, the 223/90 should be better ballistically vs the 308/185. Or at least in the same ballpark with the 200.

I can tell you that shooting with other 308's on the same relay on neighbouring targets, when a condition was missed, I got moved further then the 308's.

Same direction... just further. [Mysticplayer]

I'm sorry to say Jerry, I've found exactly the same thing. I love shooting the 223 with 90s, but the bullets do move more than they should.

There can be only two conclusions if we're both correct in this:

1) The average BC isn't as high as Bryan Litz / Berger Bullets reckon
2) When you get to a certain distance maybe there is more to how bullets perform than a simple BC+MV relationship.

 

[mysticplayer]

Laurie, I think you and I have sent way more 90's downrange then the average over the last few years.

out to 600m, fully competitive even in fairly rough air. Not saying they are gale proof but similar bouncing around vs the 308. I felt I was not at any disadvantage. Did very well at matches out to 600m

From 800 to 1000yds in bumpy air, some times, it would have been better to just aim center and close your eyes.

I tested in calm air and the accuracy was there so it wasn't a stability issue.

Given the starting wind dope on the scope, I feel the 90's might have a better BC then published. At least, we could use each others start windage and be on target (308/185 and 223/90).


From a math standpoint, I believe the bullet has slowed down enough that its momentum drops to a point where those small bubbles have an effect.

If someone with more skills then me can figure out the energy of a gust of air at 2mph over say 25yds, I bet we start to see where this value gets bigger (or at least significant) then the inertia of the small projectile thus pushing it ever so slightly this way or that.

how many mm would it take to push a bullet off course a few inches at 1000yds, starting at say 800yds? Not very much at all. it is likely more like thousandths of an inch.

This concept agrees with how it felt to shoot the 90's at LR. Just got unpredictable and drifts got "bigger".

You certainly got punished way more for an ooops.

On the up side, you learn real fast about every nook and cranny on a range. I will continue to use the 223/90 for practise and competition to 600m. But the 308/heavy will be the goto at 1000yds.

Jerry

 

[Kings X]

What barrel life are we getting out of the 6.5s now days? It was 700 rounds for the 6.5-284 back a few years. Nice rounds to shoot but couldn't practice or test because of short barrel life.
Ben - Mark and Matt both have 6.5-284 barrels in the back of the closet. They like the 2500 ACCURATE rounds out of the 284 WTR.

 

[Steve Blair]

What barrel life are we getting out of the 6.5s now days? It was 700 rounds for the 6.5-284 back a few years. Nice rounds to shoot but couldn't practice or test because of short barrel life.
Ben - Mark and Matt both have 6.5-284 barrels in the back of the closet. They like the 2500 ACCURATE rounds out of the 284 WTR.

[br]
Richard, [br]
Did most 6.5-284 shooters you know use H4350?

 

[Caliche Pit]

Concerning barrel life, is it possible that the fairly new melonite coating, I think it's called , will offset the throat erosion, barrel wear in this caliber?
If it works, it may be just enough to breathe life back into the 6.5x284. I just don't know if it works as reported?

 

[mgx1138]

Concerning barrel life, is it possible that the fairly new melonite coating, I think it's called , will offset the throat erosion, barrel wear in this caliber?
If it works, it may be just enough to breathe life back into the 6.5x284. I just don't know if it works as reported?

I am building a 6.5-284 prone gun (sling/open sights) now. I will have the barrel nitrided and will report. It'll be a while though.

 

[TC260]

I'm sorry to say Jerry, I've found exactly the same thing. I love shooting the 223 with 90s, but the bullets do move more than they should.

There can be only two conclusions if we're both correct in this:

1) The average BC isn't as high as Bryan Litz / Berger Bullets reckon
2) When you get to a certain distance maybe there is more to how bullets perform than a simple BC+MV relationship.

First let me say I don't have any more than a very basic knowledge of ballistics so bear with my ignorance here. From what it sounds like, y'all are finding different windage effects between smaller/lighter and heavier/larger bullets with similar BC's. I poked around a little bit to try to find out how windage is calculated and came across this page: http://www.jbmballistics.com/ballistics/topics/crosswind.shtml

Looking at the calculations here, I don't see BC being used specifically. I also noticed that the cross sectional area of the bullet is used to find this constant K that they're using. Seems to me that would tend to back up what you're finding in the field of smaller bullets getting blown around more than bigger bullets of the same BC. Like I said, I don't have any knowledge of ballistics and may completely misunderstanding what's going on here but I'd throw it in and see what you thought.

 

[Mark Walker in TX]

Original question "is there now a case for 6.5-284 in LR F-Class" - not for me. Nope.

Why I went to the .284 back in 2009 was not really for better ballistics than the 6.5-284, it was for equal ballistics with 2 times the barrel life. Cost for starters, and then double, if not more, time spent doing load dev and all the BS attached with that effort.

While I have moved on to my own .284 variant, the 7 Walker, I am pretty content with its performance and not interested in chasing the BBD (bigger better deal). Ride her 'til she bucks ya...

 

[Kings X]

Barrel nitriding works for some guys. I got on the band wagon when it started. I have 4 nitrided barrels. Started with 308, then 223 and 6-284 and last a 284. They last. My 6-284 drives a 115 naked at 3400 fps.
But for me - JUST ME TALKING - all four do not go to f-class matches. I have not been able to repeat the groups that I got before nitriding.
I don't know if 4350 will extend life. That is why I asked about barrel life "now days".
I would love a longer neck (add .100") and 40 degree shoulder 6.5-284. BUT the longer neck did not work for me in a 7 Long Neck WSM case. Still lasted 800 rounds.
I did shoot a 6.5 Jody ll which has a full radius shoulder. It is based on a short mag case and no fun to form. Designer claims 3000 rounds. Did not prove him wrong as gave up on making all the cases that I wanted for F-open. Barrel life also depends on what your critiria is for accuracy is.

 

[ShootDots]

I just put on a new barrel in my 6.5 x 284 and I have only been to 2 matches with it. My last barrel, a Rock Creek F-Class taper, went right at 1600 rounds before it went into the toilet.. Now for something VERY interesting.. My last barrel shot just as good from the first round to the last. The ONLY reason I gave up was because I was getting "blow-back" from gas escaping back down the entire length of the case. At 300 yards it was a "non-issue" however, past that my vertical became untenable. I got my new barrel and with 49.2grs of H4350 and 140 Hybrids I shot my VERY first clean, 200 12X's at 600 yards in Beaumont! Now I have to have some input here, I do NOT shoot my 6.5 x 284 from May thru October as the heat will destroy a barrel down here where summer temps easily exceed 100 degrees and the barrel literally can NOT cool off! So I shoot my 6.5 x 284 in cool weather and I believe that has lengthened barrel life considerably... I am just a fan of 6.5 cartridges and what they offer.

 

[BradY]

I think alot of emphasis needs to lie with the shooter. Put an average shooter behind an an accurate 300WSM and they will shoot good, put a brilliant shooter behind an accurate 6.5x284 and they would more than likely beat the other guy. My opinion on FO is you want to shoot what ever caliber you can that is reliably accurate and bucks the wind the most. For person X they may not cope with recoil over a 6.5x284, for person Y they cope with 300WSM's fine. Thats going to affect things too. If you can read the conditions better than anyone else and you know where to hold your gun no matter what caliber then your in with a chance. Relying on better ballistics or larger calibers alone isnt going to turn you into a world champ.

Ive been comparing my 260 wildcat to the straight 284 on JBM and the difference just isnt enough to switch. A 140 hybrid at 2950fps compared to a 180 vld (easier to get here) at 2820fps isnt that far apart really and I know that I cannot tell the difference in wind condition to say that a 284 will save me points. Maybe it will, but more than likely it wont. The other thing is maybe the bullet weight does have more to do with it than just BC. I know my 223 with 50gr noslers at 3400 drifted less than my 20 practical at 3800fps with 39gr sierras. I dont know why, both were very accurate, but I proved it to myself in the field.

Stepping up to a 7SAUM or WSM putting a 180 hybrid or VLD close or over 3000fps and its a different ball game compared to what I use now. Im just not so sure I can handle that recoil so instead of buying a new action or bolt to suit a magnum, I will more than likely take my first steps in the 7mm world with a 284 shehane, use my existing 308 boltface and load where I can comforably and accurately shoot. Should the 260 out perform it, well then I will stick with that or take up marbles ;D