New Rifle Caliber Question?

[mrbeer]

Hello All,

I am new to benchrest shooting. My primary interest is in 600 / 1000 yard bench and F-Class. I currently am shooting a Accurized Rem 700 in .308. I want to either buy or build a benchrest gun with the goal of shooting 600 / 1000. I want the rifle to qualify for light weight class.

After thoroughly reading through info posted on the 6mmbr webiste, I am quite confused with my future choice of caliber.

Here is why I am confused. When looking at the performance "on paper" of all chamberings presented on 6mmBR, .243 AI and .243 Win show the least amount of bullet drop than any other round and are only bested by 7mm Saum and 7mm WSM with wind drift.

That being said, it seems that many shooters are either shooting 6mm BR or an improved version for 600 / 1000.

6mmBR has 20% more drop and is effected 30% more than .243AI by wind "on paper."

Additionally, .243 and .243AI are flatter shooting than popular 7mm chamberings while only being 10% more succeptable to the wind.

What am I missing here? I went to my local clubs 1000 BR match last week and almost all of the guys were shooting 6mmBR, even in the heavy gun category. Why does 6mmBR seem to be more popular than .243 win or AI when the numbers are in favor of .243?

I know that barrel life is almost twice as long for 6BR and it costs less to reload. That being said, there are a whole lot of guys out there shooting rifles with similar barrel lives and inferior ballistics.

Since I have very little practical bench rest shooting experience, I think I must be missing something. The only other reason I can imagine one would want to shoot 6BR over .243 is recoil. I imagine .243 has 20+ % more recoil than 6BR. Since I have little experience, I do not know whether additional recoil between these two rounds makes a big difference in benchrest shooting.

I thought I was sold on 6BR for my first Bench Rifle. After reading all info presented, I think that .243 win or 243AI may be the way to go.

I still feel that I must be missing something. Please let me know your thoughts. If any of you have shot both calibers on the bench, I would love to hear your experiences.

Thanks!

 

[TerryPohl]

Accuracy is the key. A lot of people shoot the 243 and the improved, but 9 times out of 10 the little 6’s and there improved version will out shoot them.
Terry Pohl

 

[MarkS]

mrbeer,

The reason you see more 6BR and 6BR IMP's, is because the will out shoot the other 6mm's. I would go with a 6 Dasher or 6BRX. I have done the bigger 6 mm don't go there.
Everything drops at 1000 yds, it's just a few more click up.

Mark Schronce

 

[juliomorris]

Another thing is the 243 is a barrel burner. 1500-2000 rounds.

 

[mrbeer]

Mark,

Thanks for the reply. When you say that 6BR or BR imp will outshoot the other other 6mm's, what exactly do you mean? On paper, 243 AI seems like it would superior at long ranges, yet if 243 AI is .2moa "less accurate" on average than 6BR, I can see what you mean.

6PPC is "more acurate" than 6BR at 200 yards even though 6BR will probably be very accurate at 200 yards. .308 is more accurate than 30-06 at 500 yards.

Is that what you mean by outshoot?

The good news is that I just realized what with the right action, I can shoot 6BR, 243, 308 all with barrel swaps.

 

[Kenny474]

Most of the BR based rounds are more efficient and have more inherent accuracy because of their consistency than the .243 or the 243AI. The .243 has a much longer case and is much harder to get consistent ignition than with the shorter BR cases. Consistent ignition is key to long range accuracy. While the .243AI may have a bit less drop and drift, it is less consistent and therefore will be less accurate in most cases. When you have a round that is very consistent, the amount of drop and drift become less of an issue. You can hold off or click in the windage and elevation for a round that drops or drifts. But you can't do that for a round that is inconsistent. There is no way to compensate for a round that is less accurate, even if it drops or drifts less.

While the .243 and .243AI can be accurate, they will almost never be as consistently accurate as the more efficient BR based rounds.

If you are looking for an easy to tune round with decent barrel life, you will be hard pressed to find a better choice than the Dasher. Easy to tune and very consistent.

 

[mrbeer]

Thanks again for your response. It made perfect sense. The reality is that most of the guys that I saw shooting in 600 and even 1000 were shooting 6BR or an improved version. Your explanation of powder burn and case size make sense...thats must be why 6ppc is so incredibly accurate as well.

I will definitely look into 6br and the improved rounds when i build my rifle.

 

[Kenny474]

It's basically the same reason why a round with a high load density (case full of powder or nearly so) will be more accurate than one that is only 75% full. It can burn more consistently as the powder doesn't have room to move around. When the powder is in different spots from round to round, due to excessive space inside the case and not having the case full of powder, the ignition will not be as consistent as when the case is full and the powder is in a consistent shape from round to round. Also when there is less powder to burn in a smaller area of ideal shape, it can be done more consistently.

I learned a lot about that shooting light cast bullet loads in 45ACP. I had some loads that were so light I would get different velocity from pointing the gun up or down prior to firing. The powder would either be at the front or back of the case, and was giving very inconsistent results because of it. If I pointed the gun up prior to every shot, it would be reasonably consistent. If I pointed up for one and down for the next, it became very inconsistent.

The same holds true for rifle rounds. That's why most of the BR cases perform so well, they usually have a high load density and an ideal case shape that makes them very efficient. When you can burn a smaller amount of powder very consistently and still get enough velocity, you will usually have a very accurate round. Though many other variables are involved as well, as it takes a complete system working together to make an accurate rifle. But the more consistent you can make everything, the better your chances are of achieving great accuracy.

 

[MarkS]

The 6BR and IMP will shoot smaller groups than all other 6mm's. The VLD bullets don't like to go over 3050 f/s, so more case and powder, is just more powder. The Imp's are all the speed you need.

Mark Schronce

 

[blawton]

There is nothing wrong with a 6x47 either. There is a lot of guys getting them to shoot as well as the dashers or really really close now.

 

[Josh11]

Dasher or BRX is going to be my next long range barrel. Ive got the 6br right now and love the round for 600. Read the Daily Bulletin and check out the Dashers rule the 1000 yard comp.

 

[Scott Harris]

While the .243 and .243AI can be accurate, they will almost never be as consistently accurate as the more efficient BR based rounds.

If you are looking for an easy to tune round with decent barrel life, you will be hard pressed to find a better choice than the Dasher. Easy to tune and very consistent.

+1 and this coming from someone currently shooting 243WIN. The 6mmBR has the classic accuracy form factor:
-Short fat cases
-longer neck
-sharper shoulder angles

One disadvantage of this form factor is it does not feed from magazines well. Most of the folks using it have a single shot action and this is not a concern.

Hard to beat the 6mmBR and derivatives at 600 for pure ability to group in calm conditions and that is what people are referring to by saying it is in inherently accurate. Now, on a really windy day, the 243 may be very competitive indeed, especially if you are pushing a 105 Berger VLD at 3250fps like Whidden did winning the LR championship last week.

At 1K, I think it is more of an open field cartridge-wise. You might want to take a look at the 6.5x47 Lapua: another short squat accuracy cartridge that's been doing real well: feed better from a magazine if that's a concern.

 

[blawton]

And if you want to buck the wind a 338 Snipe tac can hang with the dasher for 5 shots. I am going to work with one that is Nitrided to see if we can get the 10 shot groups down. If it can it will clean house on the windy days.... Smallest group i have shoot with this one is 2.68". So it can do what the dasher does in a big case but heat is a issue.

 

[Varminator]

I have Dashers, 22 and 6mm. They are my favorite guns to shoot and very accurate. I also have 6BRs and they are my next favorite. I have 22-250s and .243s and even one very good Ackley .243 barrel that is very accurate and has a muzzle brake. What I have seen, and I am by no means at the level of the average shooter that responds here, is, the Dashers and the 6BRs produce consistant velocities and are easy to load. Accuracy comes from consistant loads. The PPC is a great design but I like the Dashers better. If you want to sacrifice barrel life, accuracy, light recoil and cartridge life for pure speed get a .243 Ackley they are a gas to shoot and pretty accurate. The most fun gun I own is a 22Dasher in 14 twist with a muzzle brake, if you don't blink you can see the bullet hit.
Mark
><MM>

 

[TheBlueEyedBear]

Interesting! I also really enjoy shooting my DASHER. Love shooting my new 6SLR and going through load developement. I also have a fiarly new 300WSM Varminter from Richard Frinklin that is a hoot to shoot and a 30-338 from Richard that I am still doing load development for. However; there was nothing like the rush of pulling the trigger on my .338 Snipe-TAC on my Missouri Breaks Elk here in Montana. At 424 yards the 269gr HAT bullet entered the right side of the Elks chest and almost completely took off the opposite shoulder (pic attached).
It simply comes down to picking the right cartridge for what you want to acheive in your shooting. Unfortunately my sight has diminshed to the point where competition is out, but these things are still a blast to shoot. Although, the DASHER does get boring some times. It is deadly accurate.

 

[Dgd6mm]

mrbeer, look at the 6CM. It's a sleeper, It does quite well all the way out to 1000+ yards.

 

[mrbeer]

Wow,

Thanks for all of the great information. I am definitely set on building my first benchrest rifle around a 6BR or improved version, most likely dasher. I shoot in a high wind area, so learning to shoot a 6mm bullet in the wind will inevitably benefit me if i choose to move up to a higher caliber in the future.

Is fire forming Dasher an easy process once you have learned?

 

[TheBlueEyedBear]

Yes, it is easy. I decided to go with the DASHER when I first took up BR shooting here in Montana. Initially the tought of fire-forming and neck turning was a scary proprosition. Once I did it and only lost a few pieces of brass,,, it really was a breeze. It is time consuming, but well worth the effort. Even with a no-turn neck; I feel neck turning (just to skim) is a prerequisit for concentricity. Well worth the time and effort.

 

[RonAKA]

I wonder how the 6BR and variants measure up to the 6.5x284 at 1000 yards? I would have thought the 6.5x284 would handle the wind better.

 

[Moderator]

I wonder how the 6BR and variants measure up to the 6.5x284 at 1000 yards? I would have thought the 6.5x284 would handle the wind better.

The 6.5x284 (and straight.284) definitely show less wind drift, and that's why they are popular in NRA long-range and F-Class, where the targets are pulled and marked between shots. But in the 1K benchrest game, one strategy is to shoot as fast as you can, to try to "ride the condition" before it changes. The low recoil and reduced gun hop of the Dasher type cases allow the bench jockies to shot faster strings. That has proven to be a winning strategy at some ranges. There are still plenty of guys running big calibers with heavy bullets in long-range benchrest however.