Rifle caliber confusion

[bcs4]

I'm a handgun guy and reloader. I haven't gotten into rifle reloading because it seems a bit more complex, and frankly I didn't want to spend all my time resizing cases.

I'm trying to choose my first rifle caliber for reloading, and I'm officially lost. I will be using the rifle for targets in general from 100 - 300 yards. Sorry in advance for writing a book.

I've been reading as much as I possibly can about what might be the best caliber for me to choose, but there simply doesn't seem to be one that presents itself as inherently better. There's so much contradictory information about what makes a caliber more accurate.

It would seem that every caliber would have the possibility for the exact same bullet profile, so am I correct that in a no wind situation, at the exact same velocity, every rifle caliber (of the same bullet design) would have the same trajectory as all the others?

If that's true (I apologize if it's not) wouldn't velocity then be the only determining factor? Thus, the higher velocity, the flatter trajectory, the less flight time, the more accuracy (again without wind as a consideration)?

Then IF velocity is the determining factor (again, sorry if it's not), wouldn't recoil and resistance to wind be the 2 determining factors in choosing a caliber for target? And since a heavier projectile would resist wind more than a lighter projectile (at the same speed), wouldn't a heavier projectile ALWAYS be a better choice?

SO, would't it always be best to choose the largest caliber that one could comfortably shoot repetitively?

I'd sure appreciate any advice. Again, sorry for making you read so much, but I didn't see any other way to explain it so you could understand where I seem to be stuck.

 

[rcmodel]

Thus, the higher velocity, the flatter trajectory, the less flight time, the more accuracy

You are confusing Apples & Oranges.

Velocity & flat trajectory have nothing to do with accuracy potential.

every caliber would have the possibility for the exact same bullet profile

Two identical bullet of the same weight, except of different calibers will not have the same trajectory.

It has to do with the Ballistic Coefficient and Sectional Density of the bullet.

Some calibers cannot handle a bullet with the same sectional density as another caliber due to pressure limitations and rifling twist limitations.

Here is some good info for you to read. By the time you read it all, you will have a much better understanding of the whole thing.
http://www.exteriorballistics.com/ebexplained/index.cfm

rc

 

[Silverado6x6]

In simpler terms I would suggest a .308 caliber, or the proven 30-06 for hunting. An extreme wide selection of bullets from varmint to big game. Currently though I prefer my .308.

Berger VLD, or Hornady A-Max handloaded offers excellent long range shooting, or try the Barnes MRX.

 

[33rowdy]

In three die handgun reloading, theirs nothing more but less. You don't have a die to bell the mouth.

Quote.
"It would seem that every caliber would have the possibility for the exact same bullet profile, so am I correct that in a no wind situation, at the exact same velocity, every rifle caliber (of the same bullet design) would have the same trajectory as all the others?"

That is confusing. Calibers and bullets all work different at their different velocities. But what I "think" you are trying to ask; If yo drop a bullet out of your hand and it takes an "x" amount of time to hit the ground. That the same is true as if a bullet is going 3500 fps. Well....at times you shoot up hill for a longer time to fall for a further distance of travel. Keep reading for that answer.

 

[bcs4]

Please understand I am not trying to be abrasive, just trying to understand.

"Velocity & flat trajectory have nothing to do with accuracy potential."

I would think if you eliminate windage, velocity and thus flatter trajectory would be the only determining factor (in the same profile projectile).

"Two identical bullet of the same weight, except of different calibers will not have the same trajectory."

How could two bullets of the same profile but of different calibers be the same weight? Wouldn't the larger caliber always be a proportionally higher weight?

"It has to do with the Ballistic Coefficient and Sectional Density of the bullet."

But based on the same bullet profile or design, Ballistic Coefficient seems to be based mostly on bullet weight, no?

"Some calibers cannot handle a bullet with the same sectional density as another caliber due to pressure limitations and rifling twist limitations."

But assuming the rifle was capable of the pressure and had the correct twist, at say 2,000 fps wouldn't 2 projectiles of different weight (of exactly the same profile, and ignoring windage) have exactly the same trajectory?

Again, please forgive my ignorance and feel free to completely ignore me if you feel you don't have time for a newb. I understand.

 

[bcs4]

"That is confusing. Calibers and bullets all work different at their different velocities. But what I "think" you are trying to ask; If yo drop a bullet out of your hand and it takes an "x" amount of time to hit the ground. That the same is true as if a bullet is going 3500 fps. Well....at times you shoot up hill for a longer time to fall for a further distance of travel. Keep reading for that answer."

Yes, that's a big part of what I'm asking. It seems like the bullet weight is the only real consideration at the same velocity because the heavier projectile fights the wind better. Of course this doesn't consider twist, but why would a modern manufacturer build a rifle that you couldn't find a projectile/velocity that matches their twist rate?

"In simpler terms I would suggest a .308 caliber, or the proven 30-06 for hunting. An extreme wide selection of bullets from varmint to big game. Currently though I prefer my .308."

A lot of what I'm reading says the 308 is the best caliber for general accuracy, yet I see other non-similar size calibers (like the 6mm) that are touting high accuracy. The only real advantage for a smaller caliber that I can think of is higher velocity. So, why would anyone choose a caliber of a lower velocity in relation to a very similar sized caliber of higher velocity unless they are concerned with recoil?

Thanks everyone for your input.

 

[rcmodel]

wouldn't 2 projectiles of different weight (of exactly the same profile, and ignoring windage) have exactly the same trajectory?

No.
The heavier bullet would have a higher Ballistic Coefficient, and at the same velocity as the other bullet, would not slow down as fast.
So it would get to the target sooner, before it dropped as much.

It would shoot "flatter" at any range.

But again, I feel like you are confusing speed & trajectory with accuracy.

Accuracy is a factor of barrel quality, bullet quality, the load being tuned to the rifle, the stock bedding, the scope, and last but not least, the nut behind the trigger.

A good shooter with an accurate rifle & load can shoot anything well.

But he can't shoot it well just because it is faster & flatter if it isn't as accurate as a slower load.

rc

 

[bcs4]

"The heavier bullet would have a higher Ballistic Coefficient, and at the same velocity as the other bullet, would not slow down as fast.
So it would get to the target sooner, before it dropped as much."

Got it! That's what I was missing, thanks!

"But he can't shoot it well just because it is faster & flatter if it isn't as accurate as a slower load."

I don't expect you to help me any more, but why would someone want a slower load on anything?

 

[bullseye308]

First of all, what calibers do you currently have, or are interested in getting? That will take a lot of the guesswork out of it. What accuracy expectations do you have at what range? Will you be happy with 4MOA, or do you need less than 1MOA? Are you competing, hunting, or just trying to see what the best you personally can do? A little more info will get you a lot more help.

 

[bcs4]

For the most part, strictly handguns. I have a Colt HBAR that's accurate enough for me, and up to this point I've only shot it up to 100 yds, but I'm going to join a club that has a 500 yd range (though I doubt I'll be shooting that distance much, who knows).

The main reason I want to buy a rifle is as a platform to do more reloading. I find I have learned quite a bit reloading handguns, but I'm ready for a bit more now.

Before I started looking into this, I would never have believed how many different considerations there were between handgun and rifle. It seems like in handgun the main consideration is matching the load to the projectile. I'm sure I'll find that's true in rifles too, but it seems 4 fold more complex so far.

 

[Afy]

For 4 MoA might I reccomend a good 7.62x39 rifle.
For 1 MoA a decent bolt gun in .308, .260 or .300 WM.

For a consistent sub MoA a decent bolt gun in 6mm BR.
That is not to say you cant get sub MoA with any of the other calibers, or 4 MOA for that either.

 

[bcs4]

I think the 6mm has confused me more than any other caliber. I don't understand why such a light bullet is considered accurate (though it obviously is!).

For instance. Why would a 60 grain 6mm @ 3,000 FPS be more accurate than a 60 grain 22-250 at 3,600 fps assuming you have the right twist for the bullet?

 

[Zcarp2]

I am confused, let me attempt an answer.

What is your main goal? Learning to reload rifle - then your .223 will be fine. Some people get the super magnums and then realize they cannot shoot a whole box of 20 cartridges and then develop a terrible flinch. This affects accuracy.

I bought a light weight 30-06 rifle and it was uncomfortable to shoot. If you want to shoot a lot and you are learning, use the smaller calibers. Benchrest shooters use heavy guns and small bullets. Physics works. These guns have little recoil compared to my light weight 30-06.

The 45-70 is wonderfully accurate. It will also shoot 400 grain bullets very slowly. Once you understand the rainbow trajectory, you will be accurate. The same can be said of the 6mm and the trajectory will be much flatter.

I don't think there is a single answer to your first post. All bullets are affected by wind. Bullet design, profile, base design, initial velocity and weight will affect flight path. Transonic bullets are also a consideration (start faster than the speed of sound and then hit the target slower than the speed of sound).

Your last question, why is a 6mm more accurate than a .22 (5.56mm)? My answer is that the bullet is not. You should look at the launcher and the operator. The entire system should be looked at. All calibers will have their intended purposes. What is yours?

 

[rcmodel]

I don't expect you to help me any more, but why would someone want a slower load on anything?

Several reasons.

NRA .30 cal Match rifle shooters prefer a lighter faster 150-155 grain bullet for short course rapid fire matches. (Less recoil)

The same guys prefer a heavier slower 168-172-178 grain bullet for long range 600 - 1,000 yards matches.
Because it will have a much higher BC, and lose less velocity at long range then the faster up close 150 grain load.

The trajectory is much higher, but the bullet with the higher BC will stay supersonic longer, and also be less affected by wind drift because it stays faster further.

Another very good reason is that almost without exception, a slightly less then Maximum load will just be more accurate then one that is maxed out on pressure.

It is better to have a 3/4 MOA load with less velocity and a higher trajectory, then a faster 1 1/2 MOA load with a flatter trajectory.

Another reason is, the most accurate rifles in the world are bench-rest competation rifles.
They universally use small capacity cases with moderate velocity.
A bigger & faster cartridge wouldn't have a prayer of winning a bench-rest match, because they simply cannot be as accurate as the smaller slower caliber.

Another reason is that higher velocity costs you big in several areas.
More powder burned per shot, markedly shorter barrel life, more recoil, and more noise.

rc

 

[bcs4]

"Your last question, why is a 6mm more accurate than a .22 (5.56mm)? My answer is that the bullet is not. You should look at the launcher and the operator. The entire system should be looked at. All calibers will have their intended purposes. What is yours?"

You seem to be saying that the 6mm and 22-250 are equally accurate. If so, why is the 6mm commonly referred to as one of the accurate calibers?

Maybe it would be easier to understand my question if you assumed I will be shooting from a sled, and I will be shooting a Tikka T3 Varmint with the correct twist for each caliber (though I know this is impossible to have a single twist that works best with all weights and velocities, just assume it is so).

 

[243winxb]

For accuracy at 100 to 300yards. 6ppc 65 to 68gr bullets. To 600yds 6br w/heavey bullets fast twist. Why, the custom bullets are made in this caliber. They even shoot well in 243win. Less recoil is always a factor.

 

[33rowdy]

QUOTE
"why is the 6mm commonly referred to as one of the accurate calibers?"

That is only one of many of the accurate calibers. That doesn't say "the one and only accurate caliber."

 

[bcs4]

Yes, I know. So what makes an accurate caliber?

 

[bullseye308]

Any caliber has ther potential to be accurate. Your definition of accurate will be the determining factor of what to you is accurate. Accuracy is a combination of barrel, bedding, crown, trigger, ammo, and shooter mostly. Caliber doesn't really determine accuracy just like color of the car doesn't determine top end.

 

[bullseye308]

What are your accuracy expectations? If you would answer the ?'s in post 9, more specific help could be provided to you.

 

[33rowdy]

By an author's opinion. I don't want to say that to be some smart alice but....it is. Some "cartridges" simply have a sweet spot for accuracy that is better than another.

My 222 Rem is a good proven accurate "cartridge" by simpley nature. It's not a fast or a high energy bullet but is accurate to 200 yards. If I want to take a gun to war, well....Look at that market. A 223, .308, 30-06, 50 BMG, ect. Those are accurate in their own class too.

 

[bcs4]

It's strange. Seems like every review about rifles I read refers to the accuracy or lack of accuracy in the round itself aside from the accuracy of the weapon being tested. I could cut and paste a bunch of stuff, but I'm almost certain you have read it too. Everyone here seems to be saying that the caliber has no affect on accuracy. That's really interesting.

 

[proplinker]

The only choice is 6PPC 62gr moving 3200-3400 no thing will shoot 100yds- 300yds better. as long as we are talking targets. and not game. Look at the bullet weight - VS - powder capacity. for example everybody knows the 308 shoots 168gr bullets very very well.....but is to much gun for the task at hand.

 

[bcs4]

"What are your accuracy expectations? If you would answer the ?'s in post 9, more specific help could be provided to you."

Sorry, I just don't see how. I am trying to find out if a specific caliber or round is more accurate than others. How would my own abilities decide which cartridges are inherently the most accurate? If I can't shoot a 20 inch group at 10 yards it doesn't mean a caliber is inaccurate, it means I'm not a good shot.

 

[33rowdy]

Let me fix my post.

Test weapons do not work the same as other test weapons. Test ammo does not work the same as other test ammo.

QUOTE
"Everyone here seems to be saying that the caliber has no affect on accuracy. That's really interesting."
Are we taliking calibers or cartridges?