Rifle caliber confusion

[bcs4]

"The only choice is 6PPC 62gr moving 3200-3400 no thing will shoot 100yds- 300yds better"

That's kind of getting to my question. Why wouldn't the 223 WSSM shoot better at the same bullet weight with a smaller diameter bullet at a higher speed?

I appreciate all the input everyone!

 

[243winxb]

http://www.benchrest.com/caliber does have an affect. Go and see what the group shooter are doing. for 1000yds 6.5X284 http://www.6mmbr.com/1000ydpg01.html

 

[bcs4]

Thanks for the great links. Lots of info at both!

 

[Jim Watson]

What makes an "accurate caliber," you ask?

Research and development, research and development. And a little luck. The 6mm PPC was designed in parallel with the .22 PPC on the same .220 Russian case. The intent was for the two calibers to be shot in different divisions of benchrest competition.
But the 6mm PPC has far outstripped the .22 PPC, shooters use it where they could have a .22 of PPC (or other) design. Maybe Messrs. Pindell and Palmisano know why, I don't.

Naturally an accurate cartridge design has to be matched with an accurate rifle, accurate ammunition, and accurate shooting.

Perhaps if you gave your application as to minimum and maximum range to be shot, the money and weight budget for the rifle and supporting equipment, and the time you are willing to put into building quality ammunition; somebody will have specific recommendations and justifications.

10 metres? You would be well equipped with a really good air rifle.
50 yards? Get a really good .22 lr and save the handloading labor.
A hundred yard benchrest rifle is not a thousand yard benchrest rifle is not a National Match rifle is not a prairie dog rifle is not a woodchuck rifle.

There is no one universal answer.

 

[bcs4]

Like I said, it will be used for 100 to 300 yards for the most part up to 500 yards. The rifle is most likely a Tikka T3 Varmint because I want a magazine and I seem to like the feel of the rifle, though I am also considering CZ and the Steyrs that CDNN has for sale. My budget isn't big. Shooting has taken up what I spent on golf, so I'd say $1,000 a year after the purchase of the rifle and allowing $300ish for a scope (I know that's not much). More than that and I have to start selling handguns. As far as reloading time is concerned, an hour or two a week or so. Needless to say none of these values is as much as necessary to become as good as most here.

It seems as if I'm finding my answer though. I'm not sure there are actually better calibers, just more accepted and researched calibers. I think I'm leaning towards the 308, though I still like the thought of the 6mm, though it's not available in the Tikka.

 

[Zak Smith]

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?

Very good deductions for someone who isn't "into" rifles! Good work.

If you look from caliber to caliber, there are more or less bullet choices, and more or less good "match" and good "long-range" (ie high BC) bullets. For example, 6.5mm has many many great long-range bullets. 7mm has fewer. 6mm has fewer, but still some notable ones. .25" has almost none.

Now, you are correct that for the same bullet design/profile, a larger caliber bullet will have a higher BC value. However, its mass will also be larger and it will require more powder to achieve the same velocity as the smaller caliber, and it will have more recoil. These are costs.

Thus, you tend to see sweet spots for long-range target cartridges, that trade off some ballistic performance for component and barrel cost and recoil.

 

[bcs4]

Thank you very much sir. That's exactly what I was looking for. I heard a rumor that all people were named Smith once, but as they did foul deeds, they were forced to take new names. Did your father tell you that once too?

 

[Zak Smith]

That's a new one to me! Sounds like an incentive for good behavior, though!

Here's an article you might find interesting re: LR cartridges


article | Practical Long-Range Rifle Shooting, Part I - Rifle & Equipment

 

[bcs4]

The Smith "fable" is surprisingly widespread. I'd guess 10% to 15% of all Smith kids have heard it (from my experience, and they're always surprised to find out that other Smith kids heard the same thing) and not just in the Midwest, where I live. I have yet to meet another surname that uses it.

Thanks for the link. It's the best explanation I've found and I saved it for future reference. Don't mean to be a bother, but are you aware of any other manufacturers that make a magazine bolt action other than Tikka, Steyr, FN, or CZ in that $700 or $800 price range?

 

[bcs4]

Holy mackeral! I just saw that you wrote it. Thanks again! Do you have any books out?

 

[Zak Smith]

Just articles (print and web) so far; working on a small book.

As for magazine-fed, if you are referring to a detachable box magazine, you can use the Badger or Surgeon "bottom metal" on a Remington (and perhaps other) actions, then use the Accuracy International AICS magazines.

 

[bcs4]

I pulled the trigger on a 308! Just put a hold on the Tikka and got $100 off. I'm almost as excited as I was when I bought my first 1911.

Thanks everyone for all the info. Now for the scope..

 

[ranger335v]

Your first premise comes close to being correct, sorta, in a way. Given that others have correctly explained that accuracy and a flat trajectory are NOT the same, I'll address the bullet part.

As RC said, bullets have two qualifications we can use to predict performance with moderate accuracy.

The first is BC, Ballistic Coefficient. It a form factor telling us (approximately) how streamlined the bullet is. The BC is not an absolute value, it changes significately as velocity changes over the full path of the bullet.

Bullets with a higher BC can cut through the air with the least resistance so they lose less velocity in a given period of time. Bullet travel is a function of the time of flight and velocity. Bullet drop is a simple function of gravity. The less time it takes for a bullet to reach a given range the less it will drop over that distance, and vice versa.

Any two bullets with the same BC will drop the same, regardless of the caliber or specific weight. That means a 55 gr. .224 bullet and a 150 gr. 308 bullet fired at 3000 fps will have the same drop at any range IF they have the same BC. Things in the real world rarely match the theory exactly but it's close enough for common work! Heavier bullets may have higher BCs but that's by no means consistant, few bullets of the same cailber and weight actually have the same BC.

The other bullet factor, SD, Sectional Density, is a pure math relationship between bullet diameter and weight. Seventy five years ago it was used in predicting the potential for penetration but, at best, it was a doubtful premise. Take two 200 gr. .308 bullets, one with a conventional round nose and the other with a spire point/boat tail partition jacket. Both have the same SD, but they sure won't have the same trajectory! NOR can they be expected to penatrate equally, the partition jacket will drill deeper everytime! But, a full metal jacket 180 gr. .308 bullet at the same velocity will out penatrate either, in spite of the 180's lower SD. The point is, bullet construction is far more important for penetration than SD or shape .

Of the two factors, I ignore SD myself but I do not ignore BC.

 

[Jim Watson]

I pulled the trigger on a 308! Just put a hold on the Tikka and got $100 off. I'm almost as excited as I was when I bought my first 1911.

Thanks everyone for all the info. Now for the scope.

A good choice in the realm of production model rifles and a well developed caliber. It will take a while before theoretical considerations get in the way of results with it.

You could either get some Black Hills Match ammunition to "break it in" and get familiarized. That would leave you with fireformed brass for reloading with good quality bullets. Or you could buy a supply of brass of the same lot number and start from scratch.

The Bushnell 3200 series of scopes has a good reputation at the entry level.

 

[bcs4]

Thanks again everyone.

Was reading recommended factory loads in something Zak wrote, can't find anything locally. Headed out this weekend though, so hopefully I'll find something.

I watching assorted auctions for scopes. I think I'm going to try to stick to Leupold or Nikon because of their warranties and maybe buy a used one in the $300 to $500 range.

Found out there is a 1,000 yard shoot in Pella Iowa (close to me) in a couple weeks. Can anyone attend those, or do they frown on visitors?

 

[Jim Watson]

If you find match ammo in stock, your stores are a lot higher class than around here. Anything I want out of the ordinary, it is mailorder or load it myself.

Most shoots are glad to have newcomers. Do your homework, have a dead nuts 100 or longer zero and figure your "comeups" for longer ranges.

Oh, by the way, if you want to shoot beyond about 600 yards, you will need an inclined scope base to add elevation. Very few scopes have enough internal elevation adjustments to make the 35 MOA or so from 100 to 1000 yards.

 

[snakeman]

i would go with a 260

 

[Scott23]

Ok, here's the skinny. Almost any of the faster 22's will do what you want for the range your talking about (100-300 yrds). Generally if you plan to handload you can get under 1 MOA at 100 yrds with a factory rifle. Yes, the weight and profile of the bullet has more effect on accuracy the further the range. I'm talking wind deflection, not bullet drop. If you don't want alot of case prep go with a 22-250 for 100-400 yrds with a 55-60 gr bullet. Also a 6mmBR useing 75 gr to 80 will also work from 100- 600 yrds as long as you do your part behind the bench. A 6PPC is reguarded as one of the most accurate in the 200yrd bench rest game, but that is a bit more involved as far as reloading and building a custom rig $$$. If high end accuracy is what your looking for get ready to open up your wallet. My recomendation would be to go with the 6BR, lots of bullet choices and tons of load data. The 6BR is a very accurate chambering and easy to load for. Go for a no turn neck, just load and shoot. Less case prep= more time on the range.

Scott

 

[bcs4]

"If you find match ammo in stock, your stores are a lot higher class than around here. Anything I want out of the ordinary, it is mailorder or load it myself."

I found Federal Gold Medal Match at $42! I didn't think the gold actually meant gold. At that price, I'll be picking up the spent brass AND the bullets.

"Most shoots are glad to have newcomers. Do your homework, have a dead nuts 100 or longer zero and figure your "comeups" for longer ranges."

I didn't mean to actually shoot. Just watch. For some reason making a fool of myself always makes me nervous.

"Oh, by the way, if you want to shoot beyond about 600 yards, you will need an inclined scope base to add elevation. Very few scopes have enough internal elevation adjustments to make the 35 MOA or so from 100 to 1000 yards."

That's very interesting and something I never would have known, thanks. Is there any way I can tell (by some feature name) which scopes might not need an inclined base? I'm guessing an inclined base would need to be removed at shorter distances then?

Thanks again!

 

[Jim Watson]

Well, watch and learn, then.

A 175 grain .308 boattail will take about 35 MOA elevation to go from 100 to 1000 yards.
Scope elevation ranges run from maybe 40 to a claimed 100 MOA. If you are centered at 100, you have half that to work with. A typical hunting scope with 40-50 MOA of adjustment, 20-25 available, is not going to do it. Some target and tackytickle scopes have more range of adjustment, but even so, you will use a lot of it and be in the high end of the elevation range, where it can affect scope clarity and the actual available windage. So we use bases cut to give us another 20-30 MOA. That lets us shoot at longer ranges near the middle of our scopes adjustment and optics. You can usually adjust back down to 100 without having to change bases.

The Burris Signature rings with eccentric insert kit is another approach to gaining more elevation than your scope will handle.

 

[Bart B.]

rcmodel says:

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.

Well, not quite. The smallest groups at 300 yards or greater I know of having more than 10 shots have all been shot with NRA high power match rifles shooting full-length sized .308 Win. cases. These used Win. 70 box magazine actions, not those heavy, stiff benchrest ones. No benchrest rifle's ever put several consecutive 10 shot groups into 3/4ths to 1-1/2 inches at 600 yards or 40 consecutive shots in under 2 inches at 600 yards.

Sierra Bullets' best 30 caliber match bullets have shot well down into the ones (under .2 MOA and even close to .1 MOA) in their test range. Shot from rail guns just like the benchresters use, their .308 Win. test barrels shoot very tiny groups. Not all the time, but like the benchrest guns, enough to know that larger cartridges can shoot tiny groups, too. Sierra uses full-length sized cases, too.

The main reason such heavy recoiling rifles don't shoot accurate in traditional bench rest matches is how they have to be shot. 13-pound traditional bench rest rifles only have a couple foot pounds of recoil with their tiny cartridges. Shot free recoil and virtually untouched by people except for pinching off their 2-oz. triggers, they are very repeatable in being accurate. A 13-pound NRA match rifle shooting the .308 Win. has many times more recoil and would fly off the rests and probably end up on the ground if shot in free recoil. People cannot hold one of these repeatable enough atop a bench to shoot their best. Clamp a good one in a machine rest and they'll equal any traditional bench rest rifle.

 

[moooose102]

i am no expert, but i will offer you my opinion. rifle accuracy equates to a lot of things going right at almost the exact same time. there are many variables. one of the more "adjustable" things you can change is velocity. it certainly is not the only factor. then there is bullet selection. which is a whole different can of worms. the biggest thing that affects rifle accuracy, that is not so easy to change is barrel vibrations. that is why we work up loads trying different velocities/ bullet weight/ s.d./ b.c. / etc. to get the most out of a particular rifle, you need to match harmonics (barrel vibration), velocity, bullet, etc. pistols are not so much affected by barrel vibrations as the barrel is much shorter, and in most cases, stouter. do some reading on accuracy and you will find out there is more information out there than you may care to read. in any case, faster is not always more accurate. it can be a lot of work to find the most accurate load for your gun. me, as long as they stay in less than an inch (30 caliber) i am happy. so far, i have not been able to get my 45/70 that small yet, but i am still working.