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Ballistics, are there proven , written in stone combinations that work pretty close to every time? Login/Join 
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posted
With o.t.c. ammo.

Example:
This Xx barrel _______ long and _____ rate of twist mated with Xo o.t.c. ammo
And
That trigger in bolt action
Will almost always produce a very specific outcome accuracy .

Any caliber will suffice





Safety, Situational Awareness and proficiency.



Neck Ties, Hats and ammo brass, Never ,ever touch'em w/o asking first
 
Posts: 52808 | Location: Henry County , Il | Registered: February 10, 2004Reply With QuoteReport This Post
Freethinker
Picture of sigfreund
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Absolute precision and accuracy are dependent on very many variables beyond the few you mentioned. Even with exceptionally precise guns and ammunition and highly skilled shooters, there is always some dispersion. If that were not the case, we’d see reports of one-hole, caliber-sized holes with as many shots as we’d care to fire at any distance.

So, my confident answer is no, there are not.

That does not mean, of course, that there are not many combinations that produce better results than most others. They still depend on variables beyond the ones you mentioned.




7/93
“Cet animal est très méchant, quand on l’attaque il se défend.”
 
Posts: 46419 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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Not so much absolute accuracy at question.

There are a few rifle makers propose 1.25 inches groups at 50 at yards.

Others promise 1" groups at 75 yards.

And some even say minute of angle groups.

Iam just guessing that those are with very specific brands and weights of ammo.





Safety, Situational Awareness and proficiency.



Neck Ties, Hats and ammo brass, Never ,ever touch'em w/o asking first
 
Posts: 52808 | Location: Henry County , Il | Registered: February 10, 2004Reply With QuoteReport This Post
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It’s been my observation that Federal Gold Medal Match 308, 168gr shoot excellent in almost everything I’ve ever tried it in. Various bolt actions, AR10’s, SCAR, and a couple of single shots.
Maybe not written in stone, but it’s known to group well in a variety of platforms.





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Kill every last one of these goddamned animals. We need a president with balls. We need leadership. We should be carpet bombing these barbarians wherever we find them, and we should be looking for them 24/7. We have to unleash Hell upon them. They understand nothing but death, so death is what we should bring them, wholesale.... Para

I left "practical" behind many years ago. It was covered with my first Glock 19. (Fredward)
 
Posts: 2422 | Location: Kentucky | Registered: July 09, 2007Reply With QuoteReport This Post
Freethinker
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quote:
Originally posted by bendable:
I am just guessing that those are with very specific brands and weights of ammo.

Hmm …. Perhaps I understand your question better now.
Long ago when I first became interested in guns, I don’t recall ever seeing any manufacturer’s claims about a rifle’s accuracy (or “precision” as many prefer to call it now). The possible first exception was about the HK PSG1 that I remember being claimed to deliver 3 inch groups at 300 yards (~1 MOA). But I think that was an “expectation,” not a guarantee. In addition, I don’t recall ever seeing any mention of what ammunition had to be used to deliver that performance. At the time I was too ignorant of long range precision shooting to focus on that question, but it’s obviously critical.

Now guarantees of a certain level of precision are relatively common, but as you point out, their details vary. For example, Tikka guarantees 1 or better MOA with five shot groups for their “tactical” models, but the same precision with three shot groups for the rest of their rifles. Why? I don’t know. Perhaps the chassis and bedding of the tac models helps as compared with the stocks used with the others. But five shots or more are better demonstrators of a rifle’s precision than just three, especially better than the three-shot group that’s picked as the best out of a dozen.

Most companies that provide an accuracy (precision) guarantee specify the use of “match” ammunition, but even what that means is usually not specified. It’s usually possible to decide what it doesn’t refer to. They’re probably not going to give us a new gun chambered for 308 Winchester if ours doesn’t group less than 1 MOA with some 50-year-old military 7.62 stuff made in Indonesia (I have no idea if that actually exists, it’s just a made up example). As another example, moderately priced ammunition that’s usually intended for hunting big game usually doesn’t produce highly precise results even from top tier rifles.

What is “match”? Both Hornady and Federal market ammunition that’s labeled as match in some way, and I have had very good results with offerings from both companies. The “match” label on a box by itself is a guarantee of nothing, though, and doesn’t always deliver on that implied promise. If I complained to Tikka that my TAC A1 models weren’t delivering <1 MOA groups with a made in Pakistan load that was labeled “SuperMatch,” they would probably tell me to pick up something like Federal’s Gold Medal Match or Hornady’s ELD Match and try again.

Another thing to consider even when a rifle has a precision guarantee, it’s usually stated that it applies to a limited range like 100 yards or meters. A rifle and ammunition combination that groups 1 MOA “all day long” at 100 yards may not always stay under 3 inches at 300 yards.

I’m not the expert some of the members here are, but those are a few thoughts.

This message has been edited. Last edited by: sigfreund,




7/93
“Cet animal est très méchant, quand on l’attaque il se défend.”
 
Posts: 46419 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
Experienced Slacker
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Perhaps others will disagree, but I believe that manufacturers build with twist rates, and barrel lengths (to a lesser degree) for whatever the most used bullet weight is for a given caliber.

For example, .308 you can pretty much bet 150gr bullets will do well, .270s typically prefer 130gr. etc.

As for specific group size claims, if there is no test target provided I have even less reason to believe it. Marketing is mostly the power of suggestion.
 
Posts: 7154 | Registered: May 12, 2004Reply With QuoteReport This Post
Freethinker
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Barrel rifling twist rates are a relatively easy thing to research and decide upon. That’s one of the basic specifications that should be listed with anything else on a manufacturer’s site.

The first and most important consideration is that the twist is fast enough to stabilize the bullet properly. If it’s not stabilized enough, at some point in its flight it will tumble and all accuracy and effectiveness will be lost.

There are some formulas for calculating minimum required twist rate, including the earliest I’m familiar with that dates back to 1879. The last is a classic that’s still cited, but it’s based on an old bullet design that’s not common today. I prefer to use the data provided by the ballistician Bryan Litz through the Applied Ballistics books. Even that information is evidently based on standard atmospheric conditions; at high altitudes and in hot, humid weather bullets will be stabilized with somewhat slower twist rates.

On the other hand, some shooters believe that spinning a bullet faster than necessary “overstabilizes” it, and that results in poorer precision. I believe that term is simply something that was made up to account for poor precision and accuracy when bullets were fired at high spin rates.

Litz says the disadvantage of spinning a bullet faster than the minimum necessary is that any imperfections in the bullet will be enhanced by a faster spin rate, and that’s what causes poorer precision. He cites the fact that benchrest shooters who strive for maximum precision at relatively close ranges usually select bullets that can be adequately stabilized with slower rifling twist rates. Those are usually lighter bullets with flat bases and are therefore shorter in length. Such bullets are less suitable for long range precision because they are more susceptible to wind drift than long, heavy boattail bullets with higher ballistic coefficients.

As a last point, bullets with thin jackets that are designed for shooting small varmints can actually disintegrate in flight if fired at high velocities with too-fast spin rates.




7/93
“Cet animal est très méchant, quand on l’attaque il se défend.”
 
Posts: 46419 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
You have cow?
I lift cow!
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Yes I think is the answer. Gotta check with the translator but it's all about removing variables in the equipment which then leaves it up the the human squeeze.

FGMM is the standard in 308 for instance. Far as I'm concerned anyway.

Generally bolt guns will remove more of the variables and be more consistent. But it's universal across all combinations of launching systems and rounds.


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Posts: 6755 | Location: Bay Area | Registered: December 09, 2007Reply With QuoteReport This Post
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I.i.u.c.
In theory
Four manufacturers
Should be able to assemble a rifle.
That has very, very similar components
That offer very very similar performance
And add to the packaging
A specific ammo for those for guns ?

So all the customer has to do is buy two cases of the ammo specified and he or she is good to go.
If of course he or she has comparable shooting skills.

Instead of buying a rifle and seven kinds of ammo,
Then taking the time ,effort, money and wear and tear to " wring out " the whole mess.





Safety, Situational Awareness and proficiency.



Neck Ties, Hats and ammo brass, Never ,ever touch'em w/o asking first
 
Posts: 52808 | Location: Henry County , Il | Registered: February 10, 2004Reply With QuoteReport This Post
Member
Picture of P250UA5
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quote:
Originally posted by bendable:
Not so much absolute accuracy at question.

There are a few rifle makers propose 1.25 inches groups at 50 at yards.

Others promise 1" groups at 75 yards.

And some even say minute of angle groups.

Iam just guessing that those are with very specific brands and weights of ammo.


My Tikka has a 1" at 100yds guarantee*
* When shot with Sako ammunition, which I've never seen on the shelf.

That said, I did manage to put 5 shots in 3 holes at 100yds, with about a 1.5" spread.




The Enemy's gate is down.
 
Posts: 12511 | Location: Spring, TX | Registered: July 11, 2011Reply With QuoteReport This Post
Freethinker
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As I have discussed elsewhere, my Tikka T3x TAC A1 models in 6.5 Creedmoor and 308 Winchester almost always give me sub-MOA groups with Federal and Hornady ammunition that is labeled as "match."

https://sigforum.com/eve/forum...935/m/7470031074/p/1

What perhaps might be more interesting to hunters or others who aren’t so interested in consistent multi-shot groups is the fact that I use both rifles in a timed drill that consists of firing (only) two shots from 200 yards at “tactical” targets without well-defined aiming points using a tripod and shooting sticks for support from the kneeling position.

If we can call two shots a “group,” these are their sizes from most recent to earlier, approximate minute of angle converted from center to center distance. When I factor in my limited shooting skills, I am very pleased with the precision of the two rifles.

308 Winchester:
0.28
0.60
0.26
<1.0 (not measured precisely)
0.69
0.33
0.20

6.5 Creedmoor
0.34
0.61
0.41
0.48
0.72
0.22
0.19




7/93
“Cet animal est très méchant, quand on l’attaque il se défend.”
 
Posts: 46419 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
I Deal In Lead
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All guns are different and so I somehow doubt that all their guns can shoot "xx" inch groups. Maybe most but certainly not all.

I first happened upon this phenomena when I was 18. A friend and I both bought .30-06 rifles that were essentially commercial Mauser actions. They were identical in every way and even had consecutive serial numbers.

Since I was a reloader, I worked up a load using my rifle and got some respectable groups, then he went out with me and tried the ammo in his gun.

It shot patterns rather than groups. That rifle really hated my load and I had to work up a different load for it.

Lesson learned.
 
Posts: 10526 | Location: Gilbert Arizona | Registered: March 21, 2013Reply With QuoteReport This Post
Freethinker
Picture of sigfreund
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quote:
Originally posted by Flash-LB:
I first happened upon this phenomena when I was 18.

I am curious when that was and what the rifles were.

I noted in another thread that you applied for a job as a recently-graduated engineer in 1976, which would, I’m estimating, mean that you were 18 about 1970, or 52 or so years ago. Although many shooters our age pine for the blue steel and walnut rifles of that era, even moderately-priced rifles today are generally capable of putting bullets closer together on targets than was common then. To reiterate, precision guarantees, especially at a 1 MOA level, were all but unknown at one time, whereas they are often seen today.

Although (as usual) this article omits some important details about the testing, it does list 10 current rifles that performed very well.
https://www.fieldandstream.com...es-weve-ever-tested/


As another example, at one time there was so much inconsistency in military rifles that they were routinely test fired for accuracy (precision) at the factory. If one didn’t meet a usually rather loose standard, it would be redone or rejected. It was common to select rifles destined for sniper use by just picking the ones that performed the best out of the ones tested. I’m not aware of any such routine testing for military weapons today. Sniper rifles get tested by the ultimate users of course and if one wasn’t satisfactory we could expect it to be addressed by the manufacturer, but any others?

In short, I can’t attest that all rifles today are better than their 50-year-old predecessors, but I’m pretty sure that on average they are.




7/93
“Cet animal est très méchant, quand on l’attaque il se défend.”
 
Posts: 46419 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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There may not be a secret sauce for great accuracy, but the are principles that almost always result in great accuracy.

If factory ammo is part of the equation, then the ammo and the rifle must be designed & built around the accepted specifications -- like SAAMI. Then comes consistent and repeatable builds -- the assemblers must limit the variations across products built.

High-volume rifle manufacturers that are building products to sell at a lower price point will not produce the best accuracy. Any accuracy guarantees from such manufacturers will be generous, to allow for when tolerance stacking doesn't work in their favor. Value-line rifles may produce great accuracy with one rifle, but not the next.

The most accuracy rifles are assembled in smaller quantities, using higher quality components, with attention to detail throughout the process. And of course, such rifles are more expensive.

The bolt action is a critical component of great accuracy. The face must be square to the bore, and it must close firmly. High quality actions include Defiance, Terminus, Kelbly, Zermatt, Stiller, BAT, Surgeon, Impact. Remington 700 actions can be quite accurate, or not so much. Gunsmiths can "true" a 700 action to improve its performance.

The barrel is a very critical component of great accuracy. Factors include straightness of the blank, straightness of the bore, consistency of the bore & rifling, and the dimensions of the chamber. Hammer forging can produce some pretty darn good barrels, but they aren't the top of the heap for accuracy. Chrome lined barrels will never win accuracy contests. Melonite bore treating hasn't been the accuracy savior once thought. The most accurate barrels will almost always have cut rifling. Button rifling can be good, especially if the barrel is stress relieved after rifling. Great barrel manufacturers include Bartlein, Krieger, Proof, Hawk Hill, Benchmark, Rock Creek, Broughton.

I'll use 223 Remington as a caliber example for factory ammo. A well designed & built 223 rifle with a barrel twist of 1:9 will almost always shoot Federal GMM 69 and Hornady Vmax 55 well. With twist rates of 1:8 or 1:7, add Federal GMM 77 and Hornady HPBT Match 75. Of course there are a number of ammo manufacturers which produce similar products with similar results. Black Hills, Fiocchi, and ADI are examples.

Next is 308 Winchester. Twist rates on modern 308 barrels are often in the 1:10 to 1:11.25 ballpark. With a well designed & built rifle the consistent ammo choices include Federal GMM 168, Federal GMM 175, and Hornady Amax 168. There are some match-grade loads using Berger bullets, and they can produce outstanding accuracy, too.

The challenge with accuracy guarantees is that many shooters are not up to the task. They just have not developed the shooting fundamentals to exploit the accuracy potential of the rifle/ammo/sights system. There are custom built rifles that can consistently produce 3/8 MOA accuracy, 1/4 MOA accuracy, or even less -- but the pool of shooters capable of shooting this well on a daily basis is small.
 
Posts: 7503 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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