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"Inherent accuracy"...

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Unread 03-27-2004, 03:04 PM
Platinum Member
Join Date: Jun 2001
Location: Palmer, Alaska
Posts: 2,539
Re: "Inherent accuracy"...

If so, is it less powder burned, or a shorter fatter design?

Seems less powder with the 308 is all, but...

Changing only "one" variable at a time to test each of these would take more than I think most have contemplated. Can you control ALL things to even test one variable at a time in cases designs or anything else... I think all a guy can ever do is reduce the number of variables.
Brent Moffitt
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Unread 03-27-2004, 03:41 PM
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Join Date: Jan 2004
Location: North Dakota
Posts: 891
Re: "Inherent accuracy"...

I decided I'd stick my neck out and post my view.
O.k. lets say that all cases are perfect in their dimensions and all rifles are perfect. I would have to say I believe case construction does play a role in accuracy.For instance a .30-06 case has appox. .032 of side taper and a 17 degree shoulder and is 2.109 in lenghth to base of the neck.Now when your primer is ignigted behind all the powder in the case, it actually shoves the bullet and the unburnt powder into the barrel as it is burning the powder. More so in the .30-06 due to a funnel effect and lenghth verses width. as compared to a .300 WSM with .017 side taper, 35 degree shoulder and 1.805 in lenghth from base to neck.The more you disturb the powder before it is all burnt the more inconsistencies you will theory My idea of an inherently accurate case would be to make a case that would be as long as it is wide and completly round in the combustion chamber and to have a riser from your primer pocket to the center of the combustion chamber so that it would ignite the powder in the center of the chamber and burn out evenly in all directions.Thus I would say that to an extent yes, there are more inherently accurate cases then others in comparison.
In comparison I would say the .308 is more inherently accurate then the .30-06 and the 6ppc is more inherently accurate then the .222 and the 6br is more inherently then the .243. and so on and so forth.In my mind shorter and fater and a sharper shouldered case makes a more inherently accurate case.
these are just my views.And I appologize for my lack of ability to explain my ideas.
without God their is no hope for this country
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Unread 03-27-2004, 04:07 PM
MAX MAX is offline
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Join Date: Sep 2001
Posts: 263
Re: "Inherent accuracy"...

Ric, I alluded to that in my first post on this thread.

Now for my oral report, Chapter 1:

Went to BRC, got a reply wherein a fellow listed a whole long list of things to read, 3 of which I happen to have at home. BTW, I stepped right into the middle of a thread on this subject, and...JMO but I didn't take it that those fellas put a lot of stock in the idea. Of course, that's just subjective evaluation of a subjective discussion.

First three references suggested that are available:

Designing and Forming Custom Cartridges by Ken Howell. Couldn't find one reference to the subject of which we speak.

Rifle Accuracy Facts by Harold Vaughn. Again, the term was not used although there is discussion in regards the benefits of small cartridges as I mentioned previously.

The Ultimate in Rifle Accuracy by Glenn Newick. Now I don't know Glenn from Gatorade, but he is a successful Benchrest competitor and is all over the 6mm PPC. He apparently knows the P-P fellows and has a bit of literary talent. I'm not going to quote him specifically, but in essence: The case design does NOT in and of itself create accuracy. It is the blend of capacity, flash hole size, bullet weight and quality, and powder burn characteristics; these matched with proper chamber cuts, leades and loads, brass quality...and a half dozen other issues, that create the accuracy.

This is nothing more than what is required to make any cartridge shoot well. This entire subject needs to be taken in context of application. Short range bench shooters that use this class of cartridge are dealing with the most benign of environments. Flight time is short, wind effect minimal, and target resolution is very high. Typically, flat base bullets of 60-70 grains(6mm) are used, and in the application, yes the PPC is accurate when mated with an accurate rifle and effective shooter. It is a VERY narrow application. The SR/BR class cartridges are essentially useless beyond 300 yards or so.

This is not the case with longer range disciplines. Everything else has to get involved, and the "inherent accuracy" of your cartridge is the least of all concerns. Briefly aside, Blaine mentioned the evolution of competition regarding the 06/.308, and its true. Then again, it is a structured environment that negates benefit that accrues to the 06 as the distance is not too long. And the brass was bountiful, the service rifles of the day used the same round, etc. etc. Is the.308 the darling of the 1000 yard line? When/Where does it's inherent accuracy vanish?

Well, it's off to cyberspace once again, searching for real data. Proof to me on the subject does not mean that most people use it and shoot bug holes a lot of the time, and swear by it, cross their heart and so forth. I search for technical reports, substantiated research based on sound physical principals. Dreary old or new tech reports. I'd really like to read some of Dr. Palmisano's work. He was either a devoted surgeon or ballistician. I want to know which was his passion.

Hey, one of the P's was a heart surgeon, the other a gunsmith. They didn't do bad for their dabbling. I'll be back.
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Unread 03-27-2004, 04:55 PM
Posts: n/a
Re: "Inherent accuracy"...


Yup, gotta agree with what you are saying...


Not picking on you.. in your opinion you have the belief that short fat is the way to go.. I am not dissagreeing with you because in my belief you are partially correct.. but you say that you would want ALL the powder burnt in the case.. I have to dissagree with that.. I think that may lead to a host of other problems in ation constuction and the characteristics of the numerous that are avaialable.

The 308 can be more accurate than the 30-06 but WHY? is it the case design only? I don't think completely... Maybe a shorter action has somthing to do with it?

SR BR rifles are built for 1-200 yards the bullets they shoot as Max said are usless after 300 yards.. matter of fact you charge weight can vary as much as .3 grs and not affect bullet POI, this has been proven numerous times...

as I said there are many more variables that come into play when you talk of why a cartridge is accurate.. it is NOT only the case design but the design as well as the constution of the action, the trueing of the action, lugs, etc... even how the barrel is attached to the reciever...
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Unread 03-27-2004, 05:27 PM
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Join Date: May 2001
Location: Casper Wy
Posts: 1,377
Re: "Inherent accuracy"...

proper amount of input
Great statement and might just be the bottom line to the question.
Lets beat STL with his example for a minute(or two [img]images/icons/tongue.gif[/img] .He suggests that the 50bmg is a walk in the park to get good groups out of.He however didnt go into this quite as haphasard as he would have a rookie believe.First off he is a diciplined shooter properly trained in good form and the Wolf has conditioned him a little for the recoil.He chose a good gun with a great brake,then put good rings on it with a great scope!He then reloaded 750Amaxes(measured for length to the millionth [img]images/icons/grin.gif[/img] and H50BMG(again proven performers).I doubt too that he gives his walking encyclopedia and calculator of a spotter enough credit [img]images/icons/wink.gif[/img].I wonder too if his results would have ben the same 5 years ago?
Inherently accurate or inaccurate?Yes its a factor but definatly not the biggest factor as there is no substitute for proper settup,trigger time and correct translation of the results.
"Make everything as simple as possible, but not simpler." -Albert Einstein (1879-1955)
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Unread 03-27-2004, 05:43 PM
Bronze Member
Join Date: Sep 2001
Location: San Jose, CA
Posts: 66
Re: "Inherent accuracy"...

Brent, I don't know the answer as to the whys. But what I do postulate is that people who ocmpete will gravitate to the most accurate setup possible. The fact that scores shot up with the introduction of the .308 and ultimately the bullseye had to be reduced in size means to me that competitors were shooting better (actually much better) with the .308 than with the 30-06. Given the huge number of different people, different rifles, and different equipment with the only commonality being the cartridge, I conclude that the interior ballistics of the .308 are superior to the 30-06. Exactly why, I can't say.

It will be interesting to watch what happens to the 300 WM now that the 300 WSM has arrived. If "short and fat" is the reason for superior interior ballistics, then we should see the WSM line of cartridges outperform their slimmer cousins in terms of accuracy in a wide variety of applications and over a sufficient period of time.
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Unread 03-27-2004, 06:47 PM
MAX MAX is offline
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Join Date: Sep 2001
Posts: 263
Re: "Inherent accuracy"...

Just reviewing NBRSA records: 5 shot groups @ 100,200,300 yards. Most were made before the PPC cartridges gained fame, only 3 out of 12 as I recall shot in the 90's or later. Few in the 80's, rest in the '70's. Hmmmm. It appears that there is more interest in agg. scoring now...or something. Most dates on agg. score records are fairly recent.

Short cases may offer some benefit in regards to ignition in that the powder column is shorter. It compounds the problem of stuffing enough propellant in the case to get the job done. When your chamber is wider than it is long, you might want to try another hobby. [img]images/icons/grin.gif[/img]
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