What makes a rifle accurate?

Furync

Furync

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ok ok I know I started a wide subject but... I'm curious...

I've been shooting ever since I was a small kid and I'm pretty good with a rifle, I understand some of the mechanics of accurate guns but i still lack some knowledge...

Are there any guides out there that would explain what makes an accurate rifle, accurate?

I've been hunting a lot and shooting a lot, I shot only once with a scope in my entire life (i am 26, been shooting for ohh.... 20 years?) and now i'm getting the urge to shoot far and accurate. The longest shot I get while deer hunting is 50 yards at most, so i dont have anything capable of longshots. My only "long range" rifle is my rem 7600 in .308 (pump with open sights), so I'll obviously be buying something for the purpose of "varminting". My main purpose for long and accurate shots would be for coyotes.

I've been looking into a few calibers... .243 and .223 have caught my eye. I've read people beeing able to reload .243's to like 4000 fps... I like that :) but dont really need that. And .223 because i've seen a cheap Norinco bolt action with scope rails (JW-103 i think) at leverarms.com
But i'm not ruling out any caliber yet.

So, single shots and bolt action rifles (i want a bolt)are the most accurate because they have the least moving parts. The longer the barrel, the more powder you can burn... how do you know how long a barrel you need? And what about the rate of twist of the rifling? i have no idea how that works...

Sorry for the long post and any help is greatly appreciated!!!
Thank you CGNers!!
 
The quality of the barrel,the crown,the trueness of the action,installing the barrel true in the action,the trueness of the chamber,proper bedding,a fast lock time and a good trigger are probably the factors that have the biggest influence on the accuracy of a rifle.Of course a rifle is only accurate with proper loads.
 
"...The longer the barrel, the more powder you can burn..." Um, no. That applies to BP, but not smokeless.
An accurate rifle is a combination of all of the items stubblejumper mentions working together. However, the operator has a significant part to play too.
Try and find a copy of 'The Accurate Rifle' (Claymore Pub Corp ISBN: 1886681066) by Warren Page. My copy is in a box around here someplace. Your local public library or local gun shop may have it. If not Amazon has it.
 
Twist rate dictates what bullet weight the barrels rifling will stabilize, slow twist rate is not normally conducive with heavy bullets. Some calibers ( usually the overbore 1s) benefit from longer barrels, but there is a point where it gets detrimental as well. The tighter the tolerances of machinework and trueness of everything being centered greatly improves accuracy, if the bullet is exactly center of the bore as it enters the bore, and if the lugs support the cartridge equally, typically the rifle will shoot better. Usually bolt guns are favored for accuacy, simply because they are the easiest to get everything aligned well. There are some falling blocks that are truly great shooters as well as some s/as, you just have to work a bit harder to get them perfect in the machining dept. :mrgreen:
 
Based on your intended use you can purchase an over the counter" factory rifle" that will get the job done. Either Winchester or Remington have very good Varmit rifles that will do the deed. Caliber??? I would go with 243 Win. Enjoy Bill.
 
To be honest every single component used in the gun, the reloads, the rest you are using as well as technique. A lot of variables. I just got my copy of the Benchrest Primer and it is amazing to see the articles in it, mindboggling!!!!!!!!! Get a copy and enjoy!!!!!!!!! :mrgreen: :mrgreen:


Calvin
 
Need help. Was a joint project with another person. He had the comp skills and was helping me out, I just blabbed. Now, his new job doesn't allow the time so my site is stalled.

Anyone know anything about building websites?

Jerry
 
Jerry - you might want to revise the paragraph:

Quote: Checking the chamber is easy. Take fireformed brass (full pressure loads) and measure run out of the case body and neck. It should be zero to 2 thou. Anymore and the odds of this rifle shooting tiny groups is slim. end quote

This only makes sense if the brass has uniform wall thickness. Most brass isn't so the test in most cases is misleading.

Thats as far as I got........
 
Actually, what I stated is correct. With near max pressures the OUTSIDE of the case is formed to the chamber. Doesn't matter what is on the inside. You are measuring the external dimensions.

If you were right, any shooter measuring runout would be wasting their time.

Runout can also be visualized as a 'wobble' in the case like a banana or crocked/bent neck. Rare are the oval chambers as they are easy to QC. What many don't check is if that reamer was just a bit off as it hit the rifling.

Having a reamer not concentric with the bore will never allow a barrel to shoot its best.

Jerry
 
103159 - care to explain your comment a bit?

Chambers are easily checked by comparing the external dimensions off the brass once fired in a particular rifle, the thickness of the brass doesn't really make a difference as far as I can tell.
 
Jerry, I disagree but if you want to maintain the error that is up to you. You could include some of the information you just mentioned to try to make sense of the paragraph. Keep in mind that brass is elastic to a point The thicker the brass the more stress it can tolerate.

If the thin section of brass yields first (and it will) you will wind up irregular expansion. This would give you a false reading. A chamber with generous clearance will really show this.

If the brass were uniform the odds of showing a out of round chamber would be better. Regrettably for the application you are trying to use it, it is not. I believe Merrill Martin a past PS writer did some extensive work on brass deformation.

The best way to check the chamber is with appropriate instrumentation......

No ifs.........I am correct well the theory is :wink: . Checking fired brass gives you a chance to dump the non-uniform brass which would normally destroy the perfect alignment we try to achieve...

Tight chambers also keep brass expansion to a minimum.

Full pressure loads is a tough one for people to follow since most do not have a method of determining what the chamber pressure actually is.

Sorry but YOUR SUGGESTION IS INCORRECT.

I will say that it is super to see the efforts you are putting forward to educate people Jerry - great work.
 
The chamber cast is a really good indicator. A person has to make sure they follow the instructions of the casting material. Wait too long to measure the casting material (pending type) and a false reading could be had due to shrinkage.

However, for runout I think shrinkage should have no effect since it is uniform.
 
Thanks -

So the thickness of the brass affects the elasticity, thus one side of the brass may bounce back more or fail to stretch as much. (in a nutshell?)

Never match prep'd brass here how much does the thickness vary on brass? (on average)
 
What actually happens is the thin side will yield first and blow out taking up the clearance. The thicker side will of course move the least if at all. This gives the impression of an irregular chamber.

Some people feel that the cartridge laying on one side can impact the expansion and I think to a very small degree it probably does.
 
I agree with 103159. You can have a perfectly concentric chamber, yet fired brass from that perfect chamber will show runout after firing if it has a thicker wall on one side. The thin side of the brass will stretch more than the thick side when fired expanding to fill the chamber, then when the brass springs back (shrinks)after firing the thin side will contract more than the thick side, as it never stretched to begin with, you will have a fired case that is not quite round. This is more noticable the looser the chamber.
 
When testing for concentricity, never depend on the results on one case. You take at least 5 to get an average. This eliminates the issues above as it is statistically improbable that all brass with have the same defects in the same locations orientated in the chamber the same way.

Problem solved. Big issue is the concentricity of the neck. If the body is a little askew but the throat true with the bore, this chamber can still shoot very well. Would just need a different form of sizing. Also, since the brass is annealed in the neck, the issue of inconsistent expansion is greatly reduced. Neck turning anyone?

The body runout is used as a reference to align the neck. That reading is not really all that important. Just compare before and after (use new brass when testing).

As to the pressure question, any factory ammo or like load is sufficient.

so the method DOES have use. As with all things, the procedures to eliminate errors have to be followed. More importantly, understood.

As to the chamber cast method of measuring, I have played quite a bit with Cerrosafe. I believe this method has more room for error then the above.

If you ever casted bullets, you know that to get concentric and consistent bullets the mold has to reach an appropriate and stable temp. How do you do this with a barrel?

Many times I have poured in the alloy and found lines, air bubbles and other defects that you would commonly find during casting, poor casting. I decided that the room for error was too great. Big issue is that a cooler 'side' of the chamber would allow the alloy to cool and shrink way more then a hot 'side'.

Except for dipping into a heated oil bath to equilibrate, manual heating of a barrel or just pouring cold will lead to very poor results. Just make a few casts and measure, I bet none are repeatable. Do five in a row. Pour, cool, knock out, repeat. I bet the first will be the smallest and the last the largest. I can effectively make this guess because the barrel is not hot.

As to the shrinkage issue, already part of the industry. The amount that cerrosafe shrinks over a given period of time is well understood and a reamer maker will take that into account. They just need to know when the cast was made. Read the instructions...

maybe someone isn't quite covering all the facts...

Jerry

PS concentricity as it refers to the chamber is not how round it is, but how aligned it is with the bore. An oval chamber with a perfectly true neck and shoulder will shoot very well. Brass life will suck but the gun will shoot well all else being proper.
 
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