While playing with a new rifle, and fighting some accuracy issues, it's made me really think about what makes a rifle accurate? By accuracy, I mean relatively small groups, which is really just consistency. Getting the same result each time the trigger is pulled. Leaving the shooter out of the equation for this discussion, because I have a good idea of how much of the inaccuracy is due to me.

What can move a rifle from a 1.5-2.0" shooter to a ~.75" shooter?

What makes a barrel accurate? What is it about the construction that will allow it to respond differently, or impart some inconsistent force on the bullet?

Inconsistent contact on some part of the barrel, or even action, is an easy one to see. Bedding and ensuring no contact on the forend should prevent that. Likewise ensuring the mag is not doing anything weird would be important.

Bolt lug contact. What if both aren't touching? Even that seems like it would respond the same each time. Apparently not?

What about the bolt face? I hear about squaring the bolt face. Savage uses the floating bolt head to ensure it aligns each time. What if a bolt face is a bit off?

What else?

are you shooting factory ammo or handloads?

if handloads, try shooting a "known load" - for me in general I like Sierra Game Kings and H4350/4831...generally one or two grains off max.

Run the OAL 2/1000's off the lands (*cup and core only...not mono metals)...

If that doesn't work, then try bedding the action.


If that doesn't work, consider selling it.

Shooting factory. .308 Federal Gold Medal Match, 168gn.

I understand variables in hand loading impact accuracy. I guess I want to better understand the 'why' behind the hand loading variables, but also the rifle itself.

As for bolt lug contact. Savage 340's only had one lug. I've had 4 of them in .222, .223, .225 and .30-30. All were capable of sub MOA accuracy.

Proper glass bedding should be the first step. Freefloat the barrel or some rifles like to be FL bedded. This may require a little experimentation. Hand load your own ammo. Consistency in and dialing in your handloads is a key ingredient to ringing out every ounce of accuracy. You don't need to shoot match grade bullets/ammo to get excellent accuracy out of your rifle (hint).. Minimize TIR/runout in your ammo. Chamber dimensions, rifling, lands, bore dimensions, crown and overall health of your bore affect accuracy. Consistency in everything (including shooter skill/form/habits) has an influence in accuracy...

I've seldom seen glass bedding markedly improve accuracy.

You don't know how to properly glass bed a rifle then..

That's a real group.

I've built custom rifles that sold for 3500.00 and my customers were satisfied. I currently build custom 1911's that sell for 2500 - 4,000.00. My employers apparently think I know what I'm doing as they keep paying me every week. I think there's a good chance I can bed a rifle about as well as anybody.

I have.....and I do mean markedly!

I did say seldom. Not never. It has been rare.

A good trigger adjusted right is the first thing I'd do. I don't agree with the advice to seat bullets .002" off the lands. That's close enough so that some could be in the lands, and others not.

prm this may be an over simplification but I feel a gun that has been #1 bedded correctly w/#2 a good crown and a #3 a good barrel should shoot around a half inch w/several different loads. I have only 1 rifle of a cabinet full that will do it. To me, time of bullet in barrel and consistent barrel vibrations w/the bullet leaving the barrel at the same key point each time matters...a bunch. I think some people are lucky and get a shooter doing some of those things but not many. It does start in the bedding to me. When one realizes how little a rifle has to move to pull a shot an inch at 100yards he'll be well on the way to getting accurate, consistent shooting. Of course hand loads that have .002 or less run out is a must as well. powdr

A good barrel,good bedding and good construction.If it's not built correctly,a rifle will not shoot well.

I agree that with a good barrel and bedding a hunting rifle should shoot three shot groups in the .5"-.75" range. Maybe a bit more if limited to factory ammo. But what is it about a barrel that makes it good? As a barrel maker, what are you paying attention to when making the best barrel possible? What aspects of the construction does a competition bench rifle maker focus on?

Being much lighter and fired off basic bags using factory ammo I certainly don't expect bench rifle results, but I want to do what I can to make improvements.

This is not an apples for apples discussion.
There are vatrious groups of opinion here and they are independent of each other in requirements.
1. Handloaders
2. Factory ammo
3. Accurised rifles
4. rifle platform

1 - Handloaders want the best accuracy and the top velocity
2 - Factory ammo likes accuracy but compromises on velocity
3 - Accurised generally means within the capability of the user or check book
4. Rifle Platform is more attuned to rifle sum part component specs.

Accuracy can be a fluke and it can be created. I have seen factory rifles out shoot customs, most of us have.
I have made accurate rifles by building them to a spec.
I have tweaked both factory and built rifle to gain accuracy improvements or as some would say, consistency in the best accuracy obtained, simply meaning reliably in uniform groups.

The rifle itself is a torqued platform consisting of layers that each can have detriment with accuracy.
layer 1 - action screws
layer 2 - floor plate
layer 3 - stock
layer 4 - bedding, both action and barrel and trigger cut out and bolt recess and tang mortise.
layer 5 - barreled action
layer 6 - Magazine box
layer 7 - scope bases
layer 8 - lower rings
layer 9 - scope tube
layer 10 - top rings
layer 11 - top ring screws.

Everything is torqued and while attention is given to bedding and barrel floating, all else can be troublesome and create a binding or torquing within the lock up that can tension the stresses within the lock up.

After all this, we have the variables like muzzle crown, barrel profile in relation to the cartridge, trigger settings, ergonomics of the stock design, shooter stance or pressures applied to the stock and rifle platform during the shot and the big one.........scopes.

Be prepared to toss an expensive name brand scope in the trash and accept what is, as money doesn't guarantee what you thought you would receive.

Notice I have not mentioned the load yet.........

How much accuracy do you want? an MOA rifle is a good rifle to some and inadequate to others.
Most accept .75 MOA but would like .5 MOA. Are you good enough to shoot that well?
If you want better than .5 MOA, be prepared to spend money and not stop until you get there and then that achievement is only as current as that particular barrel wear on that particular tube.

It is as hard or easy as you make it remembering that in most instances, the majority on here are talking about hunting rifles, not bench rest rigs.

prm,

If you can borrow a copy of RIFLE ACCURACY FACTS, by Harold R. Vaughan, it will tell you more about what actually affects accuracy than asking questions on the Campfire for a year. I wrote "borrow" because they're rare and expensive. Vaughan is an actual rocket scientist who did extensive technical lab work to put the book together.

There are some other good books that provide good information, including several on modern benchrest and target shooting, because they not only address the rifle itself but the realities of how shooting technique can affect accuracy. Three that come to mind are THE ULTIMATE IN RIFLE ACCURACY by Glenn Newick, EXTREME RIFLE ACCURACY by Mike Ratigan, and THE RIFLE SHOOTER by David Tubb.

In addition there's some good stuff to be learned from Warren Page's old reference work, THE ACCURATE RIFLE, and most of the books by Bryan Litz, though they involve exterior ballistics (especially at long range) more than the rifle itself.

I am quite pleased with .75 MOA from a hunting rifle shooting off of simple bags at the range. Some days a bit better, some days worse.

Mule Deer, Thanks for the recommendations, they appear to be exactly what I'm looking for. I really want to better understand the 'why' behind what is happening.

A barrel makes or breaks a rifle in my opinion. I half agree with Blackheart...bedding only helps if there were a bedding issue prior. I have several factory rifles that are not bedded and shoot lights out. If an action is a poor fit for the stock, then obviously bedding will make a difference.

Don't forget the Book of Rifle Accuracy by Tony Boyer. The most winning shooter in benchrest history.

I just want to know what it is about a barrel that makes it good. Is it the rifling, consistency of inner diameter or what?

Angels (because the reverse is caused by gremlins.)

Consistency of diameter both bore and groove, straightness, proper stress relief, inner/outer concentricity, ...

Just thinking out loud.

Stress relief is one thing I can see changing POI from shot to shot. But other inconsistencies, while not ideal, remain the same from shot to shot so how could they result in shot to shot variation? That's what I keep wondering. I have some learning to do clearly.

The most perfect barrel in the world won't work perfectly if the bullets aren't as much like each other as possible, and seated straightly in consistent brass.

And then there is the person pulling the trigger. Which is the biggest factor IMO.

Holy Moly, just went to Amazon to see what they are priced at...I been collecting the wrong things. $300-500? Good Grief...

It is a good book for sure.

D

Yeah, I was astounded to find out what they were going for, since mine was purchased for the cover price ($29.95 or whatever it was) whent he book was new. Then a year or two ago this same subject came up here, and I suggested somebody pick up a copy--and found out what my copy was worth!

Don't think JB has ever had a quote that I agree with more than this one

Buy a Savage

prm I have two of the books John suggested if your interested in borrowing them. powdr

I've done that. Now I'm trying to broaden my experience at working on accuracy. With my Savage 10FP you just point in the general direction and little tiny groups appear. Seems that easy anyway.

Biggest factor in the field by a long shot.

I may just take you up on that!

How is the barrel with respect to copper fouling?

Harold Vaughn made the same comment in Rifle Accuracy Facts. OTOH, if your Mauser barrel rises in the channel as you loosen the action screw, it will normally not shoot accurately. Something between the front and rear screws is too high, putting pressure in the wrong place.

Of course, properly floating the barrel does make a difference in most designs.

I had a fun conversation with one of the experts at Pac-Nor, who tended to "inherit" some of the barrels that were headed for the trash. His claim was that barrels with noticeable curvature often shot very well. Go figure.

Barrel whip is a big issue. Sound travels about 10X as fast in steel as it does in air. The shock of the firing pin drop and all that follows travels down the barrel faster than the bullet. When the bullet exits, the tip of the barrel is moving in an arc. If the bullet exits when the tip is at the end of the arc, the rifle will be more accurate. That's what you're tuning when you adjust the BOSS system or fiddle with seating depth and charge.

FWIW, my starting point is with the bullet .030" off the lands. I seldom find reason to change that later.

It did a very good copper mine imitation. I shot some Tubbs final finish through it and then UBC'd it and now it's not bad.

For grins I bedded the rifle in question and I don't think it made any difference. Bedding is something that is either needed or not. If it's not moving in the stock it's not moving and thus no need. Hard to know though, so I just bed my rifles.

I have some Tubbs Final Finish coming today, and two boxes of Black Hills ammo. I have played more with the current scope and it is tracking fine and there does not seem to be any parallax. I'll stick with it for now, but I will have another at the range with me and be ready to swap out.

I might tend to agree with Blackheart if we were talking about bedding and McMillan stocks. Even McMillan says it's "not necessary". As others have stated, the barrel and how it's installed is probably the single most important factor in a rifles accuracy. A "straight and concentric action" is probably second combined with a good trigger. As part of the barrel install includes a good clean crown. After that, as Mule Deer stated, "straight ammo" for a good bullet start down the barrel. That takes care of the rifle so the rest is up to the shooter.

As to "good barrels" being a necessary accuracy ingredient. I've seen obviously crooked barrels that shot fantastic. Others that were pitted from one end to the other and still shot great. I've got a rifle with one land that is obviously fugged up {shorter than the rest and enough so that you can see it looking down the bore with the naked eye} and it's still an honest, consistent MOA shooter. A chamber that's not cut concentric to the bore and/or a bad crown are more certainly detrimental to accuracy than many barrel/bore imperfections.

Both very good books!

FYI, I did shoot all 50 rounds of Tubbs Final Finish through the rifle that got me to thinking about this in the first place. The barrel is now like glass, cleans up much easier, a AND based on two 3-shot groups it appears to shoot better. Next steps are to apply DBC, shoot it in and ensure its sighted in.

no the way to understand accuracy is to get a remington and put a Krieger barrel on it then shoot it. 6ppc , 222 , 308 6.5-284.

no get a sako 85 in 6ppc.

What makes a rifle accurate , the Gunsmith you use to build it, some are just better than other. Today's factory rifle will group as good or better than pre 50's benchrest rifle

If glass bedding don't improve accuracy why do benchrest shooter do it? Every gun I ever glass bedded and that's been a lot always shot better with it done.

Glass bedding helps if there's a bedding problem, not so much if the existing bedding is working.

I've never seen a glass bedding job hurt accuracy, only help.

DF

And that's if the glass bedding is done right, not everyone can glass bed and do it right. I have zero movement on my dial indicator when done right. That 0.0, some bench shooter say that .002 is good enough. Every factory rifle I ever checked even Remington 40X's have problems.

Too much time is wasted on theory and supposition. Pictures of groups only look good on the Campfire. The best thing to do is drive out into the field, drink a can of Coke and throw it out the window. Drive until you are about as far as you would normally shoot and shoot at the can until you can hit it.

Then go shooting and fine tune the rifle if it needs it. Results are what you are after, save the pictures for the guys that can't shoot...

Some critter just had a bad day.

Could have been someone's mother...

DF

I concur....

get a a rifle like this.....http://www.accurateshooter.com/featured/f-open-champ-kenny-adams-7mm-rsaum/

I came home Thursday afternoon to a box full of reading material. Big thanks for Powdr for sharing his books. They will be well read in a short time! One big example of what is good about this place.

This and

It will keep accuracy stable across different environments'.

Snake