Building and tuning an accurate 10/22

[Dolomite_supafly]

I posted this in another thread and thought I would repost it here.

Ok here is a quick run down of what I feel it takes to have an accurate 10/22.

First, a quality trigger.

Whether you buy a complete trigger (Kidd is the best) or buy parts to replace or modify the factory parts the one thing you need is a predictable trigger. A heavy predictable trigger is still better than a lightweight unpredictable trigger. I would even say a decent trigger is the most important part of any 10/22 build. You also want a trigger that has the minimum amount of pretravel as well as the minimal amount of overtravel but most importantly you want a reliable trigger.

I use factory parts in all of my guns so I add my own overtravel screw. I also use shims to remove as much of the side travel as I can. It is impossible to get a quality homebrew trigger without removing the side to side movement found in ALL factory 10/22 triggers. I replace springs with lighter weight ones but I also change sear angles and polish various parts. It has taken me a long time to figure out what works and what doesn't. I will not go into it here as there is too much liability if someone doesn't get it right. It can also lead to a gun that is illegal.

Second, a quality barrel.

There are several makers of 10/22 barrels that would fill this need. The chamber is what makes or breaks a barrels accuracy in most cases. You need to make sure the chamber is a Bentz spec or a modified Bentz for a semi auto.

Another option is to have the factory barrel setback. I have set mine back ~.165. This puts the bullet into the rifling like a match barrel but because the ID is larger than a Bentz chamber it tends to be more reliable. They tend to be a lot more accurate than a factory barrel but not quite as accurate as a Bentz chambered barrel. The Bentz chamber also keeps the bullet from just falling into the chamber and the force of bolt is what is used to seat the bullet to a precise headspace to the same every time.

Barrel contour can have an impact on accuracy as well as the length. All things being equal a short, fat barrel will be more accurate than a long thin barrel. The reason is harmonics tend to be less with those short, fat barrels. And because they have less harmonics they tend to be accurate with a wider range of ammunition.

You might see muzzle devices on the end of barrels. These are only used to tweak the barrel harmonics.

And finally, make sure the barrel is either completely free floated or completely bedded. I will say that a completely free floated barrel tends to be accurate with a smaller variety of ammunition but it will be very accurate. One the flip side a completely bedded barrel will be more accurate with a wider variety of ammuntion but will generally not be able to be as accurate as a completely free floated barrel. This is because of harmonics. A bedded barrel has less harmonics so it is more accurate with differnt ammunition but you can't tune it like you can a free floated barrel.

Make sure the barrel fits properly in the receiver and does not droop. If it does there is an adjustable "V" block that is available to address the issue. Most aftermarket barrels have a very tight fit so this may not be an issue. And when installing a tight barrel you can put the receiver in boiling water to expand it to allow the barrel to drop in. You might even need to freeze the barrel.

When installing the barrel make sure the extractor is centered in the extractor groove in the barrel. Most cycling issues are a result of the extractor not being properly centered.

Third, a properly prepared bolt.

The factory bolt is built for one thing and one thing only, reliability. And because of this accuracy suffers greatly. With a .22 headspace is critical and the factory bolt is so loose it is not wonder they are not accurate especially when combined with the loose factory barrel.

The rim on a average .22 round is ~.041"-~.042" thick, depending on brand. The factory bolt is set for a rim that is ~.045" and sometimes larger. That leaves ~.002-~.003" of slop and although it doesn't sound like a lot this can cause inconsistent shot to shot accuracy. How do you fix it? Well you machine the front of the bolt until the recess is .0425", this eleminates most of the slop without affecting reliability.

Next, if you look at the firing pin the tip can move around quite a bit. This means the tip can strike the round on the edge or farther in and this can also effect consistent ignition. So how do you fix that? You drill and pin the firing pin in place to keep if from moving up in its channel.

Looking at the firing pin you see the tip is square. Although it works it is not ideal. It needs to be slightly angled so that it strikes the outer edge of the rim first. This does two things. First it hits the rim with more force creating a more reliable ignition. It also changes the flame front of the priming compound so it doesn't travel along the case wall. It is angled down and into the bulk of the powder. As the round is chambered the powder is on the botton of the case and without a profiled firing pin the flame front tends to stay along the top of the case. This means the powder may be ignited at the back, middle or front and each one has it's own velocity range, believe it or not. To test this take your rifle and cahmber a round, point it up so all the powder is against the primer. Do this for say 5 rounds. Next do the same thing except take the gun and point it down so the powder is more forward in the case. You will see a distinctive difference in shot placement.

And finally, champfer the rear of the bolt. This doesn't affect accuracy so much as reliability with standard and subsonic velocity rounds.

And for those of you who can;t machine the bolt yourself there are several smiths out there that can do it for you. The best is Randy at CPC. http://community-2.w...work/index.html

He also pins the firing pin in place as well champfer the bolt. He also reworks the extractor but a VQ extractor will help a stock bolt that is having cycling issues.

Third, decent optic mounts.

Although the factory mounts work they are rarely square and true. And when there is pent up energy in the form uneven clamping forces they can squirm around affecting harmonics of the gun as well as zero. The scope adds to the guns overall harmonics and if it is under uneven clamping forces it too can affect harmoincs. A decent mount as well as decent rings are a must. And make sure to use blue Loctite on any screws because a 22 is notorious for working screws loose. When considering mounts choose something with the least amount of junctions. That is don;t have a mount on the receiver, then a riser block on that, then the rings on that. If you need additional height for a comfortable sight picture use higher rings. Each of the junctions can, and often do, affect harmonics. There is also a greater chance that one of the many screws will loosen.

Fourth, a comfortable stock.

Without a comfortable stock you are not going to keep the same consistent position. You will find yourself always adjusting your firing postition looking for a comfortable position. Every time you break your position it changes the impact of the bullet, the guns harmonics as well as your concentration.

Along with you fitting the stock well you need to make sure your gun is comfortable in the stock. Because if it is not sitting comfortably in the stock it will squirm and move with every shot. The way to ensure there are no pressure points is to bed the receiver and/or the barrel. You also need to torque the action screw to a consistent amount. Having a loose, then tight screw will also affect the harmonics of the gun. A decent in.lbs wrench can be had for under $50. While that is not needed for most it isn't a lot in the overall scheme of cost in making a 10/22 shoot.

Fifth, ammunition.

All ammunition is not created equal and more importantly each gun reacts differently with each kind of ammunition or even lot numbers. The ammunition that works well in your buddy's Savage may not work well in your Savage. The reason is barrel harmonics as well as the overall harmonics of the gun can affect accuracy. Ideally you want the bullet to exit the barrel at exactly the same point on the harminic node and that node is different between every single gun. Think of it like harmonic DNA.

This is were accuracy testing is key in determining what your particular ammunition likes. I have a 22 that absolutely hates Eley match EPS. Unfortunately I found this out after buying plenty. I still used it for testing other guns but in the end it was too expensive for my needs.

When testing you need to clean the barrel between brands because the lube used on one brand might affect the accuracy of the next brand. When testing I do this. I run a bore snake down the bore a few times. I fire 25, yes 25, fouling shots. Then I fire five 5 shot groups. Record the results then I start over with the bore snake. You will generally have a couple of brands that stand out. And with these brands you begin the tuning process that I will go into below.

Sixth, tuning.

Now that you have you gun set up and have a few candidates for ammunition it is time to tune the gun to the ammunition. If you haven't bedded the barrel, which I generally do not recommend, do this. Take the action out of the stock and place foam pressure pad about an inch from the end of the stock. I generally use a foam ear plug I cut in half. Then fire five 5 shot groups with a brand of ammunition. Record the results. Then I move the foam pressure pad back and additional inch. Shoot five more 5 shot groups. I continue to do this until I reach the "V" block. You will have a place where the groups seem to shrink substantially. This is the ideal spot for that particular brand of ammunition. If you change brands or even lot numbers you might need to test again. The foam should not raise the barrel but just dampen the microscopic vibrations in the barrel.

Another part of tuning is the in.lbs that are applied to the action screw. For this I suggest leaving it at one setting but it might be what is needed to get to the next level of accuracy.

I also suggest shooting off a solid platform like soft bags or something similar. Bipods can affect harmonics as well. If you need to use a bipod make sure to load them to prevent as much harmincs as possible. And finally avoid hard surfaces. For some reason when firing off a hard surface it has a negative affect on accuracy. I use rice filled bags or even my shooting bag laying on its side. Both work well for me.

And finally.

Just a few tips from someone who has shot rimfires consistently for over 35 years. Never clean unless you see a significant degradationin accuracy with a known performer. The barrels need a build up of lube to work well in most cases. And leaving the barrels dirtly actually give a decent amount of protection. This is why most older, delapidated rimfires have nicer barrels than similar centerfire barrels.

Another note on cleaning. Do not clean from the muzzle end. This can damage the crown which is the last thing a bullet touches before leaving the gun. A damaged crown can have a major impact on accuracy. On guns that can't have a rod run down the bore from the breech use a bore snake. And clean your bore snake often. The cloth can get imbedded with carbon and other materials that can scratch or damage the bore and crown.

I am also a firm believer in glasses. Not just for safety but to reduce eye strain behind a scope. It helps you see the target and reticle better which in turn helps you shoot better. There are even optometrists out there who are familiar with the shooting sports and can adjust a prescription to help. There is nothing wrong with shooting glasses, you should be wearing them anyways so why not get some additional benefits.

Keep a written record of weather conditions. All of the tweaks as well as the ammunitions performance changes with weather conditions and altitude.

And now on to the most important aspect of getting a 10/22, or any gun for that matter, to shoot well, you. You need to practice and practice a lot. Even if you can't afford the best equipment, the best gun or the best optics practice is the common factor in all winners. So practice and practice often and you will be a better shooter.

I welcome any questions and I am sure I am missing a few things. If I did please add to the discussion because it will help me as well as many other shooters who might read this.

Dolomite

Edited April 9, 2012 by Dolomite_supafly

[gjohnsoniv]

You are a wealth of knowledge.

[Ramjo]

You call that quick? Haha. I assume you are referring to a competition worthy 22 here in describing all these modifications?

[Dolomite_supafly]

There is plenty more to it but that is the quick version.

Also, there isn't a 10/22 that is competitive against anything other than other 10/22's. You can spend well over a thousand on a 10/22 and have it beat by a bolt gun costing hundreds less.

10/22's are great tinkering guns and that is what makes them great.

Dolomite

[Ramjo]

It's one of those guns that probably everybody owns.

[babelt]

It's one of those guns that probably everybody owns.

Not me I have a 597!

Sent from my DROID RAZR using Tapatalk

[gjohnsoniv]

It's one of those guns that probably everybody owns.

It's a rifle everybody should own.

[LI0NSFAN]

Good to have a couple 10/22's. They are great guns and other than the bolt, parts are cheap and easy to replace if needed.

Edited April 19, 2012 by climberscott_1999