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-   -   Improving the Accuracy of a Factory Rifle (http://www.firearmstalk.com/forums/f18/improving-accuracy-factory-rifle-19037/)

Dillinger 10-11-2009 11:10 PM

Improving the Accuracy of a Factory Rifle
 
Improving the Factory Bolt-Gun: Phase One

Frequently I answer threads with people wondering what is a good, budget rifle to buy for hunting or entry level target shooting, and the OP wants to know what are some improvements that can be done that don’t cost a lot of money.

For this thread, we will assume that you have done your research and you have found a bolt action rifle that fits your budget, have found a scope and rings that you like, can afford, and can’t afford ( or don’t care ) to reload at this time.

Having the scope correctly mounted is crucial, as is having the right length of pull on the stock, to ensure you can squeeze the accuracy out of the rifle that you want. Again, we will assume that you have had this entry level stuff done already.

1. Trigger Job. I can’t stress the importance of having a good, crisp, clean breaking trigger on your weapon. Trigger pull weights vary by the type of application (as “light” as 2 ounces on a benchrest competition rifle and as “heavy” as 3.5# of 4.5# for a winter edition hunting rifle).

A really good trigger has very little “creep”. This is the amount of travel from untouched to the point that the trigger has resistance just before the trigger goes to work.

The trigger should “break like a glass rod” when it goes bang. That is, the pressure should increase very slightly before it “breaks” and the rifle goes off. This process is in reference to having a glass rod, supported between a couple of points and slowly loading weight onto the middle. When the “glass” has had enough, it will not begin to sag, or weaken and crack, it will out right break. Your trigger should break the same way.

After the break, your trigger should have very little “over travel” before it resets. Most factory triggers have over travel that is considered “extensive”. Over travel isn’t a killer to accuracy, but it will definitely affect your ability to get back on target quickly.

Trigger jobs come in a couple of forms. Reworking of the factory trigger, or putting in a replacement, after market trigger.

Reworking of the factory trigger is best left to a professional gunsmith, because you usually are permanently altering the metal surfaces of 2 or 3 levers that make the trigger work. This process usually takes an hour or so and would cost anywhere from $50 to $100 depending on the gun shop.

Aftermarket triggers come in various forms, usually they are custom designed for your rifle, almost always feature a full three lever design, and come pre-tuned to a specific pull weight.

Aftermarket triggers are considered “better” but that is not always the case. If your gunsmith is skilled in a good trigger job, he can usually save you a hundred or so dollars by reworking your factory trigger into a great shooter.



Every gunsmith has weapons in their shop that are either waiting to be picked up, or are their own work. Ask them to try one of their custom trigger jobs.
  • It should have very little creep, a crisp, clean break and very little travel to reset.
  • On a boltgun, it’s important to check for a trigger that is too light and could result in a “slam fire”. This condition is when the bolt is closed aggressively, as if you are quickly chambering another round because you are amped over your deer/elk, and the weapon goes off. If this happens, the weapon’s trigger is TOO LIGHT and is UNSAFE. Any weapon that “slam fires” needs to be reworked until that condition no longer exists.
If you try one of your smiths’ triggers and it meets those criteria, you have got yourself a good one.

A reworked factory trigger is always going to cost you less money than purchasing an aftermarket trigger and having it installed. Unless, of course, you got a REALLY great deal on that trigger. :D

The factory trigger is the easiest, cheapest and should probably be one of your first 2 or 3 changes to improve the accuracy of your recent addition.

Next: Glass Bedding the Factory Action

Dillinger 10-12-2009 12:18 AM

Next: Glass Bedding the Factory Action

2) The Glass/Pillar Bed Job

Most factory rifles do not come with free floated barrels and they do not come with actions that are glass and/or pillar bedded.

Why is this important?

A rifle action has a ton of stressors that are placed on it when it is trying to contain a small explosion and force a non-threaded round into a threaded bore of a barrel.

You see, “rifling” is really the “lands” and “grooves” that you can see in your barrel. The high points and the low points are set in a spiral to get your rifles’ bullet spinning on an axis to obtain the ultimate accuracy. The problem is; when a bullet leaves the brass cartridge, it has NO desire to start spinning on an axis; it has to be forced into that condition.

At the point that your rifles’ firing pin sets of the primer, which ignites the gun powder, which sends the bullet flying, there is recoil. Your rifle action has to absorb that pressure. The pressure is a back, or North to South pressure, in line with the rifle stock and barrel.

Now, when the bullet leaves the brass cartridge and is forced into the threads of the barrel, the rifle action is asked to absorb this pressure, which is West to East, at almost the same time.

Now, most rifle actions have a grand total of ( 2 ) WHOLE action screws that are to absorb all this change in explosive energy, mating the rifle’s action to your rifle’s stock.

So, how does this relate to improving accuracy JD?

If your rifle’s action has two screws that mate the action to the stock, and if your barrel is not floated off your stock, it would stand to reason that outside pressures on that stock could influence your action and barrel to do something OTHER than what you want.

You have to realize, the action is supporting that 22” or 26” barrel you have just hanging out there. You ever try to hold a 26” broom handle out to the side and let your kid, or your dog jump, up and swing on it? Give it a try and let me know how good you are at keeping the handle in line with where you are aiming it. ;)

Stocks are mass produced. They are not custom fit to your rifle action at the factory that just purchased 100,000 units. It would be nice if that was the case, but it isn’t. And it’s twice as bad if you like a wood stock, because wood swells, cracks and changes dimensions based on a lot of factors, not the least of which is humidity.

So, how do you defend against that??

You take a solid rifle action and you build a base for it that is like your hand going into a really comfortable glove. The glove insulates, protects and keeps your hand happy. A glass, and/or pillar, bed job is just that.

This action creates a custom, hand in glove fit, for your rifle action. The increase is a couple of thousandths’ of an inch, but done correctly, it free floats your barrel from ANY outside influence and it gives the action a complete, custom fit base. When the screws are tightened, that action isn’t going ANYWHERE due to outside forces under ignition.

A good fiberglass bedding job is probably going to cost you $75-$150 bucks, done correctly, but the results will almost always speak for themselves on a factory rifle. A free floated barrel and an action with a nice, secure, base that won’t move or change under stress of ignition allows for the shooter to maintain more consistency from one shot to another.

The more things that are the same from one shot to the next leads to tighter groups, leads to better scores and better overall shooting.

So, there are two, easy, cheap and pretty quick “upgrades” to your factory rifle that, done properly, will definitely tighten up your groups and make your rifle shoot much better.

JD

cpttango30 10-12-2009 01:45 AM

Don't forget a recrown job they don't cost much and can enhance accuracy of a factory rifle.

stalkingbear 10-12-2009 02:27 PM

Whenever I glass bed a rifle I usually like to bed the rearmost couple of inches of the barrel and then free float the rest. It seems a lot more stable that way and still offers the same degree of accuracy.

ItsmeShane 10-13-2009 10:23 PM

i would definitely consider the trigger job, but the gun i am planning to buy here in a few weeks already has a free floating barrel.

stalkingbear 10-14-2009 05:47 PM

Hand lapping
 
Another valuable accurizing tool that we can do to factory rifles is hand lapping the bolt lugs. Why lap the bolt lugs you ask when the rifle shoots ok as is?

The simple reason is when the bolt lugs are not contacting the back of their recesses in the receiver the bolt WILL flex slightly. When a cartridge is fired the back thrust on the bolt will flex the bolt until the lugs come in contact with the receiver.

That flexing causes 2 things. 1 is it causes the action to flex slightly. That very slight amount of "wiggle" wrecks havoc with your zero & bedding after awhile. That's not too much of a problem if the action is bedded solidly into the stock.

The 2nd is bullet alignment. When the bolt flexes unevenly that MAY cause the bullet to be very slightly cockeyed as it starts down the throat into the bore. This can affect accuracy to a point,depending on how far the bolt lug is away from full contact.

Rifles with "floating" bolt heads such as savage don't have that problem, perhaps 1 of the reasons they shoot so well for being a cheaply made rifle.

To hand lap a bolt you'll need
400-600 lapping compound
machinist dye or a marker
gun scrubber or other cleaner to flush the lapping compound away

First clean all the oil from the bolt & bolt raceway. If you can't, put some of the dye on the back of the locking lugs. Work the bolt several times.
You should see how much the locking lugs are in contact with the receiver. Usually you'll have 1 lug contacting more than the other (in 2 lug rifles). Now liberally (hate that word lol) apply the lapping compound to the locking lugs. Work the bolt several dozen times, periodically applying more lapping compound. Now clean all the compound off and reapply the dye to the back of the lugs. You SHOULD see an improvement in the area of contact of the lugs. Keep up the above steps as necessary until you see where all the locking lugs are contacting at least 75%.


Next is hand lapping the bore but I'll let JD explain that.

cpttango30 10-17-2009 04:32 PM

5 Attachment(s)
Here are some pics that should expound on Stalkingbears post about lapping lugs.
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cpttango30 10-17-2009 04:34 PM

1 Attachment(s)
A close up shot of the second lug.
Attachment 6876

Dillinger 10-17-2009 04:40 PM

Awesome pictures Tango!! Thank you for taking the time to show everyone the inner workings of the lugs.

Really well done!!

JD

stalkingbear 10-17-2009 05:25 PM

Thanks for the GREAT pics tango! A picture really is worth 1,000 words. They explain what I was trying to without success.


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