Getting More From Your Factory Built Gun
Terry Huff - Gunsmith & Accuracy Buff
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Shop Phone: (334) 347-6172
Cell Phone: (334) 406-8331
I just thought I would share some of my thoughts and information on my services that are available to you.
Not everyone is interested in more accuracy and shooting at greater distances but some people are.
These are some thoughts to consider before you get too far into this paper.
·Not every gun is capable of great accuracy.
· Not every caliber is capable of great accuracy.
· Lever guns may never get better than 2 1/2 to 3 in. groups.
· Pumps and auto loaders may never get better than 1 1/2 to 2 in. groups.
· Some but not all bolt actions are capable of groups under 1 inch but have the most potential of any guns.
· All types of guns can have finished crowns, bores lapped, precision scope mounting or a better sighting system
mounted, custom ammunition and some trigger work performed.
· AR type guns and pistols and revolvers can also receive accuracy enhancements.
Accurizing The Factory Rifle-
There are many things that can be done to make a factory rifle more accurate. Some have a more dramatic effect and some do not. Regardless, these effects are additive and as more accuracy is obtained then the additive effect is less noticeable. Getting a gun shooting 2 1/2 " groups to shoot 1 1/2" -2" group is easy, 1 1/2" down under 1 inch is harder and ½ -¼ in. even harder and under ¼ inch is probably not possible with a factory gun.
Some items are expensive and then some are not. I usually stop when I get a hunting rifle under one inch and a varmint rifle under ½ inch for five shot groups. Usually you have no more than the cost of the rifle tied up in the improvements. Not just the gun but also the caliber of the gun. Some calibers are highly accurate and some never will be. Likewise a gun that puts five rounds under 1/4 inch was most likely built from scratch by someone very good and has had everything possible done to it and is a target caliber.
I hunt with six different guns that put five rounds under 1 inch and with two varmint rifles that group five rounds under ½ inch. The least expensive a. Mossberg ATR 100 in 30-06 and the most expensive, a Ruger M 77 Mark II in 280 Remington.
Within the last few years people have demanded better accuracy in the long guns that they buy. Probably the first thing that was done is they used a better trigger getting away from the old gritty trigger that had creep and up to 5 to 6 pound pull, due to fear of lawsuits. Some are customer adjustable and some without removing the stock. Now better barrels and action bedding blocks and better stocks are on some factory rifles. What is next remains to be seen. If you want to get more accuracy just buy a new gun. Several manufacturers will guarantee you three shot one MOA accuracy. I feel five rounds are necessary! -three rounds are easier than five rounds - try it!
Scope mounting -
And also a factor related to the gun is a sight and the mounting their of. At one time only bench rest shooters and their little secrets used precision scope mounting. Now tactical rifle users and savvy hunters are picking up on it. Look at the cover of your Brownell's catalog #62 and you'll see some of the tools involved.
First, the proper rings and bases for the scope are mounted. A one piece base should be very close to the perfect base but they are not made for every gun and sometimes get in the way of shell ejection.
Once the proper equipment is installed like normal, then alignment rods are clamped into the rings. If the tips are far off, then one base must be shimmed. Once alignment is achieved you have a choice, you can start with a lapping bar and lapping compound which is very slow and laborous or you can spend $125 and get a ring reamer which would only take a few turns and then lap out the rest of the way to 80 percent contact area. This is what it takes for maximum holding power with the proper screw torque and not to place the scope in a stress, which robs it of its accuracy potential.
Now we're ready to install the scope. If there is still a gap on both sides of the ring caps then we tighten the screws. If there is not, we must lay it flat on a file and remove material until there is a gap. After all this we must clean and re-blue them if they are steel rings and then clean off the blue and re-oil them before we can proceed.
We are now ready to place the scope in the rings after wiping all the oil off. Now tighten the screws down -how tight? That's where are your torque wrench comes in, you know the special one you payed $60-$160 for it just to do this job .Oh! I can use my automotive one right? Not unless you spent 500 to 600 dollars for it to read in in/lbs down to as low as the15 in/lbs. for aluminum rings.
You can easily spend over $300 and buy the necessary tools or pay me $45, or buy a scope from me and I will do it for nothing extra.
I have a Herter's J-9 Mark X that has the proper bases but there is a copper shim about .032 inch or 1/32nd of an inch epoxyed to the receiver and base forever. It shoots under 1 inch, five round groups with several loads. It's a 30-06 Springfield.
Finish Crowning a Barrel-
This is something no manufacturer does but is very important to accuracy and is the least expensive thing that can be done to improve accuracy. You must have a good crown to start with whether it be a flat crown, recessed target crown, 11° M – 1 Garand crown,
recessed 45° crown or any number of variations so these. Many factory crowns are square with the bore but have a small burr where the bullet exits the barrel. This tears off a small amount of guilding metal and throws the bullet off-balance and as distances increase
so does the gyration of the bullet off course. This process uses lapping compound starting with very coarse and ending with very fine. Cutting a very smooth bevel all the way around the opening lands and grooves. Inspection with very high power magnification as the
process progresses. This only cost about $15-$20 and is the best money you have ever spent. Deep nicks and grooves in a damaged crown require more expensive and time-consuming repairs as will be discussed in barrel re-crowning.
Free-floating the Barrel-
Many guns – Remington's, Ruger's, Marlins and more come with some up pressure on the forend tip of the stock. Ruger feels so strongly that it voids the warranty if you remove it. As a barrel whips, this is supposed to make the whipping more consistent. Maybe on a synthetic stock if you get the action screws the exact torque they should be, but not on a pretty wood stock which changes as the moisture in the wood changes.
Others like Savage not only free-floated the barrel but they are adding extra rigidity to their synthetic stocks beyond their pillar bedding. Maybe that could be why they are the most accurate rifles out of the box. That and the Accu-trigger and quality control. Accuracy buffs have developed a way to bed two adjustable screws in the stock forend so you can tune the up pressure for maximum accuracy, but for the most part rifles are more accurate free-floated.
Lapping the Bore-
Factory rifles are never lapped and only high-end aftermarket and match grade barrels are lapped. A factory barrel cost the manufacturer about $60 and that was for a chrome- molly barrel stock, boring, rifling, threading and chambering. High-end barrel blanks can cost as much as the gun you're putting them on and come unthreaded or even size to thread, unchambered, uncrowned, and unpolished finish.
Barrel steel is very tough and like all alloy steels is subject to have hard spots and soft spots. Therefore the rifling which is only approximately .006 inch deep can have high spots and low spots. When the bullet traveling at 2500 to 4000 ft./s and pushed by 60,000 pounds of pressure travels over one of the high spots it constricts the bullet and removes a small amount of guilding metal, sometimes no more than what looks like copper color on the metal. That is to start with, and as each bullet passes over it until the obstruction is so large that it is pullingbig chunks out and that may be in several spots in one barrel.
Spin a top with chunks out of one side and see what happens. A bullet traveling at approximately 3500 ft./s with a normal twist leaves the barrel at approximately 100,000 RPM. Now why do you think you can't hit the target?
Lapping removes the high spots and smooths out the tooling marks and aligns everything with the length and not across the bore. When the bore is polished and the high spots are removed then it takes a lot longer to build up fouling and makes cleaning out the fouling much quicker and easier.
If you take a rifle to a gunsmith to get the copper fouling removed, you will not likely get a price. Most gunsmiths charge time and materials to remove copper or guilding metal fouling. Case in point, I have spent as much as five hours removing fouling before I can lap the barrel. It must all be removed whether you do it or I do. There is no magic trick, however we do have some chemical formulas you can't buy. Strong ammonia-based chemicals that work cannot be left in the barrel more than 10 to 15 minutes, so the elbow grease is very extensive. Patching and swabbing for hours on end.
After lapping you can clean the powder fouling out easily with anything in about two trips of wet followed by two dry patches and you have removed the fouling from a hunting season, even if you fire 15 to 20 rounds. I clean my guns only once a year and spend less than 30 minutes on the inside and outside. $125-$150 is a fair price for lapping.
While we're on the subject of lapping and cleaning barrels, I have customers come to me all the time with "Something is broken on my gun, it used to be accurate, shoot 1 inch groups and now it's all over the place". My first question is "Have you cleaned your gun?". The answer is usually "yes" but when I dig a little deeper I find that what they used to clean the gun will never remove copper fouling, only powder fouling. I prefer to start with a good powder solvent with a mild copper cleaner that can be left in the barrel overnight like Unisolve from Midway USA. Then the next day I use a fairly aggressive cleaner like Barnes CR10, Sweet's 7.62 or Montana Extreme. Following their directions until no blue is left on the patch.
Another thing that helps is to wet the bore with Aero Kroll and leave it in a week if you want. It actually gets under the fouling and if you push a tight fuzzy patch on a jag through it, it will snag a jagged edge and I have had large chunks of black copper come out. The ammonia cleaners had worked on them but since they were so large it would take hours more to dissolve them.
So if you tire of scrubbing with chemicals and your patches are still blue, try the Kroll and come back in a day or two. You might be surprised like I was.
Now you're bore is cleaner that it is ever been and there is no blue on your patches. Now you have to foul it again slightly by firing 2 to 3 rounds before your accuracy will return. I save some old cartridges that don't shoot accurately in my gun or that I don't like or that they're just cheap for this reason.
If you are going to shoot it right away or even if you are not, run an oil patch down the bore. I like to use molybdenum disulfide oil, just don't forget to wipe the oil out before you fire the gun. Dry patches will not remove all the oil as some will stay in the metal because it is porous. I like Molly D because it will handle up to 100,000 PSI and some amount stays in the metal.
While we're on the subject, most everyone has heard of Molly coated bullets. Yes, they can give you up to 100 ft./s velocity increase, cut copper fouling almost out and ruin your gun forever. You must pre-treat your bore with a Molly D oil to aid in the process and then shoot " X " number of rounds. For the hunter it will probably never be a problem but for prairie dog hunter or a match shooter, Molly can build up in the barrel and be as bad as copper fouling, and guess what? Bore cleaners won't touch it. I have no advice but to alternate between Molly and non-Molly bullets but whatever ratio. Who knows?
Bedding the action-
Glass bedding will improve accuracy. If pillar bedding is added that is even better. Full block bedding and forearm bedding blocks are even better. What you do is dependent on two things- how much you want to spend and how accurate you want to get. Remember no one thing will be a cure-all. Improvements are additive and no one knows how much the improvements will add to the performance.
We will start with the simplest and least expensive truing the bolt face perpendicular with the bore, but that increases headspace. Lapping the bolt locking lugs so pressures equal on both lugs, but that increases headspace. Lapping the barrel/receiver union or barrel/recoil lugs/receiver union removes side torque when the barrel is tightened but decreases headspace. Headspace must first be checked but doing all of these together will usually yield little change in headspace. The most ideal headspace is .001 inch.
If headspace gets out of tolerance greater than .006 inches then the barrel and the receiver must be turned in a lathe to bring them back in tolerance – referred to as re-justifying a barrel.
Blueprinting a rifle-
Blueprinting involves a bit more work and almost all of it machining first and then some lapping to true everything, bolt, action frame and barrel to the centerline of the bore. It pretty much is rebuilding a rifle from scratch to its original specifications with no error. A new barrel is required as the action is turned down in a lathe and then the threads are partially removed so they can be trued. The barrel tendon is turned 10 thousandths of an inch larger and then new threads are cut. Then the action block is also threaded oversized to match, lining the new threads with the receiver's centerline of the bore.
At this time usually most customers opt for a match grade chamber. Irregardless the bore is lined in the lathe not the outside of the barrel and also the other end is set with a dial indicator to the bore. A match chamber requires cutting very slowly .010 to.015 in. at a time removing the reamer, cleaning it, re-oil it and blow out all the chips then repeat the process again and again and again.
If you have a Remington, Savage, Marlin, Stevens or rifle built with a separate recoil lug then it must be reamed to fit the new oversized barrel tendon. Some customers will opt for a new thicker lug with a different shape. The barrel will have to be turned to match this thickness.
As you can see, blueprinting is about all machine work and is time-consuming and costly but available. Lapping only remove small amounts and is not as true is blueprinting but the hunter will never know the difference.
Custom ammunition –
If your goals are similar to mine, I should have put this section right after lapping the barrel. To get custom ammunition, I must have your rifle. After you select your bullet or tell me the game you want to hunt, then I must work up the load to the point of maximum accuracy, maximum power or a combination. This requires loading about 25 or 30 rounds and firing them in your gun starting with a low powder charge and working up. Sometimes the first powder is the right one for your gun but sometimes three or four powders are used to come up with the best. That's 100 or more rounds if the fourth powders is used with cleaning in between and then fouling the bore again. Every gun is different so the cost must be time and materials and can be quite expensive.
You can probably find someone who will load you up some "hot loads" and if you do, you are as stupid as he is. If your gun blows up, are you going to sue him, if you're still alive? Without a pressure barrel and some way to check the pressure like the manufacturer does you are out on limb.
You must have brass fired from your gun to get maximum accuracy. When the job is done additional rounds can be ordered or any re-loader that can follow directions can in your special brass or even your match prep brass, load your ammunition superior to factory rounds and they are safe in your gun, but only in your gun.
Removing stuck live rounds is very expensive from any gunsmith. Chambers can vary slightly and if yours is oversized and your friend is only the minimum, you could fire his ammo in your gun, but not yours in his gun. But if he does then the both of you have a big problem. Don't do it! Factory ammunition and full-length re-sized ammo is built to minimum S. A. A. M. I. Specifications and built to fit any gun by any manufacturer. Custom ammo is built to fit your gun only, after firing aligns everything better with your bore, headspace, and chamber dimensions.
Triggers, springs,and light firing pins-
There are many more tricks to better accuracy such as stronger firing pin springs, lighter firing pins, better triggers or making the factory one better by polishing parts. I adjust a trigger down and pull weight is usually not as important as making a gritty trigger smooth. I would do both and remove any creep and over travel. The pull weight should be adjusted, and I will never bring it below 3 pounds on a hunting gun. Too many other variables make this dangerous.
Target guns are used at a bench and aimed downrange before they are loaded and aren't moved around, and triggers for them are adjustable down to a couple ounces, not pounds of pull.
Now here comes the catch, you may want all of the above improvements but there may be no one who makes them for your gun. If you own a Remington 700 you will probably find more aftermarket parts than for any other gun.
You can probably find a firing pin spring for any gun if you know the size and the poundage of the factory spring. This will shorten the lock time (the time from when you squeeze the trigger until the gun fires). During this time your body can move more than you think and decreasing that time increases accuracy.
The lighter firing pin makes that time even less but cost a good bit more, then again availability is limited to only a few guns.
Aftermarket triggers are also limited. Again the more popular guns may have triggers available from six or more manufacturers and there may not be any for your gun. Triggers for Remington 700 can vary in price from $75.00 up to several hundred dollars. Timney makes several Remington 700 triggers that start just under $150 and are an excellent choice. Other procedures that can be done to triggers are stoning or polishing of the moving parts and/or change spring rates in the assembly. These are trial and error and take a lot of time. If you have a choice, replaced the trigger with a good adjustable aftermarket trigger. All I have to do is install it and adjusted it and it's a done deal.
Let's suppose you don't reload and you don't want custom ammunition. Factory ammo today is really pretty good. First decide what you want to shoot and remember that high price doesn't mean it will be more accurate. Remington core-locks are about the most reasonably priced ammo and actually shoot well in many guns. You decide and then we start our magic and test fire as we go until your goal is reached.
There may be more steps than with custom ammo, but if you start with ammo that shoots best in your gun, then they will be minimal.