UtahRifle.com
Custom Rifles - Precision Gunsmithing

Tech Info

This page is dedicated to the technical side of Custom Firearms - Ballistics, Calibers, Barrels, Twist Rates etc. 


Q: What makes an Accurate Rifle?

A: The origins of accuracy or inaccuracy in a rifle may be difficult to distinguish in an off-the-shelf hunting rifle that is capable of shooting mere one to two inch groups. A couple ten thousandths of an inch variation in a barrel's interior dimension doesn't matter much in a hunting rifle that shoots only 1 or 2 MOA, but the variation will show up in a rifle capable of shooting five shots into .250 inches or less at 100 yards (.25 MOA).
  A quality match or select match grade barrel is the first item that must be present if one desires the highest accuracy possible. The twist rate must also match the desired velocity and bullet weight that is to be used. Factory rifles typically use a twist rates that will allow a reasonable amount of accuracy out of a wide range of bullet weights, but the typical factory rifle is not optimized for high velocity. Thats where the a custom twist rate will provide the best results. (Ever try to use low grade gas in a Ferrari?!) The chamber of a barrel must also be cut correctly with Match Grade tolerances (not SAAMI spec) and share exactly the same center with the bore and be fitted to a quality action that is true and stiff. The bolt lugs must be lapped and the action must be correctly bedded to a quality stock and mounted with a good scope. A trigger that is crisp and light will enhance accuracy as well. Bullets or ammunition of known quality must also be used.



Q: What calibers do you recommend for a Custom Rifle?

A:
Thats a broad question! It depends a lot upon the application, target shooting, competition shooting, or Hunting. For Hunting  It mainly hinges on what game you are hunting, but we can generally narrow the choices down to about a 1/2 dozen or so calibers. For general target shooting and some smaller Varmints the 22LR is a good round in a custom rifle (we make one using a Ruger 10/22 action and 28 inch stainless bull barrel that is capable of shooting groups that can be covered with a nickel at 100 yds or one ragged hole at 50 yds) The 22 LR is the best caliber to hone your shooting skills on since ammo is inexpensive and the good habits you develop in shooting can be applied to all other calibers.

    For varmint hunting, medium size game or plinking you can't beat the .223, for larger game up to whitetail deer size animals the 22-250 or the 220 Swift are both great calibers in a custom high velocity rifle. We have personal experience shooting Texas Whitetail at 300 yds+ with Custom .223, 22-250 and 220 Swift Rifles, all were immediate one shot kills. Another awesome caliber for Mule deer sized game that has more power than the .224 caliber rounds and one that is often overlooked is the 6mm Remington, our favorite bullet weight for this caliber is 80-85 grains, another benefit is that the recoil is relatively mild and a muzzle brake is not required. The 6mm will run circles around the 243 and is a good choice when taking Mule Deer sized game and smaller at fairly long ranges. Our 6mm Rem Rifles have been chronographed 3550 FPS using the 80 gr. Barnes Tipped TSX, and at 3650 FPS using the Sierra Gameking SBT. 

    For Larger Game like Moose or Elk at long range the 7mm STW or the 300 Ultra Mag are a favorite.  The 7mm STW is the most efficient cartridge in 7mm producing velocities in the range of 3800 FPS using 140 gr bullets. The Remington 300 Ultra Mag is probably the best overall round for large game at long range. It is a very efficient round and reloading components are readily available. The Utah Rifle 300 Ultra Mag Ballistics are as good as the Weatherby 30-378 but brass is much less expensive and one gets more reloads on used brass with the beltless 300 Ultra Mag than on any belted magnum cartridge. It is important to note that on large magnums like the 300 Ultra Mag, barrel length should be at least 28 inches long for maximum velocity and efficiency. Most factory magnum rifles have barrels that are only 24 to 26 inches long, meaning lost velocity and more fouling. Another caliber that makes a good Elk or Deer Rifle with minimal recoil and doesn't require a muzzle brake is the 270 WSM. In our opinion its the only WSM that is worth having. Our 270 WSM rifles produce velocities similar to a 270 Weatherby Mag but with a lot less recoil, an added bonus is that ammo and brass costs are much less as well. Another favorite caliber is the 6.5x284 Winchester / Norma, this is a great caliber for taking Elk sized Game out to 700 yards and Deer sized Game out to 800 Yards, this caliber is very accurate, has minimal recoil, and has many bullet choices with high BC's and sectional densities. A step up from the 6.5-284 is the 6.5 Remington Magnum, velocities are comparable to the 264 Win Mag with a lot less recoil, a great caliber.

    Of course we also do .308 for palma match and tactical rifles, 7mm Remington Mag, 7mm WSM, 300 Winchester Mag, 6mm-06 wildcat, as well as 338 Ultra Mag, 338 Edge and 338 Lapua for those in the 338 competition regime as well as any other caliber a customer would want.
 


Q:
Do I need to use a Ballistics Program in my shooting regimen?

A:
No, you don't have to but it helps when shooting and allows for conservation of ammo as well when trying to determine bullet drop. There are several Ballistics Programs for the PC that are available. The best program that we have found is the Exbal-LF Program by NightForce Optics located in Orfino, ID. We also have one that is a free shareware program for the PC and works quite well. Email us and we'll be glad to send it to you free!



Q: How does Trigger Pull relate to Accuracy? 

A:
 It is probably one of the most important factors next to barrel and action quality and load development. Most factory rifles are now being set in the range of 6 - 8 lbs pull with some even set higher. It is almost impossible to shoot quality repeatable groups while trying to fight this kind of weight. We do not recommend that factory triggers be adjusted unless they are designed for it like the new Remington "X" trigger.  Some models cannot be adjusted safely like the older Ruger M77 trigger. For our Custom Rifles based on the Remington 700 action we like to install either Timney or Jewell Custom Triggers. They both break cleanly and have a great safety record. For those on a budget, the Timney is a fine trigger and and can be set by the factory down to 1.5 lbs. For those who want the best, we highly recommend the Jewell Trigger, it is the best trigger on the market bar none, these can be set as low as 4 ounces for benchrest purposes.




Q: What makes an Accurate Barrel? 

A: An accurate barrel should possess several characteristics if it is going to be a "tack-driver". These include the concentricity of the bore, uniformity of the rifling geometry, twist rate, and quality of the internal bore surface. If the width of the lands or the depth of the grooves varies, that barrel is never going to shoot accurately. Likewise, if the interior surface finish of the barrel is poor then the barrel lacks the end-to-end uniformity required to shoot well. A rough finish will also foul badly, causing accuracy problems. The direction of the bore surface finish is very important too with the correct finish being parallel to the bullet travel. If there are reamer marks left inside the barrel on the tops of the lands they will be perpendicular to the bullet travel and tend to foul. This is why the extra money spent on a hand lapped match grade barrel is one of the best investments you can make in a rifle. Also, hand lapping the bore in a factory barrel can also aid in accuracy as well make the factory barrel easier to clean
.



Q: What Bullets do you Recommend for Hunting in your Custom Rifles?


A: Many good quality hunting bullets are now being manufactured but a few stand out among the crowd, the critical factor is getting a quality bullet that will hold up to high velocities and is tough enough to hold together on big game. Price vs. Performance in .224 caliber (22 centerfire) the Sierra SBT Boatails in 55 grain are an inexpensive and good shooting bullet, they are really good performing bullet in all 22 centerfire calibers except maybe for the 220 swift, where velocity of this round is a bit much for this bullet. The best as far as weight retention and pure killing ability is the Speer Trophy Bonded Bear Claw in 55 gr. Unfortunately, Speer in their infinite wisdom has discontinued this bullet and it is no longer available to the general public. However, we have a good supply of these in stock for our Custom Rifle customers.
   In the larger calibers like .257, 270, 7mm (.284), 308, 338 caliber etc., the Nosler Partition is an excellent bullet, it holds together well at high velocities and it is a much better choice on large game than the Accubond or similar bonded bullets. The Swift A-Frame is also a quality bullet. Also, for those that prefer an unleaded bullet the Barnes Tipped TSX is a great round as well and has a great ballistic coefficient. The only knock on the all copper bullets is that great care has to be taken in selecting the correct weight for a given velocity and caliber along with barrel twist rate as they are typically a longer bullet than their leaded counterparts. A custom handload tuned to your particular firearm will always outperform factory ammo. To see what a quality bullet can do at high velocity, see the pic below, a solid steel 1/4 inch plate shot with a Utah Rifle Custom 220 Swift at 100 yds, no wonder this was P.O. Ackley's favorite caliber!






Q: Do you have any tips for doing Handloads for a Custom Rifle?

A:
Yes, several, but the most important is being safe and knowing what your doing at all times. If you've never reloaded before ask someone who has to help you along for the first time, read as many books and articles on the subject, all of the major bullet manufacturers have at least one chapter dedicated to reloading the safe and correct way. Never mix powders. Always know what type of powder you are using, the specific application or caliber it is intended for and always start near the minimum load based on the manufacturers tables and work up gradually to your desired load.  If you think you are in over your head, drop us an email and we'd be glad to help by doing your load development for you - It is always better to be safe than taking a chance and having something go wrong and have a dangerous situation on your hands - Remember, money can be replaced but your eyes, limbs and life cannot!

The information below depicts some tried and true techniques that we have learned from experience over the years when trying to develop the most accurate handloads for your firearm. 

Uniformity is key for accurate loads. The most critical areas to focus on for best accuracy are case preparation, bullet seating and an accurate powder charge. If your scale does not give you absolute repeatable loads accurate to 0.1 grains (test it regularly with a calibrated source), get rid of it and invest in a quality scale. A powder variance of even as little as 0.1 grains between loads will absolutely give you lousy results, trust us on this one.

Weigh every powder charge to ensure each case gets exactly the same charge.

Match grade primers are more expensive but they are also more consistent. Don't mix primer brands or types within a batch. Do experiment with different primers to find the one that works best for your gun.

Different brands of cases and even within a brand can vary in case wall thickness and web thickness in the head. This affects powder capacity and pressure. Differing case wall thickness will also cause cases to react differently when they are fired, affecting consistency. One way to increase uniformity is to sort your cases by brand or manufacturer and lot number.  Perhaps, even better, many top competition shooters sort their cases by weight to get better uniformity. A variance of 1.0% of case weight within a batch is acceptable.

Trim every case to exactly the same length as specified in your loading manual, ensuring each case mouth is perfectly square

Lightly debur the inside and outside of the flash holes to ensure they are the same diameter and free of burrs

Generally, faster powders give better accuracy unless you’re loading big magnums. Select a powder towards the fast end of those listed for your particular bullet combination, yet still fills at least 90% of your case. Faster powders will generally create less gas volume which disturbs the bullet less after it exits the muzzle. With slower powders, this bullet disturbance results in what is called "tip-off" where the bullet is thrown off-course by the high pressure gas pushing around the sides of the bullet after it exits the barrel. For big magnums a consistent slower powder is usually the ticket.

A powder charge that nearly fills the case (85% minimum) seems to provide more consistent pressures from one round to the next.

For target shooting, select a match grade bullet. Their construction and weight are more consistent and are optimized for accuracy. However, do not use match bullets for hunting -- even if a match bullet is a hollow point, it is not designed to expand and is more likely to ricochet than a bullet designed for hunting. See the QA section above on quality hunting bullets.

 Boat tail bullets usually offer the best ballistic coefficient when searching for accuracy. However, you may often find that a flat-base bullet shoots the best in your firearm. Do pay attention to Ballistic Coefficients for long range shooting (the higher the better).

Seat bullets to a uniform depth, with no greater than .005 inches variance with .001 inches being the goal. A bullet comparator is a very useful tool as the ogive can vary with most bullets even within the same lot.

When trying to develop a Benchrest loads and especially for competition shooting, be sure to spin the bullets you are using on a Juenke Bullet Spinner to separate them based on uniformity and quality. This is an expensive piece of equipment, so if its not in your budget call us and we can spin and sort your bullets for you for a minimal charge.

If you are using a Benchrest Quality Press like a Forster or Bonanza Coax Press, disregard this step – All others pay attention - When seating the bullet, seat it about halfway, then rotate the case halfway around in the shellholder and complete the seating process. This technique sometimes averages out any remaining misalignment.

Use match grade or benchrest dies if possible. They cost more, but they give better support to the case and bullet to ensure straighter bullet seating.

Seat the bullets so they come close to the rifling. To find this seating depth, make a dummy round (no primer or powder) and use a marker or grease pencil or lamp black to color the bullet. Chamber the round and adjust seating depth until you see that the bullet is contacting the rifling. Then adjust the seating die to seat a bit deeper and tighten the lock ring. Start with a distance off the lans of say 0.020 to 0.030 of an inch. For large magnums, sometimes freebore will enhance accuracy and minimize pressure.

Consider the twist rate of your firearm when selecting bullet lengths. Heavier bullets in a given caliber need a faster twist for stabilization, lighter bullets and maximum velocity loads tend to like a slower twist rate.

Keep careful records of what you load, so that when you hit the magic formula, you can duplicate it.
 



    Please email us at
    mag@hiwaay.net for further inquiries or questions