December 12th, 2018

Tuning Barrels for Enhanced Precision and Accuracy

Anschutz Tuner

When a shot is fired through it, a barrel will exhibit harmonics. Tuning these harmonics (the “waves” that propagate through the barrel) can alter point of impact and, if you’re lucky, reduce group size. Barrel tuners have been used successfully in rimfire benchrest for many years (see photo above). While there are competing theories as to how and why barrel tuners work on rimfire rifles, there is no question that the accuracy of some rimfire barrels can be improved with the addition of a tuner. By changing the position of weights at the end of the barrel, we’ve seen shooters shrink their average group size as well as adjust the “sweet spot” for different lots of rimfire ammo. On the other hand, tuners can be the source of great frustration; some installations may yield little or no benefit. A shooter may have to experiment with a variety of different tuner designs (and weights) to find the optimal configuration.

Gene Bukys Barrel Tuner 333smittyCenterfire Tuners–Still a Work in Progress
In centerfire benchrest competition, the vast majority of competitors do not use tuners, though a few short-range shooters such as Gene Bukys and Jackie Schmidt have enjoyed considerable success. Gene has won major championships with tuned rifles. In 2011 Gene won both the Super Shoot and World Benchrest Championship (WBC), and Gene recently set a new NBRSA Sporter Class Grand Agg Record.

Centerfire benchrest guns typically employ shorter barrels with a much fatter contour (larger diameter) than rimfire rifles. Because centerfire rounds produce much higher pressures and velocities that a 22LR, a centerfire barrel also exhibits much different vibration characteristics than a typical rimfire barrel. Nonetheless, there are pioneers working with centerfire tuners who believe that tuning may be the “next leap forward” in centerfire accuracy.

Shown below is a switch-barrel benchrest rifle built by Forum member Eddie W. of Texas. It features a dual-port Hall “M” action with a ShadeTree Engineering Tuner crafted by Butch Lambert. The gun is designed to take both a 6PPC barrel for group shooting and a 30BR barrel for score shooting. The gun was barreled by Wayne Shaw, and Eddie did the stock work himself. Eddie reports: “It is a very accurate rifle.”

Lambert Tuner

Will we see more tuners on centerfire rifles? Only time will tell. Some folks believe that, since one can easily adjust the loads shot by centerfire guns (by tinkering with the powder charge and seating depth), tuners have limited utility. On the other hand, tuner advocates such as Gene Beggs believe tuners can help keep your group sizes small even as conditions (temperature, humidity) change. Gene believes that, with an appropriate tuner, you can spend less time fiddling with the load specs (changing your powder charge) and instead “dial in” your sweet spot using the tuner.

Lambert Tuner

Permalink Gunsmithing, Tech Tip 2 Comments »
February 1st, 2017

Tuning Balance-Beam Scales For Precision and Repeatability

Tuning Balance Beam Scale

While many folks enjoy the convenience of an electronic powder scale/dispenser such as the RCBS Chargemaster, some hand-loaders still prefer to use a traditional balance beam. Balance beam scales are simple, compact, and don’t suffer from electronic “glitches”. Moreover, even if you use a digital dispenser at home, when you’re doing load development at the range, a balance-beam scale may be more convenient. A scale doesn’t require electrical power, so you don’t need to bring battery packs or string long power cables. Just bring some kind of box to shelter your beam scale from the wind.

While designs like the RCBS 10-10 are decent performers as built, they can be made much more precise (and repeatable), by “tuning” of key parts. Forum member Scott Parker (aka SParker) optimizes a variety of popular beam scales, including the Ohaus 10-10 (USA-made model), RCBS 10-10 (USA-made model), RCBS 5-10, Lyman M5, Lyman D5, and others. You send Scott your scale, he tunes the key components, tests for precision and repeatability, and ships it back to you. The price is very affordable (under $85.00).

Scott tells us: “I have tuned several 10-10s. They all have turned out very sensitive, consistent and hold linearity like a dream. If only they came that way from the factory. The sensitivity after tuning is such that one kernel of powder registers a poise beam deflection. For repeatability, I remove the pan and replace it for the zero 10 times. The zero line and the poise beam balance line must coincide for each of those 10 tries. I then set the poises to read 250.0 grains. I remove and replace the pan 10 times with the calibration weight. For linearity, the poise beam balance line and the zero line should coincide within the line width. This is roughly one half a kernel of powder. For repeatability, the poise beam balance line must return to that same balance point ten times. I then adjust the poises back to zero and recheck the zero. I have a master’s degree in chemistry, thus I am very familiar with laboratory balances. Email me at vld223 [at] yahoo.com or give me a call at (661) 364-1199.”

The video above, created by British shooter Mark (aka 1967spud), shows a 10-10 beam scale that has been “tuned” by Scott Parker. In the video, you can see that the 10-10 scale is now sensitive to one (1) kernel of powder. Mark also demonstrates the’s scale’s repeatability by lifting and replacing a pan multiple times. You can contact Mark via his website, www.1967spud.com. To enquire about balance-beam scale tuning, call Scott Parker at (661) 364-1199, or send email to: vld223 [at] Yahoo.com.

Video tip from Boyd Allen. We welcome reader submissions.
Permalink Reloading, Tech Tip 5 Comments »
December 9th, 2012

Tuning Savage Actions Using Action Screw Torque Settings

This article originally appeared in the SAVAGE ACCURACY Blog

Stan Pate is the Captain of Savage’s National Championship F-TR Team. In this article, Stan explains how to adjust the action-screw tension on a three-screw Savage target action to achieve the best accuracy. The procedure described here can be used for any Savage action, including the two-action-screw models. However, the optimal settings for each particular rifle may vary slightly.

Match shooters need to get that extra accuracy edge from our ammunition and firearm. It is easy to get one of the Savage rifles to shoot accurately — even to match standards. If you are looking for that little bit more from your rifle, then please read a method that I have found that works for me. For those of you that are familiar with tuning a receiver (such as a match rimfire action), this article will be nothing new. For the rest of you, this might be new material. The goal here is to find the “sweet spot” for the rifle in relation to the torque settings used on the receiver screws. The proper torque settings [can vary] from rifle to rifle, but they will usually have a noticeable effect on consistent group sizes. A properly-torqued rifle will optimize the “harmonics” of the barreled action using the receiver screws so that the gun delivers peak consistency.

Here is the process I have found that works for me in tuning a Savage rifle receiver to peak accuracy. To use my process you first must already have a load that shoots accurately and consistently in your rifle, and I always use a fouled barrel like I’d be shooting in a match. This process works for me in both the model 10 (two receiver screws), and the model 12 (three receiver screws).

Seat Recoil Lug and Start with Front Action Screw(s)
On the model 12, I will first ensure that the recoil lug is seated securely against the stock by just lightly tightening up the front receiver screw then gently but firmly bumping the butt pad against the floor. Next I will tighten up the front two receiver screws to 30 inch-pounds starting at 20 inch-pounds and working up to the 30 inch-pounds in 5 inch-pound increments, and always tightening the front screw first and then the second screw. Once the front two receiver screws are torqued to the final torque setting, I will set the rear receiver screw to 5 inch-pounds and shoot a 5-shot group [to evaluate accuracy].

Increase Torque Incrementally on Rear Action Screw
After the group is shot and I am satisfied that I called all of the shots as good shots I will allow the rifle to cool off to about the temperature that the fist group was shot at. I will then add 5 inch-pounds to the rear receiver screw and shoot another five-shot group and allow the rifle to cool again. I repeat this process until I have tightened the rear receiver screw to 40 inch-pounds or have seen the groups get smaller and then start getting larger again. Once you have seen the groups decrease and then start to increase in size then you will have found the area of torque to work in. You can then can fine tune this to the exact inch-pound torque settings.

Tuning a Model 10 with Two Receiver Screws
The Savage model 10 action, which has two receiver screws, uses the same process as the three-screw model 12. Measure your group sizes and place the measurements in front of you so that you can see the bell curve showing where your best groups were achieved. NOTE — there may be a better way of doing this and if you should have one, I’d be very interested in hearing it. Good shooting and I hope to see you all on the range. – Stan Pate

This is on the Palma rifle using the torque settings of 30 inch pounds on the front two reciever screws, and 15 inch pounds on the tang screw, it is approximately 1/2″ center to center.
This is my second torque setting which for this rifle and this load is the optimal setting of 30 inch pounds on the front two reciever screws and 25 inch pounds on the tang screw, this group is approximately .180″ center to center.
This is the third torque setting which for this rifle is moving away from the optimal torque setting towards the heavy side of the scale. This torque setting results shows that you will usually see a “bell curve” of accuracy as you move into the optimal torque setting. This group is almost .7″ and the torque setting was 40 inch pounds.

This article was edited for length to appear in the Daily Bulletin.

Permalink Competition, Gunsmithing 15 Comments »
January 25th, 2010

SHOT Show Report: Adjustable barrel weights from AirForce

For decades rimfire shooters have used muzzle weights and various types of tuners to optimize barrel harmonics. Just in the last few years have tuners started to appear on centerfire bench guns. And for centerfire rifles, partly by reason of benchrest rules, most of the tuning systems are fairly heavy metal cylinders placed at the end of the muzzle.

AirForce flexi-weight

AirForce flexi-weightIt is well-established that mid-barrel tuners can work on rimfire rifles, and we also know that certain types of materials (such as rubber, cork, and Delrin) can have beneficial damping effects on both rimfire and centerfire barrels. Given these facts, we were quite interested in the new Flexi-Weight System introduced by AirForce Airguns at the 2010 SHOT Show.

The Flexi-Weight system consists of a cluster of 3 to 6 metal weights, held in place by a rubber O-ring. Multiple Flexi-Weight clusters can be installed on a single gun and the fore-to-aft position is easily adjusted. The shooter can simply slide a Flexi-Weight cluster back and forth along the barrel until he finds the optimal position.

We have no idea whether Flexi-Weights can improve accuracy on a centerfire rifle, but it’s worth a try. Flexi-weights are affordable ($29.95 for a set of five, 48 gram weights) and you can slip them on your barrel without cutting threads or making any other permanent modifications. The weights are designed to fit a 1.25″ diameter tube. For more info, visit Airforceairguns.com or call (877) 247-4867. Airforce Airguns is a U.S. company based in Fort Worth, Texas.

AirForce flexi-weight

Permalink Competition, New Product No Comments »