September 2nd, 2017

Fore and Aft Rifle, Rest, and Bag Positioning for Accuracy

Benchrest stock

To get the best accuracy out of any benchrest rifle, you need to find the optimal position of front rest and rear bag. The important point to remember is that each rig is different. One gun may perform best with the front rest right at the tip of the forearm (Position ‘D’ in photo), while another gun will work best with the rest positioned much further back. This Editor’s own 6BR sits in a laminated stock that is pretty flexy in the front. It shoots best with the front rest’s sandbag located a good 6″ back from the forearm tip (position ‘A’).

Here’s some benchrest advice that can help you reduce vertical and shoot tighter groups… without spending another penny. Many benchrest shooters spend a fortune on equipment and devote countless hours to meticulous handloading, but they never experiment with their rifle’s position/balance on the bags. This article explains why you should test your rifle in various positions. What you learn may surprise you (and improve your scores).

Next time you go to the range, experiment with the position of your rifle on the front rest, and try a couple different positions for the rear bag. You may find that the rifle handles much better after you’ve made a small change in the placement of your gun on the bags. Recoil can be tamed a bit, and tracking can improve significantly, if you optimize the front rest and rear bag positioning.

front rest Sally benchrest IBS
This competitor has the front rest positioned fairly far forward but not all the way out. Note the stop on the front rest — this limits forward stock travel.

Balance Your Gun BEFORE You Spend Hours Tuning Loads
In the pursuit of ultimate accuracy, shooters may spend countless hours on brass prep, bullet selection, and load tuning. Yet the same shooters may pay little attention to how their gun is set-up on the bags. When you have acquired a new rifle, you should do some basic experimentation to find the optimal position for the forearm on the front rest, and the best position for the rear bag. Small changes can make a big difference.

Joel Kendrick

Joel Kendrick, past IBS 600-yard Shooter of the Year, has observed that by adjusting forearm position on the front rest, he can tune out vertical. He has one carbon-fiber-reinforced stock that is extremely rigid. When it was placed with the front rest right under the very tip of the forearm, the gun tended to hop, creating vertical. By sliding the whole gun forward (with more forearm overhang ahead of the front sandbag), he was able to get the whole rig to settle down. That resulted in less vertical dispersion, and the gun tracked much better.

stock position benchrest forearm sandbag front rest
Fore/aft stock position is important even with very wide fore-ends.

Likewise, the placement of the rear bag is very important. Many shooters, by default, will simply place the rear bag the same distance from the front rest with all their guns. In fact, different stocks and different calibers will NOT behave the same. By moving the rear bag forward and aft, you can adjust the rifle’s overall balance and this can improve the tracking significantly. One of our shooters had a Savage 6BR F-Class rifle. By default he had his rear bag set almost all the way at the end of the buttstock. When he slid the rear bag a couple inches forward the gun tracked much better. He immediately noticed that the gun returned to point of aim better (crosshairs would stay on target from shot to shot), AND the gun torqued (twisted) less. The difference was quite noticeable.

A small change in the position of the forearm on the front rest, or in the placement of the rear bag, can make a big difference in how your gun performs. You should experiment with the forearm placement, trying different positions on the front rest. Likewise, you can move the rear bag back and forth a few inches. Once you establish the optimal positions of front rest and rear bag, you should find that your gun tracks better and returns to battery more reliably. You may then discover that the gun shoots smaller groups, with less vertical dispersion. And all these benefits are possible without purchasing any expensive new gear.

Rifle photo courtesy Johnson’s Precision Gunsmithing (Bakersfield, CA).

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March 20th, 2015

Horus Video Explains Sources of Zero Shift in Rifle Scopes

YouTube Preview Image

In the above video, a spokesman for Horus Vision explains how and why scopes can experience zero shift. First, just cleaning the gun can cause a small shift in point of impact. Second, when you re-tighten rings and ring bases, this can cause a change in zero. Horus recommends that you use a torque wrench to confirm that you maintain the same torque settings each time. The same goes for action screw tension — tensioning your action screws can shift the point of impact.

Other factors that can cause a change in zero:

Temperature
Dramatic ranges of temperature will change your zero, because the air density affects the velocity of the bullet. With increased temperature, there may be a higher velocity (depending on your powder).

Gun Handling and Body Position
You rifle’s point of impact will be affected by the way you hold the gun. A “hard hold” with firm grip and heavy cheek weld can give you a different POI than if you lightly address the gun. Even when shooting a benchrest gun, the amount of shoulder you put into the rifle can affect where it prints on paper.

Type of Rifle Support — Bench vs. Field
Whenever you change the type of rifle support you use, the point of impact can shift slightly. Moving from a bipod to a pedestal rest can cause a change. Similar, if you switch from a mechanical rest to sandbags, the gun can perform differently. That’s why, before a hunt, you should zero the gun with a set-up similar to what you would actually use in the field — such as a rucksack or shooting sticks.

shooterXbag.com sandbag

Transportation of Firearms
Even if you don’t mishandle your weapon, it is possible that a shift of zero could occur during transport. We’ve seen zero settings change when a tight plastic gun case put a side load on the turrets. And in the field, if the turret knobs are not covered, they can rub against clothing, gear, storage bags, scabbard, etc. If the knobs turn, it will definitely move your reticle slightly and cause your point of impact to be off.

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