Ysterhout Dot Net
Purpose Specific Rifle
Barrel and Bullets
One relies on the other, but both must be carefully considered.
The first decision to make, and the one that limits how far the rifle will ultimately shoot, is the bullet you will use. The limit of pressure will determine the muzzle velocity of the bullet, and when combined with the BC and available elevation in the scope, determines the limit of the target range of the rifle.
The barrel decision is then made based on the bullets you will be using for ELR, the decision being what twist rate.
Why does this twist decision limit the distance you can shoot to with the rifle ? Because a slower twist can't stabilise heavier bullets, which have a higher BC than lighter bullets, and in ELR, BC trumps velocity. You will understand this perfectly after you shoot your first ELR match that requires a 15 MOA windage adjustment at one mile with a bullet G7 of 0.34 . You'll then wish you had a G7 of 0.5, but realise can't use it anyway, because your barrel twist is wrong.
Determine the highest BC bullet you will be using. Calculate the required twist for that bullet. Order the barrel in that twist.
At this point, don't be too fixated on velocity. A 1.0 G1 @ 2650 gets to 2 miles in 54 mils. BC trumps speed in ELR.
The barrel profile is a matter of preference.
The length of the barrel determines which powder will work best, and may limit your powder choices if it's too short. Depending on the caliber / bullet weight combination, not every powder will give 100% burn in the available inches of tube.
For an explanation of why the length of barrel limits powder choice, refer to The Powder
You want to have 100% burn in the available tube length.
Tools like GRT and Quickload are very good estimation tools for which powder will give 100% predicted burn in the given barrel length.
Aim for 100% burn and 100% case fill. That will give the most consistent results. How you get there and with which powder involves a lot of trial and error, money and time.
Action
An ELR rifle is a target rifle, and is best built with a target action. These are single shot. A magazine fed action is not a target action. It may be, and often is used in a target build, it is not a target rifle action.
Single shot actions are much more rigid, delivering better consistency and accuracy.
Stock
An ELR stock is based on the bechrest format, with changes.
The fore-end is longer, so that the bipod can be mounted closer to the muzzle than to the bolt. The stock needs an adjustable cheek-piece. The butt-pad should be vertically adjustable, and there is no need for a drop in comb.
The stock is thicker throughout it's length, imparting greater rigidity.
Scope and Mount
The scope partly determines the maximum available elevation adjustment. The mount and rings also contribute to how much useable elevation is available.
Whichever scope you choose, you have half that elevation available to dial, on a zero MOA or MIL base. Pick a rail / rings system that gives you half of the available elevation in the scope, so that you have the full range of elevation available for dialing. I mention rail / rings as some ring sets have elevation offsets. Sustac, for example, provides 34mm rings with a 40 moa elevation offset.
You will most likely need some form of an elevation adjustable mount as well. Ivey, Era-Tac, etc.
Bipod
The bipod is solid, does not have rubber feet, and the legs and feet should be able to be tightened so there is no play. In the bigger rifles, the weight of the firing pin is enought to impart motion to the rifle, therefore moving the muzzle, and if the bipod has play in it, it can cause shot to shot inconsistency.
Rear Rest
The rear rest is solid, without any bounce. Some form of bag rider is a control advantage, especially an adjustable one.
