F-Class Centerfire Prone and the F-AR15 Rifle

By John Dink and Dr. Jim Clary

F-Class is an outgrowth of Palma shooting, which requires the shooter to use micrometer aperture (iron) sights and shoot a 7.62mm NATO (.308 Win.) caliber rifle at ranges from 600 to 1,000 yards. The goal of F-Class, which originated in Canada in the 1990�s, was to allow shooters who no longer had the vision or physical strength for Palma to continue shooting at a competitive level for many more years. It is also an ideal way to interest younger shooters and new shooters to high power shooting. F-Class shooting is divided into two categories:

F-Class Open - The most flexible as it allows the shooter to use any target rifle with a bull barrel and scope to shoot off a front rest with a rear bag in calibers up to .338 Win. Mag.

F-Class/Target Rifle - This is referred to as F/TR and is restricted to the .223 Remington and .308 Winchester. In this category, shooting is off a bipod, rather than the front rest, but still with a rear bag. Most F/TR shooters shoot the .308 Winchester in order to be competitive at 1,000 yards. Hence, the .223 Remington, although allowed, is rarely used by serious F/TR competitors.

John is the Match Director for Centerfire Prone at ZIA Rifle and Pistol Club, Albuquerque, New Mexico. Realizing the popularity of AR-type rifles on the range, John has created a new Mid-Range (600 yard) F-Class format for AR15-type rifles, using the same targets with � MOA "X" and 1 MOA 10-ring @ 600 yards. This new venue is essentially plinking for F-Class shooters, without the high set-up cost. Another reason for creating this new category is that not many rifle ranges across the country have 1,000 yard capability; hence F-Class shooters practice at 600 yards. This gives them trigger time, but given the evolution and development of F-Class rifles, 600 yards presents little challenge, except in the worst winds.

Switching to a .223 format for AR platforms provides an opportunity for new and younger shooters to get into the game at much reduced expense. New AR shooters will find keeping all their rounds in the black at 600 yards a challenge. Consistently shooting 10�s or better will take considerable more effort and should provide enough challenge for even the most seasoned F-Class shooter.

The new format, F-AR15, will be a spin-off of F-TR, but will be restricted to .223/5.56x45mm NATO shooting 68 � 77 grain Match type bullets. They must be loaded at magazine length of 2.260� OAL or less and fired from the magazine, as the firearm was originally designed to be used. No single loading of long seated bullets will be permitted and no wildcat cartridges will be allowed (at least for now) in order to keep the playing field level. Also, no bullets cored with anything other than lead will be allowed. This is a SAFETY issue for people in the pits and there will be no exceptions.

Flash hiders and Suppressors are fine, but muzzle brakes will be restricted due to interaction with other shooters on the line. Anyone who has ever been next to someone firing a high-power rifle with a muzzle brake can appreciate this restriction. At Zia, John will try and accommodate those with brakes by putting them on the end of the line, but if it becomes a burden for other shooters, their use will be re-evaluated.

F-Class F-AR15 rifle photos.

The above trio of photographs show a typical setup optimized for F-AR15. In the first (AR15 rifle) picture, the forend is free-floated with the bipod attached. If the forend was still connected to the bore per the standard AR design, you would have accuracy issues as the load changed on the bipod. One can see the necessity for having a rear bag tall enough for magazine clearance.

It is desirable to have an adjustable butt stock. The LOP needed when using a highly magnified optic changes with your position, off hand, kneeling and prone. If you use a fixed stock, you may wish to optimize the scope eye relief for that position. The rear bag pictured is about as high end as it gets, Edgewood Leather. However, we need to emphasize that, as you will need a bag height that works with your magazine and bipod height.

The scope setup picture above illustrates the scope/rail configuration. Again high end, but the point is you will need an extended rail to put the scope's eye relief where it is needed for prone shooting. You will also need to address the internal elevation range on your scope. Not all scopes will get the job done. The Nightforce NXS scope pictured has 100 MOA of vertical adjustment and a 20 MOA tilted rail was not needed. However, with a 1� scope, you will most likely require the 20 MOA tilted rail.

The final picture illustrates the bipod attachment. Any prone sized bipod from the Harris type on up to the Sinclair F-Class bipod will work. However, think ahead as to how you will attach your bipod to your for end. A GG&G bipod is pictured and is attached to the 1913 rail. It is a very secure and stable attachment. Note that the gas block is covered. The reason for this is Mirage. The heat from the gas block will give false indications of mirage that is used for estimating the wind. Another option is an extra long sunshade, or a mirage band.

The basic specifications for an F-AR15 rifle are:

  • 1:8 or 1:7 twist barrel � 1:9 if you only want to shoot 69 grain bullets
  • Match type chamber specifications � without too much free-bore
  • Flat-top
  • Match-trigger
  • Free-floating forend
  • 16-24 inch barrels (longer is better) � the most accurate barrel tested was a 20-incher
  • Optical riser/rail with 20 MOA of slope
  • High quality target scope (10x is about the minimum)
  • Solidly mounted Prone length Bipod

We expect that most AR shooters will take their existing rifles out to the range, to see how they perform and THEN decide what modifications they need to make to their individual gun. The same holds true for reloads. However, to provide a starting point for reloading for this kind of shooting, we provide the following suggestions.

POWDER: When it comes to powder, stay with single-base stick (extruded) types; ball powders need not apply. With more than 60 years of hand-loading experience between us, we have never seen a ball powder perform as well as stick powders for match-grade accuracy at longer distances. This is especially true in the Southwest or other areas where temperatures extremes of 40+ degrees from morning to late afternoon are common. There are several good powder choices available from Hodgdon and IMR and each shooter will have to determine what works best in their gun.

CASES: New Lake City brass is a bargain and of good quality, but if you decide to get really serious, you will want to use Lapua brass, which many F-Class shooters prefer. However, we expect that a lot of new shooters will try their once-fired brass. We have seen no real issues with fired brass, but expect to loose about 5% to10% after each firing, due to primer pocket issues.

BULLETS: Nosler 69 grain and 77 grain shoot well and are cost effective. However, if you want to optimize, you should consider shooting Bergers. They are costly, but they tend to deliver. Again, the bullet you decide upon will depend upon your gun, your goals and how much money you are willing to spend. The 75-77 grain bullets will always win the wind drift game, but not all barrels will shoot them as well as the 68-69 grain bullets.

PRIMERS: Use BR4 or 205M primers as a starting point, although Remington 7-1/2 and Wolf SRM�s have yielded excellent results for many shooters.

The F-AR15 format provides AR-shooters an opportunity to compete in a semi-formal venue at a substantially lower cost than regular F-Class. Think of F-AR15 as being to HIGHPOWER what F-TR is to PALMA.

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