OCTOBER 10, 2013

Skill Set: SPR Part II - Parts 'n Tools

In my previous column I outlined the SPR concept. I'm building a similar rifle but maintaining the ability to use it for defensive purposes. This week we're talking parts. Keep in mind I chose these parts for my rifle; you may have a different opinion/ preference. Regardless, use quality parts. (All part numbers listed are from "Big B," Brownells.) The one name that constantly came up during barrel research was White Oak. They offer a "SPR" profile barrel (#100-009-961) designed for accuracy out to six hundred. The stainless steel eighteen-inch barrel has a Wylde chamber, for both .223 and 5.56, a 1-7 twist and mid-length gas system. Leupold's Mark AR MOD 1 FireDot scope (#526-000-185) designed for the SPR fit my needs perfectly. It has a mil type reticle, an illuminated green center dot, and adjustable knobs. Magnification is 1.5 - 4, with a 20mm objective. The 1.5x magnification is low enough you can keep both eyes open, with the green dot on, using it like any other red-dot type system, although eye alignment is more critical. For distance you've got 4x magnification. "But," you ask, "is 4x enough magnification?" Yes. Most work done with these type rifles - except for the military - is close, as in like thirty to fifty yards. At these distances low magnification doesn't restrict your field of view to the point of being a disadvantage. Most serious riflemen I know keep their scopes dialed down on the lowest power anyway, dialing it up if necessary. Out to mid-range 4x is plenty. The scope's smaller size and reduced weight are additional advantages. Furniture: PRI's Gen III Delta twelve-inch handguard (#714-000-021). It is carbon fiber, for strength and heat dissipation, has rails to attach anything necessary, and the triangular shape feels good in the hand. (Stoner was pretty smart.) I wanted an adjustable stock for length of pull and height for proper eye alignment with the scope. Magpul's Gen II PRS stock (#100-002-457) does this. Everyone has a favorite grip. Mine is the original DuckBill Tactical Grip . For small parts I use quality, true mil-spec parts. "Big B" has 'em. I'm using ALG's "ACT" trigger (#100-009-797). Not a true "precision" trigger, but this rifle is for defensive work as well as mid-distance shooting. For details on the "ACT" trigger see Skill Set: Archive 2013-09-19. I chose WMD's NiB-X bolt group (#100-011-664). It's machined to gov specs, coated with nickel boron, which is harder than chrome, reduces friction and easy to clean. In the WMD I installed a Colt "Gold" extractor spring (#160-304-025) and solid, one-piece original style firing pin retaining pin (#231-000-029). A MechArmor charging handle, with heavy-duty, ambi latch, cycles the action: MechArmor. The ambi design means you can use the right hand to cycle the action. This works well for some positions you may be firing from. The handle's extension provides a good grip when using a rear mounted traditional type optic. MHT's "M-605" upper, a flat-top without external forward assist based on Colt's 605 upper houses everything: MHT Defense. I'm also using their lower. Keep in mind these parts fill the anticipated needs of this rifle for me. When building any weapon your primary focus should be on intended application. For example you can use a defensive type rifle to shoot matches; a competition weapon might not be ideal for fighting. Next, in part III, we'll talk tools and assembly tips. In the meantime, stay safe. --Tiger McKee Tiger McKee is director of Shootrite Firearms Academy, located in northern Alabama. He is the author of "The Book of Two Guns," writes for several firearms/tactical publications, and is featured on GunTalk's DVD, "Fighting With The 1911 - http://shootrite.org/dvd/dvd.html Website: www.shootrite.org http://www.facebook.com/pages/Shootrite-Firearms-Academy/156608611038230?ref=ts