Chris

Chris

Project 1760: Homesmithing the One Mile Rifle

Part 1: Cartridge selection Long range precision shooting has come a long ways. A thousand yards used to be a magical number, but advances in ballistics understanding and rifle and ammunition technology have effectively moved that target closer. It is now commonplace to find thousand yard benchrest competitors shooting 10 shot strings under minute of angle, or roughly 10″. Think about that for a minute. In years past, a rifle that would hold less than minute of angle at 600 yards was considered to be exceptional. Now you need to shoot considerably less than minute of angle at 1000 yards to even be competitive, and if you expect to win you need to shoot closer to half a minute. Thousand yard benchrest competitors are now closing in on the quarter minute mark:Part 1: Cartridge selection Long range precision shooting has come a long ways. A thousand yards used to be a magical number, but advances in ballistics understanding and rifle and ammunition technology have effectively moved that target closer. It is now commonplace to find thousand yard benchrest competitors shooting 10 shot strings under minute of angle, or roughly 10″. Think about that for a minute. In years past, a rifle that would hold less than minute of angle at 600 yards was considered to be exceptional. Now you need to shoot considerably less than minute of angle at 1000 yards to even be competitive, and if you expect to win you need to shoot closer to half a minute. Thousand yard benchrest competitors are now closing in on the quarter minute mark:

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accurateshooter.com best 10 shot 1000 yard group in history Videos on You Tube abound of shooters hitting steel plates at 1500 yards and further with .308’s and even 3000 yards with more specialized calibers. I’ve been shooting .308 out to 1000 yards for a while, but I’m starting to feel left behind. It’s time to push the envelope. To show just how far long range shooting has come, I’m going to combine this with another project I’ve been wanting to do for a while. I’ve always been a DIY kind of guy, and I’ve always tried to educate myself and do most of my own work instead of just calling up a good gunsmith and having something made to order. That’s the easy route, although for something like this it requires a rather large budget.  I’m going to make this a DIY project where I buy the factory rifle, optics, rings, cases, bullets, powder etc and prepare the entire platform myself, at home, with no expensive machine work (I don’t have a lathe in my garage), using tools that are easily and inexpensively available from well known and reputable gunsmith suppliers Brownell’s and Midway USA. One thing about extreme long range shooting, you aren’t going to do very well at it with ammunition you buy.

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This is the province of the precision handloader, where all of the aggregate skills of creating the ammunition to good position and reading the wind are tested thoroughly. That means for specialized calibers new reloading dies will be required, at a minimum, along with quality cases and bullets, all of which have gotten extremely expensive. The goal of this project is to keep the budget under control, and that means creating a precision rifle and ammunition all by my lonesome. Known as “homesmithing” there’s an entire market out there for people who like to do their own tinkering, and I intend to tap what’s available to homesmith a reasonably available factory rifle into a one mile precision machine.

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Choices, choices….. There are literally dozens of wildcat cartridges out there designed and specialized for long range shooting, but since this is a home project I have to consider only calibers available from the factory in suitable rifles. I have a nice tactical .308 but videos on the internet notwithstanding, I know that shooting any bullet at extreme long range requires that it stay supersonic to the range desired or you risk losing stability as the bullet passes back through the sound barrier. I’ve seen many a short barreled .308 exhibit this problem at a thousand yards with bullets cutting slots in the target from tumbling, if they hit it at all, from losing stability on every third or fourth or fifth shot. My .308 has a 26″ barrel on it but there’s no keeping a .308 supersonic at one mile, likewise a .30-’06, so those are out. 338-lapua-comparisonLooking at the factory catalogs brings me to two cartridges that have found favor with the military for reaching out a little further than standard sniper rifles and can be found in factory rifles: the .300 Winchester Magnum and the .338 Lapua Magnum. (The .50 BMG is of course a contender at these ranges but is an automatic $5k+ investment and thus is disqualified by the expense.) Both the .300 Win Mag and the .338 Lapua are supersonic at 1760 with heavy bullet loads, but one cartridge does have an advantage. The .300 Win Mag pushing a 200 grain SMK to 2900 fps starts a .596 BC bullet at a higher velocity than the Lapua. The favored Lapua load is the 300 grain SMK at .768 BC and 2600 fps (both rifles with 26″ barrels). The superior BC of the heavy .338 bullet is the clear winner at one mile. It drops 3 MOA less, drifts 4 MOA less in a full value 10 mph wind, and stays decisively supersonic while the .30 caliber round is threatening to drop into the danger zone. Dies and reloading components for the .338 Lapua will be slightly more expensive but it is clearly a one mile cartridge while the .300 Win Mag looks better suited to 1500 yard ranges. I’m a far cry from being an expert wind reader, so I will take all the “bullet fu” I can get before I ever pull the trigger. In the next installment of Project 1760, I’ll cover rifle selection. You might be surprised to find you can get into extreme long range shooting a lot cheaper than you might think. [caption id="attachment_981" align="aligncenter" width="640"]Firearms, Tactical & Defense Training Firearms, Tactical & Defense Training[/caption]

MY AR10 SDM Build

A couple of months ago I mentioned on Special Forces Preppers that I was building an AR10 platform rifle to upgrade to the .308 cartridge. That project is now finished, although I am still working up loads for it. A couple of months ago I mentioned on Special Forces Preppers that I was building an AR10 platform rifle to upgrade to the .308 cartridge.  That project is now finished, although I am still working up loads for it. I feel it may be helpful to head off the "....but what about....?" replies by running through a short discussion of my criteria for building this particular rifle.  The most important criterion was for a rifle that could function as the primary armament for a squad designated marksman, while retaining some tactical utility.  As such, it needed to stay short and light enough to at least be usable in tactical situations, while still having sufficient power at extended range to be effective at +500 yards versus the standard carbine armament, or around 800 yards overall.  I felt that a mid-length AR10 in .308 Win was the best platform to build such a "compromise" on. And.... the finished product. 2315837

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So let's get right to it, from back to front: Stock:  Magpul PRS.  Stock options on the .308 platform are not wide, and although it's a little heavy, it's not heavy enough to unbalance the rifle.  The ability to maintain a solid, consistent cheek weld with optics that are fairly high above the bore (compared to bolt guns) put this stock over the top for me. Buffer Spring:  I have to mention this separately because no, I don't just use a stock spring, and yes, there is a very good reason why.  David Tubb's CS springs are awesome for many applications but possibly nowhere are they more useful than on an AR platform.  For every reason you would use one on an AR15, it's doubly important on an AR10 just because the volume of gas is so much greater.  If you didn't know:  yes, the buffer spring is an important part of your semiauto gas system. Lower:  DPMS Gen1.  Because it's what I had.  Got a really good deal on a complete rifle, and parted out the upper and other parts I didn't need for basically what I paid for the whole thing.  There are slightly nicer lowers available with larger trigger guards for gloves, but I didn't think it was worth the trouble. Grip:  Ergo Grip.  This is probably a matter of taste, and this is what my taste is. Trigger:  Geissele B-G2 S-E.  I prefer a two-stage trigger for precision shooting. This is Geissele's Enhanced two-stage trigger, which means it has a first stage of 2.3 lbs and a second stage of 1.2 lbs, instead of a total weight of 4.5 lbs like you will find on a LOT of AR platform triggers.  It was expensive, and worth every penny IMO. Upper:  Aero Precision M4.  Yes it's an M4 style upper not an A3, meaning it has the M4 feedramp cuts.  You can't get this in a Gen1 DPMS brand upper. Charging Handle:  An AR platform with a scope on it needs a good charging handle, and the standard ones have problems with the latch that just begs for an upgrade.  I chose the Bravo Company BCM Gunfighter Medium handle.  You can spend a bunch of money on a charging handle.  I compromised in a lot of ways here, this one has an improved, extended latch and was reasonably priced. Bolt Carrier Group:  Alex Pro Armory.  One of the few sources for nickel boron coated bolt carrier parts for AR10 that I could find, and they also use 9310 steel for the bolt (win!).  It's cheaper to order directly from them than it is to buy from Brownell's or Midway. Barrel extension:  I don't know what brand it is, as it was provided by the gunsmith that did the barrel.  All I know is it has M4 feedramp cuts, which is important if you are using an M4 upper. Barrel:  Shilen stainless 18", custom configured by Craddock Precision.  The barrel is ported for a mid length gas system, tapered to .835" from chamber to gas block, then stepped down to .750" at the gas block and same diameter to the muzzle threads, fully fluted fore and aft of the gas block.  I wanted the stiffest, lightest barrel I could get away with without fouling up the balance of the rifle.  Paul Craddock suggested adding the extra meat between the chamber and the gas block and I'm glad we did. Handguard:  Troy Alpha.  I can't say enough good things about this handguard.  It's super light, which lets me put more weight on the barrel where it actually does something.  The accessory rails are easy to install and configure, and I absolutely love the rubber insert "squid grips" that give a slightly larger, slightly tacky surface to index your support hand on for normal positions.  The downside is that you are going to have to pick your gas block very, very carefully to make sure it fits under the darn thing. Gas Block:  JP Enterprises JPGS-5G.  It's low profile, blackened stainless, and adjustable.  That last part is important because I expect this rifle to function flawlessly with both 175gr and 150gr loads, out of an 18" barrel with mid length gas system.  Some ability for adjustment is very handy.  There really wasn't a second choice here. Compensator:  BattleComp BABC.  Not only a compensator with value for reducing muzzle climb, but also a flash hider that doesn't direct any gas downwards, reducing dust signature when firing prone. Cerakote:  Brothers in Arms, Tulsa OK.  A veteran owned business.  Highly recommended. Sights: Flip up iron sights:  MagPul MBUS Scope:  Vortex Viper PST 6.5-24x50 in LaRue SPR1.5 mount.  This optic is being used for load development.  It will actually wear a Burris XTR II 3-15x50 34mm tube optic when they can be bothered to start shipping them. Tactical Sight:  Aimpoint PRO in LaRue quick detach mount. I must mention I went with a swappable optic setup instead of a microsight on a 45 degree canted mount because I want to be able to integrate an NVG monocle with the red dot at a later date. I hope this was informative.

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Barrel Cleaning Part 1

I don't often make absolute statements, especially about firearms. There's always somebody out there who did it different and has good results, so even if you know why, it's best to just nod your head and "go along to get along".I don't often make absolute statements, especially about firearms. There's always somebody out there who did it different and has good results, so even if you know why, it's best to just nod your head and "go along to get along". On the other hand, there are some things that just have to be said, and you aren't going to hear them from the normal shooting press, whom I perceive to be generally scared to death of offending anyone who is an advertiser, or might someday be an advertiser. I have quite a bit more freedom than that.

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Damn the torpedoes, full speed ahead: If you don't know what you are doing, the worst thing you can do to a rifle is shove a cleaning rod down the barrel. That's right. I'm going to fill you in on something that competitive shooters have known for 20 or more years, but hasn't really seemed to percolate out to the general shooting public. You've probably heard that competitive shooters are fanatics about keeping their rifles, and especially the bores, shiny clean. You may have even heard some apocryphal stories about gunsmiths who received rifles that "just wouldn't shoot good anymore" and all they needed was a good cleaning. All of this is at least partially true. But without the right equipment, pushing a discount store cleaning rod down the barrel of your rifle can permanently damage the rifling, especially in the critical throat area where the rifling begins ahead of the chamber and at the muzzle. You can also end up with cleaning solvents leaking out of and under the action, softening the critical bedding areas. All of these things, and more, can ruin the fine accuracy of a perfectly good rifle, just from doing something that you THINK is helpful.

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Damage to the bore is generally caused by the cleaning rod contacting the barrel steel, and the use of some types of bore cleaners can make the damage occur faster. Sectioned rods are out. They just have too much flex in them. Pushing them down the bore with a jag and patch that actually fit will result in the rod contacting the bore. In addition, the sections never fit together absolutely perfectly, resulting in ridges that can pick up carbon grit and/or physically damage the barrel itself. Never ever use a stainless steel cleaning rod.... for that matter, never put anything that's stainless steel in the bore of your rifle. You don't need anything that's anywhere close to the hardness of the barrel steel itself in there. Likewise, don't use uncoated brass or aluminum rods. They can pick up carbon grit or abrasive bore cleaners that can do a very fine job of unintentional lapping. Just ask a machinist what you can do with an aluminum rod charged with grit. [caption id="attachment_664" align="aligncenter" width="500"]Pic from Gunn Innovations www.spinjag.com Pic from Gunn Innovations www.spinjag.com[/caption] This is an extreme example, but that's often the best way to illustrate a point. The point is: either do it the simple way, or go whole hog, but don't inbetween it. (I'm not one of those people who advocate never cleaning a rifle. Torture tests are interesting but I was taught to acquire fine tools and then take care of them.) [caption id="attachment_665" align="aligncenter" width="660"]CLP and a bore snake is the fast and easy way to bore clean without damage. CLP and a bore snake is the fast and easy way to bore clean without damage.[/caption] The simple way is with a basic bore solvent and a bore snake. Squirt a little solvent down the bore, being careful to get it into the chamber and not into the action, and then drop the bore snake weight down the barrel while keeping the bore pointed down. Step on the string end of the bore snake with your foot and pull on the rifle to get the bore snake started in the bore. This procedure keeps the solvent from running back into the action. Once you have the bore sealed, you can invert the rifle and pull the bore snake all of the way out. If you suspect the bore is especially dirty, you can repeat this procedure several times. Before you finish, pull the bore snake through the bore several times without adding solvent, and you are done with bore cleaning. [caption id="attachment_666" align="alignleft" width="300"]A correct cleaning rod is one piece, coated, has a ball bearing spin handle, and is specific to the caliber of the bore you are cleaning A correct cleaning rod is one piece, coated, has a ball bearing spin handle, and is specific to the caliber of the bore you are cleaning[/caption] This is the correct kind of cleaning rod. It's one piece brass covered in a protective nylon coating, it's caliber specific to prevent flexing, and it has a ball bearing on the handle so brushing and patching tools rotate with the rifling. The one pictured is a Dewey. Boretech also makes some fine cleaning rods. There are probably others but these are the two that I have used, and the ones I see other competitive shooters using. Even with the proper coated cleaning rod, you don't just shove it down the bore. You need what's called a rod guide to hold the rod centered in the bore. For any rifle that can be cleaned from the chamber end (bolt guns and ARs) they can also seal the chamber so solvent doesn't leak back into the receiver. Rod guides are available from a few places but I highly recommend the ones from Sinclair International, purveyors of many fine tools and supplies for cleaning and reloading. [caption id="attachment_667" align="aligncenter" width="400"]Sinclair bore guides are made of machined delrin plastic with an O-ring seal. Sinclair bore guides are made of machined delrin plastic with an O-ring seal.[/caption] The bore guide is inserted into the receiver where it guides the rod, seals the chamber, and provides a port to apply solvents, so you can keep cleaners in the barrel and not on your rifle. For an AR platform they also sell some handy little links that hold the receivers apart just right for cleaning. This is how it looks on an AR: [caption id="attachment_668" align="aligncenter" width="225"]Sinclair makes the bore guide and the link used to hold the receivers apart. Sinclair makes the bore guide and the link used to hold the receivers apart.[/caption] This is doing it right. The rifle is held so it's slightly muzzle down, allowing excess cleaner to run out the end of the barrel instead of into the action. A bore guide is in the receiver to seal the chamber and guide the cleaning rod. [caption id="attachment_669" align="aligncenter" width="660"]Doing it right. Doing it right.[/caption] In part two, I'll cover the proper process for using a cleaning rod in more detail, including more specifics about brushes, jags, patches, and cleaning compounds.
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