PRECISION SHOOTING - June 1999

June 1999

Shooting; The Plumbers Nightmare

by Ian Cheeseman

"Well fitted in arts, glorious in arms." William Shakespeare —Love’s Labour’s Lost

The phrase, "form follows function" is well known to engineers and designers around the world. It has led to some of the most aesthetically pleasing objects and devices ever seen.

Ferrari sports cars, particularly those of the late 1950s and early 1960s, Holland and Holland shotguns and double rifles, the SR-71 Blackbird reconnaissance plane... all are striking examples of how good looking a functional object can be.

There are also many examples of function resulting in a form that is undistinguished or even downright ugly. The A10 Warthog ground attack plane, which may be the most effective of its type ever built; the original VW Beetle, possibly the homeliest car ever to hit the road; and the British Stirling sub-machine gun, which was as reliable as it was ugly... all developed fiercely loyal bands of users, none of whom would truthfully say that the objects of their loyalty belonged in an art gallery.

Although it can be made to fit better than a Brooks Brothers suit, my Armalite AR10-based match rifle definitely falls into the category of ugly but capable. If you lay it down beside a traditional, bolt-action, across-the-course gun it looks like a plumber’s nightmare. (See photo #1) However, handsome is as handsome does, as my dad used to say, and this rifle performs handsomely in competition. My mum used to describe potential girlfriends who were somewhat homely as having a nice personality or a good sense of humor, in which case the AR10 is a cross between Miss Manners and Bob Hope.

I first considered a gas-operated, across-the-course gun in 1997, after an abysmal performance in the National Championships at Camp Perry. Because of severe back pain I could not assume any good positions, particularly in the sitting and prone rapid fire events. Matters were at their worst when I was trying to manipulate the bolt on my Winchester-based match rifle. I watched many competitors shooting AR15-based match rifles in .223 Remington that year and they were having a great time, until they got back to 600 yards where they often got beaten-up by the wind, a problem which did not effect my 6.5mm caliber, 142 grain Sierra Match Kings (SMK) nearly as much.

As John Feamster (Black Magic, The Ultra Accurate AR-15, published by PS) and Glen Zediker (The Competitive AR15, advertised in PS) both explain in their excellent books, the AR10 and its cousin the Knight SR25, have never been subjected to combat as a battle rifle, so the bugs inherent in any new design were not fully worked out over years of use, as is the case with the AR15/M16. As a result, you really do need to go to a knowledgeable gunsmith if you want to make a success of this type of project. You also need to be prepared to be your own modification specialist and to be flexible in finding solutions. There aren’t any long-proven loads or perceived wisdom for the AR10/SR25. This is mainly experimental stuff.

Scott Medesha (PS/TS Advertiser) was one of a handful of gunsmiths who was building AR10 match rifles two years ago, and certainly one of the most successful. I had watched Scott at work

in the shop he sets up during the NRA Nationals at Camp Perry and it was obvious that he did good work. I also spoke to as many people as possible who had guns built by him. They unanimously said that he did great work and stood behind it. However, several of them also said that it took many months to get a job completed, a common problem with the best gunsmiths. I must say that was not my experience, but enough people told me they did have long waits that I think it is worth mentioning, if you are going to order from Scott. Whatever the length of time, I think the finished product is worth waiting for.

Scott has built at least 15 of these esoteric rifles and worked on twice that number. He built the first in 1996, when the AR10 became available from Armalite. Because I like to complicate matters even more than most people, I asked Scott to build my gun in my favorite wildcat caliber, the 6.5x51 LPR, a cartridge developed by Palma team member Larry Racine. This is based on the 6.5x55 Swedish Mauser but, by leaving the reamer 4mm short and forming cases from .308 Winchester brass, you get a cartridge that will feed through a short action or from standard M14-size magazines, or those of similar type used in the AR10.

The advantages of this case over the 6.5-08 (now a factory chambering — the 260 Remington) are: a sharper shoulder, 25o versus 18o; a little more body taper, which aids extraction; and a slightly smaller case capacity that improves load density. I have used this caliber in my course guns since 1995 with a great deal of success. The downside of semi-autos and wildcat cartridges is that the cases are sometimes thrown into the long weeds, which means I spend a lot of time on my knees searching for my brass.

Most of the other AR10 rifles Scott has built, or worked on, have been in 6.5-08 with the balance in .308 Winchester. I had Larry Racine chamber the barrel for this gun and then send it to Scott to finish to a length of 26 inches and then install. I have always had good luck with Krieger barrels and this is what was used this time. Scott has some good insight into barrels and, as he is not only a great riflesmith but also a fierce competitor, I asked him for his thoughts.

"I’ve had good, consistent results with Kriegers, Schneiders, Harts, Obermeyers, etc.," he commented. "I feel that there are lots of good barrel makers out there, and you shouldnt go wrong with any of them. I also feel you can make just as accurate a barrel by buttoning or by cutting the rifling, but cut barrels last longer. I lean towards more shots for my buck, so I mostly use Kriegers." Its nice to have your own opinion confirmed by an expert.

David Tubb, a PS columnist, won the 1997 High Power National Championship with a match rifle based on the Knight SR25, a similar, some say more refined, version of the Armalite AR10 design. Both rifles are beefier versions of the AR15/M16 that has been the United States’ issue service rifle for more than 30 years. The AR10 is considerably cheaper out of the box than the SR25 and because you throw away most everything except the upper and lower receivers and bolt assembly, I see no real advantage in basing a match rifle on the SR25 chassis, but this is a personal opinion.

As I am convinced that present and former national champions such as David Tubb, Mitch Maxberry, Mid Tompkins and Nancy Gallagher could all easily win any match they entered using a slingshot and some smooth pebbles, I take note of their equipment choices but do not think there is any advantage in slavishly following them. Having said that, it would be foolish not to pay some attention to people who regularly beat the hide off of all comers.

David Tubb equates his SR25 to a Free Rifle of the type seen in Olympic smallbore and ISU 300 meter competition. As set up by Scott Medesha, these rifles are truly adaptable to any body shape or shooting style. Starting at the front and working backwards: the front sight base is adjustable for cant and height, the forearm/handguard tube rotates and has a fully adjustable

handstop, and the bolt release is set up for right hand use (see photo #2). The rear sight base is adjustable for cant and eye relief, and the receiver is milled out for a bolt handle attached to the bolt carrier (see photo #3). This allows Scott to fit the adjustable cheek piece that moves both vertically and horizontally, and the butt which is adjustable for length, height and cant (see photo #4). Even Quasimodo could get a comfortable fit with this rifle.

This winter, 1998/99, has seen my first real attempts at load development for the AR10 because, when the gun arrived in April 1998, I loaded 50 rounds with 107 grain, moly-coated SMKs over 37.0 grains of Vihta Vuori N150 in a new, reformed, LC91 Match case with a Winchester LR primer. This is backed off from a load I have used in my bolt guns with some success. (WARNING: This load is safe in my rifle, using my loading methods and was originally worked up for the 6.5x51 LPR wildcat cartridge with great care. You would be a damned fool if you did not take similar care and precautions. ALSO: Remember that this is NOT a 6.5-08 or .260 Remington and the load data is NOT interchangeable.) The results from this load were good, with groups off the bench right around .75 of an inch at 100 yards; and under two inches, slow fire from position at 200 yards. With a lot of pressure at work and not much time, I decided just to go with that load for short range for the rest of the 1998 season.

Similarly, I shot the 600 yard load I use in my bolt gun. This is a stiff load of Vihta Vuori N160, in a Lapua case with an RWS primer. This too worked straight away so I did not immediately try to reinvent the wheel. (Read the warning in the previous paragraph again.)

One problem immediately appeared. The bolt would not consistently lock back with the N150 load. This was easily surmountable by pulling on the cocking handle, but I discussed it with Scott at Camp Perry in August and he suggested using a slower powder. I have been working with Vihta Vuori N160, which has a better pressure curve. It solved the problem and so far is giving good groups, particularly as noted, at 600 yards.

I asked Scott about his loads as he has much more experience than I do with the AR10 in competition. "The .308 is the same as any .308 rifle, 4895 is always a good choice and 4064, Varget, or any good powder in that range should work well," he explained. "In the 6.5-08, I’ve had very good luck using Reloader 22 with heavy bullets (43.5 gr. in a Rem BR case, #71/2 primer, and a Cauteroucio 141 gr. VLD won the 1996 Air Force Cup for me at Camp Perry)." (WARNING: This load is safe in Scott Medesha’s rifle, using his loading methods and was originally worked with great care. You would be a damned fool if you did not take similar care and precautions.)

"Presently I’m shooting Varget under the new Sierra 107 gr. MatchKing at all ranges to 600 yards, with great results," he continued. "I’ve been shooting a 6.5-08 for at least 10 years in various types of rifles. The same loads shoot equally well in all of them. AR’s don’t seem to be any fussier than bolt rifles, as far as I can tell." Scott’s success with the 107 grain bullet at 600 yards is somewhat frowned on by Kevin Thomas, the Chief Ballistician at Sierra bullets who says that that is not what it is designed for, according to Scott. However, as Scott won a regional championship in his home state this year using the 107 at 200, 300 and 600 yards, he is going to stick with it.

Learning to actually shoot the monster mouse gun was interesting, to say the least. Positions are different from my bolt guns and the effects of recoil and the large bolt and carrier returning to battery are completely different from a bolt gun and somewhat different from an AR15-based match rifle. The main difference with the AR10 is that you have to hang on real hard, much like an M14. Finding good positions was also a challenge, not least because of an act of stupidity on my part involving snow and my two sons. As a result of trying snow boarding for the first time at the advanced age of 49, I managed to accumulate several pulled groin muscles that took nine months to heal.

This meant I had to use the open leg sitting position that is one of former national champion Mitch Maxberry’s trademarks. I have pulled his target at the nationals on a couple of occasions when he has nailed a 100-9X or similar sitting string and this position is astoundingly successful for him, but not so good for the rest of us mortals. Still, I wasn’t dropping too many points in sitting, and the improvement in the prone rapids was astounding. The key to success in both rapid positions is to hold hard to the gun both when firing and in recoil as the gun cycles, otherwise you find the barrel pitching forward as the bolt and carrier strips off the next round in the magazine and feeds it. If you don’t have a tight grip on things, you are constantly having to re-acquire the sight picture from a long way out of line. This phenomenon also makes a good natural point of aim (NPoA) essential as the torque of the big gun can move your position around if it is not solid. AR15 shooters do not have such great problems because recoil is lower and the weights and forces involved are much lower.

The first couple of matches that I shot with the big black gun offered many opportunities to excel, none of which I took. In fact, I once again proved that, despite the best equipment in the e and five, which may not be technically the best way to do it, but I dont have to count so high.

Once I had overcome my own incompetence and learned to hang on tight, the AR10 became fun to shoot. It really shines in the prone events where I have cleaned a couple of prone rapid events and averaged 197 in the three prone rapid matches at the 1998 Nationals. I took it to the long range regional at Quantico and shot a 189-9 at 1,000 yards with a cross-fire. Sitting is more difficult, as getting a good solid position and NPoA is essential. I shot an average of 192 with the big black gun in 1998, compared with a 195 average with my bolt gun in 1996.

Sitting scores at the nationals were atypical. On day one I missed my stool, which I use to lower my less than sylph-like frame to the mat, with the result that I was lying on my back looking at the sky and being careful not to touch the trigger. By the time I got upright and started shooting I had 22 seconds for ten rounds and a magazine change. I got them all off but my score was only 183. Offhand is offhand, but it is complicated by the trigger mechanism which strongly resembles a flintlock in design and lock speed. My average dropped from 189 with my bolt gun to 184 with the AR10, but with more practice and using the approach method advocated by David Tubb I think it will improve.

One item of equipment that is a challenge for owners of both the SR25 and AR10 is the magazine design. Each has its own distinctive type, with the SR25’s costing as much as $100 each, according to Scott. AR10 magazines are much cheaper but come standard in the 10 round variety that only just stick out beyond the magazine well. Armalite will modify your GI M14 magazines in about three weeks at a cost of $25 per magazine. It is worth getting three done for the rapid fire stages where being able to grab hold of the whole magazine is sometimes a life saver. (see photo #5)

All around I have found the AR10 an interesting experience. It has been extremely reliable with no breakdowns, and my experience is confirmed by Scott Medesha, "There aren’t any

components on the AR10 that are prone to failure. So far things are holding-up very well." The SR25 and AR10 both had some initial problems with firing pin holes being too large and the SR25 early bolt latches were too soft, but these problems have been resolved. Scott does recommend a small kit of parts, just in case. "As with most guns, a spare extractor with spring, a firing pin and ejector would be handy (although I haven’t had any of these fail for me)."

As enjoyable as the AR10 is, it is not cheap to buy or run. Scott charges around $1,400 to build a full race gun on an Armalite rifle supplied by you. Unfortunately, Armalite will only sell complete rifles at this time so the cost, compared with a similarly tricked out AR15, can be quite steep. Another consideration is that ammunition costs at least twice as much to make as .223 fodder.

I have both the AR10 and a Compass Lake AR15 built by Frank White, that I shoot regularly. The AR15 is almost unbeatable in reduced course matches, which we have to shoot in Connecticut, but for sheer shooting competence out to the longest ranges, even if it is ugly, I will go for the AR10.

Scott Medesha

Medesha Firearms

PO Box 367

Apache Junction, AZ 85217

(602) 986-5876

Black Magic, The Ultra Accurate AR-15

Available from Precision Shooting

(860) 645-8776

The Competitive AR15

Zediker Publishing

1-800-BOOK LOG

Compass Lake Engineering

719 White Drive

Alford, FL 32420

ArmaLite, Incorporated

P.O. Box 299

Geneseo, IL 61254

1-800-336-0184