February 2006

AR-15 Barrel Swapping: $1300 Later, We’d Pass On All Three

After a great deal of time and effort, weíd likely not buy Olympic Armsí Ultra Match, Merchantís Service Rifle Match Barrel Model 2, or Evolutionís Match Barrel, all for different reasons.

Ray Ordorica didnít much like the results from any of the changed barrels. Here he tries the Oly Ultra Match. We thought the expense and trouble of fitting upgraded barrels to be largely not worth the slight benefit. Note the absence of a flash hider.

We tested the fine Olympic Arms K3B (AR-15) in the December 2005 issue, and liked it a whole lot. It was one of the better AR-15s we’ve seen. It had an excellent trigger and lots of good stuff like a flash hider, 30-round mag, and a collapsible stock. Though it probably had enough accuracy for almost anything, on the order of 3 inches at 100 yards, we wanted more. To that end we decided to test three “drop-in” barrels obtained from Brownells to see if we could get tighter groups for our money. When we told the fine folk at Brownells what we intended to do, they asked us if we had the required tools. We planned to use the services of a gunsmith on our staff who had zero experience with AR-15s, so we had no tools at all. Therefore we acquired not only three 16-inch barrels, but also all the tools needed to do a barrel swap on the K3B Oly.

The barrels were Olympic Arms’ own stainless-steel Ultra Match (Brownells No. 795-020-016), $318; Merchant’s Service Rifle Match Barrel Model 2 with 1:8 twist (565-015-802). $397; and Evolution’s Match Barrel (298-015-015), $415. We stuck with 16-inch tubes because we didn’t want to sacrifice handiness for accuracy if we could help it. When everything arrived, it seemed like a daunting array of tools. There was a high-impact polymer (Rynite) block (Peace River Upper Receiver Action Block, Brownells #702-003-015, $44) that fitted around the action to hold it in the vise, with an insert to keep the action from collapsing under stress. Next was a serrated barrel wrench (Smith Enterprises Armorer’s Wrench, Brownells’ #851-115-001, $37); a strap wrench for “free-floated” forends (Glenair AR Strap Wrench, 382-100-015, $24); and a set of snap-ring pliers (531-460-000, $12). There was also a tool that made removing the two-piece forend extremely easy (Darrel’s Custom E-Z OFF Hand Guard Tool, 100-000-438, $25). These tools came to about $142, and though you might not need them all, you’d surely need the block and wrench, which will set you back $81 plus shipping. Any tool expenditure probably won’t make a lot of sense for only one job, especially if your local gunsmith can do it for you. But the use of a gunsmith makes these less than drop-in barrels -- unless you define the job as dropping in to your gunsmith and dropping money into his pocket.

No instructions came with the barrels, so we were temporarily stymied. But a search of the Internet found a detailed and well-illustrated set of steps to follow, so we jumped in. We suggest you start by looking at http://www.ar15.com/, and follow your nose. Here’s what we discovered about each barrel.

Olympic Arms Ultra Match, $318
We thought it made the most sense to start with Oly’s own upgraded stainless barrel, which came with front sight attached, and a matte-blued finish. The first step in changing it was to unload the gun and remove the bolt. Then remove the two-piece hand guard, which the two-pronged “delta-ring” tool made easy. The lower receiver must be attached to use this tool, because one leg of it goes into the magazine port. Press down on the handles to remove tension from the sprung retainer (delta ring), and off come the forend panels. Next, drift out the roll pin, retaining the gas tube with a small pin punch, and pull the tube out of the gun. The trick is not to lose the small roll pin. With the tube out, pull the two main action cross pins to take the gun down to the barrel assembly, and fit it into the molded block. Be sure to insert the rear support, and close the port cover before you clamp it all up in a suitable vise. Fit the serrated wrench around the serrated barrel nut and, with everything solidly mounted, unscrew the nut. Loosen the block in the vise (it clamps hard enough to keep the barrel in place) and withdraw the barrel. Simple, eh? We thought so, though it would be nearly impossible without the special block and wrench. A minute with the snap-ring pliers got the delta ring swapped to the replacement barrel, which had its own nut.

The Olympic Arms K3B here has the upgraded Oly Arms Ultra Match barrel fitted. We found this barrel gave slightly better accuracy than the original unit, tested in December 2005. The cost of the needed tools combined with the steep price of the barrel made the job mighty questionable, we thought. We didnít need to touch the sight adjustment with the new barrel.

To fit the Oly barrel, we followed the on-line advice of first cleaning everything including the new barrel, and then greasing the threads prior to assembly. The trick, per the Internet, was to tighten and loosen the barrel nut three times. The final time we gave it a good lick and found that one of the notches was perfectly lined up for the gas tube. We assembled the rest of the rifle, and repaired

to the range

with some of the same ammo we had tried with the original K3B.

With Black Hills 62-grain ammo we got groups of 3.6 inches at 100 yards, compared to 3.7 inches in the original setup. With Wolf ball, we now got 2.4 inches at 100 versus 3.2 inches with the original barrel. With our heavy-bullet handload we got 2.6 inches now, versus 3.0 inches before. The overall net gain was very slight, but definite. We tested the new barrel in very poor weather, and were surprised at how well the K3B rewarded us. So it might be lots better than we could prove. The rifle required exactly no sight adjustments to get on paper, so we figure the Oly Arms folks clearly know what they’re doing.

Merchant’s Service Rifle Match Barrel Model 2, $397
Next up was the Merchant stainless barrel, which came in the white, with a front sight base that we’d have to attach. The barrel also included a barrel nut and a front ring to accept the hand guard, and some instructions concerning mounting the front sight. First we had to tap a hole under the front sight. We had an 8-32 tap on hand, and the aluminum cut easily. This hole accepted a set screw that held the front sight in place temporarily, permitting the final adjustment of the sight to zero the rifle with the rear sight centered. The final locking of the front sight base would be from using the appropriate Loc-Tite to secure it to the barrel. We didn’t do that for two reasons. First, for our limited testing the set screw held it all in place just fine; and second, we had big problems with this barrel.

The first problem was that the hand guard ring was not round, which our hand guards required, but triangular for the older-style hand guards. So we could not use our original hand guard. We don’t know why both a round and triangular ring could not be provided on a $400 barrel. They are inexpensive stampings. So we chose to use a “free-floated” forend (DPMS, 231-015-007, $50), which was provided by Brownells. One piece of the two-piece free-floated forend was a barrel nut, so off came the old one and on went the new. We used the Glenair strap wrench to get it tight, with a hole lined up for the gas tube. Then we remounted the front sight base, stole the front sight, locking plunger, and flash hider from the original Oly barrel, and went shooting.

This is the Oly with the problematic Merchantís Service Rifle Match stainless barrel. This shows the free-floated DPMS forend, necessary because the proper forend retention ring was not included. This setup tore case rims. We donít know why. The flash hider, forend, and front-sight post insert were not included.

Imagine our surprise when the second shot failed to fire. On inspection we found the first fired case had not made it out of the chamber. We had cleaned the chamber and barrel before testing. We poked the case out, and tried again. Another stuck case with the rim torn off was our result. We had been firing Black Hills’ 62-grain load, which had worked perfectly in many rifles. We tried the Wolf steel-case ammo and managed a five-shot group of 8.8 inches at 100 yards. Four of them went into 3.8 inches, which was not at all promising. A third try with the Black Hills fodder gave us another stuck case. We then cleaned the chamber yet again, thoroughly, and found the rifle still tried to tear the rims off the BH ammo. We concluded there was something wrong here that required serious gunsmithing, and abandoned further testing until we could look into it. If it was a case of too-short headspace, that takes this barrel out of the drop-in category.

Evolution Match Barrel, $415
This was the most expensive barrel of the test, and provided the least. It came with no front sight, nor was there any way to clamp one on. The gas block was pinned in place and would have had to be removed to let us install the DPMS free-floating nut and forend. No big problem there, but even if we had put that barrel onto the rifle there’s no way we could find to put an appropriate front sight onto it. The barrel diameter at the sight-mounting position, all the way to the integral muzzle brake, was 0.720-inch in diameter, which would have to be built up or shimmed to accept a 0.750-inch sight base. The 1:9-twist stainless barrel appeared to be well made, but we chose to not install it because we would not be able to shoot it without a sight.

Gun Tests Recommends
• Olympic Arms Ultra Match, $318. Conditional Buy. Is the accuracy benefit worth $318? We doubt it, even if you already had all the tools on hand. Also, you lose the flash hider with this upgrade, which we found intolerable for this rifle. We conclude this was an easy refit, as long as you have access to the barrel block and armorer’s wrench. We suspect very few will want this slight benefit for all the money involved. This is not a match rifle, after all. Some will want a no-compromise barrel on the fine K3B, and this is probably the best way to get it.

• Merchant’s Service Rifle Match Barrel Model 2, $397. Don’t Buy. We were not in the least happy with this setup, nor with the torn case rims, nor with the lack of a five-cent ring for the round hand guards, nor with the questionable securing of the front sight base. What would amount to basically a glued-in-place front sight has no place on a fighting rifle, which may be called upon to hit various things, and to take many harsh blows in the field. The front sight would need to be drilled and pinned before we would be happy with it. That could be done here, but that’s more tools, more fuss and bother, and more expense. We were at first excited about trying this 1:8-inch-twist barrel with heavy bullets, but that was not to be. There is no way we’d buy this barrel without taking it to a qualified gunsmith for installation. In fairness, this barrel was not touted as “drop-in” in the Brownells catalog, but our conclusion remains the same for the home workman.

• Evolution Match Barrel, $415. Don’t Buy. We concluded we had made a mistake in choosing this barrel for our iron-sighted rifle. A better choice might have been DPMS’s BL-11 barrel, $185 (Brownells’ #231-000-024), which is supposed to be a bona-fide drop-in rig. Workmanship on the Evolution was beautiful, though, so we hope to try this barrel in a flat-top receiver with scope sight. Stay tuned.