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.260 Match Ammo Comparison
Table of Contents Introduction and Test Procedures Just a few months ago we conducted a comparison article with many of the available 308 Match loads that are out there (Article can be found here). It was a fun and interesting article to write and showed some interesting things and we plan to continue to update the test with the addition of other match loadings. Now, enter the .260 remington, a cartridge that is growing in popularity in long range tactical shooting, and with good reason. The cartridge has excellent long range ballistics due to the high high ballistic coefficient (BC) .264 caliber bullets that are available. The 260 is simply a .308 necked down to .264 (6.5mm). It was a wildcat cartridge for many years and was known as the 6.5-08 until Remington standardized it as the 260 Remington. There was a bit of a controversy when they first standardized the cartridge because A-Square had submitted all the required material to SAAMI several months before Remington submitted their "intention" to standardize a 6.5mm 308 loading. But for some reason SAAMI decided to go with Remington and the 260 Remington cartridge instead of the 6.5-08 A-Square. Controversy aside, the 260 is a gem of a cartridge allowing excellent ballistics in a short action and it has displayed excellent accuracy as well. But the problem has always been factory support for the cartridge as there are very few rifles chambered for the cartridge and very few factory loadings, of which only a few make any effort at taking advantage of the long range capability of the cartridge. In fact, it seems to have fallen out of favor at Remington, as they decided to create a match loading for the short range 6.8 SPC cartridge instead a good match loading for the .260 and they even chambered the 700P in 6.8 SPC which makes me scratch his head even further?! But, the .260 has taken off in shooting competitions and has gained great popularity there which has kept the cartridge alive and now has started to raise the awareness of the capability of this little cartridge. In fact, it raised it enough that there are now match loadings available from some of the mid size ammo makers. And that is where this review comes in. HSM and Black Hills each came out with their own version of a 260 match load, 123gr for HSM and 139gr for Black Hills. And just very recently, Cor-Bon came out with their own loadings, one of each the 123gr and 139gr. We assembled all 4 of these loadings and decided to put them through the same battery of tests that we do with the 308 loads. In case you missed it, the test procedure is as follows:
The Test Rifles Now, as with the 308 comparison, we needed two rifles and unfortunately at first we used a borrowed Terry Cross KMW for the 2nd rifle as we have our own custom built SC2 260. We have since acquired a Tactical Rifle M40T2 in .260 and that has become our standard 2nd rifle. The first rifle is our own .260 tactical rifle (SC2) we built a few years back for another project/idea which will be written up soon in the members area. It is built on a Remington 700 action that had just a few minor things done to the action including squaring the action face and lapping the lugs, but that is about it. I may even have a factory recoil lug on it but I honestly do not remember if I replaced it with a better one of the same thickness or not. It has a Montana Rifleman 22" barrel With 1:8" twist. The barrel has a JP Recoil Eliminator brake installed, which was done for the other writeup I'm doing, though a brake is typically not needed because the recoil of the 260 is mild. (Very mild with the brake!) It is all sitting in a HS Precision thumbhole stock with Aluminum bedding block. It is NOT glass bedded and is only using the standard bedding block. The floorplate is a HS Precision 10 round detachable box magazine. The rifle is quite light and very handy with the shorter Remington Varmint contour 22" barrel. But the single most amazing thing is that somehow this rifle turned into a .25 MOA rifle! It has always amazed me and I attribute it to a good barrel and a little bit of luck because like I said, there really was not much work done to the rifle. Normally it has a Burris XTR 3-12x mounted on top, but I wanted 16x for these tests, so I put a Leupold Mk4 16x up on top for the ammo tests. 
My custom Remington 700 Test rifle (SC2) with leupold mk4 16x The second test rifle is the very nice KMW Long Range Solutions Custom .260 we had here for review. You can read about this rifle in detail in the review as it is a very nice rifle. The barrel is a full 4" longer than the other test rifle at 26". It is built on the excellent Surgeon Tactical action and is bedded in a McMillan A5 stock. It has the Badger Ordnance detachable magazine floorplate that uses the AI magazines. This rifle shot very well in the evaluation, often shooting well below .5 MOA. The scope is a US Optics SN3 T-Pal with 3.2-17x magnification. For the tests, the magnification was set at 16x. The SN3 is a very good tactical scope, but the crosshairs are a bit thick for real precision work which may have hurt some of the groups a little. Overall this rifle and scope make an EXCELLENT 260 long range tactical package. 
KMW Custom 260 at the range Since the KMW was on loan for T&E and we continued to need to review additional ammo as it came out, we needed to adopt a second rifle for additional ammo tests. We now have a Tactical Rifles M40T2 that is custom built using their own action mounted in a manners stock. This is a very sweet shooting rifle that performed well in the full writeup. It is mounted with a Weaver Tactical 3-15x50mm scope and for the tests and evaluations we have the scope set to 15x. A shade under the desired 16x but we do not feel this has hampered performance at all. 
Tactical Rifles M40T2 These rifles should serve as a good sample of what might be expected with this ammo performing in various custom tactical rifles. Since there are really no "Factory" tactical rifles chambered in .260 all three rifles ended up being custom built, but should still provide a good overall impression of various tactical .260 rifles and ammo. Test Results 
l-r: HSM 123gr, Cor-Bon 123gr, Cor-Bon 139gr, Black Hills 139gr 
Monolithic Munitions 130gr Match This initial test included 4 manufacturers of match grade 260 ammunition including HSM, Blackhills, and two loads from Cor-Bon. We have since tested another load from Monolithic Munitions and it is included here as well. The summary of the results are included in the tables below, but be sure to visit each manufacturers result page to find out more specific details on how the ammo performed as well as photos of the ammo, best groups fired, price, and other bits of info.
Conclusion and Thoughts After all of the shooting was completed, there were a few interesting points that came up. First, all of these loads are great long range loads, far outpacing the 308, which is the parent cartridge for the .260. Just as an example, in the chart below I took the 260 loads that drop the most as well as the one the drops the least and put them side by side with the 168 and 175 Federal Gold Medal Match 308 loads as a comparison of the drop at various points out to 1000 meters. It is quite evident of the performance gain the .260 has over the 308 even in the least performing rifle and ammo combination in the test. I also included the federal GMM 300 Win Mag load as well to show that both of the Cor-Bon loads as well as the Black Hills load out of the KMW rifle has slightly better ballistics than the mighty 300 Win Mag, though with far less energy on target and more wind drift.
With the exception of the Black Hills load in the SC2 rifle, they are all very accurate loads. In regards to that Black Hills load, at first I thought the SC2 was just not stabilizing the heavy 139gr bullet, as I have always had very good luck with the excellent Black Hills ammunition. But then when the Cor-Bon 139gr load shot so well out of the SC2 it ruled out stabilization as the issue. I really just think that the SC2 simply does not like something about that ammo. I have a few more boxes of it here and I will shoot some more to see if any other clues show up as to why it doesn't like that ammo. At one point a while back when I was researching various loads for the project that the SC2 rifle was built for, I was researching ballistics fairly extensively and noticed that the 123gr Lapua Scenar has nearly the same ballistic coeffecient (.547) as the 190gr 308 Sierra Matchking Bullet (.533) that is used in the Federal 300 Win Mag Gold Medal Match Load, also known as the A191 and is an excellent long range load. With a slightly higher BC it means if you could push that 123gr Scenar at 2900 fps the ballistics would be very similar to the A191. While the 260 would not have the same energy at that range, it WOULD have exceptional long range ballistics out of a short action with very mild recoil, and that to me would be an excellent sniping cartridge with a light rifle and a reduced report of the rifle, especially if you had a suppressor attached. To top it off, the ballistic arc is so similar between the 123gr Scenar and the 190gr SMK, that you could use the same BDC for the two loads if launched at 2900 fps. It so happens that Leupold has this BDC for their M3 knobs as well as others such as Nightforce. In fact, I included the 123gr Cor-Bon load in the table above so you could see the similarity in ballistic path between it and the Federal 300 Win Mag load. At 1000m it is getting a bit separated but still only by about 10". Similarly, the very high BC of the 139gr bullet (.615) would give similar drop at 1000 yards if it is launched at 2800 fps, though the arc does not match as nicely and the use of the 300 WM BDC would not be recommended. Of the five loads tested so far, none of them met this velocity out of the SC2 with its short 22" barrel and muzzlebrake. But three of the five accomplished this out of the KMW rifle with its 26" barrel. The HSM 123gr load (2847fps) was the only one that did not reach the 2900 (or 2800 fps for 139gr loads) velocity needed from that 26" barrel. It is interesting to note how much of a difference the barrel length makes in relation to the velocity at the muzzle. With the 308, a 26" barrel vs. a 22" barrel gives you little gain, look at the average velocities in the 308 ammo comparison, the shorter barrel actually had a higher average velocity than the 26" barrel which I commented about in that article. The average gain for these 260 loads (139 and 123gr loadings) was 103.5 fps, over 25 fps per inch of barrel. For the 260, it is probably worth it to go with the longer barrel where as with the 308 it is not worth it if only looking at velocity. The follow up test with the Monolithic ammunition did not produce as much of a difference in velocity as the other loads, but the TR M40T2 rifle only has a 2" longer barrel than the SC2. You may have noticed that all four of the original loads tested use the Lapua Scenar bullets of 123gr and 139gr variety. The reason is because these Lapua bullets are excellent match bullets, and more importantly they have very high Ballistic Coefficients. There are other bullet makers that have as high or higher BC's, but they are more expensive and not as easy to procure, and again, these Lapua bullets are excellent quality. We recently tested the Monolithic ammo that uses the excellent Norma 130gr Diamond Line bullet with a similarly high BC (.548) as the 123gr Lapua, but with 7 extra grains of weight which helps in the wind. I would additionally like to see a high velocity 108gr load at some point as well. If the 108gr Lapua Scenar can be pushed to about 3000-3100 fps it too makes a very fast and excellent long range load with even less drop. The 108gr has a BC of .478 which is higher than the 168gr 308 Sierra Match King (.462). But I am satisfied with the choice of the 123gr through 139gr bullets as they are probably the better choice for now until popularity increases. Sierra has gotten into the higher BC mid weight bullets as well with the introduction of their 6.5mm 123gr Matchking Bullet with a BC of .510. Of course, their 142gr Matchking is another excellent bullet with a BC of .595. So which is the best load to go with? Honestly, with these loads, it is a matter of finding which one your rifle likes best. The SC2 rifle loves the HSM in terms of accuracy and shot the best group of the tests so far, but the SC2 still shot sub .25 MOA groups with both of the Cor-bon loads as well, though for some odd reason it would not shoot the Black Hills ammo at all, but yet the KMW rifle shot it with no problem. That was the only anomaly in the test, and everything else shot very well. All five loads are excellent match grade loads. The HSM was the slowest load, much like it was in the 308 comparison, but it showed excellent accuracy. The Black-Hills load showed great promise for long range potential with good velocities with the 139gr bullet and the two Cor-Bon loads showed both excellent accuracy and very good velocities. The new Monolithic ammo with the Norma bullet had the highest velocity from the SC2 rifle which we attribute to the powder they used as it seems to get the most velocity from the shorter barrels. The accuracy was very good and this makes another exellent choice for the 260. It is just wonderful to have 5 great options for the .260 and hopefully the popularity will continue to grow. We plan to test two new HSM loads using the Berger 130gr bullet and the Sierra Matchking 142gr soon, so stay tuned! 
Getting down to business. |
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