6XC Build, Modern Spartan Systems Product Test, Exact Shooting Die 1st Results

I got my Exact Shooting sizing die and Coach and I tried it out against his brass on his existing 6XC match rifle (below). It’s a thoroughly customized Savage 110 that looks as much like a hunting rifle as it could without being anything like a common hunting rifle. It’s been blueprinted and fitted to a custom stock set up for metallic silhouette competition. You may have trouble seeing it but there’s a very vertical pistol grip with a pronounced palm swell, a very high Monte Carlo cheek piece and a wide fore-end all tightly bedded to the 110 action. It sports a single shot sled and a very rare Canjar single-set trigger. Up top is a US Optics SN3 3.8-22×44 MOA ERGO parallax optic. This bad boy has over 1300 rounds through it and is still going strong but we have to assume it’s got only so much life left. In testing with the Exact Shooting sizing die we discovered that his brass was so highly variant between Lapua 6XC and fireformed RP .22-250 cases and number of firings that we weren’t getting the consistency needed to show any difference on paper or on the chronograph. The thing grouped one-hole to begin with and we were in single-digit SD’s anyway so no surprises there. That said, what we had noticed was its tendency to throw random flyers off quite a few minutes of angle during matches and we had no identifiable cause for it other than the brass or shooter error.

We set up his brass to run .003″ neck tension and .0025″ and .0035″ an found no useful differences on paper. That’s using a .2645, .265 and .2655 bushing with his old brass. When the new brass came in the necks were thicker and so we had to neck turn but that’s getting ahead of things. Thankfully the Exact Shooting die comes with several bushings in .0005″ increments so setting neck tension extremely precisely is as trivial as measuring and selecting a bushing.

In tracking his scores, we see that Coach went from 16-24% to 35% just by changing from his 6.5BR running a Vortex Viper PST scope to the 6XC with a US Optics SN3 scope. Prior to sizing his brass with the Exact Shooting die his scores were peaking at 35%. After we started using the Exact die his scores didn’t shoot up very dramatically if you’re paying attention to the raw score thought they did increase by several hits. But, when you break it into percentages and track that month to month you can see a real difference. The first match on the new dies he scored 46.6%, the second match was 55%. Next month we’ll get a third set of results. His average fluctuation in scores from match to match when there’s no equipment change is +/-6%.

So, when we get off of analyzing paper targets and into match conditions the difference is 11.6%-20% improvement in score from not using the Exact die to using it. That’s far enough outside his average fluctuation that we can regard this as statistically relevant and significant because the ONLY change that’s been made is what die we’re using to size his brass. It’s also showing sign of an upward trajectory that we may not have found the far side of yet. If he shoots 60-65% next month that will be a sure sign.

Coach setting up for stage 2. Scotty and Meccastreisand spotting and keeping score.

Now I’ve got 2 new barrels in from Columbia River Arms. 27 inch blanks in 6mm with 1:8 rifling twist on 3-land polygonal Caudle type rifling. We’ve got a custom chamber reamer being cut which will keep brass at minimum dimension. We’ve got new brass that’s been neck turned to fit the new chamber and we’ve got Coach’s old barrel to do initial load development with so we don’t send any shots we don’t need to down the new barrels.

A pair of blanks and a custom reamer gets 2 identical chambers.

At the same time, because we’ve got 3 barrels in 6XC that will be available we’ll be testing some cleaning and lubrication products from Modern Spartan Systems. I’ve seen their Timken bearing race friction test and was surprised enough to give them a shot. Coach & I will be running one test which is to recondition his existing 6XC barrel using their product line and see what that does on paper as well as under match conditions. We’ll also be leaving 1 of the new barrels untreated and running the other barrel with the Modern Spartan Systems cleaning and lubrication products. I can hear you objecting now saying stuff about Coach and I being different shooters so how will we know and blah blah. Well, the reason we’re building 2 identically performing and identically chambered rifles is so that we can bring only 1 rifle to a match, splitting carrying it and being able to improve our scores by having effectively a follow-up shot on every target. That will cause a bump in our scores right away so we’ll test that with Coach’s existing 6XC to get an idea of what a second-strike opportunity does to our scores.

Testing on the old rifle illuminates the gain we’ll get from sharing a rifle. Sharing a pair of rifles with only one major difference (use of MSS products or non-use of them) and switching back and forth from one match to the next gives us the ability to clearly see what the cleaning and lubrication does for us over and above the sharing of a rifle. Looked at over several matches  this is a great way of showing where differences in scores come in and gives a good way of assigning causal factors. None of this is ever likely to show up on paper. Even if it did, the statistical differences found in short range group size testing and velocity testing where the differences are relatively small is not helpful. We want to see what happens to our scores. That’s where the rubber meets the road so to speak.

Carbon Destroyer

Crystal Clear

Accuracy Oil

So how about some specs? Well, our custom 6XC chamber will use a .270″ neck which provides .003″ of total clearance. That’s very tight on purpose. We don’t want brass being worked hard and .003″ means just enough clearance for good bullet release without overworking the necks. The body diameter at the web will be .472″ which gives .003″ total clearance to our brass out-of-the-bag and should not suffer from sticky bolt lift like some 6XC’s can as our die sizes to minimum leaving a base at .469″. Freebore is being set to give us an initial bullet seating depth that puts the shank/boat-tail junction of the bullet .030″ below the neck/shoulder junction of the case with 115gn DTAC bullets. We’re targeting 2950fps for the eventual load which should be doable on about 40 grains of something like H4350 or H4831 but we will try Reloader 23 and H1000 and similar magnum-y powders. Things could come in +/- 75fps from that so we’ll see how it all breaks out when we get there. Both barrels have to shoot the load identically for us to be happy which promises to complicate load development.

We’ll be taking the Modern Spartan Systems cleaning product suite for a little ride on more than the new 6XC barrels over the coming months. Others including TiborasaurusRex have taken this stuff for a test run but nobody seems to have done much scientific testing and reported on it so we’re going to. This test is going to require something like 100-150 rounds per gun and will be carried out across nearly 100 guns over the next several months. We’re going to try it on Trapdoor Springfields, Sharps rolling block .45-70’s, black powder cannons, metallic silhouette race guns, .22LR match bolt-action rifles & semi-auto pistols, 1911’s, Glocks, Springfield XD’s, Colt/S&W/Dan Wesson revolvers, shotguns, military surplus rifles, plain ol’ hunting rifles, AR-15’s, front-stuffer .50cal black powder cap-lock rifles & pistols and more. We’ll do a test of performance & reliability, then fully strip-clean each gun, then do the test again after treating them with MSS goodies.

Not the actual collection being tested but the actual collection does in fact contain at least one of each of those, and then some.

We’ll be testing for groups, velocities of course but also for ease of cleaning as well as how long to copper equilibrium for those guns shooting jacketed bullets and resistance to leading on those shooting plain cast lead bullets that are going way too damned fast. There will be a big focus on corrosion resistance too since many of these guns are black powder shooters and all are exposed regularly to dust which is both thick and highly alkalai and has caused us issues with inducing surface rusting over the years. There are also a couple tests we have planned which we’re keeping under wraps for now so nobody steals the idea. Suffice it to say, those could make for some really interesting findings. Or they could make for a null result. Never know. Stay tuned!

Advertisements