6XC Load Development – Analysis Time


This little case seems to really like being as full as possible and/or run a little hard and put away a little bit wet if you get my meaning. We broke in the barrel with 15 shots but as you can see from the data below, around shot #6 things stabilized. By round 10 I had warmed up the barrel a bit and was vacillating between baking rounds in the chamber while I wiggled around trying to get a natural point of aim and firing quickly when I was already at a good NPoA.

All discussions of load data and charge weights come with the “don’t copy me and hurt yourself” disclaimer. Don’t just run my loads, work up to them. These are all on Norma brass, F210 primers, 115gn DTAC bullets and COAL at 2.8″.

Around shot #6 things pretty well started to stabilize. Inconsistently going between firing quickly and baking rounds in a warm-ish chamber widened the ES a bit around shot 11.

After grinding out the first 15 rounds to break in the bore and establish a zero; this was a BRAND NEW barrel after all, we took a little break and went to check the target. The new barrel shot to such a different POI than the prior barrel that it took quite a few shots just to get on steel at 100yrds. By round 10 we were on steel at what seemed like pretty close to POI=POA. Enough to move to the BoxToBench Precision 100yrd Load Development Target and dialed the zero in on the cold zero aiming point. 5 rounds at the cold zero put us at 15 shots and we were already seeing each set of 2 bullet holes (because: adjust, fire 2, adjust) either touching or very close to it. We’re pretty excited about the performance we’re seeing so far.

After the first 15 shots and letting the gun cool down I settled in to go for groups for record. Starting off we did the Coach’s match load (CML) which is 38.5gn of H4350. Then the RL-23 was run followed by N550 and IMR-4166. To wrap things up we came back to the H4350 and did the 39.5gn load then finished out our paper punching with 5 at 39 grains. After that I had 5 rounds left and wanted to drop a shot on the 900 yard target so we went up there and I rang the gong for 5 rounds of 38.5gn. There’s a called flyer (obvious) on 4 of the 6 aiming points. I wasn’t in the most stable position and I knew it.

 

My velocities are a solid 150fps above what Coach gets from his Enfield rifled barrel of the same length with the same load. Ok, to be completely transparent, it’s not EXACTLY the same load. We do actually seat the bullets about .120 deeper forn my new barrel than Coach’s barrel but I can’t see 150fps difference from that. This is the polygonal rifling in full effect. Less friction because you’re not engraving the bullet, you’re swaging then and then twizzlering them, if only ever so slightly.

So now on to the powder results. H4350 you see the curves change shape as you fill the case up. To my eye it almost looks like someone’s grabbed on to the right side and started pulling the string taut. Group sizes went down as powder charges went up but we’re talking about going from a .75″ group to a .71″ group to a .3″ group. The academic in me is crying out to be let loose with a scale and all of my reloading supplies to do a 1/10th grain at a time experiment. But, that’s expensive and I have other matters to attend to. The experienced rifle shooter in me says, “You do realize that any one of those is sufficient for the 1000yrd stuff you’re doing right?” The competitive rifle shooter in me says, “Take the 39.5 and let’s go home and load ammo before you change your mind again.”

This is Coach’s match load in his current barrel. Featuring a tight 10.87fps standard deviation from my gun and a not disappointing .75″ group this load showed promise. I just don’t want to tune it. In Coach’s gun this load runs 150fps slower, has a 32fps SD and turns in the same .75″ groups.
The group size collapsed on this load down to .4″ until I popped a flyer into it (which I called) that took the final group to .71″. 40fps ES is a bit on the broad side for me out of a 5 shot sample size. I could maybe do half of that. This load does suggest it might want just a little more powder.
When we give it 39.5 grains the dissonant came into harmony and it made a .3″ group with 2fps SD’s and 5fps ES. It’s running mild pressures and making within a gnat’s ass of 3,000 fps where I’d draw the velocity line anyway. 2900-2950 was our target and we’re there with a solid load.

Onward and upward. We still have loads to analyze. Everyone knows that after my experience with it in .243AI and 6.5x55AU that I’m a big fan of Reloader 23. It’s sloooooooow burning and has been returning impressive velocities with reasonable pressures from very heavy for caliber bullets in relatively long bores from very overbore cases… as you would expect it to do if you are at all familiar with Boyle’s Gas Law. We had no idea how much to start with so we did exactly what Coach did with it for my .243AI. We filled the case up to the body:shoulder junction, dumped it out and weighed it and put that much into 5 cases. It came out at 38 grains with no drop tube, just a funnel and a weighing pan.

Reloader 23 showed me with my .243AI that it likes a full case (I’m sensing a trend here with these slow burning magnum powders) and that it’s pretty hard to put enough into a 6mm case based on a .473 case head to blow the damned thing up if you’re seating to SAAMI/CIP lengths. 38 grains produced pretty nice velocity. A testament to the efficiency of the 6XC case setup. Still with 28fps SD’s, 66fps ES and a .68″ group of 5, it would “do” but I’d want to develop it more if I were to use it. We did find that RL-23 is a great option. Somewhere around 40 grains should give high 2900’s at reasonable pressures even when seating bullets deepish.

                                That right there is porn star sloppy.

Pressing on, we have N550. A double base NG/NC powder known for being a little temperature touchy after 90F and for being pretty darned expensive. 36.5 grains of N550 gave us a nice narrow 11.95fps SD’s on ES’s of only 29fps. Still a little tall but velocities were touching 2900 and pressures were VERY low. It also grouped a .2″ group of 5 shots. Oh man am I tempted to increase my powder budget by 25%. We figure we could fill the case on this stuff somewhere around 39 grains at 3,000fps. But, I don’t want to develop a load; much less an expensive one, if one jumps out at me and that H4350 load at 39.5 grains is hard to beat even with stupid tight groups.

             A lot of promise in this one. Super stable velocity potential.

Now we cross into “Coach style load” territory. So far we’ve been on the very slow side of the slow side of the rifle powder spectrum. Now we’re going to cross the street where the Beatles fans turn into Stones fans and start dragging their knuckles. Not really. Just making fun of coach. The defining line between a “Me” style and a “Coach” style of handload is I like my powder to burn all the way down the barrel giving consistent pressure all the way without a huge spike of pressure in the case itself. My way is easier on brass but harder on barrel throats because there’s more grit coming out of the case neck this way. Coach likes his pressure to form in the case, for all the combustion events to happen in that space and then to use the built up pressure. He also tends to jam bullets rather than jump them where I jump them at least a little bit normally.

Making a Coach style recipe means you know you’ll see pressure sooner or later in your experimenting. That being the case and the fact that there was no data for IMR-4166 (which is around Varget/IMR-4895 burn speed) we elected to hot-foot bloody educated guess it. I calculated that 37.5 grains was about the most we’d want to try and so we tried that. It came back hot enough to imprint my ejector hole on the brass so that’s at least 1 full grain too much juice. It did however make 3080fps with a 2fps SD and a 6fps ES for 5 rounds. Drop a grain or two and you’re right up around 2950-3000fps. What a smoker though! Too bad the pressures were simply too high.

      If it wasn’t running north of 70,000psi This would be my new load.

Below you can see the velocities as they came out of the gun during testing.  You can see it took about 5 rounds to season the bore and then it’s pretty much standard load development wavy gravy until you get to 2 very specific sections whose extreme flatness gives away that something very cool happened there and needed to be paid attention to.

So while N550 turned in the best group and ok SD’s, the extremely tight SD’s and the super tight group out of the 39.5gn load of H4350 has won the day. I might mess with bullet jump a little but really, I’m happy. Best not to waste barrel life.

On the topic of barrel life. Common wisdom is somewhere north of 1500 rounds but under 2000 before it’s smoked. Well that’s about a year and a half or 2 worth of life. That’s from a conventional Enfield rifled gun. I run Columbia River Arms polygonally rifled barrels which have been giving me very long barrel life and I used only HBN coated bullets for the last 1000 rounds (it’s at north of 1300 rounds now).

                     6XC Dimensions

My .243AI still runs like a laser. I only took it off because seating depth was longer than my magazine, but there’s plenty of bullet still in the case yet. I could take it another 500+ rounds if I was willing to single feed. Pushing 115’s at 3200 can’t have been gentle on it and the expectation was that by 1000 rounds it was going to look like 5 miles of rough road down the bore but it’s not. It’s smooth as glass still and makes tiny 1000 yard groups. So if we take this barrel life thing to mean the point at which the boat tail is up inside the neck of a loaded case when seated equals cooked, my .243AI will have gotten something like 2000 rounds before its death. Thanks to some combination of the HBN coating and the polygonal rifling.

Well then, I expect something like 4,000 rounds of life from my 6XC and something like 6,000 rounds from Coach’s since we’re giving his the Modern Sparts Systems Accuracy Oil treatment for its whole life. If I pull 4,000 rounds out of this barrel I’ll be surprised as hell. 3,000 rounds wouldn’t go amiss though and would be well representative of my real expectations.

How will it all turn out? Stay tuned to find out.

 

 

 

 

 

 

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I did well. I was on track to be in the top 3 but as it heated up I got a little heat exhausted and started making mistakes and bad shots. No excuses… it was me and I blew it. So, here’s 1 crap stage and 2 great stages. Make sure to like the video and subscribe to my YouTube channel.

I got 3rd place biatches! W00t! In a field of 30 shooters I came in with a solid 3rd place overall as well as for the prone class with the DodgerDog Hot Dog Gun in .243 Ackley Improved. Running 115gn DTAC projectiles with a super high .620 G1 BC at 3180FPS is almost cheating. The winner used a .308Win and 2nd place used a 6.5 Creedmoore but 3rd, 4th and 5th places in prone gun ran 6mm’s at 3,000fps or better with my Ackley being the fastest by at least 100fps.

Coach, JoeV and I started on stage 2 and after the first shot we were starting to get our wind call for the first part of the day nailed down. Coach goose-egged the first stage because of a turret being spun off zero. JoeV and I both crushed it missing 2 and 1 respectively which was pretty good given we were in the “guess the wind” part of the day instead of the bit that comes later… the “know the wind” bit.

Coach brought his wood stocked Savage 110 in 6XC running 115 DTAC’s at 2900. He’s getting consistently better and his scores are trending upward even though he and his rifle aren’t fully friends just yet. Coach’s rifle is shown below on the left. It’s got a Canjar single set trigger (amazing) and a US Optics 3.8-22×44 scope on a 35mm tube and looks pretty plain jane. It is not. Scoring a 21 at the end of the day is really good particularly as he’s still learning to dial DOPE instead of hold it. This is a different game than he’s got 40 years playing.

JoeV brought his 6.5CM chambered Weatherby Vanguard in a custom bedded tactical style stock wearing an SWFA 10×42 optic with Harris 6-9″ S-type bipod and AAC brake. The gun itself doesn’t stand out as anything other than how to spend money the most wisely if performance per dollar spent is the measure. Joe’s pretty humble about his rifle and I think he wishes it was flashier but it’s a friggen laser beam and he’s a ninja with it. One of these days I’m going to trade him guns for a match and see how we each do. Joe’s won the match before with my .243AI so I don’t doubt he could do it again. Damn! The Marines really train their riflemen don’t they!

So… Stage 3 we did well. Stage 4 we did exceedingly well. Stage 5 we did well. You see how this is going. It was a great day with great weather until the wind picked up in the back half of the day. We had a good time hanging out and shooting and when it was all said and done we’d done very well as a team.

Have some video fun! I guess we didn’t get stage 4. Sigh. We always miss one.

 

When I picked it up, I got it only because it could take my 20 & 30 round AR-15 magazines and I was in to squirrel shooting and preparing a trip to Cedarville, CA for their annual Squirrel Wars event. I was going to not spend all day loading mags this time and didn’t want to use an AR-15 again. Bolt action seemed better.

I ran over to my closest Big5 Sporting Goods and they had one on the rack with a $50 off sale price. So I snagged that right up. It was a 24″ varmint model and I was happy as a clam, for about 2 days. Within those 2 days I pulled it apart and found it was bedded with plastic, the stock leaned to the right down the barrel channel and action screw torque was unrepeatable. Fine. It’ll shoot. Right?

Iteration 1. Bushnell ET-1040 Mil/Mil and a Harris 6-9″ Swivel bipod w/ podlock.

Well, I tossed on a Bushnell 10x40mm optic, some Burris Signature Series 1″ rings and a bipod and went to the range with some steel cased russian 55gn FMJ. The gun printed nothing inside 1.5″ at 100yrds. Ok, let’s start replacing parts. That’s always the right thing to do. Right? Using better ammo wouldn’t help, obviously. That said, I did start some handloads for it and found it had certain proclivities toward heavy weight bullets and being pushed to primer popping pressures.

Round 2. FIGHT!

So, I found out the Bushnell optic was not tracking consistently. While it was back at Bushnell being replaced (This is a common theme with the 10×40’s. Of 4 of them I’d bought, 3 needed RMA’d) I added a 16×42 fixed power SWFA SS optic and 30mm Burris Signature Series rings. I took that out squirrel shooting and was not impressed. Accuracy with 40-55gn ammo was horrid. With heavier stuff it started performing though. So, change of plans. It’s not a squirrel gun anymore. It’s a match rifle. See, I’d just gotten into a regular local prone long range precision match and needed something inexpensive to shoot there. Well, one trip in and that factory stock was shit-canned. Replaced with an MDT LSS chassis, DPMS PSG-1 pistol grip and a Magpul MOE buttstock. That did really well and I managed to turn in the 2nd highest score ever with a .223 at my regular long range match. That still stands. I haven’t bested it to date.

US Optics Scopes, MDT LSS chassis and Burris Signature Series rings on Project Rolling Stone (5.56) and Project Gabriel (7.62)

Not too much time passed and I came into a big bonus so I wanted a major optics upgrade. A quick call to US Optics and I had 2x ST-10’s on the way for various rifles. Epic scopes. Simply wonderful. I took that out with my spotter/best friend, The Disco Tripper, and we turned in some groups on steel. Man that combo could shoot. Running 70gn Berger VLD’s and 75gn Hornady BTHP it was an easy gun to hit long range steel with. I mostly kept those ST-10’s on my bigger guns and used the 16x SWFA optics though. They’re a lot harder to use than an ST-10 but I wanted the extra magnification for the aim-small-miss-small thing.

650m results from Project Rolling Stone

Once we got to this point my coach started harassing me about trying a bedding job on the chassis. So we grabbed some epoxy and fully bedded the recoil lug and skim bedded the action. I also added a MOE cheek riser to the butt. Instant improvement came from the bedding in that no more flyers plagued me. That settled her ass down nicely and I shot quite a few matches as well as a bunch of informal plinking sessions with the gun. The cheek riser had the rifle as comfortable as if it were injection molded around me. I’ve not yet gotten the rifle in its current form to fit quite that nicely, mostly due to time.

The day I set the 2nd place .223 record, setting up for a 900 yard shot, which I hit. Waiting for my spotter to figure out a set of binoculars.

I have been able to shoot the living piss out of it regardless of whatever else is going on because it’s a .223 and very inexpensive to load for. That’s been a saving grace with this project.

Up on The Grassy Knoll. Stage 2 at Avenal. About to start missing.

It was about the time that my barrel was starting to really age that I also decided to upgrade basically all of my scopes. I started with some more US Optics in the form of an ER-25 for my .308. Not the best choice. It worked great on the big 7mm Remington Magnum (below far left) but not so much on the .308. It was also just too damned big for my safe. No rifle fit in there with the ER-25 on it so I had to bounce that optic and began a long journey of horse trading to end up with what I have now which is more US Optics but these fit in my safe and you’ll see them further down in this article. One thing I was really trying to nail down was parts commonality so I could take parts off of one and put them on another if the occasion arose that it was necessary. My mindset was really into TEOTWAWKI at the time. I’m in a better place now that President Daddy is in the White House.

Some of MeccaStreisand’s long range rifles. 7mag, 7mag, .308, .223, .223

It wasn’t too long after I’d bounced the larger US Optics ER-25 and an ST-10 in favor of a set of Vortex Razor 2 HD’s. One in 3-18×50 and the other in 4.5-27×56. They are excellent scopes but I hate hate hate pinch screws on turret knobs for exactly the reason that I bounced those Vortex optics. They loosen enough to not adjust when you twist em’ but they still click and it happened multiple times on both turrets of both scopes. Plus they’re heavy as all get out and the 3-18x on the MVP was in MOA because that’s what I could get at the time. All combined I just was not happy. So, I looked around and looked around and finally after almost a year found a US Optics B-17 I could sell the 3-18x Razor and buy. Excellent choice. I guess I’m just a US Optics guy.

I ditched the factory trigger early on and got myself a Jard and a Timney. The Timney spends most time on the rifle. The Jard is special purpose and breaks at just ounces. It’s not a safe trigger for most use cases but it’s brilliant when I’m trying to hit chicken eggs at 500m. The Timney doesn’t have that annoying blade in the middle of it but otherwise is set about the same, 2.5lbs.

All in the family. Upgrades coming rifle by rifle, step by step.

The first Razor 2 to go away was the 4.5-27x Razor II because I had a buyer for it and something on the line to replace it with. I sold it and had enough money left to buy a used US Optics SN3 3.8-22×44 ERGO on a 35mm tube in MOA with a really slick Dragunov style reticle that heavily uses chevrons. It’s a battle ready optic for sure. My coach decided to get into long range prone though and needed a scope so that went on his gun. Now I needed another. Begin the long look for just the right swap.

Black Hole Weapons barrel. Wrong thread patten but that’s a simple fix.

I shot Project Rolling Stone in variations of one form for a good long time. Long enough to burn out the barrel. Truth be told I’d more or less killed that barrel the week I got the gun. I had a bunch of steel cased Russian bulk ammo with bullets that were copper washed steel and started the gun on those. That must have eaten half the barrel life. By the time I’d had around 3K rounds out of it (IIRC, it’s been a while) that barrel just wouldn’t reliably hold the match level accuracy I needed. It was fine for a sportsman, and I gave that barrel away to a sportsman later on, but not for a match long range precision gun. Thing is, only 1 outfit had reportedly made any small ring MVP barrels and they made them shouldered instead of barrel-nutted. I also wanted a particular barrel maker’s barrel. Black Hole Weaponry. Why? Well, their pipes are just too easy to deal with, shoot excellently, clean easily, are inexpensive, stainless and come threaded at no extra charge.

Once I got that barrel situation settled then I wanted to do a little something with the finish. So I got the idea to make it look like a Sonoran coral snake. 3 months of beating on my local Cerakote guy and getting nothing but excuses later I finally got it back, literally hot from the oven and the scale pattern was backward. Fuck! Well, such is life. Only dorks and herpetologists ever notice. What everyone notices is he didn’t finish the last 4 inches of the pipe. Dick! I eventually got it back and had my 26″ pipe at 1:7 twist in Caudle 3-groove polygonal rifled 416R stainless steel. I bought a bunch of 73gn ELD-M projectiles and a ton of new PPU brass and have been swatting steel on the regular with it since.

Sonoran Coral Snake Cerakote

It was such a hassle dealing with the Cerakote guy that I did my .308 barrel with rattle can spray paint and it actually turned out pretty cool despite me not having much experience with this sort of thing. I used the mesh plastic thingy they send barrels in to make the scale pattern and 3 colors of paint with blue painters tape.

.308 barrel with Texas Coral Snake pattern by Krylon and me.

Then at some point one of the guys at Primary Arms and another guy from Accuracy Solutions were both interested in how their assorted products would do at my monthly long range prone match. Being a good sport and a bit curious, I set out to find out. I added a Primary Arms 4-14x FFP ACSS HUD/DMR optic and an Accuracy Solutions BipodEXT to the gun. I also switched out the Magpul MOE based butt section for an XLR Industries Tactical stock to gain full adjustability which I wanted for various reasons but mostly because I needed a proper cheek weld with the PA optic on there. The Primary Arms scope works beautifully if you trust and use the BDC reticle and did not do well at all when using the mil dots and calculating. The BipodEXT was brilliant. It put the axis of rotation in 2 dimensions in front of the muzzle which increased the lever length enough to make it like shooting from a machine rest. All wiggle was gone!

The Snake Gun equipped with BipodEXT and Primary Arms 4-14x FFP ACSS.

Having finished with testing stuff I didn’t want to use long term and written the appropriate articles, I went back to perfecting the combo and slapped a US Optics B-17 on top. To finish the whole thing I bounced my usual Harris 6-9″ swivel type bipod and put a new AccuTac BR5 into my kit. That’s a beast of a bipod.

Project Rolling Stone in its current form.

I get a lot of strange looks and a lot of people stopping by to make comments from snide to supportive about the rifle and all my rifles for that matter. It’s my toy and I’ll play with it how I like to so I don’t mind when they get snide or chiding. All my match guns are meant to elicit a visceral response. Partly that’s to destabilize my co-competitors mentally so I have a better chance of them doing shitty. Part of it is just for conversation starting. Part of it is, I like these rifles and I like to make them look how I like them to look. I betcha you’ll never find another coral snake gun or another hot dog gun but everyone and their sister has a Hello Kitty AR-15 or a scale pattern on the entirety of their AR-15 or shark teeth, etc… Just because they’re unoriginal repeating pieces of camel poo doesn’t mean I have to be unoriginal.

Project Gabriel in its current form which I call “The Hot Dog Gun”

If you do the math, this gun has cost me a pure fortune. $600 for the base gun, $750 in various stock parts, $5500 in various optics, $40o-ish on triggers, $300 on barrels, $300 on rings and mounts, $10 in muzzle devices (A2 birdcage) and $100 in Cerakote and spray paint. So there you go. I’m about $8,000 in if I’d had to buy each piece at full price. Thankfully, I did a lot of swapping this for that and either reselling or directly trading most of the time so my actual spend on the gun as it sits is closer to $2500US in real money spent.

That said, for $2500 I’ve got a .223 that will easily swat a bad guy or a critter to well beyond the effective range of the bullet it shoots and shoots well under .75MOA. It’s got the best parts on the aftermarket on it without resorting to blatantly overly expensive bits that are just more expensive without being any better. I know a lot of folks with $2500 in an AR-15 that couldn’t shoot a 3/4MOA group to save their skin. I’m pretty happy with what I have here.