Just finished with a long awaited project. Took the barrel my Dad chambered in 6XC that he improved with a 40 degree shoulder and straighter case, and re fit it to my ARC Coup De Grace action. Fire forming brass with some of my old F class loads (109 Bergers and 4831SC) in the straight 6XC, I am getting .537" 10 shot groups at 100yds. I think this thing will be tack driver with a little more load development. This should give the 115 class bullets a little more push for the 1000yd targets.
6XC Improved
- Thread starter sapper299
- Start date
How much velocity gain is there?
I suppose the brass is stable.
I just can’t bring myself to get on the fire form program. Shit costs too much, my time is limited, some people don’t mind, say they fire form and it’s good accuracy and everything. But then you gotta tweet shit again on formed brass.
I’m a huge xc fan. Enjoy your rifle. Looks like you gotter on the run.
I suppose the brass is stable.
I just can’t bring myself to get on the fire form program. Shit costs too much, my time is limited, some people don’t mind, say they fire form and it’s good accuracy and everything. But then you gotta tweet shit again on formed brass.
I’m a huge xc fan. Enjoy your rifle. Looks like you gotter on the run.
Petey
Gold $$ Contributor
Hard to "Improve" the 6XC. Not much improving needed from the original IMO, but some people like to tinker. I'm guessing you blew the 30 degree shoulder out, put on a 40 degree just so you could stuff it with more slower burning powder to get the same results?
Kinda like the 6 Comp Match was supposed to do, get longer barrel life than the XC by improving a .243 case and dumping 10 more grains of H1000 to get the same velocities as the XC, resulting in less barrel life at the end of the day. (All things proven on my bench)
Not knocking it! If there's a better way or you like to tinker, have at it. My guess is you're burning 2-4 more grains of 4831 than 4350 and not getting any more velocity, or if so maybe 50-100 fps? At the cost of fireforming brass, special dies, extra steps... eh. I'll stick with the standard XC and +/- 39.5 grs of 4350 at 3080fps with those class bullets. (which is a middle node, not even hot rodding it)
By the way, I'll be chambering up my 9th XC barrel for 1000 yard competition, so I'm a little familiar with the round, winning all along the way.
I'd be interested in hearing the actual results, myself.
Kinda like the 6 Comp Match was supposed to do, get longer barrel life than the XC by improving a .243 case and dumping 10 more grains of H1000 to get the same velocities as the XC, resulting in less barrel life at the end of the day. (All things proven on my bench)
Not knocking it! If there's a better way or you like to tinker, have at it. My guess is you're burning 2-4 more grains of 4831 than 4350 and not getting any more velocity, or if so maybe 50-100 fps? At the cost of fireforming brass, special dies, extra steps... eh. I'll stick with the standard XC and +/- 39.5 grs of 4350 at 3080fps with those class bullets. (which is a middle node, not even hot rodding it)
By the way, I'll be chambering up my 9th XC barrel for 1000 yard competition, so I'm a little familiar with the round, winning all along the way.
I'd be interested in hearing the actual results, myself.
This "improved" is not what I would consider a huge step forward, but it did help push the 115 a little better. 42-44 grains of 4831SC is running 3150 or faster (I have not found the top end of the pressure range). This will be barrel #6 for me, just the first one in the improved variation. I typically do not shoot anywhere near max velocity, it never seems to be the most accurate so I stay in the upper end of the middle velocity range. My Dad developed this after shooting 600yd and 1000yd F Class as a way to get that 115gr DTAC and RDF, to handle windy days a little better. Since he no longer shoots, I got all of the reamers, dies, rifles, brass and other components. I spend most of my time building customers rifles and not really getting the chance to build for myself, so this one was on the shelf for a few years. I will post some pictures of the brass when I get a moment. But so far, fire forming has been fun as I am getting 10 shot .537" size groups at 100yds with a load I developed for a different PRS rifle and has been sitting on the shelf for the last 4 years. That's pretty good for old ammo that has not been tailored to this barrel.
urbanrifleman
Site $$ Sponsor
You basically have a 6 Creedmoor in terms of capacity.
I say go nuts and have fun. I have some of my dad’s pet projects too, even if I don’t understand them, they’re still fun.
LRP Norma brass is what I have the most of, so that's what gets used.
My 6 XC Launches 5 qty, 107 SMK's, "Jammed" @ 2987 to 3,000 FPS, into,..ONE Hole group's from, the LOW,.. 2's to mid, 3's ! ( 10.5 lb, Braked, Light Varmint, 24" bbl. ) The Lower Node / velocity, shoots Best !
NOTHING Needs,.. "Changing",. IMO
Bigger than 1/2 MOA, Group's,.. I "Scrap", the Load !
D. Tubb Version 1, 1-7.5 Twist, Norma Brass, Forster Dies, F-210 M's, StaBall 65 Powder "Thrown Chg's".
The 6 XC, Feeds like Butter, in My Rem 700, Short action. It Shoots 108 gr Elite Hunters, real Well, also.
NOTHING Needs,.. "Changing",. IMO
Bigger than 1/2 MOA, Group's,.. I "Scrap", the Load !
D. Tubb Version 1, 1-7.5 Twist, Norma Brass, Forster Dies, F-210 M's, StaBall 65 Powder "Thrown Chg's".
The 6 XC, Feeds like Butter, in My Rem 700, Short action. It Shoots 108 gr Elite Hunters, real Well, also.
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Are you jumping or jaming the 108 elite hunters i want to try them
I was Jumping them, .025 ( Getting Group's in, the 3's -4's ) and After Reading some Old Research on Here, about, the 107 SMK's Accuracy improvements, w/ being "Lightly Jammed" and Testing them for, Myself.
I Never got around to, Further Development of the 108 grain Elite Hunt Bullet,.. Sorry.
For my Uses ( for Steel Plate Fun ), the 107 SMK gets it Done, Fine and, IS, way CHEAPER !
YES, I'd Try "Jamming" them, next Time,.. If, I were to Finish my "Load Devlopmt" for, the 108's !
Watch Pressures ! and Good Luck ! Saving My 108's for, an Antelope Tag.
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Part of the reason David Tubb chose the body taper that he did on the 6XC was because it facilitates faster bolt manipulations in rapid fire strings - as the pressure drops and the cases returns to it's original size it pulls away from the chamber walls - making it feel less "sticky" than say a .243AI or even a 6mm Comp Match. If that isn't important to you, but the extra speed is, good luck and have fun!
Getting it to shoot won't be a problem based on the great performance of the 6XC and 6mm Creedmoor.
For faster speeds though, I really like the 6mm Comp Match. Fireform during standing practice with 105's. Then getting 115gr DTac's or Berger's going around 3100fps from a 26in barrel is fairly easy with H1000 or Ramshot Magnum.
Getting it to shoot won't be a problem based on the great performance of the 6XC and 6mm Creedmoor.
For faster speeds though, I really like the 6mm Comp Match. Fireform during standing practice with 105's. Then getting 115gr DTac's or Berger's going around 3100fps from a 26in barrel is fairly easy with H1000 or Ramshot Magnum.
Here is the result. I was worried about the case taper and extraction issues as we had these with the XC early on back in the late 2015 timeframe. After speaking with Tubb about it, we polished the chamber differently and it ran smooth as can be after that. This one is no different, extracts just fine and in this ARC action, is as fast as the Defiance Machine actions we build with. Not trying to say anything was wrong with the original 6XC, loved it and used it for decades. This is just able to shoot the heavy 115 a smidge faster and that seems to have made a difference in a few points in the F class matches it has been shot in on heavy wind days. How well it shoots in PRS vs my 25GT, time will tell.
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I have 107 i will try them
DLT
Silver $$ Contributor
Absolutely
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