OK, since this has been setting a while..... I'm going to share an experience.
It's long, so don't read it if you've the attention span of a millennial gnat or are too important for my rambles.
First I have to be clear. The answers you've gotten are from real people who compete with real rails. I don't even belong in the same ROOM with them. I've never shot a real 100/200 Group Match only 600yd stuff.
But I do own a good rail. A State Of The Art rail by Craig Kensler. I plan to learn to shoot it.
Soo..... I spec'd a new 6PPC reamer of my own design. And I chambered up 4 barrels;
-a
new LV barrel for a glued in light varmint gun and a
very used 12" twist that had over 1200 .243AI and a few hundred 6BR thru it. This barrel is firecracked for 3-4 inches so I bandsawed it off to get into something less alligatored and made up a fireform barrel.
-a
new HV barrel, also on a proven glue in platform
-and a
new railgun barrel. For my new railgun.
I blew out 5 cases in the FF barrel using a casefull of Clays. I need a faster powder (ain't got one) but got some perty good cases.
Soooo, I cleaned the (very used) 12" twister up and since't it was on the gun used it to bring the scope in with a thrown together load of some old 322 and some 70gr Starke's. It made a snowman. Another group made a littler snowman, with no head.
All good, as expected.
Screwed on the new barrel shoot/clean/check for copper/shoot clean 5 times. Getting blustery, made a duck. Another group, paid more attention, big roundish hole.
OK, all good.
So now the HV gun. (These are all the same load, just 70gr bullets with H322 at about 3300-3330 (too hot for H322, but testing a new lot of Lapua cases))
Again, one big raggedy hole looked like I could fit my pinky in, 2nd group, paid attention, got it taller than wide.....but ALL GOOD.
So now the rail.
First shot on paper, 2nd shot 1/2" lower!!!
Holee KRAppppp already got the worserest group of the whole shebang!
I found out YOU STILL GOTTA PULL THE TRIGGER STRAIGHT BACK, on a rail.
And it hadda' settle in a little.....But that's another story. I did get it to group as good as the others, but it sure warn't magic! It shot JUST LIKE the other two setups. I bounced those 5 cases back and forth between the three guns and honestly could not see a difference. At about 15-16 reloads the primers were getting loose so I switched to 133 and some benchrest bullets and shot a round robin. They're all FINE, I've got notes for each barrel and a plan to tune them individually but the big ol' inch-four-fitty barrel sure didn't make "tinier ragged holes" it just made the same size holes as the other two!
So, this opinion (single experience, actually) ain't worth NUTTIN, I haven't even had a chance to tune up the rail, but I fully expect it to be same-same to tune based on this single experience.
I did build a 6BR barrel for it, to prove a point, but for now I'ma' just shoot these three guns together as 6PPC's with the same batch of cases so's I don't get all corn-fuzzled at a match.
K.I.S.S=me
To give you an idea of where I'm coming from..... I got my first real bench gun, built by a Bench Rest Gunsmith around 1994, and in the next ten yrs acquired 3 more and mebbeso 10 barrels....... and the first thing you learn about a REAL BR gun is, it'll never shoot BAD. It will shoot any load you throw at it better than the best varmint gun you've ever seen, you'll never expect to see paper in any group, ever.....but to make it shoot GOOD
now that's a whole nuther balla'worms
Seeing two distinct bullet holes on the first two shots with my new rail was a real reset button for me....STOP....and SHOOT!!..... it ain't a magic bullet!
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edit!
OK..... FULL STOP!!!!
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I FORGOT TO STATE CLEARLY.... the fireform load with a caseful of Clays shotgun powder was NO BULLET!! JUST POWDER!!!!!
