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6 PPC BARREL TWIST ?

jcm24m

Silver $$ Contributor
I will be shooting 100 & 200 bench for score. I will be using 65-68 grain bullets, some flat and some boat tail. I currently have a 14 twist barrel and will be replacing it. Should I replace it with a 13 or 13.5 or stay with the 14 twist barrel. I was told the 68 boat tail will not stabilize in the 14 very well. What is everybody using ? Help is needed by a newbie at this game. I do not want to do this twice. THANKS
 
IMO I'd go with a 13.5. That's what most of the guy's that I know who shoot a PPC use. I'm not a big fan of a 6PPC at 100 yards or meter's in a score match because I feel handicapped. At 200 yards I'd feel more positive. I have been shooting score for 8 seasons and this year was the first time I've ever shot 2 matches with 2 guns a heavy 30BR and a LV 6PPC at 100 yards in a score match. I figured it would be fun shooting something different and it was but the 1st match I shot with the PPC was a disaster because I didn't see that I neglected to shoot all 5 targets on the last match and ended up getting a 40-1X with the PPC and ended up 16th out of 18 guns and 4th with my 30BR. The 2nd time in September turned out a lot better. I ended up creedmoring myself. I ended up 1st with the 30 and 2nd with the PPC shooting identical 250-17 X's out of 16 guns. Usually 17 x's wouldn't come close to winning a match but I got lucky. Like I said it was fun shooting that PPC. I have a dozen 6 PPC barrels, all 13.5 TW and both times I used 67gr Bib's flat base bullets.
 
Thats Berger..... they may believe in the Tooth Fairy too..... I even shoot a 70 gr. high BC. bullet out of the 13.5 at sub .1..... jim
Tooth fairy....?......maybe Randy Robinette will chime in on stability factors of bullets. But then again, it has been published before.
 
Gyroscopic stability has little to do with weight - it's the length that matters! The mass, for any weight range suitable for a particular jacket/bullet length, is simply along for the ride. For a 6mm bullet, measuring 0.845" long (typical for a 68 gr FB) the twist rate should not be less than 1:13" - the contemporary 13.5" twist fad is, "half a step in the right direction" - 1:13" is the number which produces Sg1.4Sg.:eek:;)

IT works better than the traditional 1:14", because it IS better . . . and 1:13" (sg1.4) is better yet! Add a BT, and go straight to 1:12" and don't look back . . . or, go old school and shoot FB bullets made on the 0.790" long jacket in combination with 1:14"twist, which produces Sg1.4.

DO this, and stand the hummer:bummer ratio on it's head, as we did with the correct
thirty caliber model, where, since 1997, we have been shooting bullets/barrell twist-rate combinations delivering Sg1.4 - Sg1.9 and from the same barrel makers, precious few bummer, or, ho-hummer barrels.
With correct twist rate, one does not have to purchase barrel after barrel looking for that, "good one" - they are all good!
;)RG
 
I shoot both of Barts 68 boat tails and his 68 gr flat base and they flat hammer in a 13.5 twist ..... I am now testing a .300 bc 70 gr. boat tail in the same twist 13.5 twist and it shoot as good..... jim
 
I can’t speak to “stable enough” in the way Randy did, but here is some real life experience for reference.

Had a 15-14 1/4 that shot real good. Not internet good, but won half the super shoot good. Feeling real ambitious went to shoot in low 30’s. Something was really wrong. 1” gun at 100 yards. Went to look at Bullet holes. Not round. Gun shot at 42 degrees. Bullets measured 864. Found some boat tails that were 850, maybe a little less. Shot a hole. Shot another hole. This was a wake up call for me on how close we are cutting it on twist rate. Randy May be correct, but I follow the herd w 13.5 and haven’t had problems.

For the real techies, I was about 850 feet elevation.
 
The guy that shot the new range record at 100 yards in St Louis this year, a .044, told me he was shooting a 13.8 to 13.7 and a 66Gr BT.....Looks to me like if he would have done a little research he could have shot a decent group..............
 

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I can’t speak to “stable enough” in the way Randy did, but here is some real life experience for reference.

Had a 15-14 1/4 that shot real good. Not internet good, but won half the super shoot good. Feeling real ambitious went to shoot in low 30’s. Something was really wrong. 1” gun at 100 yards. Went to look at Bullet holes. Not round. Gun shot at 42 degrees. Bullets measured 864. Found some boat tails that were 850, maybe a little less. Shot a hole. Shot another hole. This was a wake up call for me on how close we are cutting it on twist rate. Randy May be correct, but I follow the herd w 13.5 and haven’t had problems.

For the real techies, I was about 850 feet elevation.
Here's THE deal, as Mark states, and observed, we know that marginal stability, "works", and may work very well in certain conditions (air density, as he observed in the colder environment can be a deal wrecker) . . . if one has that "good/great" barrel - even most of the time.

As most do, one can purchase multiple marginal twist rate barrels looking and hoping for that "hummer", which must test/defy the laws of physics! Or, from his favored barrel maker, purchase a barrel with a twist which produces Sg1.4+, and enjoy, "one of the best barrels he's ever owned."

Of course, in the PPC world, employing a "faster" twist amounts to heresy, or, getting out of line and not going over the cliff . . . for the individual who can afford only a barrel, or, two per season, and insists on staying in line, the hummer quest can be epic - possibly one hummer every ten to twelve years - a LOT of dinaro, head-scratching, and lost time! :eek:

Or, the average bloke, can purchase a properly twisted barrel and, unless he's been fortunate enough to score a hummer along the way, very likely have the best 6PPC barrel he's ever owned . . . and almost certainly, the least finicky 6PPC barrel he's owned. Oh, there is NO precision penalty/loss via a soundly stabilized BR quality bullet.:D Yes, some barrels will shooot better than others: however, ho-hummers and bummers will be a thing of the past . . . amazingly, the lemmings just keep going unquestioningly over the cliff.:p The correct question(s): Who do YOU know who has tried it; Do YOU know someone who knows someone who has tried it?;) RG
 
Dave maybe if you would have had a 13 twist barrel instead of the gain twist you used you would have shot a group even smaller then your .044
 
The guy that shot the new range record at 100 yards in St Louis this year, a .044, told me he was shooting a 13.8 to 13.7 and a 66Gr BT.....Looks to me like if he would have done a little research he could have shot a decent group..............
Man... I sure had to use all the willpower I could muster to keep from posting some wise@$$ remark to this post ...
No offense Dave
 
Tired of winter yet Steve, and ready to get back to shooting next year???

I feel the love.............

Happy New Year....

Later
Dave
 

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