Twist rates are a contentious subject...usually because the parties don't do apples to apples and get hung up on "who's right"....I won't argue twist rates because it's a waste of time and breath and I've done enough testing and have a ton of ballistics interior and exterior software...besides it's NOT MY PROJECT nor my yob to tell anyone how the cow ate the tomato.It's not the weight per se that decides what twist works "best", but the BULLET LENGTH...and twist rates can cover a range of lengths, it's not JUST ONE twist that works...14 twist sounds a bit slow to me, most of my present 7 mm run 8 to 10 including a 1-8, 32", 28 Nosler I built for shooting the 1.65" 195 gr Berger Extreme bullets, but I haven't tested ANY 7 mm projectiles/barrels at that slow of a twist so I'm looking forward to see how the barrel performs. MOST of the 7 mm barrels I've used were 1-9.25 or 1-9.5 and stabilized bullets from 100 to 175 and covered almost all the "standard" available cartridges and even most of the wildcats I've built/shot.You've got me thinking about doing a Texan barrel in 338 or 375 cal...with the BC's those bullets have even in the shorted length bullets, they would work very well out to maybe 150 yds where the 45 cals have started dropping like rocks.Time and testing will tell the story.I like the 6.5 and 7 mm cals and have built many over the years using cases with H2O capacities from 20 gr to 145 gr and bullets from ≈0.600" to ≈ 1.50"...85 to 195 gr bullet weights.Those are interesting bullet designs you posted...I wonder just how they would work in Alum or brass? I like the Arsenal design...reminds me of one of my 63 cal/20 ga slugs I turned out of Alum and brass and one of my 50 cal, 700 gr Sharps Accurate Molds slug molds... Good Hunting
I have to agree to disagree somewhat... and not to get a hoohaw going..."Bowman" is just a calculator based algorithm just like Greenhills and Millers are algorithm based calculators...goto kwk.us, a free twist calculator that uses Bowman's algorithm...I've used that program many times...I use those free twist calculator programs constantly to check things out before I commit to a certain twist. MOST of my interior/exterior ballistic calculator software ask 4 questions to determine the "optimum"(which has several meanings and intimations) twist rate...VELOCITY, DIAMETER, BULLET LENGTH and BOAT TAIL OR NOT...it only takes a bit of mucking about to get "good enough for Gov'ment work"...been using them for years and they always do the job...but if Bowman works for you then go for it....I'm not arguing the point of which is "best", only pointing out that twist rates come in all flavors for many varieties and can be obtain very easy.As to the other slight disagreements...Yes, you can ALWAYS FIND things/bullets/etc, that won't work, but I have bullets in 6.5 and 7 mm on my bullet shelf that are perfectly OK for ANY AG in those calibers to use...in other words they're are NOT too long or too heavy and I have rifles shooting 75 to 90 gr 6.5 7 mm bullets at AG velos in my small volume "Whisper" cases at velos I can load from ≈700-1200 fs, shot in "standard" twist rates for those cals...besides there are CNC bullet makers that will turn out just about ANY caliber and ANY weight bullet/pellet...a few right here in my neck of the woods...IF I order a run of a thou or so at a buck, buck and a half a pop...DEFINITELY NOT HAPPENING. Actually I have "Whispers" from 17 to 30 cal on the 221 Fireball case and played with a Shortened 375 Super Mag case that was a bit more than a "whisper" without a muffler on it.Well, Hey...if Kolbe said it then why even bother with the 14 twist??? What's good for General Bull Moose is good for the USA?? The "Ideal" is something I've NEVER seen, but if it's OK with you...USE IT...I won't mind...Charts and graphs are very good on computers...they show you lots of good things and I use them all the time...but not so OK in real life...they are just tools to use to develop with as ar all the computer software out there...and just how many of the "unwashed masses" have access to such neat toys...?? It's all good and whatever fit's your pistol...USE IT...the only way to know that it works, if it works, is to build it, then test it...Lord knows how many things I've built that DIDN'T WORK...BUT EVERY ONE OF THEM TAUGHT ME SOMETHING GOOD...and that is the most important thing to take away from a "failure" that wasn't a failure at all.NONE of what I've said or pointed out was meant to to start a juvenile, mindless dust up...it was meant to point out just some other aspects of this new AG sport...Ya'll need to stop going postal or extremist...it DOESN'T HELP ANYONE...and many of you just don't have a clue what 65 years of HANDS ON EXPERIENCE DOING THINGS OUTSIDE THE ENVELOPE and the hard way WITHOUT all the fanciness available today, CAN TEACH instead of becoming "online experts".Besides a 120 gr Vmax is NOT the best bullet to use in a 28 Nosler because the 28 Nosler was designed for HUNTING larger game using heavier constructed bullets and NOT for shooting sage rats...get real if you want to play. I was building 22-243 Middlesteds and 25, 6 mm and 6.5 -284's and BIGGER CASED WILDCATS LONG BEFORE THE 'NET WAS AROUND and learning about which bullet would survive or not, which twists worked or not and just how far I could push before the gun came apart...EMPIRICALLY...that is by hands on...and I have a nice 6 MM BR stub switch barrel on a NEF chassis that does VERY well with 55, 58 and 60 gr VARMINTING bullets to as far as I can see...but this link ISN'T about what hivel PG you or I have or what distances we can/have shoot paper or game at...it's about TEACHING and NOT BRAGGING. I thought/hoping I was getting away from the total garbage of many of the PG forums.Teaching/sharing is NOT ABOUT "MY dog is bigger/badder/meaner/uglier than YOUR dog"...it's about showing other ways of doing similar things in a different manor and NOT about cherry picking to prove some existential/esoteric and usually useless point.Good Shooting
•Minimum groove diameter of .255", so 30 caliber is about as small as I can do. 7mm will have shallow grooves and no gas check.
Watching this thread, I too tjink the 7mm is a good in between cal for hunting small game, I have a shin sung 50 cal that would probably be a excellent donor rifle ,large air cyl and valve should be large enough for 7mm ,it sure as he $$ isn't big enough for .50cal ,I will measure the OD of the 50 barrel later today but I already know its bigger than the tj 's 7mm might can get them to make one in a larger OD , I have a lathe and milling mach, but cutting the breech oring slot is something l'm not sure I can do,maybe practice on a scrap piece of barrel ,anyway watching this thread for further info