Why would CZ build all their 30'06 and 300Wmg's using a 1x12" twist barrel instead of what I thought was the generally accepted 1x10" twist by every other manufacturer I can think of? Is there a benefit for the slightly slower twist ...or is it a detriment somehow?
The 300WMg Medium Mag being offered by CZ-USA is very interesting...I just wish it was in an American style stock too...along with a 338WMg.
Ron

The "traditional" 1:10" twist is really only needed with the real heavyweights 200gr and above.

Basically with "cheap" bullets you'll usually see somewhat better accuracy with the slower twist, because a twist faster than necissary tends to exaggerate any flaws in the bullet.

And if anyone bothered to actually read ballistic tables they'd realize that though those long heavy 200 and 220
bullets may give up their velocity grudgingly, but the simple fact is that they don't have as much velocity to start with...

Basically the 30-06 will be all it can be with either 165's or 180's and in 95+% of circumstances you are better off with a 165.

I've often said that if you want to shoot 220gr bullets use a 338 to do it with.

Most 30-06 owners will never shoot anything other than 150, 165 or 180gr bullets, so why make barrels with a twist rate that is only needed for bullets that very few people ever actually use?

Hey people whine about 223Rems with slow twist barrels.
I bought a 223Rem with a 1:12" twist....
Bo. Hoo. I can't shoot 68gr bullets with my 223...
I'm sure that there are groundhogs that are sleeping contentedly because I won't be firing 68gr bullets
at them.... Yeah right... I load mostly 50gr and
some 55gr, so the fact that my rifle can't shoot
bullets that I don't want to use is somewhat
less than heartbreaking.
(Frankly if I wanted to shoot 70gr bullets I'd build
a 6mmRem)

I think a 1:12" twist in a 30-06 is the CORRECT twist rate for 99% of what reasonable people will ask a 30-06 to do.


AllanD

quote:

Originally posted by verhoositz:
Why would CZ build all their 30'06 and 300Wmg's using a 1x12" twist barrel instead of what I thought was the generally accepted 1x10" twist by every other manufacturer I can think of?
Ron

I was hoping that CZ used 1/10" in ALL of their 30 cals. I wanted a CZ550 Varmint Kevlar in .308 Win and wanted to try and shoot some 210 gr. Bergers that I have on the shelf.

Hmmm? So CZ's 1x12" twist is more forgiving of cheaper lighter bullets... any specualtion on just how bad they will not stabilize the 200 & 220's ?? Are we talking 1/4" deviation at 100 or more, I assume the heavier the bullet the more the problem is exagerated.
I can understand the high light bullet usage rate in the 30 cal non magnums and CZ's desire to build on it reputation for accuracy with the most foregiving twist rate in the most used bullet category ...but I had wanted to look at buying one of the new 300WMg Medium Mag's to compliment my Win M70 SS Classic 300WMG's 1x10" twist and shoot the same ammo in both...in the highly touted as best for caliber 200 gr'ers so I guess that's out.
I fall into that great average 165-180 gr useage right now ...but LOL! Allan with what you are saying I can make a case for switching to a 338 of some sort but had felt that the two calibers were a little redundant and a 338 is too close to my CZ 9.3x62 in a short range gun so ... except for maybe in a 338RUM ...so the CZ 300WMG MedMg idea may not work after all.

I don't own a '06 but am a dedicated 270 shooter for a light deer rifle, and am looking for a super cheap 308 SS/Syn to beat up and use as a "swamp gun" to hunt creek bottom pigs and deer with and thought maybe I could commonize the reloading bench somehow...so it's back to 30 cal 180's or build a carbine length SS/syn 9.3 x 62 Piggie Special...now that might might work...
Thanks for the info.
Ron

I have been shooting 308 and 30-06 in competition for years. The 1:10 twist handles 150, 168, 175, 190, and 200 gr Match bullets with outstanding accuracy.

I never used the 1:12. As I understand it, the 1:12 was accurate up to 168 grain bullets, maybe 175's. It was only really used by guys shooting M14's. The M14 gas system could not handle bullets heavier than 180 grain anyway. But bolt gunners using the 308 regularly shot 150, 168 and 190's with the 1:10. Incidentally a 125 grain bullet shoots just great in a 1:10 twist.

Seems to me the 1:10 is more flexible choice of twist.

The problem with a 1-12 barrel is it won't handle even 180's with fine accuracy as a rule. You are much better off in general to overstabilize rather than understabilize a bullet. Individual rifles will vary, but I wouldn't be surprised to see groups double with a long 200 grain bullet in a 1-12 barrel compared to 150-165 grain bullets.

Sounds more and more like a CZ anything in 30 cal is out...I have a couple hundred mixed 30 cal 150's and 165's but another couple hundred 180's and was planning on buying some 200's to play with this spring and make my choices from there.
I really like this M70 Win Classic SS 300WMg I just picked up and have begun to look for a "car wash cleanup Swamp gun" to roam the clay black land gumbo bottomed creeks around here with.
Last trip, I drove home in my underwear and a sweater and had to hose out the bed of the truck where my clothes were from all the mud and blood off the piggie...but it's a blast!

Hello,
I have shot long range matches for several years and the all around best performing Palma Match rifle I had was a Krieger 30" barrel, 12 twist, 308 of course, and have shot numerous times 440plus scores in all manner of conditions. Those not shooting Palma, the range goes from 800, 900, and 1000 w/ peep sights only from sling/prone position. Never did clean the match (perfect score would be 450), but very few have if you look at the stats. Point being, 1/12 twist is pretty much standard in weapons of 308 being shot for duty work, not targets. There are some 11 twists out there for those who can not make up their mind I guess. Believe my situation worked due to 30" barrel and velocity attained, just happened to balance out well.

quote:

The "traditional" 1:10" twist is really only needed with the real heavyweights 200gr and above.

Actually, the 1/10 twist is only needed for extra-long bullets, such as the Sierra 200 & 220-grain HPBT's.

My understanding is that Weatherby used a 1/12" twist for the .300 Wea. Mag.

quote:

Originally posted by verhoositz:
<snip>
...but I had wanted to look at buying one of the new 300WMg Medium Mag's to compliment my Win M70 SS Classic 300WMG's 1x10" twist and shoot the same ammo in both...in the highly touted as best for caliber 200 gr'ers so I guess that's out.
I fall into that great average 165-180 gr useage right now ...but LOL! Allan with what you are saying I can make a case for switching to a 338 of some sort but had felt that the two calibers were a little redundant and a 338 is too close to my CZ 9.3x62 in a short range gun so ... except for maybe in a 338RUM ...so the CZ 300WMG MedMg idea may not work after all.
<snip>

I take issue with the "best for caliber" moniker
for the 200gr 30cal bullets.
you can usually drive the 180's enough faster so that they have an energy advantage over 200's
at any range you care to measure them at.

as for pig shooting?

I use an Remington 74 (semi-auto) in 30-06, with 165Ballistic tips loaded to about 2700fps.
And No, I didn't buy that rifle specifically for that purpose, I actually bought it to hunt deer and blackbear in NY state 20 years ago.

I'd load it down further but 49.5gr of IMR4064
is where I found the "Sweet spot"

I'd like to know why you think you need 200's to kill them....
Do you have Hogzilla nightmares?

BTW, I have a factory remington barrel for a 308Varmint stainless rifle right here... it has a 1:12" twist....

AllanD

I've been shooting a Smith and Wesson model B (Husquavarna) since 1970 in the '06.. it is a 12 twist.. It doesn"t know its not accurate.. SHHHH don't tell it.. 165s, 170 flat points, and 180s all shoot close to moa.. only a 20.5" barrel.. I should look for another one... Les

quote:

Originally posted by Les Staley:
I've been shooting a Smith and Wesson model B (Husquavarna) since 1970 in the '06.. it is a 12 twist.. It doesn"t know its not accurate.. SHHHH don't tell it.. 165s, 170 flat points, and 180s all shoot close to moa.. only a 20.5" barrel.. I should look for another one... Les

MG Julian Hatcher once told the story of a strange occurrence at Springield Armory in the days when they were buiding the M1903 Springfield. It seems every so often a rifle would go through test-firing and shoot much tighter groups than was typical. They got curious as to what was happening, and discovered that the accurate rifles had 1/11" twists instead of 1/10"! The "trouble" was traced to one rifling machine that had "slipped a gear" or something, and was cutting 1/11" twists in all barrels rifled on that machine.

The Army immediately corrected this horrible error.........

quote:

Originally posted by verhoositz:
Why would CZ build all their 30'06 and 300Wmg's using a 1x12" twist barrel instead of what I thought was the generally accepted 1x10" twist by every other manufacturer I can think of?
Ron

Ron, at least Blaser and Sako equip their .30-06 with 1:11" barrels. Maybe the slower twist rate is a European thing??

- mike

A 12 twist is optimal for an '06. The '06's case capacity is best suited for 165-180 grain bullets, and the 12 twist is is optimal for these.

I spent a year trying to choose what twist to get for my custom 30-338 rifle (to use primaily with 180's), and in the end, after a LOT of reading, chose the 12.

BTW, I get excellant accuracy shooting 200 MK's out of a 12 twist 308 target rifle.

Allan
No hogzilla nightmares here... but my hunting partner did see a hairy gentleman on the wrong side of the fence last week by a scootch that we would have had to pull the bottom 2 or 3 strands off the post to slide the critter under the wire and use my truck and a chain to pull him out of the creek bottom.
The TP&W wildlife tech we talked to said he'd heard a rumor of a hog big enough to bow and crease the front end loader bucket of a big Ford tractor...and was taken earlier this winter close to where we were in Leon County. We were hunting a WMA just west of the Trinty river about halway between Dallas and Houston. Biggest prints I saw were in the back of my hand range but we skunked with the 82 degree and 35-40 mph winds last week.

The whole idea was to match a 300WMg CZ Medium mag with my M70 Stainless and shoot the same ammo or as close as possible.

Up here on the Red River between Texas and Oklahoma where I live, we also get a fair number of good sized porkers but the conditions get to be "a little messy" ...hence my additional desire to find a super cheap stainless under the seat truck gun 308 or'06 pig shooter that it wouldn't hurt to paddle the boat with if need be.
I hunted piggies the first time back in the early 70's in the Osceloa Nat'l Forest near Lake City in North Florida and had more fun than the law should allow...but I used a 8x57 M98 stock Mauser and 196 gr sp's after beating up my nice new Ruger on the first trip and having some decent sized hogs disappear after getting hit with my Texas WT sized 25/06. Learned then to hunt the wallows with fresh bubbles on them ...with a climbable tree at hand and keep a pocketful of ammo handy.
Hogs are taking over some of the better deer hunting areas here in Texas and some landowners have declared war...and I like getting invites to do hog patrols for ranchers.
Ron

When I had a custom .300 built that was a question I had. My 'smith said the 12 twist would stabalize up to 200 grain bullets just fine, and he was right. That rifle shot consistent .75" groups, and frequently better, and it held accuracy out to the 500 yards I practiced to. Now I'm curious what the twist rate is in my Kimber. Funny, that rifle also shoots consistent .75" but it cost less than half what my customs cost.

Yeah, don't get me wrong, I do see a point in heavier bullets in the 30-06, but not for the use many seem to think
they are for.

I think that heavy weight bullets in the 30-06 are more easily "loaded down" and at lower velocity they tend to make less of a mess... less bruising and bloodshot meat.

For CLOSE encounters with Hogzilla and his kin...

But like I said, I use a semiauto for chasing hogs
so I've got another shot ready as soon as I'm done
with my recoil recovery and it's not like I'm using
"spray and pray" shooting techniques, that's hard
to do with only "one up and four down"...

AD

quote:

Originally posted by El Deguello:

quote:

The "traditional" 1:10" twist is really only needed with the real heavyweights 200gr and above.

My understanding is that Weatherby used a 1/12" twist for the .300 Wea. Mag.

The faster a "particular bullet" travels, the less twist is required to stabilize it with VELOCITY being the only factor. That is how the .300 WBY can stabilize a 200 grainer, while a 1/12 .308 Win usually won't.

Greenhill Formula TWIST calculator.