Home Forums Hunting & Shooting Custom Rifles & Wildcats twist in 6mm

Why don't we hear much about different twist rates in 6mm cartridges? I'm going to have a 240Wby or a 6mm-06 built and will be shooting bullet weights from 75 to 115 grains---mostly 80 to 85 grain Barnes--- and I would like some recommendations on twist rate. All I ever hear about is the 1 in 10 twist, but if I want to shoot some 115s, is that going to be fast enough?
Also, I'm thinking a 24" barrel length. Is that long enough for these cartridges? I'm guessing it is, but I'm guessing.

Nope you'll wanna go quicker, mine have been 10's and they won't shoot the 105's and more.

I've had 25" tubes on both my 6/06 tubes, and my buds have had tween 24-26. The fella who had the 24" was a mean killing machine with it, did things that were just unbelieveable!

To be using those slugs you must be thinking about going long (500 plus) a lot?

Dober

First, now I see that PacNor recommends a 9" twist for a 5-groove barrel. I should have looked there first, maybe, but thanks for the response. I was hoping you would comment because I know you have experience with the 6mm-06.
Would you recommend a 9" or even a faster twist, considering that I will want to play at long distances with the 115s?
This will be mainly a light deer rifle...not ultralight, but under 8# scoped and loaded.

Go 8 for the 115's.

Yep. Mine is 1:8.5", but I'm shooting 105s and have no plans to shoot the 115s in my 6BRX.

My .243 AI is going to be twisted as an 8

I have used 6mm rifles with twists from 14" to 9". I checked Berger's recommendations for their hunting VLD bullets and they recommend 7" at 115 gr, 8" at 105 gr and 9" at 95 gr.

Pick your bullet and work back I would say...jim

1 in 10 works fine for TSXs up to 100 gr at normal hunting ranges.

That's interesting considering they don't make a 100gr TSX.

Now thats funny!

Stupid Oldman at it again...........

Thanks for that. I just looked again at PacNor's twist rate chart and they go all the way down to a 5" twist in the 6mm 5-groove barrel. That's fast!

Bulletbutt, you need to think hard about the range you will be shooting and get a twist rate that fits your needs.

1-10 is what is best with the 85g Tripple shock.

Like Mark said, the 115's are for 500 Plus.

Rifles are usually throated for the types of bullets that you will be shooting, thus long throat for the 115's vs shorter throat for the 85's

You need to take into account the magaine length and cartridge OAL also. Most of the VLD bullet love to be seated touching the lands or jamming .005+.

Good luck!

So unless I'm a gunsmith or have done this before, how do I know what to ask for, as far as throat length? Let's say I want to shoot 85 TSXs and also the 105 VLD, and forget the 115s. Now I can go with a 9" twist according to Berger and from what I gather a 24" barrel will work fine. So where do I go from here?
I'm sure I shouldn't just buy some brass and bullets and start loading them so they "look right", because I'd just be guessing...and I'm sure someone has gone through this before me. Even with a wildcat like the 6mm-06 there must be some sort of accepted throat length to use with the two bullets above. I guess that's a question, more than a statement.

My 243AI is a 1-9"tw and it will run the up to and including the long Berger 105VLD. It WON'T run the 115DTAC's, tried them just out of curiosity and they wouldn't stabilize.

When you want to run the long VLD style bullets and feed from the mag you end needing a shorter throat, though at first though it would seem the opposite. If you throat in accordance for the longer bullet you shouldn't have any issues with the shorter bullets. Having to single load the long bullets was not a concession I was willing to accept.

My 243AI is throated for the 105VLD's at maglength and i have no issues with running them or the 90gr Swift SciroccoII's or the hornady 75gr V'max.

Makes me wonder if lots of people chambered for say, a wildcat such as the 6mm-06, shooting say, a 105 VLD, would we end up with many different throat lengths because of their choices of different rifles with different magazine lengths?

Bulletbutt, what I do is buy the brass and bullets, dies first. Then seat some bullets to see what I want in as far as seating depth.

Once you determine what seating depth you want you have two choices, order your own reamer(send them 3 dummy rounds with the bullet seated at the depth that you want) or find a gunsmith that has a reamer with zero freebore and then he can throat to the length that you like. It is hard to find a gunsmith that has the ability to do a little trig and has a seperate throater, and most of them charge extra for this service. Pac Nor will throat it for free when they do the work.

I have had at least a dozen or more 243 AI's with the 1-12 twists, and my reamers have zero freebore. You have to stuff the bullet down in the case, but that has never been an issue for accuracy, but in the case of the 105's, case capacity may be an issue when you stuff that long 105 deeper in the case, Brad could tell you yea or nea on that...I'd like to know myself.

Keith, Here's where I'm at with the 105 Amax's. The length is ~2.8" TTL.




The Bergers come out to a longer OAL when loaded to the lands, but they'll still feed from my HS mag.

Brad, thanks so much for going to the trouble of posting such informative info and pics.

Looks like your gunsmith knows what he is doing.

If I remember right, you were getting 3200 out of the 105's is that right?

Are you using Danzac or Moly?

Thanks in advance

Keith, I'm running moly in my rifles. I'm getting 3250fps w/the 105Amax's using Rl-17 in a 24" barrel. I could not get close to those speeds before running in to pressure while I was running Rl-22. Not too sure what to make of it yet, but it seems my rifle hit a accuracy node around 3050fps, then again at 3250. I just couldn't get to that 3250 w/'22 and ended up running them at around 3050. 3100'ish was doable (w/'22) but the acc wasn't there.

I am in the same boat trying to figure out what twist rate to go with in a .243 Win. At first, I was drawn to the 1:8. However, this might be too fast. What do you think?

My idea is to have a 24-25", #5 contour barrel to hunt and plink with. For hunting to say 400-500 yards, I want to shoot 85 TSX's, 95 Part's, and 100 grain SGK's. For plinking and paper to 600 yards, I would like to shoot 105 A-Max's, Berger 105's, and Sierra 107's.

It would be great if the 85s and the 107s both shot well but is this possible? Is this asking too much? What twist will fit my idea?