30-06 re barrel 1 in 10 or 12 twist ?

[Adk Mike]

I'm cast bullet shooter. I do not have a handle on this rifle twist stuff 1 in 10 or 1 in 12 etc. Is there a go to guide or rule of thumb so I can know the difference ?
I've got a Remington 725 I want to re barrel to 30-06 with a med barrel 24 inches long. Any thoughts ?

[oneokie]

If only cast and boolit weights 200 grain or lighter, the 12 twist will be the best choice.

[RPRNY]

http://www.ebr-inc.net/articles_Greenhill_Formula.html

As per above advice, for heavy cast at @ 2,000 - 2,250 MV, 1:12 will likely be your best bet.

[Larry Gibson]

The 12" twist will definitely be the best choice. If you are using cast up through 180 gr then you might consider a 14" twist and a 26" barrel. You can push 2600+ fps with excellent accuracy if that interests you.

Larry Gibson

[johnson1942]

i done the math what i use for all the guns ive built and this is what ive come up with. if you go 1/10 twist, a bullet that is 1.2 long will shoot to 200 yards very very accuratly but probably not good past 300 yards. a bullet 1.1 long will shoot to 1000 yards very well in a 1/10 twist. you could even go 1.05 long for 1000 yards. a 1/12 twist needs a bullet 1.1 long for accracy at its best to 200 yards. a .95 long bullet for 1000 yard shooting. this is cast boolit shooting and things can change if you go alot faster in copper clad bullets. i figured this for a .308 diam bullet. in castboolets keep to a blunter nosed bullet instead of pointed ones because at slower speeds they are more accurate. pointed bullets at slower speed have never preformed for me well and i even use a kieth nose design and it is really accurate. good luck and have fun

[Adk Mike]

Most of my cast shooting up to this point has been a US model 1917. I also have a Sears model 53 A in 30-06. My most common load is 13 of Unique with a 314299 or a 311041. Shoots good no recoil and a lot of fun. Original Battle sights on the 17 and a Lyman target sight on the Sears. This Remington will get a Lyman target sight also. One in 12 sounds like what I need. I can have a gunsmith friend install the barrel. Any thoughts where to get one ?

[country gent]

Shilen, douglas, lilja, pac-nor, harts, krieger, wilsons, all should have that barrel or make it. Obermeyers is now a part of Krieger from what I understand. Kriegers have a henry style rifleing that is supposed to be good with cast bullets. I have all the above on rifles and all have performed flawlessly. I thing to do is let the maker know what your planning and what you expect want to do and they can be very helpfull also.

[MaxJon]

The 12" twist will definitely be the best choice. If you are using cast up through 180 gr then you might consider a 14" twist and a 26" barrel. You can push 2600+ fps with excellent accuracy if that interests you.

Larry Gibson

I'm considering a 30-06 SS 12T x 26inch heavy barrel for 500m competition, for 180-190gn cast bullets. Do you think i should go 14T ?
Thanks

[vzerone]

No that's going to be 546.8 yards and that's a longs way to stabilize out a bullet that weight and length. I believe I'd go with a 12 twist.

If you're going to make a specific use rifle and put all the money into it, I'd use a match 30-06 reamer and I'd also want the throating made to specifications to the bullets you will be using. The standard 30-06 throat was designed for 220 grain bullets.

Do a lot of research before you commit.

[Texas by God]

What caliber is your Rem 725 now? They are a fairly scarce rifle ( basically a 721 with a US1917 safety) and unless your old barrel is bad maybe better left alone?

Sent from my SAMSUNG-SM-G930A using Tapatalk

[MaxJon]

Are you saying my 12T barrel won't shoot 185gn cast bullets accurately at 546yds?
I think it will shoot very well.

[Ballistics in Scotland]

Are you saying my 12T barrel won't shoot 185gn cast bullets accurately at 546yds?
I think it will shoot very well.

I'm just about sure that it will.

In a sense weight doesn't matter very much for bullet stabilisation. What does is length, density and shape. I'd consider 185gr. and 12in. doubtful with boat-tails or very long spire points, or with a material lighter than lead plus jacket. The main significance of the bullet being cast is that it is likely to be of an easily stabilised shape.

The twist required is inversely proportional to the square root of the bullet material, and directly proportional to the square root of the medium through which it passes. This has the interesting effect that a bullet fired in water, about 900 times the density of air, would require a twist 30 times as fast.

Normally satisfactory stabilisation is liable to break down at low velocity. But it is rotational velocity that counts. This doesn't decline nearly as fast as linear motion. A bullet which has lost most of its linear velocity at extreme range is usually still spinning fast enough to be stable. If you could watch a little spot marked on its exterior, you would see it travelling in a much tighter helix than it did at the muzzle.

Where a problem can arise is if you use reduced loads for practice or the elimination of backyard pests. If you half the linear velocity, you half the speed of rotation, and tumbling is extremely likely. This isn't the biggest of sacrifices, but it could let you in for buying a pistol mould.

So why prefer a slow twist over a fast one? There are three, or maybe it should be three and a half reasons. With cast bullets it reduces friction, and the possibility of leading. With a jacketed bullet driven at extreme velocities, it reduces the chances of core melting (frictional heat) and/or bullet disintegration (frictional heat and centrifugal force).

The third is that when a bullet is imperfectly balanced (which all of them are to some small extent), its centre of mass is actually travelling in an extremely tight helix while the bullet's exterior travels down that straight bore. On exiting the bore it obeys Newton's First Law by changing to straight-line motion - and that line is the last direction in which the helix was pointing. The better the bullet, the less this effect. But for a given bullet, the error increases with the faster pitch.

[Outpost75]

I can validate from my own experience what Larry says about a 14" twist in an '06. Interesting that even ordinary Ball M2 152-grain flatbased FMJ shoots much more accurately in the slow twist than it does in the 1:10". I can drive the 160-grain Harris design bullet to full jacketed velocity with IMR4064 with better accuracy than Ball M2 in the same rifle.

If you are adventurous and really want a high velocity cast bullet rifle, which will shoot accurately with 150-grain flatbased jacketed factory ammo for deer hunting, and be scary accurate with 160-grain cast bullets, as shown below, try a 15" or 16" twist barrel of target quality if you might luck into one. Otherwise I vote 1:14" unless your hunting situation requires heavy bullets for elk, etc. Then 12" is adequate.

208695208696208697

[quail4jake]

What a great summary, is this all from Hatcher's Notebook or is there another source that you recommend for interior and exterior ballistics? And thanks!:lovebooli

[MostlyLeverGuns]

There are also several barrel makers that have 1-11 twist available.

[vzerone]

I can validate from my own experience what Larry says about a 14" twist in an '06. Interesting that even ordinary Ball M2 152-grain flatbased FMJ shoots much more accurately in the slow twist than it does in the 1:10". I can drive the 160-grain Harris design bullet to full jacketed velocity with IMR4064 with better accuracy than Ball M2 in the same rifle.

If you are adventurous and really want a high velocity cast bullet rifle, which will shoot accurately with 150-grain flatbased jacketed factory ammo for deer hunting, and be scary accurate with 160-grain cast bullets, as shown below, try a 15" or 16" twist barrel of target quality if you might luck into one. Otherwise I vote 1:14" unless your hunting situation requires heavy bullets for elk, etc. Then 12" is adequate.

208695208696208697

What are you considering scary accurate and at what distance?

I find often that cast bullets shoot more accurate then jacketed (especially in the application of using a military rifle with original military ammo) is because you can fit the cast bullet to the barrel better. An example would be with the military bullet that isn't full groove size and loose in the throat.

[vzerone]

Are you saying my 12T barrel won't shoot 185gn cast bullets accurately at 546yds?
I think it will shoot very well.

Quite the opposite bullbarrel033, I'm saying it will shoot accurate.

[Larry Gibson]

I'm considering a 30-06 SS 12T x 26inch heavy barrel for 500m competition, for 180-190gn cast bullets. Do you think i should go 14T ?
Thanks

Stability is going to be based on the length of the bullet. A 311299 out of a 14" twist requires 1900 fps to be fully stabilized with a Sg of 1.4 (Sg of 1.4 means the bullet is fully stable but some accept a 1.3 Sg as stable enough) . The 311334 is about the longest standard cast bullet at 1.225" and it would need a 13" twist at 1960 fps for a Sg of 1.4. The MP 311-180 at 1.03", made expressly for the .308W, requires only 800 fps out of a 14" twist barrel for an Sg of 1.4.

If you consider jacketed bullets the Sierra 175 MK at 1.245" is barely stable at 2650 fps from the 14" twist yet it does very well at 1000 yards. The longer VLD type bullets require a faster twist such as 11 or 12". Most all FB'd jacketed bullets up through 180 gr are well stabilized by a 14" twist with practical jacketed bullet loads. All SPBT and HPBTs up through the 175 MK are also well stabilized.

Of course the slower 14" twist is best for cast bullets because the RPM stays under the RPM Threshold at 2600+ fps. A 31129 at 2400 fps will hold very well to 600 yards and farther.

[MaxJon]

The 12" twist will definitely be the best choice. If you are using cast up through 180 gr then you might consider a 14" twist and a 26" barrel. You can push 2600+ fps with excellent accuracy if that interests you.

Larry Gibson

What's your twist on this Larry?

[vzerone]

Stability is going to be based on the length of the bullet. A 311299 out of a 14" twist requires 1900 fps to be fully stabilized with a Sg of 1.4 (Sg of 1.4 means the bullet is fully stable but some accept a 1.3 Sg as stable enough) . The 311334 is about the longest standard cast bullet at 1.225" and it would need a 13" twist at 1960 fps for a Sg of 1.4. The MP 311-180 at 1.03", made expressly for the .308W, requires only 800 fps out of a 14" twist barrel for an Sg of 1.4.

If you consider jacketed bullets the Sierra 175 MK at 1.245" is barely stable at 2650 fps from the 14" twist yet it does very well at 1000 yards. The longer VLD type bullets require a faster twist such as 11 or 12". Most all FB'd jacketed bullets up through 180 gr are well stabilized by a 14" twist with practical jacketed bullet loads. All SPBT and HPBTs up through the 175 MK are also well stabilized.

Of course the slower 14" twist is best for cast bullets because the RPM stays under the RPM Threshold at 2600+ fps. A 31129 at 2400 fps will hold very well to 600 yards and farther.

That's why all the serious 1000 yard competitors use a 14 twist huh Larry? Explain this, most all the 30 calibers including the big magnums use a twist anywhere from 10 to 12. Why is that Larry if they are too fast a twist?

[MaxJon]

Stability is going to be based on the length of the bullet. A 311299 out of a 14" twist requires 1900 fps to be fully stabilized with a Sg of 1.4 (Sg of 1.4 means the bullet is fully stable but some accept a 1.3 Sg as stable enough) . The 311334 is about the longest standard cast bullet at 1.225" and it would need a 13" twist at 1960 fps for a Sg of 1.4. The MP 311-180 at 1.03", made expressly for the .308W, requires only 800 fps out of a 14" twist barrel for an Sg of 1.4.

If you consider jacketed bullets the Sierra 175 MK at 1.245" is barely stable at 2650 fps from the 14" twist yet it does very well at 1000 yards. The longer VLD type bullets require a faster twist such as 11 or 12". Most all FB'd jacketed bullets up through 180 gr are well stabilized by a 14" twist with practical jacketed bullet loads. All SPBT and HPBTs up through the 175 MK are also well stabilized.

Of course the slower 14" twist is best for cast bullets because the RPM stays under the RPM Threshold at 2600+ fps. A 31129 at 2400 fps will hold very well to 600 yards and farther.

Thanks Larry! I may go the 14T for dedicated cast bullets, he'll I hardly shoot jacketed anymore.

[MaxJon]

That's why all the serious 1000 yard competitors use a 14 twist huh Larry? Explain this, most all the 30 calibers including the big magnums use a twist anywhere from 10 to 12. Why is that Larry if they are too fast a twist?

I think Larry is saying, cast bullets don't handle high RPM as well as jacketed bullets do. So the slower twist helps keep RPM down whist still having a good velocity.
Thats my understanding, so I'm going the 14T heavy SS 26 inch barrel! Love my cast beauties!!

[vzerone]

I think Larry is saying, cast bullets don't handle high RPM as well as jacketed bullets do. So the slower twist helps keep RPM down whist still having a good velocity.
Thats my understanding, so I'm going the 14T heavy SS 26 inch barrel! Love my cast beauties!!

What it is bullbarrel033 is that many can't shoot cast at high velocity (which means high rpm) from fast twist barrels. There are a good number of people here past and present that can do it. It takes what I call extreme reloading to achieve it and it can be done and it can be done without using the very hard alloys like Linotype. Runfiverun and his daughter can do it with a very fast twist AR 15 in 5.56. RPM only acts upon bullets that are not started straight in the bore or have a defect in them. It is very hard to do with shallow rifling. Cast does require deeper rifling. Over the years manufactures have been making rifling grooves more shallow. Custom barrel makers will give you just about anything you ask for.

[runfiverun]

all of my testing has shown that the twist just finishes off what would have been poor on paper performance anyway.

[MostlyLeverGuns]

Getting a PERFECT bullet straight and truly centered in the rifling is far more critical than twist rate - provided twist is not TOO SLOW. The slower twists are more forgiving to bullet imperfections and chambers and throats that allow a bullet to enter the bore without being aligned properly. Bullets that can be damaged by the rotational stresses also benefit from the slower twist.

[vzerone]

Getting a PERFECT bullet straight and truly centered in the rifling is far more critical than twist rate - provided twist is not TOO SLOW. The slower twists are more forgiving to bullet imperfections and chambers and throats that allow a bullet to enter the bore without being aligned properly. Bullets that can be damaged by the rotational stresses also benefit from the slower twist.

That's absolutely right MostlyLeverGuns. When a bullet goes to sleep what they are talking about is the bullet is unstable right out of the muzzle. By the bullet spinning there is a gyroscopic action that is constantly trying to stabilize it. When it finally does that's when it goes to sleep. That is unless the bullet is very defective or was started into the bore very crooked. Higher rpms have a stronger gyroscopic force. Lack of this is mainly what is wrong with a slower twist and it's slower rpm, especially if the twist was just barely fast enough to stabilize the bullet. The thing that is really going on is what the rifling is doing to the bullet while it's in the bore. This explains one reason why paper patched bullets shoot better then naked cast. Larry Gibson knows this and is why he came up with his rules to shooting cast at high velocity. Hey! Who made him boss on telling us what rules we have to follow? Some of his rules are it has to be a ternary alloy. We can't paper patch it. Then he imposed some group size with so many shots and groups. He has it set up so it's hard to beat his theory. Back to the rifling damaging the bullet. You can paper patch a very soft alloy and get good accuracy with high velocity and high rpm. A cast bullet that is hardened is not the same hardness in the center as it is on it's surface. Yet this hardness on the surface isn't strong enough for some rifling. These riflings are of either a very fast twist or are very shallow. The 5.56 is a very good example of this as it has both attributes. Something changes on the surface of the bullet after it's been subjected to the above. I don't know what it is, but I'm thinking it's molecular. To tell more on my not knowing what it is, if you were to capture a fired bullet that was exposed to fast twist and/or shallow rifling and was undamaged you wouldn't see anything unusual. I've recovered bullets fired at high velocity from fast twist, not in good shape, but enough of the back end of the bullet to show me the rifling grooves. There was no skipping what so ever. There wasn't even an abnormal force side of the land ridge. An example of this is that it's extremely hard to shoot high velocity with accuracy from a 7 twist 5.56. This is because most all of them have shallow rifling grooves. On the other hand, a rifle that will shoot high velocity accurately is the 6.5x55 Swede and that rifle does have deep rifling.

Previously a few of us have searched for a formula to figure out the force put against the force side of the land in the rifling. All along it was right under our noses in the NRA Cast Book. Here it a copy of that formula.
208725

I know many of you are not interested in high velocity cast bullet shooting, but many of you do have rifles with the faster rifling twist. Don't let someone try to discourage you from shooting high velocity cast loads and don't let that person dictate what rules you have to follow. One thing is certainly true about shooting high velocity with accuracy from the faster twists and that is it isn't easy but it can be down. One of the posters in this thread has been doing it for a long time and that is runfiverun. There are many more. Another thing is that shooting Linotype at high velocity willwear your throat out exceptionally fast! You don't have to use Linotype to achieve this. It's very satisfying to shoot cast bullet at jacketed bullets with accuracy at high velocity even just at paper targets.

[vzerone]

Stability is going to be based on the length of the bullet. A 311299 out of a 14" twist requires 1900 fps to be fully stabilized with a Sg of 1.4 (Sg of 1.4 means the bullet is fully stable but some accept a 1.3 Sg as stable enough) . The 311334 is about the longest standard cast bullet at 1.225" and it would need a 13" twist at 1960 fps for a Sg of 1.4. The MP 311-180 at 1.03", made expressly for the .308W, requires only 800 fps out of a 14" twist barrel for an Sg of 1.4.

If you consider jacketed bullets the Sierra 175 MK at 1.245" is barely stable at 2650 fps from the 14" twist yet it does very well at 1000 yards. The longer VLD type bullets require a faster twist such as 11 or 12". Most all FB'd jacketed bullets up through 180 gr are well stabilized by a 14" twist with practical jacketed bullet loads. All SPBT and HPBTs up through the 175 MK are also well stabilized.

Of course the slower 14" twist is best for cast bullets because the RPM stays under the RPM Threshold at 2600+ fps. A 31129 at 2400 fps will hold very well to 600 yards and farther.

BTW that 311-180 mold by Mihec was first of designed by 45 2.1 and it was designed expressly for the 7.62 NATO as you know has different throating, not the 308W as you mentioned. Also the first company to make that mold was LEE, then BaBore, and finally Mihec.

[country gent]

Now to decide 3, 4, 5, or 6 grooves.

[swheeler]

I think Larry is saying, cast bullets don't handle high RPM as well as jacketed bullets do. So the slower twist helps keep RPM down whist still having a good velocity.
Thats my understanding, so I'm going the 14T heavy SS 26 inch barrel! Love my cast beauties!!

Sounds like a good choice.:drinks:

[vzerone]

all of my testing has shown that the twist just finishes off what would have been poor on paper performance anyway.

Great post runfiverun :drinks::drinks::drinks:

[vzerone]

Getting a PERFECT bullet straight and truly centered in the rifling is far more critical than twist rate - provided twist is not TOO SLOW. The slower twists are more forgiving to bullet imperfections and chambers and throats that allow a bullet to enter the bore without being aligned properly. Bullets that can be damaged by the rotational stresses also benefit from the slower twist.

That is some good thinking MostlyLeverGuns! :drinks::drinks::drinks:

[Outpost75]

What are you considering scary accurate and at what distance? ...


Fair question. I have a switch-barrel Sako with 14" and 16" twist .30-'06, pillar bedded into a McMillan M40A1 stock reinforced with 600 mesh stainless steel wire and aluminum box girder stiffened fore-end. Barrels are by B.J. Obermeyer with Min. SAAMI body dimensions and 0 degree, 45 minute basic forcing cone from .3104 major diameter with .339" neck.

With Sierra 155 Palmas and 52 grs. of IMR4064 in FA60NM cases neck turned 0.012", Federal 210M at 3.34" OAL series of five 10-shot groups off return to battery rest at 300 metres average 5.5cm, about 2".

Good cast loads with 40 grs. of IMR4064 with HM2-.312-160-5 quenched wheelweights, same components, light press into rifling origin with nose engraving run 6-7 cm, not too bad for cast at 2200 fps. Edge is to the 16" twist, but hard to nail down solid without access to a tube range, which I don't have anymore...

[Larry Gibson]

Here's what I call "scary accurate"....the distance is 100 yards but both hold 1.5 moa at 300 and 400 yards. Both bullets cast of Lyman #2 alloy, WQ'd and lubed with 2500+.

308W with 311466 out of 14" twist barrel taken off a Shultz & Larson Palma M98 and refitted to my M98 action (byf WWII make). Chamber finish reamed with a Clymer M118 Match reamer (that's not a ".308W chamber" btw even though they are, in actuality the same). That is not a throat that was cut to fit the bullet.......however, the bullet was sized to fit the throat which is what is important. Note the velocity is 2600+ fps.

208768


Here's a 20 shot group out of the cold clean 16" twist Broughton barrel on my CZ24 M98 action chambered in 30x60 XCB. This one does have a throat cut to fit the bullet; a NOE 30 XCB 310-165-FN. I marked the 1st shot, the fouler which is out of the group at 11 o'clock. The 2nd shot is out at 2 o'clock and the other 19 went into basically moa. This is my standard load for this rifle. The velocity is 2950 fps.

208770

That is what can really be done as demonstrated and proven using sound testing and understanding the science of ballistics and physics. Those who continue to believe in the old disproven myths will continue to babble on but actually show us nothing.

[swheeler]

Larry that is some very good shooting from both twist rates, and velocities of 2600 fps in the 1:14 twist and 2950 fps in the 16T, superb! Now for a question, do you think either one of those loads would put any or all of the shots even on 100 yd paper at the same speeds out of say a 10T barrel? I'm thinking maybe a few random hits and some sideways impacts, I guess if 4 or 5 landed close to each other you could circle those and claim accuracy. What do you think, I know you've actually tried it.

[Larry Gibson]

swheeler

"Now for a question, do you think either one of those loads would put any or all of the shots even on 100 yd paper at the same speeds out of say a 10T barrel? I'm thinking maybe a few random hits and some sideways impacts, I guess if 4 or 5 landed close to each other you could circle those and claim accuracy. What do you think, I know you've actually tried it. "

Depends on how large the "paper" was.........On a standard 100 yard military target of 21x21" aiming at the center with the 2600 fps load you may or may not keep 10 shots on paper. Probably 1 or more would be off paper. Keyholing would be apparent in some oblong shaped holes. it is possible several of the bullets would form some semblance of a "group". You might even get lucky (not really luck but simply "random dispersion" within the cone of fire) and have 3 or so land close together.

With the 2950 fps load......some might be on paper, most probably not. Keyholing would be the norm, either partial or full keyholing. If you shot enough shots you might get 10 on target with maybe 3 or so landing close together due to random dispersion.

I have pushed both the 311466 and the 30 XCB to 2700 fps in the 10, 12 and 14" twist test rifles (.308W). The results with the 10" twist were as described. With the 12" twist most of the bullets were "on paper" but above 2500 fps keyholing began. Up to 2400 fps +/- results with the 12" twist were actually quite good. With the 14" twist results were very good as shown by the target posted above.

I also have duplicated a supposed 3100 fps load with a 122 gr cast bullet, the 311465. The braggart claimed a 4 shot incredible group out of a 10" twist AR10 with a 20" barrel pushing that weight cast bullet (he use the comparable Lee bullet) with H4198. I found I could not duplicate the velocity he claimed w/o getting 65 - 70,000+ psi as measured in the test rifle. The test rifle also has a 24" barrel. At 250+ fps less than the 3100+ fps the braggart claimed I had severe keyholing and a very large dispersion on the military target with a couple shots not hitting paper. The braggart posted the "group" but it was a cropped picture showing what he claimed was 4 shots in basically a moa group. Close examination reveals there is one shot and a complete keyhole next to it. When we look at his un-cropped picture of the whole target (actually he had a couple targets side by side) we see a very large dispersion with keyholing predominant. He probably just shot a lot of rounds at the target and then claimed the close hits as a "group" cropping the photo. He also posted that in his usual attempt to "one up me" as I had just posted the 2950 fps groups and he goes out of his way to prove me wrong. Thus he had to claim a higher velocity with better accuracy out of a faster twist......his usual absurd claims.

What myself and others have shown here, plus others in other threads, by posting actual results is we can actually accomplish what we claim. Those that just talk about what they've done or what someone else has claimed are....well.....just talking about it.......

[vzerone]

Larry that is some very good shooting from both twist rates, and velocities of 2600 fps in the 1:14 twist and 2950 fps in the 16T, superb! Now for a question, do you think either one of those loads would put any or all of the shots even on 100 yd paper at the same speeds out of say a 10T barrel? I'm thinking maybe a few random hits and some sideways impacts, I guess if 4 or 5 landed close to each other you could circle those and claim accuracy. What do you think, I know you've actually tried it.

Yes they would swheeler, it's just that you and Larry can't do it especially with plain stock rifles. In fact I've never seen you get into the 6.5 Swede threads except to just run your mouth. There have been many that have done it. Ask Runfiverun about his daughter shooting the seven twist AR 15. Plus you've seen the 1/2 hole stametal shot with his 6.5 Swede, but you and Larry called him a liar. 45 2.1 has more then one Ruger scout doing that. :drinks::drinks:

[vzerone]

Here's what I call "scary accurate"....the distance is 100 yards but both hold 1.5 moa at 300 and 400 yards. Both bullets cast of Lyman #2 alloy, WQ'd and lubed with 2500+.

308W with 311466 out of 14" twist barrel taken off a Shultz & Larson Palma M98 and refitted to my M98 action (byf WWII make). Chamber finish reamed with a Clymer M118 Match reamer (that's not a ".308W chamber" btw even though they are, in actuality the same). That is not a throat that was cut to fit the bullet.......however, the bullet was sized to fit the throat which is what is important. Note the velocity is 2600+ fps.

208768


Here's a 20 shot group out of the cold clean 16" twist Broughton barrel on my CZ24 M98 action chambered in 30x60 XCB. This one does have a throat cut to fit the bullet; a NOE 30 XCB 310-165-FN. I marked the 1st shot, the fouler which is out of the group at 11 o'clock. The 2nd shot is out at 2 o'clock and the other 19 went into basically moa. This is my standard load for this rifle. The velocity is 2950 fps.

208770

That is what can really be done as demonstrated and proven using sound testing and understanding the science of ballistics and physics. Those who continue to believe in the old disproven myths will continue to babble on but actually show us nothing.

In competition they count all the holes, but it's okay for you to have holes outside the main group, but not me, starmetal, or 45 2.1 huh?

[vzerone]

Fair question. I have a switch-barrel Sako with 14" and 16" twist .30-'06, pillar bedded into a McMillan M40A1 stock reinforced with 600 mesh stainless steel wire and aluminum box girder stiffened fore-end. Barrels are by B.J. Obermeyer with Min. SAAMI body dimensions and 0 degree, 45 minute basic forcing cone from .3104 major diameter with .339" neck.

With Sierra 155 Palmas and 52 grs. of IMR4064 in FA60NM cases neck turned 0.012", Federal 210M at 3.34" OAL series of five 10-shot groups off return to battery rest at 300 metres average 5.5cm, about 2".

Good cast loads with 40 grs. of IMR4064 with HM2-.312-160-5 quenched wheelweights, same components, light press into rifling origin with nose engraving run 6-7 cm, not too bad for cast at 2200 fps. Edge is to the 16" twist, but hard to nail down solid without access to a tube range, which I don't have anymore...

That's good shooting!

[vzerone]

Notice that Outpost posts his shooting results and he filled us in pretty well on the equipment, loads, etc.. But no target pictures no and no chronograph pictures, and no ES's, SD's, etc. Outpost this by no means to demeaner you. It's a point to show the members, read on. Now if me, starmetal, or 45 2.1 done this Larry Gibson and his minions, especially swheeler would be all over us for those pictures of the targets, chronograph screen, etc., etc., and calling us liars to boot.

BTW Those cast bullets not only will stay on the target at 2700 fps or whatever high velocity, but shoot pretty respectable groups. Don't let those two birds fool you.

[Larry Gibson]

Vzerone

Try actually reading the posts before whining. All 10 shots were counted in the top group. All 20 shots were counted in the bottom group......it's written right there....a 1.6" group including the fouler.

As to what outpost75 posts....he does indeed post lots of detail along with pictures OF WHAT HE DOES. All you post is what someone else does or says they do.

Before you call the kettle black you should remember what you, your twin, 45 2.1 and others have called me and many others on this forum.

You need to get a life, try actually casting some bullets, shooting them and posting the results instead of regurgitating what you can plagiarize off the internet.

[AK4570]

Since all of my shooting/hunting takes place in the frozen North (with a fondness for heavy lead added in:-)), I'll add my vote for the 14 twist.

Best,
John

[MaxJon]

Here's what I call "scary accurate"....the distance is 100 yards but both hold 1.5 moa at 300 and 400 yards. Both bullets cast of Lyman #2 alloy, WQ'd and lubed with 2500+.

308W with 311466 out of 14" twist barrel taken off a Shultz & Larson Palma M98 and refitted to my M98 action (byf WWII make). Chamber finish reamed with a Clymer M118 Match reamer (that's not a ".308W chamber" btw even though they are, in actuality the same). That is not a throat that was cut to fit the bullet.......however, the bullet was sized to fit the throat which is what is important. Note the velocity is 2600+ fps.

208768


Here's a 20 shot group out of the cold clean 16" twist Broughton barrel on my CZ24 M98 action chambered in 30x60 XCB. This one does have a throat cut to fit the bullet; a NOE 30 XCB 310-165-FN. I marked the 1st shot, the fouler which is out of the group at 11 o'clock. The 2nd shot is out at 2 o'clock and the other 19 went into basically moa. This is my standard load for this rifle. The velocity is 2950 fps.

208770

That is what can really be done as demonstrated and proven using sound testing and understanding the science of ballistics and physics. Those who continue to believe in the old disproven myths will continue to babble on but actually show us nothing.

Nice work Larry!

[MaxJon]

Here's what I call "scary accurate"....the distance is 100 yards but both hold 1.5 moa at 300 and 400 yards. Both bullets cast of Lyman #2 alloy, WQ'd and lubed with 2500+.

308W with 311466 out of 14" twist barrel taken off a Shultz & Larson Palma M98 and refitted to my M98 action (byf WWII make). Chamber finish reamed with a Clymer M118 Match reamer (that's not a ".308W chamber" btw even though they are, in actuality the same). That is not a throat that was cut to fit the bullet.......however, the bullet was sized to fit the throat which is what is important. Note the velocity is 2600+ fps.

208768


Here's a 20 shot group out of the cold clean 16" twist Broughton barrel on my CZ24 M98 action chambered in 30x60 XCB. This one does have a throat cut to fit the bullet; a NOE 30 XCB 310-165-FN. I marked the 1st shot, the fouler which is out of the group at 11 o'clock. The 2nd shot is out at 2 o'clock and the other 19 went into basically moa. This is my standard load for this rifle. The velocity is 2950 fps.

208770

That is what can really be done as demonstrated and proven using sound testing and understanding the science of ballistics and physics. Those who continue to believe in the old disproven myths will continue to babble on but actually show us nothing.

That's really impressive Larry!

I'm about to order a heavy 26 inch SS barrel for my scoped M98 30-06, for long 190gn cast bullets for 500m competition, do I order 12 or 14T? 2600fps is plenty fast enough for our required power factor also.
Looking at your results I think 14T but I really value your genuine opinion thanks!!

[Forrest r]

FWIW:

I was wondering the same thing awhile back and asked about bbl's. Was looking at a 308w bbl for a old puma rifle & wasn't sure about the twist. I posted the bbl would have a .340" match chamber & a 1 in 14 to be used be mainly for cast bullets. The answers I got?

runfiverun posted Where are you going to find brass with .340" necks?
Larry posted That would be an excellent choice!

I had to post telling runfiverun about this thing called surplus brass and more specifically lc (nato) brass that is thicker than commercial commercial brass.

The bbl mfg I was ordering the bbl from offered 2 different match chambers. A .332" for neck turned commercial cases and .308" bullets. I opted for the .340 chamber for the thicker nato cases and .310/.311 bullets.

At the end of the day:
Years ago I shot a little high power, had a 40x/300mag combo that I used on a 1500yd range. Used cast bullets for pistols out to 200yds and 100yd/30a3 (30-06) on reduced targets/service rifle. I've acquired several 30cal molds over the decades (30+) and tinkered with then in several different 30cal firearms. Fast forward:

A couple of years ago I was at a gunshow and saw a cil 950T (puma rifle) on a rack at a give away price. It reminded me of the 40x I used to own, heavy stock/handstop rail/setup for irons & scope/etc. It had the older savage action (great/easy bbl swaps) and a good 3-way adjustable trigger in it so I bought it.
1st thing I did was rebuild the bolt ensuring consistent ignition. Then I bought a 20" 1 in 10 twist deep grooved bull bbl for it & started testing. It was nothing more than a cheap bbl from ebco. I tested that 1 in 10 with 16/17 different cast bullets along with 3 different bump die profiles along with swaging bullets. Learned a little about alloys, gc's, bullet sizing/fit, static fit. One of the bump died I made was for a static fit in that ebco bbl. Took a 230gr blackout cast bullet (lee) and bumped it to fit the 308 case/chamber/throat. The now gc'd bullet (boattail before) has the gc of the bullet sitting so the gc is centered in the bottom of the neck of the case & the arrow points to where the freebore ends and the throat taper begins as the nose turns int a bore rider with a short unsupported nose (a slump thing).
https://i.imgur.com/NzT7Yz8.jpg

The last thing I did to that ebco bbl was to take a 3/4* throat reamer and re-cut the throat. Wanted to do testing for future use of the 3/4* reamer, along with reuse the bbl and cut a match 30-06 chamber. Want to cut a 30-06 match chamber with no freebore, just chamber and a 3/4* throat. Anyway a bullet from the standard 308w throat (top) next to a bumped bullet (same bullet, 3/4* bump die), bottom. You can see where the top bullet has rifling marks on it and the bottom bullet has full length rifling marks. The wiper groove was compressed and that's where the rifling ends in that chamber. The space from the end of the case to the start of the rifling is the ball throat/freebore I want to take out when I re-cut the chamber in that bbl. Hence easier to bump/static fit any cast bullet in the long tapered throat.
https://i.imgur.com/VGFrnqc.jpg

Then I bought a 1 in 11 twist bbl with shallow grooves 308/301 and a custom chamber, 25" long, varmint contour from apache gunworks. I is cut/designed to shoot 175gr smk bullets. It was a good bbl to experiment with & the shallow riflings were extremely sensitive to small changes with cast bullets. This bbl was a good test bed for alloys/lubes/amount of lube. It got put thru the paces with different bullets/lubes/sizes/bumped profiles/etc. It's going to end up on another 308w project, a nib rifle I bought 2 years ago.

After testing cast bullets in those 2 bbl's for 2 year I was ready to buy a bbl specifically for cast bullets and posted what I was thinking. Namely a 308w varmint tapered bbl with a match chamber/.340 neck and 1 in 14 twist. I trusted Larry's advice and ended up buying a:
1 in 14 twist, varmint contour, 30", .340" match chamber with recessed target crown from shilen.

I looked at it this way:
I did do a little testing with different bbl lengths, profiles, chambers, grooves, groove depths, bullet diameters of .308/.309/.310/.311/.312, 3 different bump dies and a bunch of different lubes/alloys/molds. It wouldn't of mattered if I ordered a 1 in 10,1 in 11,1 in 12,etc. It all costs the same. So I took the slow twist path, installed the new bbl and partially bedded the receiver and took it to the range to test for function. It only took 14 shots to get a lube star on the end of the muzzle, note the high point/clearance of the bbl in relationship to the stock (excellent cooling & no bind with slings).
https://i.imgur.com/bydam1r.jpg

Went back finished bedding the bbl'd receiver and did some initial test loads. Wanted to test the bedding, test the receiver screw lengths (3 different sets) & set the torques on the action screw. Used mixed range pick-up brass (both nato and commercial), plinking bullets (bullets cast and only culled for major flaws like wrinkles), h335 powder that most people don't recommend for cast bullets and 20+ year old magnum primers (probably older/$.50 label on them). Anyway, 30* winter weather, light 7mph winds and blammo ammo.
https://i.imgur.com/tEeK5wb.jpg?1

While nothing to write home about by any means that 2679fps 10-shot group at 100yds got my attention. That 1 in 10 twist generic bbl never did that at anywhere near those velocities. The custom 1 in 11 bbl never did that at those velocities either . The 1 in 14 did it without even trying. Shot the same loads same bullet, this time the bullets were traditionally lubed. The lube gave up at the 35gr load.
https://i.imgur.com/y5CttId.jpg?1

The bullet used, the pc'd bullet just started coming in at 36gr/2650+fps, plan on testing that pc'd bullet at 37gr/38gr/39gr with some cases from the same lot. I also put another coat of 45/45/10 on the traditionally lubed bullets. The only had a little bit of lbt blue from a lyman 450 sizer and 1 coat of 45/45/10. Going to retest the 35gr/36gr loads with good brass also. The bullets used, I'm really looking forward to the re-lubed bullet tests. I'd love to see this bullet in the 2700+fps range with both lubes and pc'd coatings seeeing how I have a 6-cavity mold that rains bullets.
https://i.imgur.com/dzDCFfV.jpg

If I were you I'd measure your necks of the brass your using on some loaded rounds and have your chamber cut accordingly. Mine measures .3385 with a .310 bullet so I had a .340 neck cut. I would also go with a longer bbl. I could of got a 26" bbl for $100 less but it's money well spent to get the longer bbl. Less pressure per load for more velocity. In another post a forum member is using 24" bbl'd 308w same bullet and 39gr of h335 to get the same velocities I'm getting with that 34gr load out of that 30" bbl. I'd also look at bullet profiles/weights and try to figure out what velocities you need to carry the bullet accurately to 500m.

Snow hit hard 20+''s so I haven't been back out yet with the new bbl. Been casting/sizing/lubing/coating for when the range opens back up.

Sorry for being so long winded. Was asking the same questions awhile ago. Larry gave me excellent advice. I put my $$$ where my mouth is and pony'd up for a 1 in 14 twist.

Just another opinion

[Forrest r]

Kinda quiet of this thread.

Go figure.

[MaxJon]

Bought the 12 twist!!!

[DCM]

Kinda quiet of this thread.

Go figure.

Yeah people like vz have driven a lot of very good knowledgeable folks away or they just don't post relative info anymore because it isn't worth the aggravation when trying to help folks.
Haven't seen Jim or William Waco in a while just to name a Few of the many.

[arlon]

I have a 1-12 twist on a model 1917 30-06. I really like it. It may not be perfect for anything but it's pretty darn good at a lot of things. Maybe the 1-12 is the "jack of all trades and master of none".

[MaxJon]

I went with the 12T because I think it will love my 190gr cast beauties, but if it ends up not liking them, I still have a jword rifle that will shoot all weights south of 180gr which I will be happy with also.

[Forrest r]

Any idea what chamber/throat angle you'll be using????

[Larry Gibson]

I went with the 12T because I think it will love my 190gr cast beauties, but if it ends up not liking them, I still have a jword rifle that will shoot all weights south of 180gr which I will be happy with also.

Actually a 30-06 with 12' twist will shoot all jacketed bullets south of and including the 220 RN. The only exceptions will be the really long VLD types of 180 gr and heavier. The heavier and longer "bore riding" noses of cast bullets make them harder to get consistent accuracy with the faster we spin them. Your 190 gr cast beauties would have done quite well in the 14" twist, actually better than they will in the 12" twist. If you want to push the higher velocity envelope with a cast bullet in your soon to have 12" twist 06 you might consider a design more capable such as the NOE 310-165-FN XCB. If accuracy alone is the name of the game your 190s should do well in the 1700 - 2000+ fps range.

[MaxJon]

Actually a 30-06 with 12' twist will shoot all jacketed bullets south of and including the 220 RN. The only exceptions will be the really long VLD types of 180 gr and heavier. The heavier and longer "bore riding" noses of cast bullets make them harder to get consistent accuracy with the faster we spin them. Your 190 gr cast beauties would have done quite well in the 14" twist, actually better than they will in the 12" twist. If you want to push the higher velocity envelope with a cast bullet in your soon to have 12" twist 06 you might consider a design more capable such as the NOE 310-165-FN XCB. If accuracy alone is the name of the game your 190s should do well in the 1700 - 2000+ fps range.

Thanks Larry thats exactly what I wanted to hear! I only need about 1850fps to make the required power factor with my 190 bullet. I'm happy with my choice. It's 26 inch and 7/8" at the muzzle so hoping it will be pleasant to shoot off the bipod.

[Larry Gibson]

bullbarrel033

Sounds like it will be a nice rifle, looking forward to pictures when you get it up and running?

[MaxJon]

bullbarrel033

Sounds like it will be a nice rifle, looking forward to pictures when you get it up and running?

No worries Larry! I just have to work out how!