Twist rate for high velocity 311299 in 30-06

[Neilsuper]

I’ve been thinking about building 30-06 with a 14 or 16 twist but am not sure that it would stabilize the 311299 has anyone tried this?

[Ford SD]

I’ve been thinking about building 30-06 with a 14 or 16 twist but am not sure that it would stabilize the 311299 has anyone tried this?

12 twist will
13 should
14 maybe
15 maybe if you push it hard
16 maybe if you push it very hard

12- 13 will still shoot all but the vld jacketed bullets

the expert is Larry Gibson

do a search on the XCB bullet

[Larry Gibson]

14" twist will stabilize 311299s above 21-2200 fps. Slow burning powders such as 4350, RL19 & 22 and H4831SC are best choices. For target work I recommend the NOE XCB 310-165-FN. For hunting the 311041 or the 30-180-FN are excellent performers at HV in a 14" twist.

[trapper9260]

Would the 10" twist work better. Just wondering.

[Outpost75]

Would the 10" twist work better. Just wondering.

In the 10" twist accuracy will quickly deteriorate above about 2000 fps. Dramatically so.

[nueces5]

In the 10" twist accuracy will quickly deteriorate above about 2000 fps. Dramatically so.

Do you consider that this also applies to the 7.65 Arg?
(I just received my new lyman mold 314299)
I understand that it is 1:10

[Outpost75]

Do you consider that this also applies to the 7.65 Arg?
(I just received my new lyman mold 314299)
I understand that it is 1:10

Yes. I would think so.

[Larry Gibson]

Yes. I would think so.

As usual, Outpost is correct. Only reason most '06s and 7.65s have 10" twist is because that's what was used with the original 220 gr RN FMJ bullets.

[Neilsuper]

Ok thanks I might go with the 16 and stick with the lighter bullets it will be used for target shooting mostly I already have a 12 twist 308 that does well with the 311299

[lar45]

I have a 14 twist 30-06XCB and with the NOE 30XCB boolit I have pushed 2850 and still had groups around the 1" mark.

[Neilsuper]

What type of rifling are you guys using in the xcbs

[Larry Gibson]

With the XCB in my 3 groove Broughton barrel (31") chambered in 30x60 XCB the bullet at a length of .98" needs to be pushed relatively fast for best accuracy. As already mentioned, a 14" twist is also very versatile, more so that the 16" twist, with longer bullets such as the 311299 and handles the XCB bullet quite well.

A search of this forum for 30 XCB at high velocity should yeild a plethora of threads/posts about it.

[Neilsuper]

Ok thanks I’ll have to do some digging on whats available for barrels and reamers here in Canada

[Neilsuper]

I am also considering building a 223 bolt action for high velocity cast light bullets what velocities do you think could be achieved with 1-1.5 Moa accuracy and say 40 grain bullets in a 16-18 twist

[Forrest r]

FWIW:
I listened to Larry's excellent advice and bought a 1 in 14 twist 308w bbl. I was looking for a bbl with versatility & the 1 in 14 twist delivers just that.

While not the 311299, I tested the cramer #43 (186gr sp) in that 1 in 14 twist bbl.
[IMG][/IMG]

I tried several different powders and kept running into a barrier when going above 2450fps. The nose would slump on the bullet affecting accuracy. The cramer mold I have casts a sp & a hp version of that bullet. The hp version of that bullet always out performed the sp bullet when pushed above 2450fps confirming my suspicions about the nose slump. Typical targets with those sp vs hp bullets in the 1 in 14 twist bbl.
[IMG][/IMG]

Same 1 in 14 twist bbl using the lee 160gr tl-2r bullet that has a shorter body and stronger nose then the cramer #43.
[IMG][/IMG]

[IMG][/IMG]

[IMG][/IMG]

Just now started testing the xcb bullet & the lyman 311465.

[Larry Gibson]

I am also considering building a 223 bolt action for high velocity cast light bullets what velocities do you think could be achieved with 1-1.5 Moa accuracy and say 40 grain bullets in a 16-18 twist

With a 16" twist 2800 -2900 fps with that level of consistent accuracy may be possible. At that level everything is critical.

[bullseye67]

Good evening,

I followed Larry’s advice and built a 30-06 to shoot the XCB boolit. I went with a “15” twist and 30” barrel in
Mid Palma weight. I have run as high as 2950 FPS with H4895 and had 4” groups at 300 Meters. I have since dialed it back a bit and am using IMR4831 and a 9 1/2 Rem primer. I stopped at a nice 2800 FPS load that goes less than 2” at 200 Meters with 8 of 10 shots. Boolits are super critical at those speeds. I gave up testing loads at 100 Meters. Most of the time it ripped one ragged hole. I have had personal lessons from Larry on preparing boolits to get those speeds and accuracy. All it takes is a slight miss cast boolit and at 200 Meters it misses the group!!

Now I have a rifle that easily hits an IPSC sized target at 500 Meters and I can shoot all day at 300 Meters on a 6” plate. All for the cost of a copper gas check, and some alloy!!

But.... don’t expect lazer precision....we are still talking horrible BC’s and rainbow trajectory.

[Forrest r]

I got the bad bullet part down better than most.

[DonH]

Not .30-06 but my .32-40 is 14" twist while a friend's is 16". To stabilize the same 220 be bullet his required more velocity than mine.

[Neilsuper]

I’m not sure I need the slower twist now I hardened up my alloy to see how fast I could push it and ran out of room for powder in the 308 at 2800fps in my Remington 700 varmint laminate 12 twist shooting the Lee 155 and shot a five shot group at 100 yards right around 1 moa I am going to be testing this more this week as this might have been a fluke but the harder alloy has definitely increased my velocity with accuracy