.30 cast in 1-10" twist?

[dubber123]

I have a small game gun project going, and will soon need to pick a barrel. I have 2 choices; a .30" bore, with a 1-10" twist, or a .306" bore, with a 1-22" twist.

How well will the faster twist barrel do with 100 gr. cast boolits at 1,200 fps or less? I would normally choose the slower twist bbl, but the larget bore will likely clash with my choice of calibers, as the reamer pilot is normally used with the .300" bore. I could use a larger pilot, but I am afraid the chamber neck won't tolerate a big enough boolit, requiring me to also rent a throating reamer.

Anyone have any experience shooting these light plinker weight boolits in a .308 or 30-06? Thanks in advance.

[pdawg_shooter]

I have a small game gun project going, and will soon need to pick a barrel. I have 2 choices; a .30" bore, with a 1-10" twist, or a .306" bore, with a 1-22" twist.

How well will the faster twist barrel do with 100 gr. cast boolits at 1,200 fps or less? I would normally choose the slower twist bbl, but the larget bore will likely clash with my choice of calibers, as the reamer pilot is normally used with the .300" bore. I could use a larger pilot, but I am afraid the chamber neck won't tolerate a big enough boolit, requiring me to also rent a throating reamer.

Anyone have any experience shooting these light plinker weight boolits in a .308 or 30-06? Thanks in advance.

Large bore ?????????

[NVScouter]

by .30 bore do you mean .308/.309 or are you in the .310/.311/.312 areas?

[Willbird]

If I remember correctly....

"Bore size" is the minor dia.

"Caliber" is the major dia.

A barrel made to use a .308 bullet will often have a .300 minor dia.

I would base my choice on the avail bullet molds in the weight I desired to shoot.

You did not say what the major dia was of the barrel that had a .306 minor dia. Also what style of rigfing it will have. The major dia will determine what the throat size should be, and what dia bullet is used.

One advantage of the 1/10 twist is that you can use very heavy bullets if you want to.

Bill

[StarMetal]

Once again: They drill a hole through a barrel blank. Then they ream and hone that hole to a precise size. That is the BORE. Normally in American 30 caliber that hole is .300. They they installing rifling in that .300 hole. Use to be for a 308 Winchester the rifling groove was .004 deep. Now measuring from bottom of groove across to bottom of groove is the GROOVE diameter .308.

I think the gentleman meant the 22 rifling twist barrel has a .306 groove diameter because there aren't many bullets made for a .306 bore.

Joe

[Larry Gibson]

I have a small game gun project going, and will soon need to pick a barrel. I have 2 choices; a .30" bore, with a 1-10" twist, or a .306" bore, with a 1-22" twist.

How well will the faster twist barrel do with 100 gr. cast boolits at 1,200 fps or less? I would normally choose the slower twist bbl, but the larget bore will likely clash with my choice of calibers, as the reamer pilot is normally used with the .300" bore. I could use a larger pilot, but I am afraid the chamber neck won't tolerate a big enough boolit, requiring me to also rent a throating reamer.

Anyone have any experience shooting these light plinker weight boolits in a .308 or 30-06? Thanks in advance.

I've shot thousands of 88-120 gr cast bullets through 10" twist .308Ws and '06s. Mostly I prefer the Lee TL314-90-SWC or the commercial swaged Hornady 90 gr .32 cal SWCs. I generally size them to .311 for the .30 bores. I also use them for plinking and small game. Mostly I shoot plain based cast bullets at 800-1200 fps where I find the best accuracy for them to be. Actually much over 1100 fps with the short, stubby lighter wieght bullets in the faster 10" twist barrels and accuracy deteriorates. Of course GC'd bullets hold accuracy to a much higher level.

While my preference for cast bullets of 85-180 gr in the .308W or '06 has become a 14" twist barrel most often we take what we get which is a 10 or 12" twist. Given your choice of twists and bore sizes to use with light weight cast bullets under 1200 fps you should do well with the 10" twist .30 bore barrel.

Larry Gibson

[compass will]

my 308 (10 twist) likes cast 170 grain flat tips. I had it doing clover leafs at 100 yards before I put it away. Once I figured out which powder the gun liked (Varget) I never did get around to trying the 200 grain round nose lee. I need to save the primers for this summers lever gun silhouette matches.

both these boolits are GC

[dubber123]

OK for a little clarification, 1 choice is a .300" BORE,.308" GROOVE blank. (standard .308 Win/30-06 Springfield blank), with a 1-10" twist. The second is a .306" BORE, .312" GROOVE, 32-20 blank, that has a 1-22" twist.

I would normally choose the 32-20 blank, for it's slower twist, and not having to size my boolit of choice, (RCBS 98 gr. SWC), down much. My concern is the reamer for my chosen caliber likely won't cut a neck big enough to allow the chambering of .313" or larger boolits. Thats why I was considering the 1-10" blank. Thanks for the replies, any other info appreciated. Thanks.

[Willbird]

Depending on caliber you could always turn necks if you had to. But many standard chambers have a generous enough neck to allow use of a .312 bullet.

Bill

[dubber123]

Depending on caliber you could always turn necks if you had to. But many standard chambers have a generous enough neck to allow use of a .312 bullet.

Bill

The slower twist blank is labeled as a .312" groove, so it would have to accept .313" or .314", which I'm not sure would work without renting an additional throating reamer. The 1-10" blank looks like it may get the nod after all. Thanks.