light bullet in heavy twist-heavy bullet in light twist?

[JustC]

Is there a general rule for loading bullets not specificaly in the optimum weight range for a given twist? Let's say a light bullet in a heavy twist barrel,....if you wanted it to group the best it could, would you speed it up or slow it down?

Also, If you are running a heavy bullet through a light twist, would the opposite be the correct approach?

I think this is a question of RPM, bearing surface, etc, but that's the best I can ask it. [img]images/icons/confused.gif[/img]

[MAX]

Jugglin' velocity to address marginally compatible bullet lengths and twist rates is not especially productive. Yes it does have some effect but nowhere near what a change of twist will accomplish. 1:12 twist at 3000 fps generates 3000 RPS or 180,000 RPM at muzzle. At 3200 FPs you get 3200 RPS or 192,000 rpm. A 1:10 twist at 3000 FPs gives 3600 RPS or 216,000 RPM. Bullet length is the issue, longer bullets need quicker twists.

[JustC]

My question revolves around wanting to load some varmint or lighter bullet loads in some heavier twisted barrels. I asked about 125gr bullet loads for a 30-06 with a 10twist barrel, and quite a few members gave me rave reviews of that bullet in a 10twist, but no actuall velocities for their loads. I was simply wondering, without loading and chronographing the recipes, whether they had slowed them down to get them to stabilize properly. I guess i am looking for a starting point for the future, when I go to work loads for non-perfect bullet:twist combinations.

thanks

Just C,

There is no downside to spinning a bullet past what is necessary for stability, unless the bullet is poorly made, or has a large CG offset, then accuracy will suffer. This holds true especially for varmints, because there is not a requirement for a penetration threshold. I can promise you the 30-06 will not spin a 125 Nosler ballistic tip too fast for varmints. We use this bullet in the .308 AR-10's with 51 gr. of Varget and it goes 3,160 fps. It is my favorite short range deer load. Three years ago I shot a 235 lb. whitetail from 20 yards away, broke his right front shoulder bone going in and left a 3 inch exit hole on the opposite side 5 inches behind the left front shoulder. 11.25 was the twist, and 3,180 was the velocity.

Varget in a 30-06 should easily get you to 3,200 fps. Start at 52 grains and work your way up. If you are a velocity freak, try AA 2520 and you may see 3400 depending on your barrel length. [img]images/icons/wink.gif[/img]

[JustC]

Thanks S1. before I got into the custom stuff, I saw a rugerr 77 MK II stainless 30-06 at an NRA dinner, and just have to have it. Long story short,...the wife won an auction for it without my knowing. Shortly after, I got into the custom arena, and the rifle sat unfired in the safe. Now when I mentioned selling it to help with another project, the idea was not received with the happiness one would expect. Therefore, I am going to make this rifle shoot everything I want it to, and I'm going to have fun with it. I put a boyd nutmeg laminate on it, and I am going to get it spinning those 125gr noslers, and use it for whitetail and whatever else I see in the beanfield.

The barrel is a 1:10, so I should be OK right?

[ 04-24-2003: Message edited by: JustC ]

A 1 in 10 will just make the 125 that much more deadly. I have pushed these over 4,000 with a 1 in 11, can't spin them apart with anything I've got (you know I've tried). [img]images/icons/grin.gif[/img] [img]images/icons/grin.gif[/img] [img]images/icons/grin.gif[/img]

[JustC]

Thank you for your input S1. You have inspired my interest in this rifle and the 125gr load.