Rifling/ Bullet Weight

[Phoenix]

I understand that although a wide variety of bullet weights are available for popular calibers such as the 30-06, for best accuracy (groupings) there is really an ideal bullet weight for a given rate-of-twist Is this true? Assuming it is, what would the best bullet weight be for my Remington 7400 carbine (game considerations aside)? 

[PA_BOWHUNTER]

Most people I know that reload for the 30-06 like 165's.  I have had good luck with them put personally see better results at normal hunting ranges (0-300 yards) with 150's in my set up.

[RGFIXIT]

What's the rate of twist?
RG

[Phoenix]

RG, I don't know what the rate of twist is, I don't see it in any of the documentation that came with the rifle nor is it on the barrel. Why don't they stamp this info on the barrel?

Found it on the Remington site, it's 1 in 10"

[RGFIXIT]

Phoenix,
You can measure it exactly by using a cleaning rod with a brush...mark a start point and insert the rod down the bore until it makes a complete revolution....you then measure the length of rod it took to make that complete revolution.

RG

[Phoenix]

It is 1 in 10" RG. Gotta do something, the best I've been able to get with this rifle is a 5" group at 100 yards. I know the carbine's not the ideal weapon for accuracy, but I think I should be able to do better than that. If I can get three or less out of it I'd be happy.

[RGFIXIT]

I'll do a bit of research today and get back to you.
RG

[RGFIXIT]

Phoenix,

Here goes....Ballistics 101

To determing the correct bullet weight for your rifle's rate of twist, a gunsmith would use the "Greenhill Formula" developed by a Brittish gunsmith in the 1920's.

 The formula is T=150(d/r) for velocities from about 1500 to 2800 fps. Substitute 180 for the 150 value for velocities exceeding 2800 fps. "T" is the twist rate. "d" is the bullet diameter. "r" is the bullet length to diameter ratio (length of bullet divided by diameter).

Confused???

Then a simple rule of thumb applies. The faster the rate of twist, the longer, and therefore, heavier the bullet.

I'd try a Nosler Partition in 200 or 220 grain.  Bullet weight is not the only factor effecting accuracy in the 7400. They were never an inherently accurate firearm.

But...give it a shot....so to speak

RG

[Phoenix]

Jeesh, for a minute there I thought I was back in accident reconstruction class trying to figure slide to stop speed from drag coefficient I'm going to get a box and give her a try RG. I never tried  that heavy a bullet. I know the 7400 wasn't meant for accuracy, I bought it for its' light weight. I use it mostly for deer and seldom take a shot over 100 yards, but a five inch spread is a little more than I can live with. I'd trade it on a Thompson Encore in .243 if I didn't think I'd lose my shirt