Rebarreling my savage 243.

[Mattd212]

Hey guys. New to the forum here. I’ve been thinking about getting another barrel for my savage 243 since I’ve put a lot of rounds through it. What would be the best twist rate for primarily 55 gr bullets. Should I stick with a 1:10 or go to a 1:12.

 

[BlueWater]

Using a Hornady V-Max 58gr bullet as an example, at 75*F and 500ft altitude ...

According to the Berger Twist Rate Stability Calculator:

• 1:10" twist for a 58gr bullet will have solid stability (1.88 > 1.50 SG); and
• 1:12" twist for a 58gr bullet will have "marginal" (1.30 < 1.50 SG) stability.

Twist Rate Stability Calculator

Our newly updated Twist Rate Stability Calculator not only tells you what your SG is, but it also lets you know if you are reaching your optimized BC.

bergerbullets.com

JBM - Bullet Length List

www.jbmballistics.com

Just as a reference, there are pre-fit and chambered barrels out there, such as the ones from forum sponsor UrbanRifleman (which are 8" twist for the .243 Win, in their Savage small-shank, heavy varmint profile version).

I'm sure others will chime in with their own .243 Win suggestions for barrel twist, outside of what calculators might predict.

 

[NorCalMikie]

For .243? (6MM) Go 8 twist with a ZERO free bore and load the lightest bullets you can get your hands on. Go heavier as the throat wears. (and it will, probably faster than you want)

 

[rickt300]

My snivel about the really fast twists and velocities is that standard soft point bullets will often come apart. The Nosler Ballistic tip does very well as do most match bullets. I don't know about the VMax but the JBM calculator seems to say 1-12 is just fine. This said a 10 twist does no harm and will work with the 87 gr. VMax.

JBM - Calculations - Stability

jbmballistics.com

 

[Bojo]

My factory savage barrel in 243 win came in a 9.25 twist.
It shot 58 Zmax , 87 vmax and all the way up to and including 95 Berger vld’s well. That being said I’d go 1:8 or 1:9.

 

[moorepower]

A 1-12 twist 6br shoots 58's in a bughole, so I don't quite buy the Berger calculator. The faster twist will have more explosive hits. I would personally use a 1-8 zero freebore

 

[Mattd212]

This will also be primarily for coyote and trying to keep pelts in mind so if I’m reading that right and faster is a more explosive contact would that not be a point on the slower twist as long as it’s gunna stay accurate?

 

[rickt300]

This will also be primarily for coyote and trying to keep pelts in mind so if I’m reading that right and faster is a more explosive contact would that not be a point on the slower twist as long as it’s gunna stay accurate?

Keeping pelts intact might be a bit tough. I have settled on the 55 gr. Ballistic Tip and have found I should expect good sized holes.

 

[Mattd212]

Keeping pelts intact might be a bit tough. I have settled on the 55 gr. Ballistic Tip and have found I should expect good sized holes.

Ideally I’d just get a smaller rifle but till then I just wanna do the best I can without sacrificing too much velocity.

 

[rickt300]

I shoot coyotes just because they are destructive varmints and owe me plenty of chickens. I would be happy if when I hit one it turned into a puff of hair and left smoldering chunks of meat in a 20 foot circle. I may try the 55 gr. Nosler Varmageddon tipped bullet soon as I can find some.

 

[SShooterZ]

Look at what @urbanrifleman has to offer. He has some nice 6MM options and his barrels shoot well.

 

[Mattd212]

I shoot coyotes just because they are destructive varmints and owe me plenty of chickens. I would be happy if when I hit one it turned into a puff of hair and left smoldering chunks of meat in a 20 foot circle. I may try the 55 gr. Nosler Varmageddon tipped bullet soon as I can find some.

Can confirm the varmigeddon can make a hell of a hole. I’ve also had to where it’s hard to find the hole if it happens to slip between the ribs. If you really wanna do damage for fun. I’d suggest a heavier grain ballistic tip or varmageddon

 

[wkdickinson]

It is said that you can’t overspin a bullet, which is probably true stability wise. But you do risk them coming apart. I have an AR with a 1:9 twist barrel that shoots 50 gr Vmax great. I also have another AR with a 1:7.7 Krieger, where only about 40% of them ever get to the target. The rest go “puff” about 30 yds downrange.

 

[AckleymanII]

55's have not shot well in 8T, zero free bore reamers I have used, too many rpms. 60g Sierra was another issue Story. I use 12 twists, can go 80g Sierra at 3400 in a std 243 with zero freebore, insane small groups with IMR 4064.

 

[AckleymanII]

Bluewater, I think your calculator needs new batteries.

 

[pdhntr]

This will also be primarily for coyote and trying to keep pelts in mind so if I’m reading that right and faster is a more explosive contact would that not be a point on the slower twist as long as it’s gunna stay accurate?

I have had some success using the Speer 70 Gr. TNT on coyotes. Most were small holes going in, nothing coming out.

Jim