30 BR for Everything - Info Please

[squirrelsnpr]

I can't stop thinking about chambering a "do everything rifle" in 30BR. It sounds like if I keep it at or under 600 yards it will "do everything". In all honesty I mostly shot varmints, but would like to try matches also. I would like to use either the 110 V-Max or the 125 Nosler ballistic tips for varmints and the Sierra 135 grain MatchKing for match shooting.

Is there a twist rate that would accomodate both of these bullets? And, has anyone tried a repeater in 30BR? I know the 6BR is known for feeding issues but don't know about the 30BR. What kind of velocities would I be able to get out these bullets. I read the 30BR info page, but didn't know if I would get anything different b/c I'm planning on using different pills.
Thanks,
Mitch

 

[DCRYDER]

Im pretty sure the 135 Matchking is @ 1.075" long so according to my calculator to work in a 17 twist you would have to push it at least 3000 fps. Dont know the length of the V Maxs and B-Tips, but for the SMKs i would lean towards a 16 twist.

Calculator says 135 SMK at 2800fps minimum twist is 16.3.

 

[Chuckw]

i built myself a .250 short 308 for score shooting and have shot the 135mk from 2500 to almost 3000 with different powders and have had ZERO issues with stability in a 17 twist rock barrel. i think you will find that there are better match bullets out there but the 135mk will surprise you on occassion. people get WAY too caught up in these calculators. i know a guy who has two EXTREMELY accurate 30-30 BR guns one of which has an 18 1/4 twist hart barrel and i personally shot two groups in the low 1's through that barrel with a 135mk.

chuck

 

[Steve Blair]

It is important to distinguish between short range and long range stability. As drag slows the bullet, insufficient rotational velocity will not produce gyroscopic stability. As the bullet slows and precession (gyroscopic wobble) increases, the bullet's path is unpredictable. At worst, it will fully destabilize and tumble. If the bullet is sufficiently stable at the muzzle, upon exit it will enter a regime of diminishing precession. This is exactly like a child's top wobbling initially and then spinning true. Once the bullet achieves gyroscopic stability, it is much less likely to be destabilized by air resistance. Insufficient muzzle stability produces the opposite situation. As the bullet exits the muzzle, it enters a period of increasing precession. It may remain relatively "point on" for a short distance but will inevitably precess to full instability. This is why point blank BR shooters can shoot seemingly unstable twist/bullet combinations.

Consult ballistics tables and plan for a Miller stability factor of not much below 1.0 at the intended range. At long range, also ensure that the remaining velocity is comfortably above the speed of sound. Terminal velocity of around 1300 fps is good. Stability factor at the muzzle is irrelevant if precession, drag and transonic buffeting destabilize the bullet before it reaches the target.

 

[JohnnyJohnson]

Novel idea that might even work but who would have ever thought of it?

http://www.6mmbr.com/gunweek045.html

 

[halfmoanut]

My thinking and hearing that past 400 yds it is about pooped out. I shoot some groundhog shoots where it is popular mainly because of its line cutting abilities and we shoot 200-300-400 and they do rather well.It is a score shooters caliber with great accuracy and thousands of rounds down the tube.No expert here just what I read and hear.

 

[MarkS]

squirrelsnp,

A friend of mine Gerald Wright uses a 30BR for IBS 600 yds, and does very well. I have seen him shoot 1.0" group and does very well in score (hitting center). I tkink he shoots Berger 110gr. Go for it.

Mark Schronce

 

[squirrelsnpr]

I took the plunge. I found a 3 groove, 17 twist Lawton at a good price. Not exactly what I was looking for but it should work. The owner said he was shooting 135 MKs out to 515 yards with great success. It should finish at approx 22".

Any comments/recommendations to get the 30BR to feed reliably from a mag? Looking at the AICS mags really hard.

 

[skeetlee]

I personaly would go with a 15 twist. That way you can shoot 112,-118 for score or groupand the 125's for 600. I know a fella that has this exact set up and he does very well! Lee