I have a Tikka T3 in 204 Ruger with a 1 in 12 in. twist that does not shoot the 40 grain v max bullets very well. With that twist rate, do you think I should try a heavier bullet or lighter?

Thanks

Keith,


Rule of thumb is heavier bullets require faster twist. In other words a 1 in 9 would stabilize a heavier bullet than a 1 in 12. However I don't think it is the twist rate. Probably some other variable. I would try other bullets.

FWIW, I've have/have had several rifles chambered for 20 caliber pills. All have had 12 twist. You should have no problem with 26, 32, 33,35, 39 & 40 grainers stabilizing in a 1-12 twist barrel. There are a number of different manufacturers of 20 cal bullets including Berger, Hornady, Nosler & Sierra among the majors. Starke, Unmussig and Shroeder also do 20 cal's if I'm not mistaken.

The 40 gr. v-max is my go to bullet in the 20 Tactical. The 32 gr Sierra Blitz is my go to bullet in the 20 Vartarg.

Best

GWB

It's more than just the twist, it also depends on the length of the bullet. Longer bullets of a similar weight also need a faster twist. I use a 1:8.5" twist for .204 Ruger heavy 50 grain bullets, that works superbly with the 26 grain Varmint Grenade and everything in between.

One of the most accurate bullets I have used in the 1:12" twist is the Barnes 26 grain Varmint Grenade driven by 25.2 grains of Reloader 10x powder (4,110 fps in my barrels). This is a very explosive bullet good for targets and small varmints - devastating on ground squirrels.

Some 1:12" twist barrels won't shoot certain bullets nearing or surpassing 40 grains well, some will. It depends, among other things, on whether the twist is actually 1:12" or something else close to 1:12". Try a few Berger 35 grain Match Grade FB Varmint bullets and the 32 grain Sierra Blitz King, in addition to the lighter Hornady offering.

Thanks for the replies gentlemen.

Keith,
My Savage LPV didn't shoot the 40gr V-Max either. The 39gr Blitz Kings were a big improvement

I usually read the reviews on Midway since, I too, am not happy with my .204 shooting 39 grain blitzkings. Everyone raves about the 35 grain Bergers. They will be next on my agenda to try.

Currently using two 20 cals....both 12 twist/3 groove Pac Nors...20 Practical & 20 Vartarg....I tested the 32 V's along with the 39 Sierra and 40 Nosler & 40 V max...the 40 V max is a winner for me in both of these 20 cal's...3554 in the VT...3900 in the PT..both moly coated...the 20 PT is devastating on p/dogs at ranges some wouldn't believe...I like the 20's so much I'm building a hot rod 20BR with 9 twist for the 55 Bergers @ .381 BC...wish Hornady would build a 20 cal 50 V max !

I've been playing with some of the new lead free bullets... because they are lighter, and therefore longer for their weight...you can step up there velocity quite a bit...

havent' had a chance to shoot some over the chronograph yet, but they are definitely going to be a velocity improvement...

my other motivation is that much of the use the 204s use is duplicating what I can do with my 223s...

I have been using 34 grain HPs, 32 grain V Maxes in my 204 so far... ( have tried the 39 and 40s, and they didn't give me anything a 223 can't..)......

So I have been playing with the new Hornady 24 gr NTX and the 26 grain Varmint Grenade... they are both accurate and definitely explosive... they make 300 yds just fine...these are also long bullets for their weight...

in the 223 and 22.250 I have been playing with the Hornady 35 grain NTX, which is about as long as a 50 grain V Max...along with the 36 grain Varmint Grenade, the 35 and 40 grain lead Free Ballistic Tips..

once again, accurate explosive and flat shooting....

for those that are interested, the Hornady NTXs are definitely the accuracy leaders...even moreso than my beloved Nosler products...

Try 32grainers. They work well in my Ruger #1.

I had a Kimber Pro Varmint in .204 that shot the 40gr V-Max's into 1/4 to 1/2 groups all day at 100 yards. So, out of curiosity I got a Gunsmith friend to measure the twist. It was actually a 1:11 twist would you believe, even though the barrel is advertised as 1:12 twist.

My CZ 527 in .204 has the 1:12" twist and it doesn't shoot the 40gr VMAX as well as the 39gr Sierra Blitz kings or the 35gr Bergers.

there are 3 basic things that influence
projectile stability & thence accuracy

- length / weight of the projectile
- the twist rate of the barrel
- the velocity you launch the projectile at.
stability comes from the rpm's that the projectile spins at & a longer projectile requires more spin to stabilise than a shorter projectile.

.bullet weight is relevant to the stability but not directly as weight affecting stability.
- bullet weight affects velocity & velocity affects spin imparted by the barrel twist.
- what a bullet is made from affects both its weight & its length.

a bullet made from a lighter material is longer so it requires more spin to stabilise..........a lighter bullet will have more velocity........
BUT
in stability calcs the impact of increased length of a bullet has far more effect than increasing the spin from the velocity gain using a lighter bullet.

the nett result from using a copper core bullet when experiencing marginal stability with a lead cored bullet is increased stability from higher velocity & higher spin when using a lighter bullet which is no longer than the bullet weight you reach marginal stability at with a lead cored bullet.

You have marginal stability as bullet weight increases ( within a bullet core type) because bullet length is increasing with increasing weight & bullet velocity & thence spin is decreasing with increasing bullet weight.

within a given rifle & cartridge combination there are 2 competing dynamics affecting accuracy
- inherent vibration of the barrel harmonics when fired
&
the spin level imparted by the launch velocity.

where marginal accuracy is experienced from heavier bullets due to marginal spin you can improve the stability by increasing velocity, (within the safe pressure of the rifle), to increase spin.........
BUT
the increased stability might be accompanied by a poorer vibration in the barrel.
every rifle is different
The nett gain from a velocity increase might be :-
-significant
- a little
-nothing
- worse.

It is not very constructive to look at what one shooter is achieving with a particular bullet & calibre & barrel twist unless you also know what his MV was & can compare that to your rifle.

At marginal stability with heavier bullet/longer bullet success in another shooter's rifle is unlikely to be achieved in your rifle with the same twist if you are not able to launch it at a similar velocity to that of the other shooter.

an interesting dynamic with projectile stability is that stability increases down range ( where the projectile remains either above or below the speed of sound)
this is because projectile velocity declines much much faster than spin as the projectile moves down range...........at a given projectile length , the same spin rate at a lower velocity increases stability.

at your muzzle tho, velocity & spin are linked by the twist in the barrel.... if velocity is lower it must have a faster twist barrel to achieve the stability of the same bullet launched at a higher velocity when the stability of that particular bullet is marginal.

this whole stability dynamic is why some rifle/load combinations shoot better groups at 200-300 yards than they do at 50-100 yds.
The explanation is that the stability has increased down range as the velocity decreased and the bullet flight path has not been influenced by other external influences at launch ( ie the barrel is a "good" one).
this effect is more often seen in bullets that are long & heavy for calibre & are therefore typically launched at marginal inherent projectile stability.
A poorer barrel or poorer load combination will not show that effect as other influences on bullet path will be greater than the stability gain down range.

FWIW

quote:

Originally posted by Palladin8:
My CZ 527 in .204 has the 1:12" twist and it doesn't shoot the 40gr VMAX as well as the 39gr Sierra Blitz kings or the 35gr Bergers.

Interesting. With the 40 VMAX my 527 is dead nuts accurate, but only so so with the Sierra 39s.

quote:

Originally posted by craigster:

quote:

Originally posted by Palladin8:
My CZ 527 in .204 has the 1:12" twist and it doesn't shoot the 40gr VMAX as well as the 39gr Sierra Blitz kings or the 35gr Bergers.

Interesting. With the 40 VMAX my 527 is dead nuts accurate, but only so so with the Sierra 39s.

That is odd. I have heard several people with the CZ complain about the 40's accuracy but tout the 39s. That's why I gave them a try.

I've just started playing with a Ruger LH Hawkeye and bought one box each of Factory Hornady ammo, 32 gr, 40 gr, and 45gr.

Average of two three shot groups with the 45 gr is 0.68", with the 40 gr. 0.99" and one three shot group so far with the 32 gr of .75" all at 100 yds.


MV is 3900, 3600, 3300 from 32gr to 45 gr.

Based on this quick test I decided to start reloading with the 45 gr Hornady bullet.