Not sure of the protocol for older threads but I found this one interesting. I have gone through my first pound of Varget, mostly for 223 with Hornady 60 gr flat bottomed hollow points and also 55 gr Barnes varmint grenades. It pushed the hps fine at mid-range loads with good accuracy but I had to work up to 26.5 grains to get the same out of the vg's. The load was well compressed and I saw cratering of the primers. The vg's seat deep and there just isn't enough space in the case for the needed charge. I have switched to Reloder 10X and am getting the accuracy I need without a compressed load. This echoes the point made that it may not be the best powder for lighter bullets. Rifle is an XP10 Savage, 1 in 9 twist 22" barrel.

I have just finished testing some 308 loads. With a 190 grain BTSP I needed to be within .5 gr's of the maximum (Hodgon loads) to get acceptable accuracy. I can't say if this was Varget, the rifle twist (1 in 12) or the Remington LR primers. With 168 gr A-max's a mid-range charge was good and even better for 168 gr Barnes TSX bullets. I was using CCI LR primers in these and this may have been a factor.

My next trip to the range will be to try the CCI primers in a sample of the loads I tried for the 190 gr bullets.

The varmit grenades are not a lead-based bullet, and simular to all-copper bullets, is about 20% longer than a lead-based bullet. Unless you have a cartridge that has some exess capacity, you can get in situations where there isn't enough case volume left to achieve equivalent or higher velocities.

What Slim said. Also these long bullets have a low BC and the accuracy in my rifle drops of pretty quickly when I used even medium loads of Varget. Today I am trying another batch of them with Reloder 10x and I will post the results.

This ought to be interesting as I always thought the top weight for a 308 with 1-12" twist was 168gr bullet.

OV1, I've always wondered why so many rilfes chambered in .30-06 come with a 1-10 twist. This twist rate provides a lot of stability, some would say over-stabilized, for the range of typical .30-cal bullets. A .30-cal rifle with a 1-12 twist can easily stabilize bullet lengths up to 1.3 inches long down to 0 degrees F or colder. The 200 to 240 gr low-drag bullets do get longe enough to require the 1-10 twist.

When I did a search on bullet stability, I've noticed this issue has been discussed before.

Yeah I even started a thread on this "Bullet Stability" earlier this year and it has always been my understanding that it the weight of the bullet that determines the twist value of a rifle barrel, not the length of the bullet. See the link below for Shilen rifle barrels on the twists they use on various calibers.

www.shilen.com/caliber...wists.html

Ominivision1 wrote:

it has always been my understanding that it the weight of the bullet that determines the twist value of a rifle barrel,

Nope, bullet length is the first order function. Typically, bullet weight is proportional to length but variations in bullet length occur based on flat-base vs boat-tail, round nose vs hollow-point vs ballistic tip, and lead-based vs all-copper, etc. A flat-based, round nose, lead-based bullet is much shorter and requires less twist than a boat-tail, ballistic tip, all-copper bullet of the same weight. Play with a bullet stability equation some. Keep the bullet length constant and increase bullet weight and you will see that stability increases, e.g., less barrel twist is required.

Respectfully disagree,

The twist rate will depend on the weight of the bullet, and how long it is.. Bullets that aren't stabilized enough will never fly "true". It is the twisting of the bullet that gives it stabilization the same way that a gyroscope works. If the bullet is not stabilized by twist, it will tumble end over end (obviously not accurate). If they are over stabilized, the bullet may never go to "sleep" or settle into a twisting pattern around the bullets true center. Bullets that are over stabilized also don't nose over properly at the peak of the trajectoy.

Also something that happens when bullets are pushed very fast and they have too high of a twist rate, they sometimes just fragment and "explode" before they hit the target. You will usually see a slightly gray puff of smoke, or see fragments hit the ground and never make it to the target. This can also occur if there is a bur in the rifling of the barrel, and you are shooting thing jacketed bullets, or the jacket is badly damaged. Sometimes it just occurs from being spun too fast. Something else that is interesting is that even elevation and air density will affect the twist rate. Because of the different conditions, in less dense air, a bullet may not need quite as much twist to stabilize as it would in very dense air. There are times when shooters go to other states or locations with large differences and find out that their pet load won't shoot how it's supposed to. It's not usually a big deal, but if your bullets are right on the edge of stabilization for their weight, it does sometimes happen. It also sometimes happens that you barrel shouldn't be able to stabilize a bullet because it's too long or heavy, and the barrel might shoot that bullet better than the others. It's all quite interesting.

re read your last sentence again Slimjim,It appears to be a contridition to what the rest of your statement is saying.
I always believed the 30/06 was more capable of handling the heavier bullets and the .308 lighter ones and the rifling twists were made to suit this.

Ominivision1 wrote:

Respectfully disagree,

Sorry OV1, you aren't disagreeing with me. You are disagreeing with physics. Use a stability calculator, keep caliber and twist rate constant since they are not variables in a given rifle while varying the other parameters one at a time; weight, length, velocity, temperature, and pressure. Move the choosen parameter up and down and watch the affects. Length has the greatest affect in varying the stability factor - first order affects. Increase bullet weight while other parameters are held constant and stability goes up, not down. I was surprised to see that velocity has very little affect within a powder's min-max range. Temperture can spoil stability. A bullet that shots well and is stable at 80F during the summer may not be stable or effective in winter conditions.

This is interesting and it is always great to learn from two people who obviously know their stuff.

I promised a range on Reloder 10X loads report but later as I have to go visit the grandson. Just quickly I use the stability calculator here:

www.jbmballistics.com/...tors.shtml

The 308 190 Hornady BTSP 190 grain will stabilize in my rifle with a 1-12 twist but only if I push them at near max load. I will be doing some more testing hopefully next week with Reloder 10 loads when I take my hunting partner out to resight his Win 300m. I can feel my shoulder ache now LOL.

I second the recommendation for re22 in .270

MacD, I don't believe you will have to run your 190's to max. I use this stability calculator (pm me your email and I'll send it to you in an .xls file). It is conservative. My 270 Win load with a Hornady 130gr GMX (1.378") shows a stability of 1.14 with a 1:10 twist. This had me concerned so I contacted Hornady. Hornady uses a much more sophistocated calculator and even at 0F this bullet still has 1.1 stability which is enough to stabilize a bullet. Bullet stability increases as it goes down range. Some recommend a stability of 1.4 or greater for a hunting bullet to remain stable upon entry. I run your bullet down to 2100 fps and its still at 1.4 with this calculator which is more than stable.

Range Report: (all shot @50 meters, 60F and 10-15 kph quartering right rear (range has wind speed/heading monitor). 5 shot groups - all count.

Reloder 10X Barnes 55 Grain VG (HP)
Loads were from 19.2 to 21.2
Best load was 21.2 - Avg 3083 fps, Avg Group 0.27, Max Spread 0.39

Reloder 10X Hornady 60 Grain Varminter (HP)
Loads were from 19.0 to 20.5
Best Load was 19.5 - Avg 2590 fps, Avg Group 0.37, Max Spread 0.49

I know I slightly pushed the first shot as the guy next to me was sighting in a big magnum and he fired just before my let-off. With this shot removed my 4 shot results were Avg Group 0.28 and Max Spread 0.33

I only could get the 100 meter range for sighting my 308 as today was sighting in day for the big game season.

Another day with no chores done - I really am going to enjoy this hobby.

I'm confused, MacD. Why are your velocities so low? My 16" AR beats these velocities. Just seems very slow for a 22" barrel. I'm getting 2900 fps with 75gr bullets and 3600+ fps with 40gr bullets in my 24".