Hi , I have a 308 built on the Remington 700 action and a Walther barrel with a 1:10 twist.Conventional wisdom tells me that with this twist a heavier bullet should perform better. However I have tried Win Sivertips 180gr, Federal 165 gr Core Bonded, Hornady 165gr Custom, Sako 155gr Hammerhead and Hornady 150gr Custom Spire Point all in Factory ammo and the two lighter bullets give MOA and Sub-MOA while the heaviest bullets (Winchester Silvertips) gave about 3 inches.

I have bought a whole bunch of 165 gr Sierra Game Kings and will be re-loading, can anyone give me some idea as to why this twist would be happier with the lighter and shorter bullets????

try a Hornady 180 interlock or other 180 grain bullet. It's possible that your gun just don't like that winchester bullet.

My Remington 700 custom with a 5R Rock barrel LOVES 175gr MatchKings and as a hunting round the 178gr AMAX. With the MK and a good spotter will stay MOA out to 1,000 yards if I do my part.
What part of SA are you in? Have a good friend that lives in Pretoria. And another good friend that guides hunts to SA feguently.
Sarge

Rate of twist equates to the stability of a given projectile. It is possible to overstablize a bullet. A 1 in 10 twist in 30 caliber should stabilize anything from a 110gr to a 220gr with optimum being to the heavier end of the range. The 165 to 190gr range should serve you well. Most 308s do better with loads to the higher end of velocity ranges. Not sure what powders your using but Varget and IMR-4064 work best in mine.

I'd doubt that it has anything to do with the twist rate(unless it's not what you think it is). Have you personally verfied the twist rate? A 1 in 10" rate is plenty for the heavier bullets in a .308 if velocities are sufficient. The fact that it shoots some ammo well indicates that the barrel is not the problem. I'd look at velocity and/or seating depth first.

I think the 150grn class of bullets is a better match for the 308, If you go with the heavies, trajectory will suffer. load up some 150grn ballistic tips and a healthy dose of w748

Thanks Guys, will try some of the recomendations. Sarge I am in Johannesburg, about 40km's from Pretoria.

Here is Greenhill Formula for determining what bullet weight for twist.

bullet dia div into bullet length =X

X into 150 = Xy
Xy multiply by Bullet dia = one turn in ?

In my 308 Win SSG-69 I use Varget and 165 Sierra BTHP and 45.8 with CCI BR-2 primers in Win Cases. I use a COL of 2.80".

It is not the twist that is making the differance. Some guns just like one bullet better than another.

Cummins Cowboy, You have my vote. win 748 48gr. and a 150gr. hornady SP Rem 9.5 primer Rem brass,in my Ruger MKII gives me 2900 fps. and shoots great.

my load is 50 grns of 748 but I am told this is a very hot load, it doesn't appear to be in my 308, if you try it start in the 48grn range and work up

I have all ready tryed 49. and 50. but 48. gave good fps. and the groups awsome.

quote:

I have bought a whole bunch of 165 gr Sierra Game Kings and will be re-loading, can anyone give me some idea as to why this twist would be happier with the lighter and shorter bullets????

I'd load these bullets with around 42grs. RE15 and 9 1/2 primers, CCI 200s should work fine, also. Should give you under moa. Jay

Thanks for the info, we dont get American powders here. So we use locally produced stuff which is rather good.

Fellow South African,

I am getting very good results with 180gr Rhino bullets and 42.0gr S341 (which was developed specifically for the old R1 in the days we still had an army). OAL is 71mm, muzzle velocity 2547fps. This load shoots just under an inch at 100 meters.

Rikkie, What is the twist rate of your barrel?

Do you get the Varget or AR powders from Austria

Not that I am aware of

2208 powder

South African:

I have a Brno .308 Win with a 1:10" twist and this rifle doesn't like heavy (long) bullets at all!

Get perfect results with 130gr GS Custom HV's loaded up to max. velocity as specified by the bullet manufacturer. (S335 start with 45gr and work it up till you chrono 3200fps MV - use Magnum primer)

These bullets are performing excellent on plains game like Kudu and Impala which I took in 2005.

Visit GS Custom and learn much more from themselves.

Jagter, the GS 130GR will be the same length as a much heavier lead core bullet so thats why it will like a 1;10 twist. If you used a lighter, and therefore shorter leadcore bullet of say 130gr then I dare say it would not perform as well. Gerrie Schultz the maker of the GS Bullets will be staying at my place for the next couple of days as he is going to be at the AIM show and I will ask him what the equivalent weight should be of a lead core bullet that is the same length as his 130gr.

Well, well, with the expert under your roof and knowing what the best bullet on the market is, why do you bother with anything else?

See you at AIM on Sat.

quote:

Originally posted by South African:
Rikkie, What is the twist rate of your barrel?

1:10". It's a Frankonia Mauser. For what it's worth, I tried 200gr Claws, which wouldn't stabilise inside of 100 yards. It seems the 180 Rhino is about the longest bullet my barrel will stabilise with S341. One could experiment with different powders, but I'm very happy with the Rhino's - it's a great bullet.

Jagter, I have a number of rifles in different calibres ie 7mm and 308 and dont really want to go the route of monolithic with all of them. Makes it difficult to justify the number with the wife

South African:

quote:

However I have tried Win Sivertips 180gr, Federal 165 gr Core Bonded, Hornady 165gr Custom, Sako 155gr Hammerhead and Hornady 150gr Custom Spire Point all in Factory ammo and the two lighter bullets give MOA and Sub-MOA while the heaviest bullets (Winchester Silvertips) gave about 3 inches.

The GSCHV is about 20% longer than ordinary lead core bullets and I would say that roughly a 155gr is closest length wise to the GSCHV 130gr.

My experience with my 1:10" twist .308 is 100% in line with what you have experienced above - the 150gr giving the best grouping.

If you've used the money you spent on 165gr's to buy 130gr GSCHV's in the first place you would have had something worthwhile.
Now you are going to have difficulties in justifying the number with the wife

What did Gerard say re the above?

You are 100% right with regards to the justification. Had a chat to Gerrie and he concurs with what you have to say. I will be trying out the following GS Bullets.
1. 130grHV in 308
2. 75gr HV in 243
3. 110gr HV in 270
4. 230gr HV in 9,3 x62