Bullets

[Leeper]

I've been testing bullets in my newly built 308 for 300 meter "F" class. My initial plan was to load 168 Sierras and 4895 simply because this combo has always worked for me and I know 168's work well in a 14 twist barrel. Anyway, I decided to try these along with some 150 MKs and some 155 Palmas. I have to say here, I have never found the 155s to be anything to write home about and these test sessions just confirm this. Both the 168s and 150s outshoot the Palmas by a considerable margin. The palmas act like they want to shoot but every ten shot group will have two or three fliers which opens the group to about 2 inches (300 meters). This under cool, calm, evening conditions. The 150s will shoot a kind of scattery cluster of around 1 1/8 inches while the 168s will do under an inch. I truly don't know what the deal is with the 155s but this barrel sure seems to hate them. The 150s seem a little too wind sensitive so it's back to the 168s which is what I figured on in the first place.
I've always kind of felt that, if Sierra made a bullet of the type I needed, life was good. They always shot well. The 155 Palma seems to be an exception though. To date, I've not been able to get evn 1/2 moa out of them. I'm glad they still make 168s! Regards, Bill

 

[Ganderite]

It is not unusual for a rifle to have a clear preference.

I have developed accuracy loads for a lot of 308 target and F Class rifles and might be able to help.

Wind bucking is EVERYTHING in F Class, so the 168 is not going to work for you. Their 175 match bullet should be the answer, or the 155. Your 1:14 will shoot 175s very well.

How much bullet jump are you using? When a rifle acts up, I always try increasing the bullet jump, Try 20 and 30 thou if you have been loading close to the lands.

I assume you have weighed your brass into 0.5 or 1.0 grain lots?

Deburr the flash holes on the inside, unless you are using Lapua or Norma brass. I ran an extensive test once with a pressure gun and deburring improved the velocity and pressure SD on 9 of the 10 tests.

The recent manufactured Federal Match primers do not seem to be as good as the older ones. They are now made with a different process. CCI BR2 are good.

The powder you use is a weak link. I buy and load powder by the pickup truck load. It holds 1350 pounds in 44 pound drums. The best canister powders are VV N150, VVN140, RL15 and Varget – in that order. Your velocity SD on a 10 shot test should be under 10.

Another variable to try is increased neck tension. If you use a conventional neck sizing die, take the expander button off.

The minimum distance to test ammo is 300 yards. I aim at the corner of a patch at that distance. 500 or 600 would be better. The Sierra and other commercial match bullets are not custom bullets and I would not expect much more than a half minute from them. They key is 10 shot round groups around a half minute at 300 yards or further.

One of the police snipers, shooting in an ORA precision rifle match, hit a playing card 7 times at 700 yards. He was shooting production ammo (not weighed charges) loaded with Sierra 175s and 44 gr of RL15. It was windy, too.

 

[sunray]

Your rifle doesn't like the load you're using with the 155's. Try some IMR4064 looking for 2925 to 2950fps. IMR4064 gives more consistent accuracy than IMR4895 with 168 grain bullets too. Mind you, H4895, being slightly different from the IMR powder will do.

 

[buckbrush]

What type of .308 reamer-chamber type are you using Mr. Bill? Don't Palma shooters use specific throat dimensions and shapes for using the Palma type bullets (155 Sierra).

I have never found any bullet that will out shoot the Sierra 168 at 300m or yards in a Sammi type chamder. I believe Sierra designed the 168 for 300m ISU shooting, it debuted at the 1960 Olympic's in the hands of US shooters.

 

[tiriaq]

A bullet you might want to try is the 150 Berger flatbase. It has a VLD style ogive, so is longer than most 150s. Benchrest shooters use flat based bullets for a reason.