308 Sierra Match King 155gr

[Malxwal]

Looking for any experience on loading these with N140 or RL15, standard CCI primers in new Lapua brass. They'll be going through a standard Tikka M595 barrel, 1 in 11 twist, 24", and looking to shoot out to 400 yards.

Cheers

Malc

[Andrew]

Not used that combo of brass. powder and primer but I have shot quite a few of the 155 Sierra PALMA Match MK's through my 1-11" Savage long range hunter using Varget. I think I was loading 45.8 grains and screwing them into one hole @ 100 yards. They are designed for 600 yard shooting so you will do fine. I would venture to say that any well-built handload will shoot using these bullets.~Andrew

[Swarovski1]

44 to 45grs of n140 will be good, about 2,830 oal

[Re-Pete]

45.5grains N140, 72.3mm COL, gave 2860fps and a good group with SMK2155's in a 30" 1:11 twist barrel.

 

Usual caveats apply when considering other peoples loads...........

 

H/man

[VarmLR]

I'm getting one hole groups using the 155 SMKs and N140 using Lap brass and CCI primers when loaded at 43.1gr using a T3 with 1/11 twist (24 inch barrel). Was using 44gr but getting pressure signs when the weather warmed up and to 400 yds you really don't need the velocities of the higher loads. My advice would be to save your barrel life and load just as high as you need to go, and for 400 yds, you don't need the higher loads. On the chrony, I was averaging 2,650 fps with a 43.1gr load which is more than plenty out to 700 yds. Usual caveats apply as you need to find the safe pressures and most appropriate barrel time for your rifle.

[Malxwal]

Good stuff, thanks folks.

[Laurie]

Note that there are two 155gn Sierra MKs - the original 'Palma' (Sierra p/n 2155), now just called 'MatchKing', and its higher BC longer-nose successor (Sierra p/n 2156) which now bears the 'Palma MatchKing' name.

 

The old 2155 is still loaded in the NRA procured match ammo, originally RUAG/RWS, now from GGG. This was deliberate as this bullet is one of the most tolerant models around coping well with various chambers, freebores, throat angles and heavily eroded throats.

 

The newer 'Palma' model has a markedly higher BC, but tends to be much more finicky as to throat configurations and how much jump it endures. US 'Fullbore' and 'Palma' shooters generally reckon it shoots best with a largish jump, 40 thou', in some cases more. Some rifles I've tried it in which will shoot the old 2155 brilliantly, won't perform with this model at all no matter how much playing with loads and jumps.

 

For 400 yard shooting, the older model will perform very well and its lower BC doesn't matter much. Also consider the antediluvian 168gn Sierra MK which was designed in the 1950s for 300 metre shooting and is still one of the best short-distance models around.

[VarmLR]

It's the older 2155 model which I use and it does seem to be very tolerant of jump. It is loaded some way off the lands with the bullet loaded out as far as I dare, to magazine length giving a jump of about 80 thou. Out of interest. I tried the exact same load and seating with the Sierra 150gr gameking and it shoots almost identically at 100 yds, and with some very good consistency, regularly achieving 0.3 inch groups. One load for two bullets does keeps things nice and neat!

 

I guess Laurie that the main advantage of the 168gr SMK is that it is better at bucking the wind over 400 yds?

[Malxwal]

It's the 2155 type I have here. I have a limited time in which to get to a load that will work for me in an upcoming event, would you suggest I try .010" variations in jump from say .010" to .050" with a constant of 43.1 of N140 as a good starting point ? I see the Viht data spreads from 37gr to 44.2gr.

[alpha1]

I use 43.2 grains of N140 in my Steyr SSG with good results.

[Laurie]

Don't bother with multiple jump levels with this bullet. 15 thou' usually works just fine, and work a load up to get the MVs you want allied to hitting a barrel accuracy node.

 

Starting around 43gn N140 is a good approach, but work up. For some reason, Viht's 308 Win N140 data is ridiculously conservative with its maximum 44.2gn for this bullet for 2,712 fps from a 24-inch test barrel. Run that (44.2gn) through QuickLOAD and the MVs correspond OK give or take a few fps, but PMax is calculated at only just over 50,000 psi, or 12,000 psi down on the cartridge's SAAMI max and around 8,000 psi below what sporting loads and the NRA ammunition are loaded to.

 

Generally people get best results at 44.5gn and up, in many rifles above 45gn. It's impossible to be prescriptive about loading levels with the number of rifle chambers around and capacity variations between makes of brass, but many people using Lapua cases end up above 47gn with this bullet. If you find something between 44 and 46gn that shoots well, that's all you need and brass and barrel life will be good at these pressures.

[Malxwal]

Many thanks Laurie et al, this will help me greatly in achieving a useable load within the short time frame I have and to get drop charted.