Thread: Tikka 6.5x55 seating depth

I'm just about to assemble some 130gn loads for a T3 in dear old 6.5x55. The Tikka 6.5x55 chamber is longer than a long thing, the 130s are barely in the case if they are set out to the lands.

My inclination is just to seat them with the boat-tail at the neck and let them "make a big jump"

But I'm curious if anyone has a "formula" for seating depth in this chamber @AndyAnimal etc

I’d say let it jump and Andy is Likely using 140s

I run two of them, the Finn with the 120Bt's is running hot and I now load to spec length, I used to load out further ie just into the lands as had read this is where the best accuracy is found.
Never again, not if you want to run hot.
The standard Sako is running 140gr Amax also at spec. both rifles are an easy 1/2 moa shooter in this caliber.

So yes , jump, in the Finnish barrels at least.

I seat my 143 eldx to 80.5mm .
The load shoots better than I can.
The tikka 6.5x55 is a very forgiving cartridge and doesn't shoot any thing badly.just started mucking around with the 147 eldm but haven't come up with a final plan yet

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Don’t be afraid to jump. I’ve got my 140gr eld-m jumping 0.110”, and 129gr interlock jumping 0.060”.

Either pick a depth and forget it or I work back in 0.020” increments from 0.040” to 0.120” jump.

Greetings @Tentman,
I measured the crush length in my 6.5x55 T3 at 78.5mm for the 129 grain Interlock, 79.5mm for the 129 grain SST and 81.5mm for the 143 grain ELDX. My standard load is the 129 grain SST at a cartridge length of 78.5mm for a jump of 1mm, my standard. There seems to be plenty of seating depth and the fit in the mag. The throat in my M38 is 3.2mm longer but shoots the 129 grain and 120 grain projectiles well with a jump of 4mm or more.
Regards Grandpamac.

I'd start at 2mm and work forward in very small increments. I've said it here before, it's considered to be one of the best target calibers in Europe, where they laugh at the rest of the World for not giving 6.5's a healthy 'jump'. It also lowers pressures and can potentially allow you more speed if that is a consideration

Hey thanks guys. I shot my Tikka 6.5x55 in the weekend, very pleased with the results.

Im using Sierra 130s, they chronied at 2887, but I shot them out to 400 yards (366M) in the weekend and the verified velocity was 2920, so no puffball load. I only shot one group at 100M, 15mm. Went to the 400 mound, hit the 6" gong at 3 oclock right on the right edge (there was a sneaky wee crosswind at the target end of the range), then got the 4" with the next two rounds. Job done, ready to shoot matches or game with when I need some "reach".

Anybody got any Sierra 130gn TMKs??

@Tentman what seating depth/jump did you go with?

Went with an COL of 77.0mm which is a big jump. I tried Nosler 129gn LRABs at the same length, and although I got a very good ES and SD they shot 40mm groups . .. . Would playing with seating depth reduce 40mm down to something acceptable??

For a Tikka I would just set them a mm or 2 inside mag length and see if they group. Make sure its at least 1 cal deep inside the mouth.

One thing tho, the swede has more than enough room in the case. Finding a powder that has a flatter pressure curve that can help you fill the case more, that can really help with precision. Work up two loads, one woth 2209 and one with 2213sc. Always had better luck with the latter myself.

Originally Posted by Tentman

Would playing with seating depth reduce 40mm down to something acceptable??

Potentially yes. Group size should behave like a sine wave with changing seating depth.