Thread: Hdy 129g SST in 6.5x55 Swede

I acquired some Hornady 129g SST in 6.5mm, enough to run an incremental load test in my CZ 550 6.5x55 Swede

I partially seated a projectile in a FL sized and gauged case, unprimed, and closed the bolt on it so that the bullet engaged the lands and was then forced back into the case as the bolt closed. Plan is to seat the bullet 9 thou deeper than that for a field load.

I have some RL 19 and data from Handloader Issue #212 for this bullet with the test rifle being a Remington Model 700, barrel 22inch.

The Rec C.O.L given is 3.149 in.
In my rifle, with the bullet against the lands the C.O.L is 3.109 so less 9 thou would make my finished C.O.L. 3.1 in. This leaves the cannelure 0.189 forward of the case mouth.

Photo is of finished cartridge length.

Any recommendations/observations?

How much bullet (minus the boat tail) is in the neck? Can't be much?

Typically you want about 1 bullet diameter of contact (0.264) for neck tension and concentricity, in a mag fed load.

Those bullets shouldn't care about having a much larger jump. I'd try closer 3.000".

Had a play with those a few years ago and eventually found they worked best seated right to the cannelure with heaps of jump.

Originally Posted by Pommy

How much bullet (minus the boat tail) is in the neck? Can't be much?

Typically you want about 1 bullet diameter of contact (0.264) for neck tension and concentricity, in a mag fed load.

Those bullets shouldn't care about having a much larger jump. I'd try closer 3.000".

There is over 0.360 of the bullet in the neck, being a BT approx 0.230 is bearing surface which is still greater than bullet dia of 0.264.

Originally Posted by Woody

Had a play with those a few years ago and eventually found they worked best seated right to the cannelure with heaps of jump.

In what rifle?

From the Hornady reloading manual...

From experience loading the 154gr sst in 7mm08 I think you'll find the hornady listed C.O.L for your projectile will seat right to the cannelure, seemed to work for me so I didn't bother trying to seat them any longer.

6.5*55

Originally Posted by Woody

6.5*55

yeah sure, but early military M96, M98, modern commercial? big diff in throats etc as far as I'm aware so seating depths might become important one way or another depending on specific. yes?

Originally Posted by Pav

From the Hornady reloading manual...
Attachment 176079
From experience loading the 154gr sst in 7mm08 I think you'll find the hornady listed C.O.L for your projectile will seat right to the cannelure, seemed to work for me so I didn't bother trying to seat them any longer.

thanks, that's useful. don't have access to my manuals at the mo

Modern. However most 6.5*55s areong throated.

9 thou...... so you want to have a field load that will still be jammed hard into the lands?

Originally Posted by 257weatherby

9 thou...... so you want to have a field load that will still be jammed hard into the lands?

its 9 thou off the lands, or are you saying that's too close?

Originally Posted by 257weatherby

9 thou...... so you want to have a field load that will still be jammed hard into the lands?

@257weatherby What would you recommend?

I'd recommend not "forcing" the projectile back into the case. I'd recommend using a dremel to slot the sized neck twice, opposed, lube the projectile and as slowly and gently as possible, squeeze the bolt so as not to shove the projectile in, rather to ease the thing back into the case.

Then I'd play the black sharpie trick, adjusting until I found just touch, then find my working length from there. Unless I've missed something in the op descriptive, that pill is probably still 40 thou jammed. My rifles, I don't like jammed, I like jump, and even with the pills that urban myth claims need to be close to the lands, jump still works, I have a VLD jumping 120thou that is just as accurate as one jumped 40thou in the same rifle. Accuracy is helped by using the full case neck where reasonable too. Think concentricity and consistent neck tension.

Feel free to correct me you lot. Can't find my pants some days, but those nice young men in blue suits always bring me home again......

Originally Posted by Jhon

I acquired some Hornady 129g SST in 6.5mm, enough to run an incremental load test in my CZ 550 6.5x55 Swede

I partially seated a projectile in a FL sized and gauged case, unprimed, and closed the bolt on it so that the bullet engaged the lands and was then forced back into the case as the bolt closed. Plan is to seat the bullet 9 thou deeper than that for a field load.

I have some RL 19 and data from Handloader Issue #212 for this bullet with the test rifle being a Remington Model 700, barrel 22inch.

The Rec C.O.L given is 3.149 in.
In my rifle, with the bullet against the lands the C.O.L is 3.109 so less 9 thou would make my finished C.O.L. 3.1 in. This leaves the cannelure 0.189 forward of the case mouth.

Photo is of finished cartridge length.

Any recommendations/observations?

Attachment 176066

Greetings @Jhon,
I load that projectile in my T3 6.5x55. My LOA is 79mm, about the same as yours with the projectile seated 1mm from the lands. Some rough measurements show about 7mm of the full dia projectile in the case mouth, plenty. Ignore the cannelure as I do. My rifle shoots very well with these rounds.
Regards Grandpamac.