Currently reloading for two cartridges: 204 and 270wsm. The bullet jump doesn't seem to matter with the 204, all the loads are very accurate.

However with the 270, the bullet jump is perplexing. On the factory loads the jump is more like a pole vault, and they are still accurate. My reloads on the other hand seem to be improving with loads closer to the lands.

Guess my question is, does it matter that much for hunting loads? Should I quit stressing about the different jumps and go with the recommended COAL.

Your thoughts?

I never use the recommended COL listed in manuals, I seat all my bullets to suit my rifles.
I have found that hunting accuracy is not affected by bullet jump as much as what people lead you to believe.
All the WSM's I've loaded for have had quite short throats, so the jump with factory ammo will in fact be quite short.
If you seat your bullets to be around .015"-.030" from the lands, you won't go wrong, but altering seating depth to find the 'sweet spot' never hurts.
If your own loads are increasing accuracy, fiddle with the COL until you get the best accuracy you can.
416RigbyHunter.

Alot depends on magazine length. I seat my deer/elk bullets alittle deeper reason handling,unload & load rifle might carry afew rounds in my coat pocket etc. I make sure my rifle shoot good.

To further complicate the issue, it also depends on the type/brand of bullet. When I started reloading Barnes TSX 0.50" off the rifling like they reccommend, accuracy decreased as I increased the length of the round. When I went back to 0.50" and started decreasing the length of the round, accuracy improved.

I would optimize building the round for the rifle. Measure from the ogive for OAL and sweet spot should stay consistant. Magazine length plays the main role for repeater feeding, but I single feed several of my repeater bolt actions to obtain optimized accuracy.

quote:

Originally posted by Head Trauma:
When I started reloading Barnes TSX 0.50" off the rifling like they reccommend, accuracy decreased as I increased the length of the round. When I went back to 0.50" and started decreasing the length of the round, accuracy improved.

I think you mean 0.050". 0.50" is 1/2" and that would be one hell of a jump.

quote:

does it matter that much for hunting loads?

NO

Despite just for hunting, most folks want to maximize their guns potential.

I'm beginning to realize with my short mag and perhaps other similar rounds that they like a bit of a jump. After experimenting at the range, I noticed the shorter jumps are producing more spread.

When I get my crony, I would bet the velocities are highly variable. Could it be more pressure and hence more variablity?

Dont know.

quote:

Originally posted by garyn:
...Could it be more pressure and hence more variablity? ...

As you change the Seating Depth it alters the Barrel Harmonic. It might or might not have an effect on the Pressure, but should not be enough to notice on a chronograph.

If you use the never improved upon "Creighton Audette Load Development Method", you will quickly locate Harmonic Nodes where slightly varying(0.1-05gr or so) amounts of Powder still send the Bullet to relatively the same Point-of-Impact. Once you locate a Harmonic Node, then changing the Seating Depth has the potential to move you directly on top of the Node or away from the Node. The best distance can be either closer to the Lands or farther away - depending on how far away you are when you start.

Changing the Seating Depth and the Browning BOSS work on the same concept - fine tuning a Harmonic Node - but approach the result differently. Reloading allows varying the Seating Depth and the BOSS allows folks to fine tune Factory Ammo.

Best of luck to you.

I think it depends a lot on the rifle & bullet. Monometals like a bit more run at the lands than some others. Every rifle is diff.