Took my new to me .300 win mag Savage to the range today, had a box of Federal fusion l50 grains and a hastily assembled Ladder.

I wanted to focus my ladder center to top for the R-22 I have on hand, 208 Amaxes are expensive, and I would rather find a good load at the top than bottom.

Didn't spend the time making a dummy round to find the seating depth since I just acquired the rifle, I have not yet accumulated a lot of brass and didn't want to waste one.

So I bumped the bullet back until I could just chamber without sticking the lands, but I suspect I am either just off them or in contact.

I forgot to set the second counterweight of my scale for the first three, weighing out 70 grains rather than the intended 73, didn't notice until I had already seated the bullets, so 70, then to 73, 73.5, 74, 74.5 the top in Lyman for this bullet and powder.

So the  3  70 grain loads went to an inch and a half at 200, good, the Primers were flat, but no more so then the factory Fusion loads I had confirmed zero with at l00.

Then I jumped to the 73 grain load, two went into a half inch, the third failed to fire, bad primer apparently. ( I remember dropping one on the floor of the shop, thought I tracked it and picked it up, but it's possible it was an old one dropped long ago..)

Then went to the 73.5, the first shot stuck the bolt, so I called it a day.

Question time.  

My current plan is to bump the remaining loads back to magazine length and fill in the ladder from 70 to 73, rebuilding the 73.5 bumped back and reshoot the ladder.

Should I expect a significant drop in pressure backing the bullets off the lands, or have I reached a pressure limit for my rifle and I should pull the loads that are past 73.5?

Target.

Attached File

Tough to say as you really don't know how close you are to the rifling.
It could be 0.005 or it could be 0.150.   Big difference

Cases are full length resized and chamber freely, with a loaded bullet it requires light pressure to close the bolt.  Since I was working backwards on the die from marking the bullets to not, and still reqire some pressure to close the bolt, l'm assuming that the pressure is the bullet against the lands.

Good plan.  I presume from 70 to 73 you will using 0.5 grain increments - yes?

If you were kissing or slightly jamming the lands, I would expect lower pressures @ mag length.

I think your plan above is sound.  Reset the ladder @ mag length and shoot the ladder paying close attention & looking for pressure signs as you go.

Thanks for the replies, and yes, I generally stick with half grain steps until I find a node.

Just a side note...

Seating to magazine length doesn't necessarily mean that you aren't jamming the rounds into the lands.

I have a CTR and AIAT both in 308Win.  The magazines for both rifles are right at 2.980" OAL, however, the with the 178gr ELD-X I could only seat to a max OAL of 2.930" in the CTR and 2.895" in the AIAT or else I would be jamming them into the lands.  I know you don't want to sacrifice a piece of brass but it really is worth it in the end to verify your max OAL with a given bullet.

I'm using RE-22 with 190 and 200 grain SMK'S seated to jump .025" to the rifling. My powder charges to reach 2900 and 2800 fps respectively we're significantly lower than the data I referenced.

A lower charge and more bullet jump will need to be tried in your circumstances.

Was hoping to get input from you, your advice has been sound in the past.

All of the replies have had good advice.

Crony will go with me next time out, and I've picked up a few more cases from a friend, so one of those will be sacrificed for a headspace gauge.

I was excited to go play with the new toy and see what accuracy potential it had and jumped ahead a little.

Time to get a more serious.

I'm not at home right now, so I can't reference my data. I used Remington 9.5 Magnum primers and Winchester brass. I uniformed the primer pockets. Sierra Match Kings shoot just fine with a little jump. They shoot just fine at magazine length. There is no need to run any bullet other than VLD's right up to the rifling.

I'm surprised your light bullets would stay in the case loaded so close to the rifling. The next time I get on his site I'll post my .300WM load data. I don't have a lot, I just bought my first rifle last year in this caliber. Because you're using 150's, probably the lightest bullets listed in anyone's data, I would consider trying a faster powder and magazine length rounds.

Off the top of my head I think my loads were 4 full grains lighter than the published data I was using to reach the same velocities. Maybe the batch of powder we got is faster than what they used to create the data base. Obviously sticky bolt lift in a .300 Winchester Magnum is nothing to mess with. A dramatic reduction is in order.

Perhaps my post could be clearer; I was shooting some factory loaded 150 grain Federal Fusion ammo to call nfirm funtion and zero( at least minute of paper),
But my hand loads were 208 grain  Hornady AMAXES..

I'm going to reset the ladder starting at 70 grains of R-22 at mag length and run them over the Crony.