Pressure signs on starting charge?

[songdogslayer]

OK, I have a problem . . . the first step is acknowledging there is a problem.
I'm loading 105 Gr A-Max rounds for my Savage BVSS in .243 caliber,1 : 9.25 twist). I started with 46.5 grains of Retumbo, using Win LR primers. Brass is once-fired and then neck sized for the same rifle. I have the bullets just kissing the lands and the average velocity for a 5 shot group was 2940 fps,book indicates the velocity ought to be about 2800 fps). I'm seeing what I believe are some starting pressure signs on the base of the brass - just a tiny, tiny shade of an image which appears to be the extractor pin. No problems extracting the spent rounds . . . silky smooth there. What I don't understand is why the starting powder charge,46.5 grains) is pushing the bullet almost as fast as the max,49 grains) charge? Again, the bullets are just touching the lands, I'm using Win LR primers . . . not magnum primers. I tested the chrony by firing some of my other loads and the speeds were correct. For what it's worth, there was a 12 mph cross-wind today and the grouping on the five shot group of 105 gr A-Max was awful . . .
Suggestions? Advice?
Thanks in advance . . .
~Scott

 

[patchhound]

I hade that same problem w/ my 7saum when the brass got too tight in the chamber. Bumping the shoulder back a thou. fixed it. If you hade no other troubles with your gun my guess would be no headspace.

 

[Preacher]

It just shows you that all guns are different in their likes and dislikes, and that some barrels are faster than others, and some chambers are cut tighter than others.......
Headspace don't have a thing to do with pressure signs in the real world....
Is the book barrel and your barrel the same length ?
Jamming a bullet or even touching will raise pressures too..
Very few loading manuals have the bullet touching the lands....

 

[BlackHawk95]

Like Preacher said, touching the lands will increase pressure and velocity. The more you jam them, the faster they will get is what Ive noticed in my .243. Also, are the primers flattend or do they still have rounded edges?
And dont really worry about top velocity, find the load that shoots best. then get the velocity so you can generate a drop chart.

Try seating the bullet about .010" from the lands and see what happens.

 

[longshooter]

I would suggest checking first your powder scale for accuracy using check weights.

 

[songdogslayer]

OK, shooters, thank you for the advice. My next move will be to reduce charge down to 46 grains of Retumbo,do I need to go down to 45 or 45.5 grains?) and seat the bullets .010 off the lands.
Preacher, good point regarding the barrel in the book - it is not the same barrel nor is it the same length.
BlackHawk95, the edges of the primers are still rounded and not flush to the primer pockets like examples indicate in reloading manuals & such. However, they are not as "rounded" as an un-fired case and, also, they are .003 thou extended from the primer pocket,but this is the case with all of my fired rounds in this rifle . . . ). I use a primer pocket uniformer on all of my brass before reloading and I use a primer pocket brush after the first firing . . .
For what it's worth, I always chrony my rounds when I'm at the range - just a habbit. I will try moving the bullet .010 off the lands as you suggested and see what happens.
longshooter, I use the RCBS Chargemaster combo and I calibrate it before each use . . . so I'm good there. I'll double check it today before trying the other suggestions mentioned above.
Hey, gang, I appreciate your advice. Any other suggestions or recommendations are appreciated!
~Scott

 

[Winchester69]

As an aside, just touching is not good. With variation, bullets are both in and out of the lands. You want to be either jammed or out. Variation in bullets will have much less influence.
.

 

[songdogslayer]

Thank you, Winchester69, that certainly is sound advice. I went back out to the rifle range today with a few new loads - 45, 45.5 & 46.3 grains of Retumbo pushing the 105 gr A-MAX. I set the bullets just .010 outside the lands and had no pressure signs on any of the new loads. The 46.3 grain load was the best group,4 shots inside a penny at 100 yards and a called flier shot widened the group to nickle-sized . . . this was my third squeeze on the trigger and I knew when I touched it off that I should have taken another breath and started the squeeze over). I think I will stay with the 46.3 charge, as the velocity must have been around 2815 fps,couldn't tell exactly, as it began to snow and my chrony decided to call it a day). Thank you, everyone, for your prompt replies to my questions and, as usual, your sound and well-thought advice. This sight rules!
~Scott