40-65 Shooters

[J.Murphy]

I would like to thank gunlaker and TexasMac for their responses. I had not considered that my brass dimensions might be my problem. Coming from a High Power discipline where everyone uses Lapua brass and turning or not turning the necks were the only decisions, to BPCR where ANY brass is hard to find and especially 40-65 which only Starline headstamps and all others are formed from 45-70. I felt fortunate to have found two lots of Starline 40-65 brass and never looked back. I tried to slip fit bullets, but they were as loose as a goose, I assumed my chamber was to blame, because my first reamer had no visible neck and wasn't impressed with the second chamber either. The original post was asking how other shooters managed to slip fit their bullets. My mistake was assuming my brass had approximately the same dimensions as everyone else, big mistake, my prized 40-65 headstamped brass has an average neck wall thickness of .008". My odd collection of 45-70 cases from other makers, once formed to 40-65, had thicknesses of .010" to .011". Now to find more brass.

[TexasMac]

J.Murphy,

I'm surprised your Starline .40-65 brass necks are that thin. I have some Starline .45-70 which are 0.011" think at the mouth.

Wayne

[gunlaker]

Hopefully that does the trick!

I don't know how picky these rifles are with respect to bullet design, as I've only tried 3 different bullets, but I had a Hoch mold 400+ grains and the rifle hated it. The saeco #740 and the BACO 409400m4 (might be 409m3, the bullet was renamed at some time)

Chris.

[desert deuce]

Have to wonder if a taper crimper might solve the problem.

[J.Murphy]

desert deuce,
With partial resizing and neck tension I can get decent accuracy, but the ES is higher. My thought is that variable neck tension, even with constant annealing, plus the variable energy used to reform the brass to the chamber might be the culprit. Slip fitting in some form, with the possibility of consistent release might help, but my brass was too thin to give decent alignment. We'll see!

[desert deuce]

Speaking of "decent alignment", seating the bullet 30-50 thousandths into the rifling usually mitigates that.
The taper crimp is to keep the bullet from falling out of the case.
I use a dedicated Lyman taper crimp die for 40 & 45 and a full length sizing die for the 38's & 44's.
Works like a charm as long as the cases are annealed.

[bpcrshooter62]

I have found that the best sd is not always the best group on target

[desert deuce]

Which is why I IGNORE SD and pay more attention to ES.
Of course, ladder loads can give you a starting point.
And if starting with low volume and working up incrementally you may find a second sweet spot.
Sometimes the same volume by increasing or decreasing compression might make a difference at the target.
But you are correct, it is the target that reveals the truth. Not so much the chronograph.

[J.Murphy]

It seems to me tight grouping is important at all distances, but the velocity becomes increasingly important as the distance increases. Play with a ballistic program using a BC between .3 and .4 and you see that the vertical will kill you as the ES increases, regardless of group size. Silhouette distances are managable, but BPTR at 800 - 1,000 yards, is another story.

[desert deuce]

Precisely why I seek extreme spreads in single digits 600 yards and beyond. This is where a balanced load comes into play.

In silhouette, to 500 Meters, the pattern on the swinger will tell the story and that load has been identified in ladder loads frequently.

Beyond the Balanced Load the most important factor is the six inches between the ears that determines success or failure.