MY New Scale and Question on OAL...

[Wildalaska]

Did a batch of ammo for the M41B again last night...my last run of ammo was a little dissapointing, with 3-4 shots of the 5 I was shooting averaging 1/2 inch but flyers on the shots opening them up...

Ive got a load I am gonna work with, its 43.8 grains of RL 22..that I think will give me my velocity (2550) I am looking for..now I am play with seating as I think my prior loads were incosistently seated....

Now lat time I seated based on an OAL of 3.050, that was measured to the bullet tip. Military ball measured 3.070 to the tip. I got a comparator, and used that and am seating based on the ogive...comparing the match kings to the mil ball shows me I am seating .030 farther out, however the OAL of my rounds to the tip is now 3.030...+/- .On the other hand the seating based on the ogive has been very conssitent, varying by no more than ..002

Any advice as to this..if I am seating based on the ogive, how do I compare that to published reccomended OALs...or should I just get a chamber comparator and work on that...? some info is telling me to seat to 3.150..thats to bullet tip..but if I am seating to ogive how do I calculate to to this......

Is the deeper seating depth gonna increase pressure substanitlly?

Now the scale...guys, it is precise, exact and perfect.

Its SWMBO..yes boys, you want your powder measured to the grain, exactly, marry a Japanese girl...

WildsniperAlaska

 

[strambo]

Just measure to the tip to compare to published OALs. Use the comparitor for your own reference, the OAL don't matter except for magazine length and possibly pressure.

Is the deeper seating depth gonna increase pressure substanitlly?

Load a few lighter than your current charge (like a few at 42.5, 43 and 43.5) and check the velocity. It will probably increase pressure some, which may result in your perfect 2550 fps getting screwed up with the prior charge weight, but one of the lighter ones may now be perfect.

When messin with OALs I start deep and work out, so pressure decreases and safety isn't a factor until the ogive touches the lands. For my latest load with my .300WM, I just seated to the max OAL that will fit in my magazine and decided to say to heck with a few tenths of an inch in group size at the expese of time, $$ and bullets that don't fit in the mag. (If it was a bench rest gun...different story)

 

[larryw]

Based on SWAG on the bullet you're using (155gr HPBT?), 43.8gr or RL-22, and run through QuickLoad:

COL of 3.020 = 44966 PSI
COL of 3.050 = 44278 PSI
COL of 3.080 = 43614 PSI
COL of 3.150 = 42150 PSI

Pmax is 55114 PSI

Its SWMBO..yes boys, you want your powder measured to the grain, exactly, marry a Japanese girl...

No arguments there.

And if that's the same lady who stones the sear faces on your Trigger Happy kits weighing your powder charges, you've got a match ammo factory there!