Thursday, February 26, 2015

Light loads, mixed results

After some more reading, decided to try sizing the bullets to .311".  Also to try a recommended load in .30-06 of 3.2 grains Bullseye, and in .30-30 2.7 grains.  One more change as well: it's long been a thing, on rimless cases used for light loads like this, to enlarge the flash hole with a #30 bit.  Supposed to give more even ignition when using small charges of fast-burning powder, but also with such light loads a common problem is the shoulders of the case can wind up being shifted if the case is used a few times, affecting headspace; enlarging the flash hole alleviates this.  So picked ten cases and modified them, and did one other thing; cases so modded CANNOT be used with regular loads; it tends to blow out primers.  So used a file to cut a notch in the rim to ID them, and I'll make damn sure to keep them separate. 

Also, you might remember a few years back there was a lot of Korean milsurp .30-06 imported, from two plants: one PS headstamp, the other KA.  The KA was slightly corrosive, so a lot of people just dumped it.  Being cheap and a scrounge I picked up the stuff and kept it; cleaned thoroughly and used with new primers, it works fine.  So I used only these for the modified cases, so one more difference from the others.

First, tried the Lyman 115-grain Carbine bullet, no gas check, sized to .311 but with the previous load of 5.0 Unique.  Also, the bullet was seated so the case mouth was just a touch past the front of the lube groove.  Previous test showed that to shoot better in this rifle than with it seated to the crimp groove

I'm calling this aiming error on my part, having what amounts to two groups.  Which means re-test. 

Also with the old 5.0 Unique, the 100-grain wadcutter sized to .311

Not so hot.

Next is same bullet over the new 3.2 grains Bullseye, in a modified case
 Much better.  Yes, I realize I should have loaded one set in a standard case with the new charge so I'd only be changing one thing at a time.  I'll have to do that later.

Here we have this done: on the left is the .32-caliber SWC bullet in a non-modified case,
 and on the right in a modified case.  These are so close I can't call a real difference.

On the .30-06 the 3.2 Bullseye works.  So I've got a list:
Try the 115-grain spitzers with the 3.2 load
Try the 100-grain wadcutter and SWC bullets unsized over this load, see if the sizing made a difference.  Make sure to try the WC in modified AND non-modified cases.

On to .30-30.  Again, bullets sized .311, over 2.7 grains Bullseye.
First, the .32 roundnose bullet
 Doesn't like this one sized any better than unsized, with either powder.

The SWC bullet on the other hand,
gave a nice tight group, well worth trying again.

I did try the wadcutters over the old 5.0 Unique as well as the new charge, but I've lost the damn target pictures.  They weren't bad, but not as tight as the group from the last range session.  These will be tried again with the bullets unsized, to see if that makes a difference.

And how, I'm tired.  And want to get some sleep so as to get some stuff done in the morning before the snow starts.  'Night, all.


t said...

Have you tried the dacron fiber fill trick to keep the powder in place at the bottom of the case? Supposedly this keeps the pressure and burn rate more even for better accuracy in light loads. I've never tried it, but maybe it would help.

taminator013 said...

My last comment about the dacron was supposed to be by taminator013, but I hit publish too quick. Not enough coffee yet...................

Firehand said...

I've read a bunch about fillers over time; a few things seems to be almost essential, in some it'll work, and in some it can actually be a hazard. At this point I haven't messed with it, the simpler I can keep things the better.

taminator013 said...

Can't blame you there...........