.308 and 155 sierra Palma w/ IMR-4064

alloy · October 17, 2010, 01:56 PM

Rifle is an older Dragunov styled autoloader rifle with a 24.25 barrel, 1 in 12 twist. I don't like pummeling the rifle when I rarely get it out. Very little loading data for the rifle that I've ever found...so I don't want to beat the bejeezus out of it. First time specifically loading for it, and I was trying to use up some components, namely the powder and these projectiles, that I could never make work for me with any other rifle I've tried them in. But I have a few pounds and 5 or 6 hundred so it would be nice to not use them up shooting beer cans.

I worked up a couple strings of 5 each, and the last one the rifle started to settle down nicely.

44.3 grains IMR-4064
R-P commercial cases
CCI BR-2
155 Sierra Palmas with the moly tumbled off
COAL 2.785

I had thought that I would be hitting the upper pressure limits so I stopped with this load, when I was making up the batch...but as it worked out the primers weren't even beginning to flatten, the velocity was just starting to uniform.

The chrono average was 2781fps
The 5 shot string ran:
2770, 2777, 2780, 2791, 2791

Would you try a few more tenths, should these projectiles be flying a bit faster to stabilize as designed, or is the slower powder gonna be a limiting factor in the 24.25 barrel?

TXJohn · October 17, 2010, 07:11 PM

Looks good to me you might tinker with OAL a little it might tighten the groups or it might open them. I load 46.1 grs. of IMR 4064 with a 150 gr Sierra Gameking out of my Tikka T3Varmit but this is a max load in my rifle.

Ike666 · October 17, 2010, 09:36 PM

I just started experimenting with 155 SMKs and Berger 155 VLDs this week. Made up two stepped batches with RE-15 and Varget. Maxed both at 44.8 grains. No pressure signs in either at max out of a Win M70 with a 26" heavy barrel and 1:10 twist.

The groups for both powders printed sub-MOA at 100 yards, with the edge going to the Varget 44.8 load at 0.473.

Next week I'm going to start working up to 45+ on the chrono.

I think I like this bullet a lot.

alloy · October 17, 2010, 10:10 PM

Quote:

I think I like this bullet a lot.

This is about the quickest I have hit on something promising, and with components that I couldn't make work in a few other guns. Think the barrels were too short for the 4064.
Loading for autoloaders only, when most of my data/manuals is heavier for bolt guns...might be giving me some kind of phobia.

I think I'll try some loads for next weekend working with the COLs and maybe try a tenth more.

TXGunNut · October 17, 2010, 10:20 PM

Depends on your rifle. My latest rifle has a very small sweet spot but I've learned two things about it. A load that's too hot will string vertically, too mild will be loose or maybe a bit horizontal. YMMV. If this were my rifle I'd move up in .3gr increments for two more steps and load 5 44.3gr loads as well as 5 44.0grn loads as well just for validation. Did that today when testing a new lot of powder, results were very enlightening.
Seating depth could also be critical at this point, some rifles like the bullets almost touching the lands, some like them .020" off, some seem to have little preference as long as the bullet is at least a few thousandth's off the lands.

HiBC · October 17, 2010, 10:57 PM

Its a gas operated semi-auto.IMO,loads suggested for service rifles should be appropriate.
i have done a little experimentation with the Palma in the AR platform.
Sierra has come out with a brand new Palma within the last year or so.The older one is now a 155MK
I got excellent results with the older one,the MK.
The new one,its BC exceeds .500 ,its a bit more VLDish.
My tests,loading to 2.8 mag length and semi-auto fire,the little testing I did,I got mediocre accuracy.This is not to knock the bullet!
i'm sure the bullet is fine.Its a Sierra.
My application may not be ideal.

alloy · October 18, 2010, 02:49 PM

I resized the cases today and checked them in a Wilson case guage. Turns out the fired cases went in flush to the top shoulder just like after I resize them. It seems that all I'm actually doing to these cases is neck sizing them, altho there was about .002 growth in length. Is that common? I've never checked fired cases before, and figured they would be ballooned out somewhat.

Anyway I dropped back a few tenths, and loaded some more, and went up to 44.6 in 1 tenth increments to try Sunday.

October 17, 2010, 10:20 PM	#5
TXGunNut Senior Member Join Date: January 16, 2010 Location: If you have to ask... Posts: 2,860	Depends on your rifle. My latest rifle has a very small sweet spot but I've learned two things about it. A load that's too hot will string vertically, too mild will be loose or maybe a bit horizontal. YMMV. If this were my rifle I'd move up in .3gr increments for two more steps and load 5 44.3gr loads as well as 5 44.0grn loads as well just for validation. Did that today when testing a new lot of powder, results were very enlightening. Seating depth could also be critical at this point, some rifles like the bullets almost touching the lands, some like them .020" off, some seem to have little preference as long as the bullet is at least a few thousandth's off the lands. __________________ Life Member NRA, TSRA Smokeless powder is a passing fad! -Steve Garbe I hate rude behavior in a man. I won't tolerate it. -Woodrow F. Call Lonesome Dove My favorite recipes start out with a handful of used wheelweights.

October 17, 2010, 07:11 PM	#2
TXJohn Senior Member Join Date: March 15, 2010 Location: Ft Worth TX Posts: 163	Looks good to me you might tinker with OAL a little it might tighten the groups or it might open them. I load 46.1 grs. of IMR 4064 with a 150 gr Sierra Gameking out of my Tikka T3Varmit but this is a max load in my rifle.

October 17, 2010, 09:36 PM	#3
Ike666 Senior Member Join Date: October 10, 2009 Location: SW VA Posts: 491	I just started experimenting with 155 SMKs and Berger 155 VLDs this week. Made up two stepped batches with RE-15 and Varget. Maxed both at 44.8 grains. No pressure signs in either at max out of a Win M70 with a 26" heavy barrel and 1:10 twist. The groups for both powders printed sub-MOA at 100 yards, with the edge going to the Varget 44.8 load at 0.473. Next week I'm going to start working up to 45+ on the chrono. I think I like this bullet a lot.

October 17, 2010, 10:57 PM	#6
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,283	Its a gas operated semi-auto.IMO,loads suggested for service rifles should be appropriate. i have done a little experimentation with the Palma in the AR platform. Sierra has come out with a brand new Palma within the last year or so.The older one is now a 155MK I got excellent results with the older one,the MK. The new one,its BC exceeds .500 ,its a bit more VLDish. My tests,loading to 2.8 mag length and semi-auto fire,the little testing I did,I got mediocre accuracy.This is not to knock the bullet! i'm sure the bullet is fine.Its a Sierra. My application may not be ideal.