PDA

View Full Version : plain base/pressure/308/ ?????



mike in co
01-19-2006, 02:41 AM
ok kiddies.....somewhere in the past i brought some of this up and now i'm back.
i saw "the load/red dot" and put some together with gc boolits, but when i went to do the pb boolits....i saw the high pressure of the load. we are talking in the mid to high 30k's. i seem to remember a line about staying under 20k.....

so just what do i use to shoot 133 pb's from a 26" 308 win ??? twist is 1/13 parker hale match bbl.

i see lite loads of 4227 and 820 will do 1100 fps.........

let me knwo what else works and is the 20k limit important ???



i'm listening.......

Bret4207
01-19-2006, 09:15 AM
Mike- I've used the 13.0 Red Dot load in the 308 with PB boolits for some time. Only catch is my PB designs are 150 or less. I think the heavy comes in around 155, the lighter one is the Lyman 311410 I think, at around 130 gr. I have used some GC designs w/o the GC and they worked OK for under 35 yard or shooting. Nothing to brag about. Consider starting lower, say around 10.0 gr and work up. With 133 gr boolits you may be able to get away with much less than Harris's 13.0 Red Dot. I'd also consider the 2400 load (16.0 2400) suitably reduced and maybe Unique. Have you looked at Lymans recomendations? The some good scoop mixed in with the nonsense in their book.

As for the 20K pressure limit, IMO each rifle and load combo is a law unto itself. I don't think anything is cut in stone anymore when we've seen so many old wives tales go down the crapper. You could check with the Shuetzen guys too. They get outstanding groups with only PB at respectable speeds. Heres a link-

http://groups.msn.com/Schuetzen/_messageboard.msnw

sundog
01-19-2006, 09:46 AM
Kiddies? Kiddies!!!??? Sheesh. I might be a big kid, but I ain't no kiddie! http://castboolits.gunloads.com/images/icons/icon7.gif Besides, my toys are more expensive. Well, I think they are. Have you seen the prices of some of the kid toys nowadays????

Anyway, the Trooper beat me to the punch. I was gonna suggest 2400. Or maybe Herco or Blue Dot. 2400 ought to work. sundog

HORNET
01-19-2006, 05:00 PM
Mike,
I don't know where you heard the 20Ksi pressure limit from, but it seems to me to be bovine-processed organic fertilizer. Consider that many magnum handgun loads with plain based boolits run to 35-40 ksi and the .30 Carbine does well with p.b. also near 40 ksi ( both peak pressures, not mean effective pressures).
The sheutzen and bpcr folks frequently run loads over 25 ksi peak with extremely soft alloys, like 1 in 40, and the current scheutzen favorite .32 Dell runs very high peak pressures.
Failure of p.b. bullets has to do with the interaction of a lot more factors than just the peak pressure and the best way to find out where it happens is testing in your barrel with your alloy, your lube, etc.
The very old Lyman manuals used to offer their recommended loads which usually give a good starting point.

mike in co
01-19-2006, 07:17 PM
i used to run my 265's in 44 win mag at about 24kpsi....but its only a 7.5 in bbl and the velocity was 1340, i now shoot lbt 280 at about 1050 which is only 15kpsi.
i was looking for the 1100 to ??? velocity, my concern is also the bbl and lube...
its a 26" 308 bbl.
lube is apache blue till its gone then over to the board std by filex.

boolits are h2o quenched ww with a bit of dental( dont ask me why..but seem to cast better wiht the dental added)

i have never played with lite boolits/lite loads in a rifle......

so i'm pickin' brains