info requested for loading data: cast vs. jacketed bullets

[MSP Ret]

Info needed please, I want to load up some .280 loads and have looked up a load using PB (11.0 grains start 15.5 Max) behind a cast GC 139 grain bullet. I have half a can of PB left and have some 139 grain jacketed .284 bullets instead of the cast. Can I use the loading data for 139 GC cast for the same weight jacketed bullet? It would work out well if I could, get to use up the PB and load some low level .280's at the same time....Thanks for any input....<><.... :grin:

[safetysheriff]

MSP Ret'

What is PB ?

Take care.

SS'

[MSP Ret]

PB is an older Dupont smokeless powder. I have about 1/2 a pound (can) left and would like to use it up. If I remember correctly I used it in loads for my .45 ACP's and have found some loading data in my older Lyman cast bullet loading book  for a .280 using it (PB) with cast bullets. For a 139 grain cast w/GC it lists from 11.0 to 15.5 grains. All I have in .280 bullets (.284") are jacketed, thus the delimma and question....<><.... :grin:

[Leftoverdj]

It ain't the best of ideas, MSP, but it's doable with some warnings. The jacketed bullet has a lot more friction and builds more pressure. The PB, being a fast pistol powder, has a limited pressure range. You need a velocity of over 1000 fps for reduced loads using jacketed bullets in a rifle barrel to avoid getting one stuck.

If your cast bullet data shows a velocity of around 1500 fps for 11 grains of PB, I'd be willing to sub a jacketed bullet. I'd even be willing to use 12 grains if 11 grains showed a velocity of 1300 fps but less than 1500 fps. Either of those give you room in both velocity and pressure. The sub of the jacketed bullet can drop velocity as much as 300 fps and it can also run pressure way up. You need to leave some room for both things to happen and still be safe.

[ScatterGunner]

msp -

a given powder will run at higher pressures for jacketed bullets than for lead bullets of equal weight and similar bearing area. the jacketed bullets have a brinnell hardness of 100+ while the run-of-the-mill cast bullet runs in about 10 or so on the same scale.

PB is too fast for jacketed bullets, (PB means Porous Base) it's a shotgun powder, the standard trap or skeet load is 20.5 grains of PB with 1 1/8oz load. all the 280 loads i see in the IMR data book show the slower IMR powders, IMR4064, IMR4831,etc. slow burners !

i wouldn't use PB in a metallic center fire rifle round. save your PB for cast bullets, it's a good clean powder, cheap because the trap shooters used it in bulk.

the max load you mentioned should produce about 30,000 psi with a lead bullet with a gas check. at that pressure you are probably liquifying most of the rear of the bullet, how are the cast bullets shooting ?  you need a brinnel hardness of about 20 ! or so for that load to keep it accurate.

anyway, don't use jacketed bullet with the PB powder, you will probably get hurt and trash a handi in the process. we don't anyone hurt !

sg

[MSP Ret]

Thanks guys, I'll save the PB and load some cast .45's with it. For my jacketed .280's I will use a more appropriate powder....<><.... :grin:

[ScatterGunner]

pick up a one pound can of IMR4064 for your jacketed bullets, it'll work good from anything from the 22 hornet to 458 win mag, kinda like from squirrel to moose !

sg

[MSP Ret]

Thanks for the suggestion Scattergunner. Just got back from Maine, no coyotes to be found!!! But we did see a bunch of Moose and deer, a couple of Bald Eagles, many Partridge and songbirds, and a few Turkeys. Caught a racoon and old mangy old cat in my buddies Hav-A-Hart trap that have been into his trash and relocated them a few miles away. Heard a few owls at night, got to try a few casts with my flyrod, but the ice is (was) still in pretty heavy. Had an up close incident with a Moose but even though he sounded close enough to hit with a rock could not see him, just heard his bellowing and crashing around in the woods while set up for coyotes.  Also found the best old deer trail I have seen in a long time but the area is flagged to be cut, but the flagging does look as if it will just be an access road to some big trees out deeper in the woods. I will be there this deer season!!!....<><.... :grin:

[Ditchdigger]

MSP RET ; Ive been using some Rel. 19 with my 280, and its showing promise. The first 2 shots will nearly touch,and the next 2 will do the same thing, but 3/4" lower. That is with the Horn. 139 gr. with 56 grs. of Rel. 19, .008's from the lands. I tried .012 first, and got about the same thing with the first 2 and the 2nd 2 but about 1 1/4" apart. I'm going to try 57 grs. next about .008 off the lands next time and see if that helps.  Digger