Loading the 4570 with slightly slower powders

[Sharps40]

HA! Thanks. Hmmmmm, I can't easily thread the breach of a barrel cause I got no lathe. But I'm working on a way to do it so I can build a Blackhawk Revolving Rifle.

Still sperimentin with the 4570 loads. I'm thinkin I want to kick up into the 50s on powder charge and go to mag primers. Varget is burnin at low pressure at 1700 fps and this load bein 1634 an slower powder, betcha its burning inefficiently too. Gotta get a cool morning and cast up some more them good hollow bases. I bet, if I can stand it, some more powder, push closer to 1750 fps and my deviation numbers will drop some more. Accuracy is hard though, tuff to fine work at 100 m with a 4.5 power scope. But for now, I'm waitin on an M1 garand cheek piece so I can get into the scope right each time.

 

[Sharps40]

Earlier, I went with the loading gurus recommendations and vetted out my 45-70 1886 Winchester with slightly slower powder than normally seen in the 4570 published data. With assistance from a pal with a loading program we noted that my chosen pressure limit and velocity range would fall in about where I wanted to be, 1600 to 1700 fps with a 405g HBFN lead bullet.

I went to the range and saw that my max charge at that time, (49g H380) was producing a velocity average of 1634 fps with fine accuracy at 100 yards and hit the gong capability to 150 yards w/o any hold over.

So, back to the bench and after spending some time with my notes from blackpowder cartridge completion days I decided to polish the load a bit.

First, I upped the charge to about midway between my last loadings and the calculated max for 25K psi and measured in 50.3g of that good H380 powder. This is the one I'd like to be my single bench rifle powder feeding everything from .223 to 45-70. (So far success with all but the .223 and .22-250 remaining to be tested)

I also looked over my dies....two seat and crimp dies on hand. Checking my notes and looking over the dies and making up a test shell, I rediscovered what I used to know 20 odd years ago......bell with an M die, seat with the rcbs die backed off just enough to straighten out the mouth and final crimp with the special blackpowder lee taper crimp die with the bullet seating stem removed.

Now, the final change was a recommendation taken from H380 data and long years of loading blackpowder in this case compacted into a solid pellet.....I installed a Winchester Large Rifle Magnum primer for more zip when the bang switch is tripped.

All that said, I checked original load lengths in my data and found 2.530 was too long.......seating these slugs to 2.5 inches puts the front driving band under the crimp instead of being split by the crimp. The crimp is now neater on these slightly shorter rounds and I think will aid in providing the inertia needed to get the H380 burning well.....This crimp and the LRM primer was also what was needed to get a solid pellet of 60 to 65g of Goex fff powder burning properly too. (And when I started loading BP this way, accuracy was super and the powder burned clean so that I was able to run 200 yard 15 shot strings without cleaning from the old roller and sharps)

Lastly, I made up a jig, as indicated above, and hollowpointed some of those fine HBFN lead slugs. They have always won matches to 300 yards and performed well on deer. However, deer shot with the large slugs at black powder velocity are sick and often wobble off a few or more yards....even with a high shoulder. Looking for a bit more shock, I wanted to see if home hollow pointed heavy slugs of soft alloy would shoot with acceptable accuracy at 100 yards.....No sense letting one wobble around on public land.....theys liable to get lost in the weeds!

Here is what I wound up with and with luck, tomorrow morning at the range will see positive results.

405g HBFN on the left. Same bullet, hollow pointed and now 390g HBHP on the right.

The Lee blackpowder cartridge crimp, sort of a cross between a roll and a taper.

The view from the deers shoulder.....thet there looks purtty mean!

 

[Sharps40]

Some off hand practice at 25 yards. Trigger sure is useable now that it has the rebound removed and polished and the return spring lightened!

About here, at 50 yards bench I discovered why things were off and a shot strayed.....I put the M1 Garand leather cheekpiece on the rifle.....makes a world of difference for off hand shooting but not so much on the bench rest. After roughing in the zero I found if not carefull the thick pad would hangup in the rear of the rest and throw out a shot.....it got worse at 100 yards but, I'm still pretty happy with the new load.

I bounced my shots around at 100 from the rest. When I could hold the rifle steady and not let it bounce on the laces of the cheek pad, I put my shots in the bottom line of the 9 ring....right where they should be. I'll have to work out a bag arrangement for this rifle.....the rest is not going to be easy to use with the cheek pad in place.....Incidentally, the 1/2" thick cheek pad made it necessary to adjust the scope......3.5" left to get back to the center. I shoulda noted this from the 25 yard off hand shooting that was all landing to the right.

Oh yeah.....each group is a composite of both the HBFP and HBHP rounds. They both land in the same spot from 25 to 100 yards. So, looks like the hollowpointing jig is a success.

 

[pbhunter]

Excellent write up on your 45-70 experiment!

I like SR4759 in the 45-70 because I shoot a lot of cast in various rifles, so I bought a bunch. I will sit and cry alittle when it runs out, as they are not making it anymore. Understand your desire to use H380, and looks like it is working well.

 

[Sharps40]

Prolly not the most efficient and I could prolly load heavier too but so far the "ack-er-esy" is jes fine!

 

[woodstock]

Don't see much about 45 70 reloading, good thread. Ive been loading 300 grains Hornady HP but using Benchmark and published data

 

[Sharps40]

I need to bag the rear of the rifle and get back out at 100 yards. Would be nice to see a target without my mistakes on the bench contributing to the spread!