Sizing

[lovern98]

Hi Folks, my name is Eric and I'm new here.

Question:

How far over bore groove diameter should bullets be sized? My Henry bore slugs out at .4575, should i size to .458 or .459 or does it really matter? Just got back from some testing with a 405 grain cast from #2 Lyman alloy. Speed was avg 1868 for ten rounds with 46.5 gr RL-7. No leading and no pressure signs. But poor grouping. These were sized to .459. Would sizing to .458 make any difference in the grouping? Not sure I'm gong to stay with the 405's, they kick like hell, at least from the bench. Any help would be appreciated..

Thanks,

Eric

[KenH]

What caliber gun are you shooting? If that's a 45-70 at 1868 fps, bet has a "kick" to it with 405 grain bullets.

1800 fps is pretty fast for a cast bullet...... without LOTS of work. You normally need gas checks for cast bullets over 1200 fps or so.

What lube are you using? What bullet design - mold number etc. Powder coat? Hi-Tek?

Several questions to be answered for the VERY knowledgeable folks (not me) on this board to provide full answers.

Ken H>

[243winxb]

45/70 ? .459" diameter should be ok. Gas checked? For accuracy, i would reduce the powder charge.

[Hick]

You might want to calculate the RPM of the bullet (velocity in fps times 60 divided by the twist of the barrel in feet). For example, 2000 fps in a 1 in 12" barrel is 2000*60/1 ft = 120,000 rpm. There will be some point on the RPM scale where velocity goes to hell. For my rifles with Lyman #2 alloy this seems to be around 130,000 to 140,000. I've heard similar numbers from other sources. Using a gas check and making sure you stay below this kind of RPM will make things much, much better. But-- test your own, because results vary.

[lovern98]

Thanks!!

I will reduce the charge, since this was below the max of 48.5 but still too much. Makes sense that too much velocity would be bad for accuracy. I was using Lee liquid alox (3 coats) no gas check. There was no leading. Rate of twist is 1/20", rpm figures out to be 67,274 at that speed. I'm going to go back to a 350gr bullet with a GC anyway. Just tinkering with these.. It is a 45/70. Any recommendations on how much to reduce the charge in %? The bullets were cast from a Lyman mould, #457193..

[Yodogsandman]

I'm surprised that you hit the target at all without using gas checks at that speed.

[lovern98]

Good advice folks, thanks!!
Is there a load data place here?

[Toymaker]

195879Different rifle, but same mold. It'll give you some idea of where you're going. No reason to brutalize yourself.

[lotech]

I haven't used Reloder 7 in the .45-70 for a while, but had best results with #457193 cast of wheelweight alloy and run through a .461" die to lube. The bullet was not .461", I think it was around .459", but I don't have any on hand to measure. I probably shot this load in a Marlin 1895, a Shiloh Sharps 1874, and a Ruger #3. My notes show good accuracy with a muzzle velocity of 1420 fps in the Ruger using 35 grs. Reloder 7. This load has about as much recoil as I want to handle on a regular basis.

If possible, seat your bullets where they engrave slightly when chambered. I wouldn't get too concerned about RPM or bore diameter. Load your cartridge with the largest diameter bullet that will chamber without difficulty. That will probably be .459", maybe even .460", but exceptions abound everywhere.

With #457193, I've had better luck, accuracy-wise, with 5744. I started using #457122 (the 330-grain HP) a number of years ago, loaded to around 1500 fps. Accuracy is just as good or maybe better than #457193. Also much easier on the shoulder. SR4759 is the best powder I've found so far, but some others may work as well. Good luck-

[Whitespider]

The groove diameter of my synthetic stocked Handi-Rifle (which weighs near nothing) slugs just a touch over .456 (.4563-.4564) and I shoot a commercial (very) hard-cast 405 grain boolit sized .4585 over 50 grains of IMR-3031 (should be close to the same velocity range as your load). I don't have the intestinal fortitude to try shooting it from a bench (recoil is absolutely brutal to say the least). I use a ghost-ring rear sight, and sighted it in a touch high shooting off-hand (with a tight sling) at 50-yards. I have no idea how it groups... but I do know a milk jug has zero chance of survival at 100-yards.

I've just recently cast some Lyman #457123 330-grain HP's for it... I plan on reducing the load dramatically (possibly making it tolerable off a bench). It seems, as I age, I feel I have less and less to prove. Still, I'll keep a few of those 405-grain boolits loaded with 50-grains of IMR-3031 around... they make great party favorites when someone starts bragging about their shooting prowess (and I should be able to handle a handful of "show-off" shots at a time for a few more years yet). I always have to laugh when some braggart turns around to look at you with blood running from their nose after shooting it.

At one time I considered increasing the powder charge to a "he!!-bent" level... but... there comes a point where a detached retina from recoil becomes a possibility. If something like that happened the fun is over... as my son always says, "It's all fun 'n' games 'til the cops show up." And, as I get older, my doctor keeps saying, "Well... if it hurts... don't do it."
*

[KenH]

"Well... if it hurts... don't do it."

Boy do I wish I'd learned that many years ago!!!!