quote:

Originally posted by starmetal:
Larry, to be honest with you I think you might have been better off if you would have titled your first rpm threshold thread to "How to achieve better cast accuracy easier for the novice cast bullet shooter" or "What velocities to expect easier accuracy with cast bullets". More like a recipe to guarantee and well baked eatable cake. Not a death warrant title suggested by "exceed this rpm range and your accuracy will DIE". The formula for shooting goes bullet, powder charge, velocity, rpm, group size. Of all the things you picked out of that to start with was the rpm. I'd venture to say a high percentage of cast shooter (even jacketed) haven't a clue what the rpm of their loads are. This is not to say "Hi, I'm Larry Gibson and here's my velocity threshold for cast bullets".

quote:

Originally posted by swheeler:

quote:

How to achieve better cast accuracy easier for the novice cast bullet shooter

Exactly, and who better to explain the novice approach than Larry! Good job Larry. See I can be nice

quote:

The 7x57 chart in the article is with Wilk banded bullets!

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by starmetal:
Larry, to be honest with you I think you might have been better off if you would have titled your first rpm threshold thread to "How to achieve better cast accuracy easier for the novice cast bullet shooter" or "What velocities to expect easier accuracy with cast bullets". More like a recipe to guarantee and well baked eatable cake. Not a death warrant title suggested by "exceed this rpm range and your accuracy will DIE". The formula for shooting goes bullet, powder charge, velocity, rpm, group size. Of all the things you picked out of that to start with was the rpm. I'd venture to say a high percentage of cast shooter (even jacketed) haven't a clue what the rpm of their loads are. This is not to say "Hi, I'm Larry Gibson and here's my velocity threshold for cast bullets".

Starmeta

"exceed this rpm range and your accuracy will DIE".

Furhter evidence that you do not pay attention to what I tell you and that you still have no understanding what the RPM threshold is! How many times must I tell you it is not a limit? How many times must I tell you that it can be pushed and exceeded? How many times must I give examples to you, 45 2.1, BaBore, sweeler and others that I have done, Bass has done it and all of you have probably done it? How many times are you going to continue to ignore what I say and continue with you cockamamy arguments just for the sake of argument?

It doesn't matter what you "think" I should have titled it because you have no idea what the RPM threshold is. Learn the definition of the RPM threshold and then come back.

ONE THING THE RPM THRESHOLD IS NOT IS A LIMIT. GOT THAT? SO QUIT MAKING STUPID STATEMENTS THAT IT IS.

Go learn what it is.

Larry Gibson

quote:

Originally posted by starmetal:

Aha! The rpm threshold is not a limit. It also does not apply to banded bullets. It also does not apply to paper patched bullets. In conclusion, the rpm threshold does not apply to any bullets.

Stay tune for Larry's Muzzle Loader Musket Threshold. Find out if you've been exceeding the Musket's limitation. Boy, I can't wait to read that. Now I will learn something there because I have zero experience with muskets.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by starmetal:

Aha! The rpm threshold is not a limit. It also does not apply to banded bullets. It also does not apply to paper patched bullets. In conclusion, the rpm threshold does not apply to any bullets.

Stay tune for Larry's Muzzle Loader Musket Threshold. Find out if you've been exceeding the Musket's limitation. Boy, I can't wait to read that. Now I will learn something there because I have zero experience with muskets.

Therein lies the real problem here; you do not understand what I have told you and others over and over; the RPM threshold applies to regular cast bullets. The RPM threshold may apply to other bullets such as banded or paper patched bullets. Hoever I do not know what that threshold may be because I have not investigated it yet.

As to the rest of your statement; it is obviously you you "zero experience with muskets". Muskets for the most part are smooth bores and have no rifling hense no twist and no RPM for the projectile. Those "muskets" that may have rifling have such slow twists that high RPM is beyond their reach. Now, you might find it interesting that there does indeed seem to be an RPM threshold to RBs fired in fast twist (1-28") muzzle loaders.


Too bad facts continue to get in the way of your arguments.

Larry Gibson

quote:

Originally posted by starmetal:

I have another question for you. Say you have two cast bullets that are exactly the same except one is gas check design and the other plain base. Talking about rifle bullets. Why can't you push a plain base (for that matter an unchecked gas check bullet) as fast and accurately as the gas check design? Give me your mechanical scientific explanation of what happens with the plain base and unchecked bullets. Maybe we can come up with something to prevent what you are about to explain.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by starmetal:

I have another question for you. Say you have two cast bullets that are exactly the same except one is gas check design and the other plain base. Talking about rifle bullets. Why can't you push a plain base (for that matter an unchecked gas check bullet) as fast and accurately as the gas check design? Give me your mechanical scientific explanation of what happens with the plain base and unchecked bullets. Maybe we can come up with something to prevent what you are about to explain.

As ccelertion in eases obtration inceases and at some point the unprotected base of a PB bullet is setbck unevenl. Tus the base of such a P ulet is not square wit the born exi fm he muzzle. rotectng the base of the bullet and/or prevening uneven obturation/setack is the "echancal means.

Larry Gbson

quote:

Originally posted by starmetal:

That's what I come up with too. This sometimes happens with gas check bullets when pressures are high. How do you think we could overcome this? Especially with plain base which are immensely cheaper to shoot? I have ideas. Part of the limitation is the base of the bullet being seated past the shoulder/neck junction. I think you know where I'm going with that.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by starmetal:

That's what I come up with too. This sometimes happens with gas check bullets when pressures are high. How do you think we could overcome this? Especially with plain base which are immensely cheaper to shoot? I have ideas. Part of the limitation is the base of the bullet being seated past the shoulder/neck junction. I think you know where I'm going with that.

You are correct; first thing is not to seat the base of the bullet below the case neck (prevents riveting of the base before it enters the case neck).

Other measures are;
*Harder alloy, duh, eh!
*Minimal size lube grooves
*Case neck that fits the chamber neck with not more than .001 clearence (prevents riveting in the case neck)
*Case Neck needs to fit to within .001-.002" of the chamber neck length
*bullet driving band must fit leade
*nose of bullet must pecisely fit or be slightly ngraved by rifling
*Base of bullet may be protected by wad or reversed GC
*Slowest burning rate of powder at 105% loading density giving desired velocity

Probably a few other things but it is late and I've got to get some sleep.

Larry Gibson

quote:

Originally posted by starmetal:

That base wad is what is on my mind. Particularly a metal one. Something not so easily deformed by the pressure. I would think a long neck would be a good start for a cast cartridge and then not a real big powder capacity. You know I shot an awful lot of those Lyman 150 gr 7mm Loverins from my 7mm-08 and the base of the bullets were well within the csse powder room. They shot very very good. I could even push them some. I don't feel a Loverin is the style of bullet to really push, even if the base doesn't past the neck. What's your thoughts on that?

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by starmetal:

That base wad is what is on my mind. Particularly a metal one. Something not so easily deformed by the pressure. I would think a long neck would be a good start for a cast cartridge and then not a real big powder capacity. You know I shot an awful lot of those Lyman 150 gr 7mm Loverins from my 7mm-08 and the base of the bullets were well within the csse powder room. They shot very very good. I could even push them some. I don't feel a Loverin is the style of bullet to really push, even if the base doesn't past the neck. What's your thoughts on that?

Base wad would seem to hold promise. I think to keep from tipping with the base of the bullet it either needs sides like the inverted GC or must be of sufficient thickness.

The harder alloys don't seem to be a problem when seated below the case neck. This is either if a dacron filler is used or a slow burning powder at high loading density. This seems to protect the base of the bullet until it is into the neck/bore. However, soft cast bullets or when fast burning powders are used are the problem. Riveting and gas cutting of the base does occur.

Unless a custon design is used I've found with Lovern bullets (225426, 266455, the longer 6.5 Lovern but I don't have the #,, 311466, 311467, 323470, 323471) velocities can be pushed higher with better accuracy than with traditional nose/bore riders. However, tight fitting nose/bore riders (314299 in a .308 bore for instance) do very well also. I tried several of the older RCBS designs which were basically Loverns with oversize lube grooves di not do well at higher velocities. I believe this was because the larger lube grooves were a weak area allowing too much collapse and unwanted obturation. I have always had better results with the lighter weight for caliber and shorter Loverns at the higher velocities.

Custom designs such as Bass's 154 LBT ,30 cal do very well also. A closer look at those shows they are basically a Lovern design with fewer lube grooves, particularly in the forward half. The forward half is groove depth diameter. They have a very short stubby nose that is not a bore rider.

That custom LBT bullet is designed for the neck length of the '06. With the shoulder bumping, or slightly off, the rifling the base of the GC is right at the base of the neck. The full diameter bearing length (edge of ogive of very short nose to the base of the GC) fits in the case neck and the lead of the chamber. A good design for higher velocity cast bullet loads but needs a long necked case like the '06 or 30-30 for best results.

Larry Gibson

quote:

Originally posted by starmetal:

The 30-40 Krag comes to mind here too. Great cast round, nice long neck.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by starmetal:

The 30-40 Krag comes to mind here too. Great cast round, nice long neck.

That it is. It would be a lot better if chambered in a barrel with a 12 or even 14" twist.

Larry Gibson

quote:

That it is. It would be a lot better if chambered in a barrel with a 12 or even 14" twist.

Larry Gibson

quote:

Originally posted by starmetal:

I can't imagine my Krag shooting any better, unless it was scoped. Amazing accurate for a fixed sight rifle and my bad eyes. My Krag likes everything I can concoct for it. If you like a challenge to get a rifle shooting, the Krag isn't it...it's an easy I feel.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by starmetal:

I can't imagine my Krag shooting any better, unless it was scoped. Amazing accurate for a fixed sight rifle and my bad eyes. My Krag likes everything I can concoct for it. If you like a challenge to get a rifle shooting, the Krag isn't it...it's an easy I feel.

Most certainly, a Krag with a good bore (unfortuneately many are in poor shape from corosive ammo and poor cleaning) is very easy to load cast for. Most any RN/FN 180-22 gr cast bullets will shoot well in it with most any suitable powder. The 10" twist povides excellent accuracy up through 2000 fps with those bullets and if loaded correctly very usible accuracy is obtainable up through 2100 fps, about max for the Krag anyway.

However, I was not talking about the rifle but the 30-40 cartridge when I concured with your mention of it an its long neck. With that long neck on a action such as a Ruger #1 or #3 using a bullet such as Bass's LBT or the 311466 in a 12 or 14" twist the real potential of that cartridge can be reached. With it's moderate case capcity velocities of 2300-2500+ fps with those bullets are very probable while shooting at it's best accuracy level. I would expect, usinga good 14" twist barrel with proper rifling, to shoot consistent 10 shot groups of 1-2 moa in the 2500 fps range. Can't do that with the Krag rifle and it's 10" twist unless yo PP the bullets, possibly band the bullets (would take a different design of bullet though) or use jacketed bullets.

Larry Gibson

quote:

Originally posted by starmetal:

Larry,

The trouble with pushing the Krag (and that is in a Krag rifle, not a modern rifle) is it's not strong. I don't shoot a lot of lightweight 30 caliber cast bullets (aside from the M1 Carbine, SKS, and my 30 Lugers)so to push something like a 200 gr or 220 gr to a rpm level that would greatly exceed your threshold is a little hard to do. So can't really test those for accuracy at low and high velocity. When I get time I'll full around with it. Another thing are my aging eyes. I use to shoot some really good groups with my Krag when my eyes were better. I guess I could up the target closer see what happens.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by starmetal:

Larry,

The trouble with pushing the Krag (and that is in a Krag rifle, not a modern rifle) is it's not strong. I don't shoot a lot of lightweight 30 caliber cast bullets (aside from the M1 Carbine, SKS, and my 30 Lugers)so to push something like a 200 gr or 220 gr to a rpm level that would greatly exceed your threshold is a little hard to do. So can't really test those for accuracy at low and high velocity. When I get time I'll full around with it. Another thing are my aging eyes. I use to shoot some really good groups with my Krag when my eyes were better. I guess I could up the target closer see what happens.

Very true and such is the case wih the 30-40 in a Krag rifle. Just about the tme you reach the top end of the RPM threshold you are then limited by pressure with the 200-220 gr bullets. Probably why those cast bullets always shoot so well at about the same velocities as their jacketed counterparts. (old eyes not with standing!)

Larry Gibson

quote:

Originally posted by starmetal:
Larry I'm finding a little problem with runfiverun stating in that Twist Confusion thread that his 165 gr cast bullet shot at high velocity had 3-4 bullets not hit the cardboard at 200 yards. What rifle and twist was his using?
I can tell you that pushing the 314299 out of both my CZ 30-06 and Finn 39 ALL stated on the paper (not the cardboard) at 300 yards. In fact the groups were certainly better the minute of bowling pin. Funny that day I shot my Yugo SKS with the Lee 312-155 that same outing and it actually shot the smaller groups of the three. Grant you the velocity was slower because as you know you can only push that so fast out of the small case that is has.

Maybe you will find this interesting. Long ago Oldfeller gave me some of his 170 gr 6.5 Cruise Missiles. I was going to shoot them out of my 260 Rem on the Jap 38 action I built up. The barrel has a 1 in 9 twist. I found at about 1310 fps they became totally unstable and were hitting the target side ways. At 1400 fps they were flying pretty straight.

I'll have to dig up my records and see what velocity I was pushing the 314299 out of my CZ and M39.

quote:

Originally posted by starmetal:

You know I haven't tried the Lee 312 155 in it, have you? Wonder what that will do in my Krag. My Krag has a pretty good bore in it. The grooves are .3095 and I see some of the fellows on the forum that own them have the same size bore. Lucked out then getting one alot fatter.

You aren't getting any bites on your fishing line with me because you're using rpm threshold bait.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by starmetal:

You know I haven't tried the Lee 312 155 in it, have you? Wonder what that will do in my Krag. My Krag has a pretty good bore in it. The grooves are .3095 and I see some of the fellows on the forum that own them have the same size bore. Lucked out then getting one alot fatter.

You aren't getting any bites on your fishing line with me because you're using rpm threshold bait.

Go ahead and try it above the RPM threshold. However, we all see you've already built in the alibi or your excuse with your "old tired eyes". That way you can claim the bad groups were from you instead of the RPM threshold! Maybe you can't see so well anymore but you are getting sneaky

Larry Gibson

quote:

Originally posted by starmetal:
Larry. I lifted this from Pdawg shooter on Cast Boolits, so thank him for me:


Now I know this is banded from your rpm threshold theory, but this is an excellent of what myself and others have been trying to say. In this case a typical cast bullet, not one specifically made for paper patching, made from a typical alloy that isn't really that hard, and shooting damn good small groups at very high velocity. Whatever the paper does discount because once that bullet is in flight it IS doing very high rpm and shooting VERY good. So it's NOT the rpm, it's other things. If the NRA said the paper protects the bullet surface from softening...well that's not rpm.

quote:

Originally posted by starmetal:

When old Dad gave me his Krag I was fairly young. I could shoot it pretty good with those better eyes. The very first cast bullet I shot from it was the Lyman 311284. My best groups in those days (and with the 314299 also) where 3/4 to 1 inch five shot groups at 100 yards. I remember when I first got it and was shooting that 311284 I was in Oklahoma and shooting at place where shooters frequented that wasn't a sanctioned range. That day I found a Pepsi bottle. I set it up at 200 yards and I shot at it from the prone position laying on a canvas tarp. I popped it on the first shot and thought...I'm going to love this rifle. I also think that was the last time I ever shot glass bottles too.

I'll give that Lee bullet a try. I have a very good idea how the 311284 and 314299 shoot at 100 with my tired eyes to compare the Lee with.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by starmetal:
Larry. I lifted this from Pdawg shooter on Cast Boolits, so thank him for me:


Now I know this is banded from your rpm threshold theory, but this is an excellent of what myself and others have been trying to say. In this case a typical cast bullet, not one specifically made for paper patching, made from a typical alloy that isn't really that hard, and shooting damn good small groups at very high velocity. Whatever the paper does discount because once that bullet is in flight it IS doing very high rpm and shooting VERY good. So it's NOT the rpm, it's other things. If the NRA said the paper protects the bullet surface from softening...well that's not rpm.

He is right about one thing; that is very good load development and shooting. However he is wrong about several other things;

* It is not "In this case a typical cast bullet, not one specifically made for paper patching",

What he does is make it special for PPing. He swages it; "The bullet was then sized .3015 with a push through die. This gave me full length bearing surface." thus the bullet that started out as a regular cast bullet is swaged down so the lube grooves are smaller and so the bullet has one long bearing suface.

* He then PP's the bullet. It is no longer a regular cast bullet. So when he states; "In this case a typical cast bullet" he is wrong because he has made it into a PP'd bullet and it is no longer a "typical" cast bullet.

Haven't we been over this many times before? The RPM threshold we are discussing applies to regular cast bullets. You know the kind; lube grooves full of lube and a GC on them shot in rifles with no jacket or PP. Is that too hard to comprehend?

Larry Gibson

I do give Pdawg all the credit for developing that very accurate PP'd load. Hope to get there myself with PPing one day. I'm only in the 2400-2500 fps range with softer cast alloys for hunting loads using a 323471HP in and 8x57. I haven't tried to really go much higher as the need has not been there for me.

quote:

Originally posted by starmetal:

The alloy is still soft. The normal 311284, if you look, is just a hair more bearing surface then nose bore rider, so he didn't change it that much. Hell if anything the addition bearing surface would create more friction heat. I believe he done this to make the bullet diameter smaller as to have room for the paper thickness, not to improve the bearing surface. The nose of an unaltered 311284 is just about the right diameter for paper patching.

Still that's good high velocity shooting at high rpm (not sure what the twist on his rifle is, but say 10 to 12 in one would give 184140 to 220968 rpm) with a not so hard alloy and overstablization in your words.

quote:

Originally posted by Lamar:
actually it is a 10 twist, and it was at 300 yds.
the 50 100 and 200 yd groups were fairly linear [or near so] untill i went over the rpm threshold.
it was then that the boolits started to veer.

quote:

Originally posted by swheeler:
Larry were you a cop or a postman? For some unknown reason, whenever I start reading one of your theories a picture of CLIFF CLAVIN(remembers "Cheers" on TV) pops into my head.

quote:

Originally posted by Lamar:
actually it is a 10 twist, and it was at 300 yds.
the 50 100 and 200 yd groups were fairly linear [or near so] untill i went over the rpm threshold.
it was then that the boolits started to veer.