30-30 accuracy loads

[mainiac]

Im working with a 336a marlin in 30-30. 1949 model,with a very pretty nice bore. Using the lee 170 boolit.
My latest alloy is about 13.With this alloy,the gun shoots very,very small groups between 1600-1700 f.p.s. Sometime after 1850 or so,the gun starts shooting huge groups.Once 2000 arrives the gun is shooting around 4 inch groups.

I get no leading with this alloy,but i cant push it up to factory speeds.Using h-335 powder.
My other marlins can shoot cast right up to,and past factory speed with no issues.35 rem,32 special,,,have no issues.Is this because of the 30-30,s relatively fast twist?

Also, this boolit measures close to .309 on the nose,and engraves the rifling pretty severe.Am thinking about buying a 308041,,and am wondering if the nose cast a little thinner then this lee?Maybe this old gun,has a tight throat?

[Larry Gibson]

Is this because of the 30-30,s relatively fast twist?

BINGO!!!!

Another fine example of a load combination exceeding the RPM threshold in a 10" twist. The tight fitting nose will be benificial to increased velocities. So will using a harder alloy of 16 - 20 BHN. A little slower powder like IMR4895 or Varget may help but I relly suggest LeveRevolution Powder with that harder bullet. Try starting at 32 gr and work up to 34.5 gr with a 16 - 20 BHN bullet.

Larry Gibson

[mainiac]

H-335 is really my go to powder in these levers,cause i have alot on hand,and it works so well in all my other guns.But i should try something slower.

This gun has the 24 inch barrell,so i envisioned alot of extra speed with this gun,but if it wont shoot tight groups,speed dont mean nothing to me.

Think a heavier boolit would counteract the fast twist?

I should make up a batch of boolits from straight lino,just to see how a tough boolit will shoot...

Larry,,whats so special about the leverution powder? Sounds intresting,,would like your thoughts.....thanks


BTW,,this is the fussiest levergun i ever fooled with.From 1400-to 2000 f.p.s.,,,there is about a foot of vertical between.If i aint paying attention to what loads im shooting,and i dont adjust the peep sight before hand,,i can be clean off the paper,@ 50 yards. Never seen so much vertical.

[Marlin Junky]

H-335 is really my go to powder in these levers,cause i have alot on hand,and it works so well in all my other guns.But i should try something slower.

This gun has the 24 inch barrell,so i envisioned alot of extra speed with this gun,but if it wont shoot tight groups,speed dont mean nothing to me.

Think a heavier boolit would counteract the fast twist?

I should make up a batch of boolits from straight lino,just to see how a tough boolit will shoot...

Larry,,whats so special about the leverution powder? Sounds intresting,,would like your thoughts.....thanks


BTW,,this is the fussiest levergun i ever fooled with.From 1400-to 2000 f.p.s.,,,there is about a foot of vertical between.If i aint paying attention to what loads im shooting,and i dont adjust the peep sight before hand,,i can be clean off the paper,@ 50 yards. Never seen so much vertical.

I've got the same rifle... could be it has a very long throat. I remedied the situation with an LBT-LFN mold. Now my range buddies call this particular rifle the 30-30 Magnum. 180 grain boolit propelled by H380 to 2400 fps and 1-1.5 MOA. That's over 170,000 RPM... RPM, SCHMAR-PM.

Got a fast twist? Increase the BHN or slow down the powder burn rate so the boolit is not damaged during initial engravement. In the 30-30 Magnum's case I also strengthened the boolit by using LBT's rather unconventional cast boolit design. Now Larry's gonna tell you that there are ways to defeat the infamous RPM theory but I say it doesn't have much basis in reality if it's so easy to defeat. What we're really dealing with here is the management of shearing forces.

MJ

[mainiac]

I've got the same rifle... could be it has a very long throat. I remedied the situation with an LBT-LFN mold. Now my range buddies call this particular rifle the 30-30 Magnum. 180 grain boolit propelled by H380 to 2400 fps and 1-1.5 MOA. That's over 170,000 RPM... RPM, SCHMAR-PM.

Got a fast twist? Increase the BHN or slow down the powder burn rate so the boolit is not damaged during initial engravement. In the 30-30 Magnum's case I also strengthened the boolit by using LBT's rather unconventional cast boolit design. Now Larry's gonna tell you that there are ways to defeat the infamous RPM theory but I say it doesn't have much basis in reality if it's so easy to defeat. What we're really dealing with here is the management of shearing forces.

MJ

with this lee boolit,the rifling engraves the nose of the boolit,for about.200-.250 of an inch.Real hard deep engraving.Im thinking this may be an accuracy advantage,but sucks for hunting,being that if i load the shells in and out of the gun,multiple times,the boolit is gonna be all grooved up....i guess if i had any better luck,i would only load the shell once in the gun....

Think my next trials will be with harder boolits,only place i can go,is up the hardness. I shot some 8-9 bn alloy a few weeks back,kind of by mistake.That stuff leaded my bore terrible, at no more than 1300 f.p.s.,,first time i ever leaded with a gas check boolit.these old guns are fun to play with....

[runfiverun]

waterdrop.

[Larry Gibson]

No, MJ is incorrect, I'm not going to tell you how to "defeat" the RPM threshold. He still thinks it's still some sort of "limit". It's not, The RPM threshold is just that; a threshold. Cross over it and accuracuracy goes south, just as you've found. You can push the threshold up or down ina any cartridge capable of achieving it. Exactly where the threshold is RPM wise depends on the componants and loading techniques used.

I've already given you a couple suggestions on how to raise the RPM threshold in your rifle. The way you do that is with a better designed bullet, a harder alloy and a slower burning powder. My, oh my,....but isn't that exactly what MJ did Pitty MJ can't see he's doing exactly what I keep telling him to do. He has success at it and thinks the RPM threshold is "infamous" and doesn't exist but it does, the joke is on him

LeveRevolution is specially blended powder that has a very slow time/pressure curve allowing higher velocities with lower pressures. Well worth a try. It now is my "go to" powder for my softer cast 311041HPs for hunting. A safe load (within SAAMI MAP of 42,000 psi for the 30-30) is 36 gr. However, accuracy suffers a bit a the 2289 fps even with the 12" twist of the Winchester with 24" barrel. I back that off to 34.5 gr for a mild psi (several factory J bullet loads have a higher psi) and 2218 fps with excellent accuracy. Cast harder I can push to 2300+ fps and still stay within SAAMI psi and get excellent accuracy.

Larry Gibson

[Marlin Junky]

No, MJ is incorrect, I'm not going to tell you how to "defeat" the RPM threshold. He still thinks it's still some sort of "limit". It's not, The RPM threshold is just that; a threshold. Cross over it and accuracuracy goes south, just as you've found. You can push the threshold up or down ina any cartridge capable of achieving it. Exactly where the threshold is RPM wise depends on the componants and loading techniques used.

I've already given you a couple suggestions on how to raise the RPM threshold in your rifle. The way you do that is with a better designed bullet, a harder alloy and a slower burning powder. My, oh my,....but isn't that exactly what MJ did Pitty MJ can't see he's doing exactly what I keep telling him to do. He has success at it and thinks the RPM threshold is "infamous" and doesn't exist but it does, the joke is on him

LeveRevolution is specially blended powder that has a very slow time/pressure curve allowing higher velocities with lower pressures. Well worth a try. It now is my "go to" powder for my softer cast 311041HPs for hunting. A safe load (within SAAMI MAP of 42,000 psi for the 30-30) is 36 gr. However, accuracy suffers a bit a the 2289 fps even with the 12" twist of the Winchester with 24" barrel. I back that off to 34.5 gr for a mild psi (several factory J bullet loads have a higher psi) and 2218 fps with excellent accuracy. Cast harder I can push to 2300+ fps and still stay within SAAMI psi and get excellent accuracy.

Larry Gibson

Larry, the problem is the RPM "threshold" is only loosely correlated to diminishing accuracy and not the cause. Understanding the actual cause of diminished accuracy is what makes one a better cast boolit handloader. I'm sure you have witnessed situations where your load was significantly below your RPM threshold and it still didn't shoot worth a darn. Similarly, we all at one point in time have wondered why a load doesn't shoot OK even though the alloy is no where near it's point of plastic deformation (e.g., chamber pressure <= .9*1422*BHN). You just can't be a good cast boolit handloader if all you look at are a couple simple minded formulas. This whole RPM thing probably got started during the wildcatters heyday because hyper velocity varmint rifles started blowing apart their thin skinned varmint bullets before reaching the entended targets. And that's all I have to say about that.

mainiac,
Engraving the boolit with too much force is generally not desirable. Knowing something about old 336's, I would make a chamber impression from the shoulder forward with a dead soft plug of lead.

MJ

[Larry Gibson]

MJ

Go back and reread the OP's 1st post. He has a good load and it is accurate until he pushes it past a certain level of RPM. The accelleration of the bullet, at the point of inaccuracy, is unbalancing the bullet in the barrel. Outside of the barrel, during flight, it is the centrafugal force at that point that is the cause of the inaccuracy of the bullet in flight. Understanding that cause then enables the shooter to mitigate, as much as he can, the adverce affects of accelleration on the bullet while in the barrel.

This can be done with a properly designed bullet, correct alloy and fit, proper lube, squarely seated GC, and a slower burning powder. However, even then this only pushes the RPM threshold upwards. At some point, if the cartridge can reach that velocity, the bullet with cross the RPM threshold and accuracy will suffer.

You can also use a slower twist. The loads I shoot at 2600+ fps out of the 14" twist .308W exceed the "point of plastic deformation (e.g., chamber pressure <= .9*1422*BHN) " by quite a bit which disproves that theory. Paper patching also disproves that theory.

If you can push that 180 gr cast bullet at 2400 fps out of the 10" twist Marlin 30-30 with such accuracy then why can't you do the same in the 30-06 you got? In reality you discovered the M70 shot best down in the 1800 - 1950 fps range but instead of understanding the real cause you assume something is wrong with the old M70......in reality your accuracywith the M70 is right at or under the RPM threshold for the componants you were using. Now as to the 2400+ fps load with a 180 gr bullet out of your 30-30 with H380 powder.....you would care to share that load data would you?

Larry Gibson

BTW; "You just can't be a good cast boolit handloader if all you look at are a couple simple minded formulas." is absolutely correct. It also applies to those who choose to disbelieve or ignore some "formulas" with out proof otherwise. Maniac's example here is a good example of proof the RPM threshold exists.Your own experiences with your M70 '06 also are also proof.

[Larry Gibson]

I really don't intend this thread to turn into another "discussion" of the RPM threshold as I am doing a CastPic article on it. However, the OP, mainiac, brought the subject up with his obvious example of the RPM threshold. MJ vehemently objects to the concept regardless of his own experiences with it. In another thread DrB asked about data, graphs or charts that i may have. Well I've gone back through some old data and charted the results of 14 different load workups in 5 different cartridges with 6 different bullets using 5 different bullets; all in barrels of 9.8 - 10" twist.

In the charted data you'll see the 2 red lines. Those are the 120-140,000 RPM range where I say the RPM threshold will generally be. In all these example you see it is. If we chart out other twist barrel's loads we will find the same range of RPM where the best accuracy is found. NOTE; I said "best accuracy". Useable accuracy, within a limited effective range, can still be found above the RPM threshold.

Larry Gibson

[Marlin Junky]

Larry,

Vehemently? That's a pretty strong description... let's just say I believe the RPM Theory has limited use; however, it is loosely correlated to more pertinent variables. I did notice from your graph that there is one function which remains relatively flat beyond 160000 RPM, though. Send me a PM describing this load and barrel configuration. Perhaps you can PM me a larger, more legible file containing your chart too. I don't want to take up anymore space on this thread. I'd like to make a suggestion or two before you publish, if I may. Find yourself a 336 in .35 Remington with an "H" or earlier date code, (and a clean barrel, naturally) scope it and test against a Remington rifle with a hammer forged barrel possessing equivalent twist and length. Shouldn't be too hard to find these two test platforms. Hopefully the difference in groove diameter and chamber dimensions won't be a problem... right there is one variable (chamber dimensions) that is very difficult to control unless you're cutting your own chambers. You can "factor-in" the difference in inherent accuracy between the two firearms platforms by giving the lever action a 1/2 MOA handicap. Actually, why not just buy two 336's in 30-30! One made with a date code of "G" or "H" (stay away from the "F" date code guns because of the possible "Magnum" chamber) and one with MicroGroove rifling? Actually, that won't even work because of the difference in bore diameter... hey, testing is hard! To provide more credence to your analysis, start with no preconceived notions about RPM Theory... just shoot the two guns and report velocity, group size, pressure (you do have that capability, don't you) and RPM. Then we can all draw conclusions about which is more important: firearm attributes and design or calculating how fast the boolit spins down range. Don't forget to measure BHN and always use the same boolit mold... wow, that's even hard because of chamber variation vs. boolit fit!... I'm glad I'm not doing this... sounds too much like work! Please allow me to suggest an LBT-LFN 358-210. Then you can start all over again with an RCBS 35-200-FN that'll drop a .360-.361" boolit (you might need to call RCBS but I bet they'll accommodate you).

Looking forward to a legible version of your chart.

Thanks,
MJ

[Char-Gar]

I don't want to get into the RPM discussion, but I will only say that with both Marlin and Winchester leverguns, I get excellent accuracy, (2 MOA or less) at 2,100 fps. The charge is 29/3031 and an appropriate bulelt (fit wise) for each rifle of a nominal weight of 170 grains (gas check of course). The alloy is Lyman No. 2 at about 15 Bhn.

The Marlin is a 1972 336A and the Winchester is a 1951 Model 94 Carbine. I also get the same result in a Savage 340. I also have a Browning Traditonal Hunter SS in 30-30 and accuracy with that rifle and above load runs 1 MOA or slightly less. I use 311467 in the Browning.

The bullets are SAECO 325 in the Marlin, 311291 in the Winchester and Savage, and there are several bullets (311291, 311467, RCBS 165 Sil) that do well in the Browning. Of course, each bullet is a proper fit to the rifle.

I am pushing hard up against age 70, so am getting leery of my memory, but IIRC the Marlin twist if 1-10 and the rest are 1-12.

I have no problems pushing cast bullet past 2,000 fps with good accuracy in my numerous .308s and 30-06's, Some of the .308s are 1-12 and one is 1-10. The 30-06s of course are all 1-10.

I certainly won't claim to have the depth of scientific knowledge that some here have, but I do have many years of trigger time and many, many targets fired with various 30 calibers rifles and cast bullets. All I know is what the targets tell me.

[mainiac]

All i can really think about is my J model marlin in 32 special.This gun will shoot groups@ 50 yards well under .5 inch,,on demand,and it will do it @ 2270f.p.s. with the rcbs boolit.

I want this F model 30-30 to shoot as well.Thats what im gonna strive for.

I have considerable past experience with benchrest rifles,and with them,the barrell twist is right on the verge of not enough,and thats where they shoot the best.So,I think it all boils down to is the slowest twist possible shoots the tightest groups.Over twisting puts tremendous stress on a jacketed bullet,so i can just amagine how the cast pill feels.

[NHlever]

Shooting, especially with cast bullets is lots of fun, and a very learning experience. I've been casting, and shooting for about 50 years now, and it has been both fun, and interesting to see the changes in our craft over the years. If one reads the earliest Lyman cast bullet manuals he can see how much of it was almost witchcraft at that time. Things like boolit fit in the throat, alloy, etc. weren't understood very well. We are doing things today that were unheard of back then routinely, and yet certain truths can't be ignored. When the forces acting against a boolit exceed the strength of the alloy the boolit is made of, the boolit is damaged to one extent, or another. Damaged boolits don't group as well as undamaged ones do. We can call this truth by any name, and often it is called different things by different folks here but the results are the same. It is not some theory that needs to be proven, or defended, it is just one of the facts that we work with in our quest for ever better results.

[northmn]

I get factory velocities in my Marlin using a 188 grain (cast weight) Lee bullet designed for the 303's sized down to 310. I use a flat nose punch for sizing. I water harden the bullets after sizing and soften the nose for hunting bullets by placing them in a shallow pan of water and annealing the noses. They are harder than WW and shoot pretty fair.

DP

[Char-Gar]

mainiac.. Do not forget the 32 WS comes with 1-16 twist barrels. You have work hard to find a cast bullet load that will not shoot well in them.

The 30-30 with its 1-10 or 1-12 twist barrel will shoot cast bullets very well, do not use a 32 WS as the gold standard for 30-30s. They are two very different critters!

Shooting cast bullets in a 32 WS will spoil you very quickly with their cast bullet accuracy.

When I got my 32 WS (a 1959 Winchester 94 Carbine) I loaded up some ammo with the RCBS 170 GC bullet and 30/H-335 and went to the range. My first group like yours was 1/2 inch at 50 yards and the velocities were full snort. Easiest cast bullet accuracy load I have every found.

[mainiac]

mainiac.. Do not forget the 32 WS comes with 1-16 twist barrels. You have work hard to find a cast bullet load that will not shoot well in them.

The 30-30 with its 1-10 or 1-12 twist barrel will shoot cast bullets very well, do not use a 32 WS as the gold standard for 30-30s. They are two very different critters!

Shooting cast bullets in a 32 WS will spoil you very quickly with their cast bullet accuracy.

When I got my 32 WS (a 1959 Winchester 94 Carbine) I loaded up some ammo with the RCBS 170 GC bullet and 30/H-335 and went to the range. My first group like yours was 1/2 inch at 50 yards and the velocities were full snort. Easiest cast bullet accuracy load I have every found.

char-gar,,thats what happened to me with my 32. I have never really spent much load work time with it.I used h-335,and kept turning up the wick until the gun started to be painful,and the hotter i load it,the better it shoots.Ive tried a few powders,but come back to 335,and the gun shoots such pretty tiny groups,,its so simple

Guess this thutty-thutty,is gonna be my pay back.

[Char-Gar]

The 30-30 is not a difficult nut to crack as it is one of the better cast bullet rounds. You are just going to have to work for what you get. The 32 WS gifts us with accuracy, the 30-30 isn't so generous.

[Marlin Junky]

After looking at the pic of your chamber casting, I'm going to recommend a 150 grain LBT-LFN. I would send a chamber casting to Verl Smith too... especially if you can create a little better filled out one. I don't think your freebore is long enough to handle the 180 grain LBT-LFN; however, you should be able to get some pretty spectacular results with a 150-155 grain LBT-LFN.

MJ

[JIMinPHX]

I've found that I get my best hi speed cast .30-30 accuracy with RE7. That was using a 150-grain Lee RNFP. I haven't tried the 170.